383 terms

SBI4U Exam Review 2019


Terms in this set (...)

When electrons are not shared equally
Non Polar
When atoms of the same element are shared equally
Dipole Moment
Due to the electrons being shared unequally the electrons are on one end of the bond, one area to be more negative than the other. (seperating of charges)
2 or 3 atoms bonded in a straight line
Covalent Bond
Bond formed when atoms share electrons
ability of an atom to attract shared electrons (hold together) bonds.
Atoms are more attracted to element with higher electronegavitity
Polar Covalent Bond
Covalent bond in which two atoms have different electronegavitity, causing a seperation of charges
Non Polar Covalent Bond
Non polar bond in which identical or nearly identical electronegativities cause the charges to be distributed evenly.
Usually between two elements of the same
2 metalliods or 2 non metals
Non Polar Covalent bonds
Ionic Bond
When atoms transfer or receive electrons from other atoms
Can be positive or negative, depending on the number of electrons
Attraction between molecules of the same substance like H2O
Hydrogen Bond
weak attraction between a hydrogen atom and another atom
biological molecules containing carbon, hydrogen and oxygen.

they include sugars, starches, glycogen and cellulose
Alpha glucose
OH group on C1 is down
Beta glucose
OH group on C1 is up
condensation reaction
chemical reaction when two molecules are joined by covalent bonds.

H2O molecule is released
The molecules is broken down by the addition of water molecule
Characteristics of carbohydrates
a) soluble, easily transported

b) small, easily diffuses across cell membrane

c) quickly respired to release energy

d)easily joined to produce polysaccharides
Bonding in carbs
a) Glycosidic

b) Covalent

c) C1 + C4

d) Condensation reaction

e) Water molecule released
storage molecule
easily broken down
energy dense
a) Alpha glucose

b) Branches

c) stabilised by hydrogen bonds
a) Beta glucose

c) when one condenses, the other inverts

d) Long straight chain

c) Alpha & beta bonds
a polysaccharide used by insects and crustaceans to build an exoskeleton
A single sugar molecule such as glucose or fructose, the simplest type of sugar.
A carbohydrate polymer of many monosaccharides linked by dehydration reactions
Glycosidic linkage
Biomolecule that is insoluble in water. Fats, Phospholipids, Steroids
Primary form of fat in foods and your body. Long term energy. Made of a glycerol with three fatty acids
Main component of cell membranes. Similar to a triglyceride, except on fatty acid is replaced with a phosphate group
Class of lipids that include hormones and cholesterol
Fatty acid
Chain of carbons and hydrogens that make up fats and phospholipids
Backbone of fats and phospholipids
Saturated fats
Fats that have a hydrogen attached to every carbon. Unhealthy fat
Unsaturated fats
Fats that have at least one double bond between two carbons, missing a hydrogen. Healthier fat
Structural component of cell membranes, and precursor to some hormones
Primary male hormone responsible for regulation of the reproductive system and secondary sex characteristics
Primary female hormone responsible for development and regulation of the reproductive system and secondary sex characteristics
ester linkage
Bond between fatty acids and glycerol formed by dehydration synthesis
having both hydrophilic and hydrophobic parts.
lipid functions
source of stored energy includes fats, oils and waxes.
amino acid
Building blocks of proteins
The group in an amino acid that differentiates the type of amino acid it is
carboxyl group
(-COOH) A carbon atom both double bonded to an oxygen and single bonded to the oxygen of a hydroxyl group, found in organic acids.
amino group
The NH2 group in amino acid structure
peptide bond
bonds that hold a polypeptide together
primary structure
The first level of protein structure; the specific sequence of amino acids making up a polypeptide chain.
secondary structure
Either an alpha helix or beta pleated sheet.
alpha helix
A spiral shape constituting one form of the secondary structure of proteins, arising from a specific hydrogen-bonding structure.
beta pleated sheet
One form of the secondary structure of proteins in which the polypeptide chain folds back and forth, or where two regions of the chain lie parallel to each other and are held together by hydrogen bonds.
tertiary structure
The third level of protein structure; the overall, three-dimensional shape of a polypeptide due to interactions of the R groups of the amino acids making up the chain.
quaternary structure
Results from two or more polypeptide subunits.
A change in the shape of a protein (such as an enzyme) that can be caused by changes in temperature or pH (among other things).
the functions of nucleic acids are to _____________________
-store and transfer information
-to make protiens
Nucleic acids are made up of the following atoms___________________
H, O, N, C, P
momomers of nucleic acids are...
DNA stands for
Deoxyribonucleic Acid
RNA stands for
Ribonucleic Acid
DNA's is
double stranded
The sugar in DNA is
The nitrogen bases in DNA are
RNA's structure is...
single strand
The sugar in RNA is
structure of nucleotide
adenosine triphosphate; a molecule that acts as the main energy source for cell processes
double-ring nitrogenous base
single-ring nitrogenous base
biological cataylsts, functional proteins; their names usually end in - ase
a substance that causes or speeds up a chemical reaction
activation energy
Energy needed to get a reaction started
- the molecule upon which an enzyme acts, the enzyme will do work on the substrate; breaking it down, fusing it together, or changing its shape
active site
Region of an enzyme into which a particular substrate fits.
Ending materials in a chemical reaction.
optimal pH
specific pH at which an enzyme works the fastest
optimal temperature
The temperature at which the rate of enzymatic activity will be at its peak.
A starting material in a chemical reaction
breaks down milk sugar (lactose)
DNA polymerase III
adds DNA nucleotides to the DNA polymer
breaks down lipids
breaks down proteins
Extracellular fluid, Interstitial Fluid, Matrix
Fluid on the outside of a cell.
Hydrophilic head of a phospholipid
loves water
Hydrophobic tail of a phospholipid
hates water
A lipid that forms an essential component of animal cell membranes and acts as a precursor molecule for the synthesis of other biologically important steroids.
Passive Transport
Diffusion, osmosis, facilitated diffusion
Type of energy used in Passive Transport
Movement of a substance from a HIGH to a LOW concentration
Oxygen, Water and Carbon Dioxide
Substances that diffuse across the plasma membrane
The diffusion of water across a membrane
Hypertonic solution
Causes a cell to shrink
Hypotonic solution
Causes a cell to swell
Peripheral Proteins
On the surface of a plasma membrane
Integral proteins
Found IN the membrane and create channels
facilitated diffusion
Use of an integral protein to move a molecule from a high concentration to a low concentration across a membrane with out energy (ex. Glucose)
active transport
uses cell energy (ATP) to pull molecules from low to high concentration
bulk transport
needs energy (ATP) and is used for substances that are too large to pass through the lipid bilayer or a protein channel
2 types of bulk transport
endocytosis and exocytosis
2 Types of endