Advertisement Upgrade to remove ads

Does a primary amine act as a nucleophile or a base?

Why?

1° amine - usually acts as a nucleophile

3° amine - usually acts as a base (because they are too stericlly hindered to act as a nucleophile)

Are amines soluble in water?

Why?

If they don't have long carbon chains then YES, they are very soluble in water due to Hydrogen Bonding

How does increased branching and molecular weight affect the MP and BP of an amine?

MP and BP increases with Increased molecular weight and decreased branching

Draw ammonia and ammonium

NH₃ = ammonia

NH₃⁺ = ammonium

How does basisity change from ammonia → 1° → 2° → 3 ° amines?

Basicity decreases from tertiary to secondary to primary to ammonia due to the electron donating effects of the R- group

Are Amines with four substituents electrophiles or nucleophiles?

Electrophiles ( as long as they have at least one hydrogen)

...
Draw the mechanisms for enamine/imine tautomerization

...

How does the synthesis of an alkyl amine work?

NH₃ + CH₃Br → ?

What is a problem with this reaction?

NH₃ + CH₃Br → NH₂CH₃ + HBr

1) ammonia acts as a nucleophile, attacking the alkyl halide via SN2 and kicking off the halide ion.
2) The halide ion acts as a base, abstroacting a hydrogen to quench the charge on the nitrogen.

Note: This reaction results in many side products because the resultant amine is still a good nucleophile and can react again.

How does Gabriel Synthesis work?

What is good about Gabriel Synthesis

Formation of a primary amine from a primary alkyl halide

Avoids the side products of alkyl amine synthesis

Steps:
1) The phthalimide ion, a reactive species with a full negative charge on the nitrogen, acts as a nucleophile, attacking the alkyl halide via SN2
2) The resulting intermediate is then hydrolyzed with aqueous base, releasing a primary amine.

...
A variation of the traditional Gabriel synthesis can be used to produce a primary amine plus the product shown below. Product B is a useful synthetic precursor and is therefore the targeted product of this synthesis rather than the primary amine. To obtain product B the Gabriel synthesis should be altered in which of the following ways?

A. Acid should be added, catalyzing an intermolecular reaction to form Product B
B. NaNH₂ should be added to the alkylated amine in pace of OH⁻
C. The primary amine must be reacted with one equivalent of benzene and two carboxylic acids
D. Hydrazine should be used in place of the standard amine in the first step

After alkylation of the phthalimide ion, hydroxide is normally added to substitute both amides at their carbonyl carbons and release the primary amine. If NH₂⁻ is used instead, a product very similar to product B is formed. An Additional intermolecular reaction then forms Product B. Answer B therefore is the best choice

What are some common reducing agents capable of reducing an amines?

LiAlH₄, NaBH₄, and H₂/pressure

What can reduce Nitro groups and what do they reduce to?

reduce to the associated primary amine via all the normal reducing agents

LiAlH₄, NaBH₄, and H₂/pressure

What can reduce Nitrile groups and what do they reduce to?

reduce to the associated primary amine via all of the normal reducing agents

What can reduce imines and what do they reduce to?

reduce to the associated primary amine via catalytic hyrogenation only (requires a heterogeneous catlyst such as H₂-nickle)

What can reduce amides and what do they reduce to?

reduce to the associated primary amine via LiALH₄ only

In the addition of amines to carbonyls, What do primary amines yeild?

imines

In the addition of amines to carbonyls, What do secondary amines yeild?

enamines

...
What is Wolf-Kishner Reduction?

1) CH₃COCH₃ + H₂N-NH₂ → imine
2) imine + KOH/∆ → CH₃CH₂CH₃

Complete reduction of an aldehyde or ketone to an alane via an imine intermediate. When you do addition of amines to carbonyls starting with hydrazine as the amine, the product is an amine-substituted imine. Subsequent addition of a hot, strong base (e.g., KOH/∆ replaces the imine with two hydrogens, yielding an alkane)

...
What is Hofmann Elimination?

Formation of an alkene via elimination of an amine.
Important because it yields the LEAST substituted alkene.

Which carbonyls always undergo nucleophilic addition?

Aldehyds and Ketones

What carbonyls always under go substitution?

Carboxylic Acids
Amides
Esters
Anhydrides

Why are alpha hydrogens on a carbonyl so important?

Hydrogens on a carbon one away from the carbonyl carbon are acidic due to resonance stabilization of the conjugate base

If there are two carbonyls separated by one carbon, hydrogens on this middle carbon are very acidic.

Are ketones and aldehydes nucleophiles or electrophiles?

Electrophiles
When their carbonyl carbon is attacked by a nucleophile

What is more acidic, the alpha hydrogen of a ketone, or the alpha hydrogen of an aldehyde?

aldehyde

Ketones have a e⁻ donating group which makes the CB less stable

Are aldehydes and ketones soluble in water?

Yes - If they dont have long alkyl chains

How does the boiling point of ketones and aldehydes compare to water and alkanes?

higer than equivalent alkanes, lower than water

..
What is Aldol Condensation?

The MCAT loves the aldol condensation! it is addressed in one way or another in almost every exam.

...
What are the mechanisms for Halogenation of an Aldehyde or Ketone?

...

...
What is the Haloform Reaction?

...

Is the boiling point for a carboxylic acid high or low and why?

Carboxylic acids form strong dimers involving two hydrogen bonds; this raises boiling point significantly

are carboxylic acids soluble in water?

whithout long alkyl chains, they are soluble in water. Surprisingly, they are also soluble in non-polar sovlents (although they are clearly polar)

...
Draw the mechanisms for a Decarboxylation reaction

...

What three reagents can produce an acid chloride from a carboxylic acid?

PCl₃
PCl₅
SOCl₂

Are esters more or less soluble in water compared to alcohols? Why?

less

They act as H-bond recipients but NOT donors

What is Saponfiication

The hydrolysis of an ester to yeild an alcohol and the salt of a carboxylic acid

Steps:
1)the hydroxide ion (NaOH) or (KOH) attacks the carbonyl and pushes the C=O electrons up onto the oxygen
2) The electrons collapse back down and kick off the -OR group
3) Either the -OR group, or hydroxide ion, abstracts the arboxylic acid hydrogen, yeilding a carboxylate iuon. This accociates with the Na⁺ or K⁺ in the solution to form "soap"

...
What is Acetoacetic Ester Synthesis?

The formation of a ketone from a B-keto ester

Steps:
1) A base abstracts the acidic alpha hydrogen, leaving a carbanion
2) The carbanion attacks an alkyl halide (R-X), resulting in addition of the -R group to the alpha carbon.
3) Hot acid during workup causes loss of the entire -COOR group.

What is a better leaving group ⁻OH or ⁻OR and why?

⁻OH because "R" is an electron donating group

List all carboxylic Acid derivatives in order of most stable to least stable

This patter is the exact opposite of the order of better leaving groups

Amide>Ester>Carboxylic Acid>Anhydride>Acid Cloride

Are amides soluble in water?

Primary and Secondary amides can hydrogen bond and are thus water soluble as long as they lack long alkyl chains. Tertiary amides cannot H-bond and are thus considered to have low water solubility

What is the Hofmann degradation?

Primary amides react in strong, basic solutions of Cl₂ or Br₂ to form primary amines. The mechanism includes decarboxylation, and thus shortens the length of the carbon chain

This reaction is important because it allows you to add an amine to a tertiary carbon. This is impossible via the "Synthesis of an Alkyl Amine" reaction discussed earlier.

What does electronegativity tell us about the relative reactivities of the carbons in a C=O vs a C=N bond?

the C=O carbon is more reactive because O is more electronative and therefore more polar (which will make hydrogen bonds easier)

Is hydrogen electron donating or withdrawing?

neither

Are alkenes electron withdrawing or donating?

weakly electron withdrawing

A 3° carbon must react via what mechanism?

SN1 or E1

What is a weaker acid, alcohols or water?

alcohols are always weaker acids due to the donating effect of the -R group

What increases basicity,

electron donating or withdrawing groups?

Electron donating groups increase basicity, while elctron withdrawing groups decrease basicity

What does the integumentary system consist of?

Includes the hair, nails, skin and the oil and sweat glands located within the skin.

What are the functions of the integumentary system?

Thermoregulation, protection, environmental sensory input, excretion, innate immunity, blood reservoir, vitamin D synthesis.

What is the epidermis made up of?

Made up of avascular, dead, keratinized cells.

What does the dermis consist of?

Contains blood vessels, hair follicles, sebaceous glands (oil), sudoriferous glands (sweat) and nerve endings. The dermis is a connective tissue.

How does the skin play a role in thermoregulation?

Blood vessels migrate closer to the surface of the skin and DILATE when heat needs to be released and migrate downward and CONSTRICT when heat needs to be retained. Blushing is the result of the dilation of superficial blood vessels.

What are three major characteristics of skeletal muscle?

They are voluntary, striated and multinucleate.

Provide a conceptual definition of:

1) Tendons
2) Ligaments
3) Agonist
4) Antagonist
5) Synergist

1) Tendons: connect muscle to bone
2) Ligaments: connect bone to bone
3) Agonist: The agonist is the muscle responsible for the movement. When the agonist contracts the antagonist stretches.
4) Antagonist: When the antagonist contracts the agonist stretches.
5) Synergist: Muscles that assist the agonist by stabilizing the origin bone or by positioning the insertion bone during the movement.

Why are the hinges formed by muscles and bones an example of a poor lever system with a mechanical disadvantage?

They act to increase the required force of a muscle contraction. A greater force than mg is required to lift a mas m. This is done in order to reduce the bulk of the body and increase the range of movement. If the muscle has a shorter lever arm, it is closer to the body, and thus creates less bulk.

Describe the anatomy of a skeletal muscle including the different subunits, sarcolemma, myofibrils, sarcomeres, and sarcoplasmic reticulum.

.
A muscle group is a bundle of many fasciculi. A fasciculi is a bundle of many long, tubular cells called "muscle fibers." Around each muscle fiber si a specialized cell membrane called the "sarcolemma." Inside each muscle cell/fiber are many nuclei (multinucleate). Nearly the entire volume of each cell/fiber is filled with smaller round tubes called myofibrils. Myofibrils are small bundles of actin and myosin fibers interconnected in repeating units called sarcomeres. Small bundles of myofibrils are surrounded by portions of the muscle cell's endoplasmic reticulum, called the sarcoplasmic reticulum. It is the sarcoplasmic reticulum that sequesters Ca²⁺ away from the sarcomere prior to contraction.

Provide a conceptual definition for each of the following as they relate to the sarcomere:

1) Thick filament
2) Thin filament
3) Actin
4) Myosin
5) Myosin Heads
6) A band
7) I band
8) H zone
9) M line
10) Z line

.
1) Thick filament: made up of the protein myosin. Several long myosin molecules wrap around each other to form one thick filament.

2) Thin filament: Composed mainly of the globular protein actin.

3) Actin: Makes up the thin filaments

4) Myosin: Makes up thick filaments

5) Myosin Heads: Each myosin head crawls along the actin in a 5 stage cycle.

6) A band: The band measuring from the one end of the thick filament to the other end of the thick filament. Does not shorten.

7) I band: The band of only actin which shortens during contraction.

8) H zone: The band consisting of only thick filaments from end of one thin filament to end of another thin filament. Shortens during contraction.

9) M line: The middle of the sarcomere and is a line directly down the thick filaments.

10) Z line: Looks like a z, the line at the two ends of a sarcomere and consists of only thin filaments. Z lines come closer together during a contraction

What neurotransmitter is released at a neuromuscular junction? As an AP reaches a skeletal muscle where does the AP move? During contraction is calcium pumped into or out of the SR?

Acetylcholine. The AP spreads along the muscle cell sarcolemma and down specialized T-tubules that dive deep into the muscle cell. The T-tubules allow for a uniform contraction of the muscle by allowing the AP to spread through the muscle cell more rapidly. The AP is transferred to the SR, which suddenly beomces permeable to Ca²⁺ ions. At the end of each cycle, Ca²⁺ is actively pumped back into the SR. During contraction the SR becomes permeable to Ca²⁺ which is released into the myosin and causes troponin to pull the tropomyosin back, exposing the active site on the actin, and allowing the myosin head to bind.

Describe the sliding filament mechanism. Which position of the myosin heads is low energy and which position is high energy?

Myosin and actin work together sliding alongside each other to create the contractile force of skeletal muscle. Each myosin head crawls along the actin in a 5 stage cycle:

1) Tropomyosin covers an active site on the actin preventing the myosin head from binding. The myosin head remains cocked in a high-energy position with a phosphate and ADP group attached.

2) In the presence of Ca²⁺ ions, troponin pulls the tropomyosin back, exposing the active site, allowing the myosin head to bind to the actin.

3) The myosin head expels a phosphate and ADP and bends into a low energy position, dragging the actin along with it. This is called the power stroke because it causes the shortening of the sarcomere and the muscle contraction.

4) ATP attaches to the myosin head. This releases the myosin head from the active site, which is covered immediately by tropomyosin.

5) ATP splits to Pi and ADP causing the myosin head to cock into the high-energy position.

What happens to muscles if no ATP is present or if no Ca²⁺ is present?

If no ATP is present, the myosin heads cannot detach from actin and the muscle will be stuck in a contracted position called "rigor."

If no Ca²⁺ is present, we do NOT get rigor, but lack of contraction called "flaccidity."

What is a motor unit and how does it affect delicate movements, gross movements, and the strength of the contraction?

All of the cells/fibers in a skeletal muscle do not fire simultaneously during a contraction. Groups of muscle cells called "motor units" are innervated by a single neuron. Motor units come in all different sizes from large to small.

Delicate movements = very small motor units
Gross movements=larger motor units

The strength of a given contraction depends on the:
1) number of motor units being used
2) size of the motor units being used
3) frequency of action potentials (i.e., stimulation)

Describe the important features of skeletal muscles regarding energy storage, oxygen storage, and rate of division.

Skeletal muscles store large amounts of glycogen; they also require a lot of oxygen and thus have their own oxygen storage molecule, myoglobin. Myoglobin is basically one subunit of a hemoglobin molecule, capable of holding only one O₂. Mature (differentiated) skeletal muscles, like neurons, are in G₀ phase and do not divide.

List three major characteristics of cardiac muscle:

1) Voluntary/involuntary
2) Striated/Smooth
3) No nucleus/One nucleus/mutinucleate

Involuntary, Striated, One Nucleus

How does cardiac muscle contract?

Cardiac muscle contains sarcomeres and uses the same sliding filament mechanism as skeletal muscle.

What are some special features of cardiac muscle? Oxygen storage, spread of action potential, division.

Like skeletal muscle, cardiac muscle utilizes myoglobin. It also contains VERY large numbers of mitochondria to prevent fatigue. Cardiac muscle cells/fibers are connected by intercalated discs containing gap junctions. It is thru these junctions that the action potential passes after reaching the end of the purkinje fibers. Unlike skeletal muscle cells, cardiac cells continue dividing after differentiation.

Do heart muscle cells contract in response to innervation by a nerve?

No. The pacemaker (SA Node) is autorhythmic. Nerves are not required for the heart to beat, although they may modify the pace. Heart muscle will contract periodically in the absence of a stimulus.

List three major characteristics of smooth muscle:

1) Voluntary/involuntary
2) Striated/Smooth
3) No nucleus/One nucleus/mutinucleate

Involuntary, non-striated, one nucleus

Describe the important features of smooth muscle involving contraction.

Smooth muscle is NOT arranged in sarcomeres; however they do contain thick and thin filaments. Smooth muscle does NOT contract via the sliding filament mechanism. It also does not contain troponin. Instead, a complex cascade involving calmodulin (another calcium binding protein) causes contraction. (Not required for the MCAT).

Provide conceptual definitions for each of the following (regarding smooth muscle):

1) Single unit
2) Multi Unit
3) Dense Bodies
4) Intermediate Filaments

1) Single unit: AKA Visceral. The most common type of smooth muscle. The cells are connected by gap junctions spreading the AP from a single neuron through a large group of cells, and allowing the cells to contract as a single unit. Found in small arteries and veins, the stomach, intestines, uterus, and urinary bladder.

2) Multi Unit: Each multiunit smooth muscle fiber is attached directly to a neuron. A group of multiunit smooth muscle fibers can contract independently of other muscle fibers in the same location. Found in the large arteries, bronchioles, pili muscles attached to hair follicles, and the iris.

3) Dense Bodies and Intermediate Filaments: Smooth muscle cells contain intermediate filaments which are attached to dense bodies spread throughout the cell. The thick and thin filaments are attached to the intermediate filaments, and, when they contract, they cause the intermediate filaments to pull the dense bodies together. Upon contraction, the smooth muscle cell shrinks length-wise.

What are the major functions of bone?

Support, protection, movement, mineral storage (calcium and phosphate), energy storage (as fat in the marrow) and blood cell formation.

Name and describe the different bone cell types.

Osteocytes: mature bone cells surrounded by a mineral matrix.

Osteoclasts: bone cells that break down and resorb bone matrix, releasing the component minerals (Ca²⁺ and P) back into the blood.

Osteoblasts: immature bone cells that secrete collagen, organic compounds, and minerals forming a bone matrix around themselves. Once they are completely enclosed by matrix, they differentiate into osteocytes.

Describe the hormones that regulate bone cells. Which hormones effect which cells and in what specific ways?

Parathyroid hormone: Stimulate osteoclasts to reabsorb bone mineral, liberating calcium into blood. Bone resorption is the normal destruction of bone by osteoclasts, which are indirectly stimulated by PTH. Stimulation is indirect since osteoclasts do not have a receptor for PTH; rather, PTH binds to osteoblasts, the cells responsible for creating bone. Binding stimulates osteoblasts to increase their expression of RANKL and inhibits their expression of Osteoprotegerin(OPG). OPG binds to RANKL and blocks it from interacting with RANK, a receptor for RANKL. The binding of RANKL to RANK (facilitated by the decreased amount of OPG) stimulates these osteoclast precursors to fuse, forming new osteoclasts, which ultimately enhances bone resorption.

Calcitonin: Decrease blood calcium by inhibiting osteoclasts. The calcitonin receptor, found on osteoclasts, is a G protein-coupled receptor, which is coupled by Gs to adenylate cyclase and thereby to the generation of cAMP in target cells.

Provide conceptual definitions for each of the following:

1) Hematopoeisis
2) Red bone marrow
3) Yellow bone marrow
4) Spongy bone
5) Compact bone

.
1) Hematopoeisis: Formation of blood cellular components. All cellular blood components are derived from haematopoietic stem cells. Haematopoietic stem cells (HSCs) reside in the medulla of the bone (bone marrow) and have the unique ability to give rise to all of the different mature blood cell types. HSCs are self renewing: when they proliferate, at least some of their daughter cells remain as HSCs, so the pool of stem cells does not become depleted.

2) Red bone marrow: Site of hemopoeisis or red blood cell development.

3) Yellow bone marrow: Contains adipose cells for fat storage.

4) Spongy bone: Contains red bone marrow. Located at the ends of long bones.

5) Compact bone: Surrounds the medullary cavity which holds yellow bone marrow. Cortical bone facilitates bone's main functions: to support the whole body, protect organs, provide levers for movement, and store and release chemical elements, mainly calcium. As its name implies, cortical bone forms the cortex, or outer shell, of most bones.

Describe the anatomy of a long bone.

Two epiphysese (bulbous ends) cushioned by cartilage; the ends are filled with spongy bone and the shaft in between is made of compact bone; the center is a hollow cavity filled with yellow bone marrow.

What is Hydroxyapetite?

A compound of Calcium, Phosphate, and Hydroxate. It is the mineral matrix responsible for a bone's strength and is the form in which most all of the body's calcium is stored.

What is cartilage? Where is it found? Describe its perfusion.

A connective tissue made of collagen.

No perfusion or innervation.

Found in appendages such as the nose and ears, at the ends of long bones, between vertebrae, and the ribs-sternum (sternocostal) joints, etc.

What are the three different kinds of joints?

1) Fibrous (skull bones)
2) Cartilaginous (ribs to sternum)
3) Synovial (knee, elbow, etc.)

List the function and anatomy of each of the following:

1) Penis
2) Testicles
3) Scrotum
4) Seminiferous Tubules
5) Epididymis
6) Vas Deferens
7) Seminal Vesicles
8) Prostate Gland
9) Bulbourethral gland

.
1) Penis:

2) Testicles: The primary functions of the testes are to produce sperm (spermatogenesis) and to produce androgens, primarily testosterone. The presence of both testosterone and follicle-stimulating hormone (FSH) is needed to support spermatogenesis. Contains very fine coiled tubes called seminiferous tubules.

3) Scrotum: : Keep the temperature of the testes slightly lower than that of the rest of the body. The temperature is controlled by the scrotum moving the testicles closer to the abdomen when the ambient temperature is cold, and further away when it is hot.

4) Seminiferous Tubules: located in the testes, and are the specific location of meiosis, and the subsequent creation of gametes, namely spermatozoa.

5) Epididymis: Sperm acquires motility, mature, and are stored. Tightly-coiled tube connecting the efferent ducts from the rear of each testicle to its vas deferens. During ejaculation, sperm flow from the lower portion of the epididymis (which functions as a storage reservoir). They have not been activated by products from the prostate gland, and they are unable to swim, but are transported via the peristaltic action of muscle layers within the vas deferens, and are mixed with the diluting fluids of the seminal vesicles and other accessory glands prior to ejaculation (forming semen).

6) Vas Deferens: Transport sperm from the epididymis in anticipation of ejaculation. During ejaculation the smooth muscle in the walls of the vas deferens contracts reflexively, thus propelling the sperm forward. This is also known as peristalsis.

7) Seminal Vesicles: The seminal vesicles secrete a significant proportion of the fluid that ultimately becomes semen. Lipofuscin granules from dead epithelial cells give the secretion its yellowish color. Seminal vesicle fluid is alkaline, resulting in human semen having a mildly alkaline pH.[3] The alkalinity of semen helps neutralize the acidity of the vaginal tract, prolonging the lifespan of sperm. Acidic ejaculate (pH <7.2) may be associated with Ejaculatory duct obstruction. The vesicle produces a substance that causes the semen to become sticky/jelly-like after ejaculation, which is thought to be useful in keeping the semen near the womb. The thick secretions from the seminal vesicles contain proteins, enzymes, fructose, mucus, vitamin C, flavins, phosphorylcholine and prostaglandins.

8) Prostate Gland: The function of the prostate is to secrete a slightly alkaline fluid, milky or white in appearance, that usually constitutes 20-30% of the volume of the semen along with spermatozoa and seminal vesicle fluid. The alkalinity of semen helps neutralize the acidity of the vaginal tract, prolonging the lifespan of sperm. The alkalinization of semen is primarily accomplished through secretion from the seminal vesicles. The prostatic fluid is expelled in the first ejaculate fractions, together with most of the spermatozoa. In comparison with the few spermatozoa expelled together with mainly seminal vesicular fluid, those expelled in prostatic fluid have better motility, longer survival and better protection of the genetic material (DNA). The prostate also contains some smooth muscles that help expel semen during ejaculation. Prostatic secretions vary among species. They are generally composed of simple sugars and are often slightly alkaline.

9) Bulbourethral gland: During sexual arousal each gland produces a clear, salty, viscous secretion known as pre-ejaculate. This fluid helps to lubricate the urethra for spermatozoa to pass through, neutralizing traces of acidic urine in the urethra,[2] and helps flush out any residual urine or foreign matter. It is possible for this fluid to pick up sperm, remaining in the urethral bulb from previous ejaculations, and carry them out prior to the next ejaculation.

List the basic anatomy of a sperm cell and where they are produced and stored.

.
Sperm (single=spermatazoa) are produced by the testicles in the seminiferous tubules and stored and nutured in the epididymis. They are a single cell consisting of a head (cell body) and tail (flagella). They contain lots of mitochondria. The acrosome is an organelle that develops over the anterior half of the head in the spermatozoa (sperm cells) of many animals. It is a cap-like structure derived from the Golgi apparatus. The acrosome contains digestive enzymes (including hyaluronidase and acrosin). These enzymes break down the outer membrane of the ovum, called the zona pellucida, allowing the haploid nucleus in the sperm cell to join with the haploid nucleus in the ovum.

Name and describe the specific purpose of each substance secreted into the ejaculate by the seminal vesicles, prostate gland and bulbourethral gland (cowper's gland).

Seminal Vesicles: Secrete fructose rich fluid that serves as an energy source for the sperm. The two seminal vesicles contribute approximately 60 percent of the fluids passed from the human male during ejaculation. The secretion of the seminal vesicles constitutes the bulk of the seminal fluid (semen). It is a thick fluid that contains the sugar fructose, proteins, citric acid, inorganic phosphorus, potassium, and prostaglandins. Once this fluid joins the sperm in the ejaculatory duct, fructose acts as the main energy source for the sperm outside the body. Prostaglandins are believed to aid fertilization by causing the mucous lining of the cervix to be more receptive to sperm as well as by aiding the movement of the sperm toward the ovum with peristaltic contractions of the uterus and fallopian tubes.

Prostate Gland: Releases an alkaline milky fluid that protects the sperm from the acidic environment of the female. The function of the prostate is to secrete a slightly alkaline fluid, milky or white in appearance,[5] that usually constitutes 20-30% of the volume of the semen along with spermatozoa and seminal vesicle fluid. The alkalinity of semen helps neutralize the acidity of the vaginal tract, prolonging the lifespan of sperm. The alkalinization of semen is primarily accomplished through secretion from the seminal vesicles.[6] The prostatic fluid is expelled in the first ejaculate fractions, together with most of the spermatozoa. In comparison with the few spermatozoa expelled together with mainly seminal vesicular fluid, those expelled in prostatic fluid have better motility, longer survival and better protection of the genetic material (DNA). Generally composed of simple sugars and are often slightly alkaline.

Bulbourethral Gland: Release a small amount of viscous fluid prior to ejaculation. During sexual arousal each gland produces a clear, salty, viscous secretion known as pre-ejaculate. This fluid helps to lubricate the urethra for spermatozoa to pass through, neutralizing traces of acidic urine in the urethra,[2] and helps flush out any residual urine or foreign matter. It is possible for this fluid to pick up sperm, remaining in the urethral bulb from previous ejaculations, and carry them out prior to the next ejaculation.

Describe the ejaculatory pathway.

Seminiferous Tubules
Epididymis
Vas deferens
(seminal vesicles, prostate gland, bulbourethral gland all secrete various lubricants and nutrients)
Urethra
Penis

Describe the basic anatomy and function of the following:

1) Vagina
2) Cervix
3) Uterus
4) Fallopian Tubes
5) Ovaries

1) Vagina: A fibromuscular tubular tract which is a sex organ and has two main functions; sexual intercourse and childbirth.
2) Cervix: The lower, narrow portion of the uterus where it joins with the top end of the vagina. It is cylindrical or conical in shape and protrudes through the upper anterior vaginal wall. The cervix has an opening to allow sperm and menstrual fluid to move through.
3) Uterus: The reproductive function of the uterus is to accept a fertilized ovum which passes through the utero-tubal junction from the fallopian tube. It implants into the endometrium, and derives nourishment from blood vessels which develop exclusively for this purpose. The fertilized ovum becomes an embryo, attaches to a wall of the uterus, creates a placenta, and develops into a fetus (gestates) until childbirth.
4) Fallopian Tubes: Two very fine tubes lined with ciliated epithelia, leading from the ovaries of female mammals into the uterus, via the utero-tubal junction.
5) Ovaries: The ovaries aren't attached to the fallopian tubes but to the outer layer of the uterus via the ovarian ligaments. Usually each ovary takes turns releasing eggs every month; however, if there was a case where one ovary was absent or dysfunctional then the other ovary would continue providing eggs to be released. Ovaries secrete both estrogen and progesterone. Estrogen is responsible for the appearance of secondary sex characteristics of anatomically female people at puberty and for the maturation and maintenance of the reproductive organs in their mature functional state. Progesterone functions with estrogen by promoting menstrual cycle changes in the endometrium.

Describe the development of an egg.

Oogenesis. At birth, all of the immature ova, know as primary oocytes, that a female will produce during her lifetime are already in her ovaries. Primary oocytes are diploid cells that form by mitosis in the ovary. After the first period one primary oocyted per month completes meiosis I, yielding two daughter cells of unequal size-a secondary oocyte and a small cell known as a polar body. The secondary oocyte is expelled from the follicle during ovulation. Meiosis II does not occur until fertilization. After fertilization it is called an ovum. (At birth the oocyte is arrested at Prophase I.)

Describe the menstrual cycle and the hormones involved.

1. Begins with FSH, which stimulates the maturation of the follicle in the ovary (FSH also stimulates maturation of sperm in males)

2. LH then stimulates cells in the ovaries to secrete estrogen (estradiol), which prepares the uterine wall for pregnancy.

3. Just before ovulation, a surge in estrogen causes a surge in LH (luteal surge), which causes ovulation.

4. If no fertilization occurs the corpeus luteum degrades and the menstrual lining sluffs off.

5. If implantation does occur, the corpus luteum secretes estrogen and progesterone, maintaining pregnancy.

(The corpus luteum develops from an ovarian follicle during the luteal phase of the menstrual cycle or estrous cycle, following the release of a secondary oocyte from the follicle during ovulation. While the oocyte (later the zygote if fertilization occurs) traverses the Fallopian tube into the uterus, the corpus luteum remains in the ovary.)

Where does fertilization and implantation normally occur?

Fertilization usually occurs in the fallopian tubes. Sperm and egg, traveling toward one another, generally meet here. Implantation normally occurs in the uterus, but can occur in the fallopian tubes, leading to a "tubal," or "ectopic" pregnancy.

Describe what happens with low and high levels of estrogen/progesterone?

If they go up unexpectedly, high levels could cause unexpected mensturation. This is sometimes see in elderly women given estrogen/progesterone therapy for treatment of osteoporosis. By contrast, below normal levels of estrogen/progesterone lead to the symptoms of menopause. Of course to have menstruation, or the sloughing off of the uterine lining, we must first have a build-up of that lining. Build-up and maintenance of the uterine lining is one of the normal functions associated with estrogen/progesterone.

What are the general symptoms of menopause?

Hot flashes, vaginal dryness, atrophy of breast tissue. All of these are the result of decreased estrogen and progesterone levels.

Describe what cleavage, morula, blastocyst, gastrulation, and neurulation are.

Cleavage: Mitosis without change in size. This begins while the zygote is still in the Fallopian tube.

Morula: 8-cell zygote. At this stage the embryo does not grow during cleavage. Any one of these eight cells at this stage could produce a complete individual.

Blastocyst: The morula continue to divide for four days forming a hollow ball filled with fluid called the blastocyst. It is the blastocyst that lodges int the uterus during implantation.

Gastrulation: at about week 2, cells migrate to form the three germ layers.

Neurulation: at about week 3, the notochord forms from the mesoderm and induces the overlying ectoderm to form the neural plate, which becomes the neural tube, then the spinal cord.

What structures consist of the ectoderm, mesoderm, and endoderm?

Ectoderm: epidermis, nails, tooth enamel, lens of the eye, pituitary gland, central, peripheral, and autonomic nervous system.

Mesoderm: Dermis, muscle, bone, connective tissue, kidneys, genitalia, and most internal organs EXCEPT the liver and pancreas.

Endoderm: the entire digestive tract, thyroid, parathyroid, urinary bladder, the LINING ONLY of the lungs, the liver and pancreas.

1.

1) C ; Answer choices A and D both support the concept that information inherent in each cell determines differentiation as evidenced by the fact that removing a cell and placing it in a new environment has no effect. Answer choice B indicates that each of the two split cells developed into a complete creature, which would support the idea that the entire set of determinants was found genetically in each cell. If Scientist A were correct, we might expect both cells to differentiate into matching tissues due to environmental factors, not into highly variable, complete organisms. Thus, C is the best answer. If a cell develops differently based on its surrounding cells, this would support Scientist A's hypothesis.

2.

2) B ; Statement I is true, all cells in the human body do have a complete copy of the genome. Statement II is also true; an excellent example of this is the cells of the endoderm releasing local hormones that "induce" the overlying ectoderm to develop into the dorsal hollow nerve chord. Statement III is true in general, for all cells beginning their development. At some point near the end of development, however, they will lose this totipotent ability, and thus the statement is NOT true as written.

3. Osteoporosis, a condition causing chronic loss of bone mass, is nearly twice as common in women as it is in men. This is most likely because:

A. women have a different bone structure than men
B. women have different calcium uptake mechanisms than men
C. women are born with fewer bones than men
D. women are born with lower bone density than men

3) D; Answer D is the correct answer. It's not one of those "jump out at you as right"-type answers, but the other three should be easy to confidently eliminate. Women are indeed born with lower bone density and tend to not increase bone density during life via heavy lifting as do men. Answer A is false because there are no systematic bone differences based on sex that would account for osteoporosis. Answer B is false because men and women both have the same physiology when it comes to calcium uptake. Had it said something about hormonal differences, this could have been a correct answer. Answer C is false because women do not have fewer bones. Answer D is thus the best answer.

5. Aging women are often prescribed estrogen supplements to help offset the effects of osteoporosis. Which of the following is a likely result of such treatment?

A. Decreased pituitary activity due to negative feedback
B. Inappropriate lactation not associated with pregnancy or childbirth
C. Loss of female secondary sex characteristics
D. Increased pituitary activity due to positive feedback

5) A; Answer B is false because oxytocin and prolactin are associated with lactation and let down, not estrogen. C is false because estrogen actually stimulates female secondary sex characteristics. Finally, Answer D is false because FSH secretion by the pituitary would be inhibited by the presence of estrogen, not stimulated by it. For the same reason, Answer A is true. Estrogens (or progesterone, or testosterone) inhibit the release of GnRH (Gonadotropin Releasing Hormone) from the hypothalamus. GnRH is the hormone that prompts release of FSH from the pituitary, which stimulates the follicle to release estrogens and progesterone (or the sertoli cells to release testosterone in males). Estrogen is the final step in the cycle and if it is present, it will inhibit GnRH, stopping the loop.

8.

8) D; Answer A is false because it leaves out the embryo and the corpeus luteum. Answer B is false because it leaves out the hypothalamus and because FSH and LH are anterior pituitary hormones NOT posterior pituitary. Answer C is incorrect because it also leaves out the hypothalamus. Answer D, however, correctly orders all of the major structures involved in ovulation thru pregnancy in females. If you aren't sure what each structure does and which hormone it secretes, review this topic with your tutor.

12. Which of the following statements is/are true regarding the organization of mammalian skeletal muscle?

I. Myofibrils are bundled into groups called fasciculi
II. T-tubules located in the sarcoplasmic reticulum allow for conduction of action potentials deep into the muscle fiber
III. Each muscle cell contains multiple nuclei

A. I only
B. III only
C. II and III
D. I, II, and III

12) B; Statement I is false because myofibrils are bundled into muscle fibers or cells, not fasciculi. Statement II is false because T-tubules are invaginations of the sarcolemma (cell membrane) not the sarcoplasmic reticulum (specialized ER). Finally, Statement III is true, making Answer B the best answer.

36. An osteoblast cell found in a newborn child's bone structure ultimately originated from:

A. a totipotent cell that could have developed into any other cell type given the correct environmental conditions
B. a pluripotent cell that could have developed into muscle, bone or skin, but not other cell types
C. a totipotent cell genetically programmed to develop into a bone cell
D. a pluripotent cell influenced by both genetic and environmental factors

36) A; Answer B is false because, although at some point along the way the cell would have been pluripotent (partially differentiated), it "ultimately" originated (as the question stem states) from a totipotent cell. Answer C is false because all cells contain the same exact DNA. Finally, Answer D is false because, as said before, it was originally totipotent. Answer A is thus correct. Originally, embryonic cells are totipotent and can develop into ANY of the cells of the body.

40. An assay of a bone sample from the hip of a fracture patient is expected to contain which of the following?

I. Phosphorous
II. Calcium
III. Oxygen
IV. Nitrogen

A. I only
B. I and II
C. I, II, and III
D. I, II, III, and IV

40) D; Bone is made of hydroxyapetite, which contains Ca, PO4 and -OH. This makes Statements I thru III true. Nitrogen is NOT part of bone matrix, but it would be found in a sample of hip bone because it would be found in the proteins within the bone cells. Thus, all of the listed elements would be expected and D is the best answer.

What are the functions of the Kidney

Maintain homeostasis of bodily fluids (especially blood plasma)
Control plasma pH
regulate blood volume and pressure

...
What is the Renal Pelvis and Ureter?

...

...
Draw a nephron, label the parts, and describe the function of each

...

Compare and contrast ureters and urethra

The ureters carry urine from the renal pelvis portion of the kidneys to the bladder. The urethra carries urine from the bladder to the external urinary orifice. You have two ureters, but only one urethra.

Describe the interplay between:

The juxtaglomerular apparatus, the renin-angiotensin pathway, aldosterone, and the distal convoluted tubules of the kidney

The renin-angiotensin system (RAS) or the renin-angiotensin-aldosterone system (RAAS) is a hormone system that regulates blood pressure and water (fluid) balance.
When blood volume is low, juxtaglomerular cells in the kidneys secrete renin directly into circulation. Plasma renin then carries out the conversion of angiotensinogen released by the liver to angiotensin I. Angiotensin I is subsequently converted to angiotensin II by the enzyme angiotensin converting enzyme found in the lungs. Angiotensin II is a potent vaso-active peptide that causes blood vessels to constrict, resulting in increased blood pressure. Angiotensin II also stimulates the secretion of the hormone aldosterone from the adrenal cortex. Aldosterone causes the distal convoluted tubules of the kidneys to increase the reabsorption of sodium and water into the blood. This increases the volume of fluid in the body, which also increases blood pressure.

If the renin-angiotensin-aldosterone system is too active, blood pressure will be too high. There are many drugs that interrupt different steps in this system to lower blood pressure

juxtaglomerular apparatus

a specialized region of the nephron responsible for production and secretion of the enzyme renin

What does ADH do?

acts on the kidney's collecting duct making it permeable to water. In the absence of ADH the collecting duct is impermeable to water. Because the collecting duct passes through the highly-concentrated medulla, as soon as the membrane become permeable there is a large net flow of water out of the filtrate, concentrating the urine.

The net effect = water retention and increased blood pressure

What makes up the nervous system?

includes the brain, spinal cord, peripheral nerves, neural support cells AND sensory organs such as the eyes and ears

...

Neurons are:

(1)Frozen in G₀ phase (unable to divide)
(2) Depend entirely on glucose for energy
(3) Don't require insulin for glucose uptake
(4) Have very low glycogen and Oxygen storage capability and thus require high perfusion (blood flow)

The opening of the voltage-gated sodium channels causes a sudden spike in the membrane potential, from _____ mV to somewhere around ____mV

What is this process referred to as?

-70 mV to around +40mV

Depolarization

About what voltage is th3e threshold potential at?

-55mV

When do the K⁺ channels open in action potential propagation?

Just before maximum depolarization is reached, the Na⁺ channels begin to close and the K⁺ channels begin to open

How low does the membrane potential go during hyperolarization and why?

The potassium channels are somewhat slow to close as the membrane potential approaches -70 mV. Thus, the membrane potential actually dips to around -90mV before gradually returning to the resting potential.

"Absolute refractory period" vs "relative refractory period"

After initiation of an action potential, the refractory period is defined two ways:

(1) The absolute refractory period is the interval during which a second action potential absolutely cannot be initiated, no matter how large a stimulus is applied.

(2)The relative refractory period is the interval immediately following during which initiation of a second action potential is inhibited but not impossible

The relative refractory period immediately follows the absolute

Why does it take a stronger stimulus than normal to cause an action potential during the relative refractory period?

hyperpolarization of the membrane, that is, the membrane potential becomes transiently more negative than the normal resting potential. Until the potassium conductance returns to the resting value, a greater stimulus will be required to reach the initiation threshold for a second depolarization. The return to the equilibrium resting potential marks the end of the relative refractory period

What is the slowest part of signal transmission down a nerve?

Transmission across the synapse is by far the slowest part of signal transmission

Where are Electrical Synapses found in humans?

The retina, smooth muscle, cardiac muscle, and the CNS

Brownian motion

the presumably random drifting of particles suspended in a fluid (a liquid or a gas) or the mathematical model used to describe such random movements, which is often called a particle theory.

What is another term for an activator?

Inhibitor?

Agonist = activator

Antagonist = inhibitor

What are ependymal cells

cells lining the cerebrospinal fluid cavities

What percentage of all neurons are interneurons?

90%

All of the following changes to the physiology of the cell membrane of a neuron would decrease the sensitivity of that neuron to the propagation of a new action potential, EXCEPT:

A. a complete inhibition of ATP production and availability in the cell
B. administration of a drug that up-regulates the function of the sodium-potassium pump
C. increased selective permeability of the neuronal membrane to sodium ions
D. increased rate of diffusion of potassium ions relative to sodium ions

C; See manual for explication

Why is visceral pain often referred (i.e., felt at a location other than the actual source)?

It is part of the sensory subdivision of the autonomic nervous system which is not well developed.

What two pain divisions make up the motor subdivision of the autonomic nervous system?

Sympathetic and Parasympathetic

What type of neurotransmitter is found at the ganglia and effectors of the sympathetic nervous system?

Acetocholine at the ganglia and norepinephrine at the effector

What is the neurotransmitter used in the parasympathetic nervous system?

Acetylcholiine

Where are the neuron cell bodies located in the sympathetic nervous system?

far from the effectors

Where are the neuron cell bodies located in the parasympathetic nervous system?

very close to, or inside, the effector

Rods vs Cones

Rods = highly sensitive, perceive black and white only

Cones = less sensitive, perceive color

...
Draw a diagram of the human eye and label the following: Cornea, sclera, pupil, iris, aqueous humor, vitreous humor, lens, suspensory ligaments, ciliary muscles, retina, and optic nerve.

...

...
How do you correct far- and near-sightedness?

...

What does most of the bending of light rays?

Light rays are bent most by the cornea, and subsequently adjusted by the lens

What do the ciliary muscles do when you focus on a book very near your face?

What happens to the curvature of the lens? Focal point? power of the lens?

Ciliary muscles contract, lens becomes more curved (convex), focal point decreases and power increases.

What does the outer ear include?

The Pinna (earlobe) and auditory canal

What does the Middle Ear include?

Includes the tympanic membrane and three middle ear bones: Malleus, incus & stapes

What does the Inner ear include

the Cochlea, semicircular canals and the vestibulocochlear nerve

...
Draw and label all of the parts of the inner ear.

...

...
Draw a cross-section of the cochlea showing the three compartments and the organ of Corti.

...

Compare and Contrast:

Exocrine and Endocrine Glands

Exocrine glands release enzymes or other liquids into the external environment (which includes the digestive tract and epithelial lined orifices; substances released include sweat, oil, mucus, digestive enzymes, etc.)

Endocrine glands release hormones into the internal fluids of the body (e.g. blood, lymph, etc)

What hormones come from the Pancreas?

Gucagon and Insulin

(also releases several digestive enzymes, but this is an exocrine function: not an endocrine function)

What is the full name of the hormone hCG

What does it do?

human Chorionic Gonadotropin

What hormones are Steroids?

Cortisol and Aldosterone from the Adrenal Cortex
and
Estrogen, progesterone and Testosterone from the gonads

What hormones are tyrosines?

T₃/T₄ which are lipid-soluble

Epi/Norepi which are water-soluble

Patient A has high blood glucose levels. Which hormone is likely to be found in highest concentration in her blood?

Insulin

Patient B has low blood glucose levels. Which hormone is likely to be in highest concentration in his blood?

Glucagon

Patient A has osteoporosis. Which hormone will be found in highest concentration in her blood?

Parathyroid

Patient B suffers from calcinuria, a disease resulting in chronically low blood calcium. Which hormone will be found in highest concentration in his blood.

Calcitonin

Polycystic Ovary Syndrome results in numerous follicles, or fluid-filled egg sacs, forming on the surface of a woman's ovaries. Ovulation is greatly inhibited or irregular and multiple cysts build up over time. A researcher has discovered that female lab animals who are given high levels of "male hormones," called androgens, exhibit almost identical symptoms. The researcher hopes to develop a drug that associates with the androgens in a woman's body and prevents them from binding to their receptors. To be effective, it is important that the drug:

A. be lipid-soluble
B. be water-soluble
C. have a short half-life under physiological conditions
D. bind reversibly to its target

A

What organ secretes two types of hormones?

The Thyroid. It secretes both a tyrosine derivative and a peptide hormone

Which of the following best accounts for the fact that a stronger stimulus is required to initiate an action potential during the relative refractory period?

A. Compared with resting potential, sodium ion concentration inside the cell is much higher, requiring a larger threshold stimulus
B. Compared with resting potential, sodium ion concentration inside the cell is much lower, requiring a larger threshold stimulus.
C. Excess potassium ions inside the cell create a larger negative potential, which must be overome be a larger threshold stimulus.
D. Excess potassium ions outside the cell create a larger negative potential, which must be overcome by a larger threshold stimulus

D

Which or the following statements is/are true concerning the use of neurotransmitters in the autonomic nervous system?

I. All parasympathetic synapses utilize acetylchholine
II. All sympathetic synapses utilize acetylcholine
III. Both acetylcholine and norepinephrine are used by the parasympathetic nervous system
IV. Acetylcholine is used at pre-ganglionic synapses in the sympathetic nervous system

A. I and III
B. I and IV
C. II and III
C. II and IV

B

Which of the following most completely describes the nerve endings in the eye that cause pupil dilation?

A. Sympathetic, norepinephrine
B. Parasympathetic, acetylcholine
C. Sympathetic, acetylcholine
D. Parasympathetic, norepinephrine

A

As winter approaches, the Siberian muskrat gorges itself on high-carbohydrate food in order to store up fat for its long hibernation. Which of the following hormones is likely to be found in highest concentration in the muskrat's liver during the fall and winter, receptively?

A. glucagon, then insulin
B. insulin, then glucagon and cortisol
C. insulin, then glucagon
D. glucagon, then insulin and cortisol

B ; Recall that insulin and glucagon, like all hormones, tend to return things to normal physiological levels. Thus, while the muskrat is gorging on carbs, the blood concentration of glucose due to the absorption of these carbs will be higher than normal and insulin would be secreted to return things to normal. During the winter, there will be NO absorption because the muskrat won't be eating, so blood glucose will be lower than normal and glucagon will be present to raise the blood glucose levels to normal. Next, you must ask yourself what cortisol does? It is a stress hormone whose main effect is to promote gluconeogenesis (the reverse of glycolysis) and promote fat metabolism. This is very likely to be present during a stressful hibernation when the muskrat will need to accomplish both of these tasks in order to maintain its normal blood glucose levels. B is thus the best answer.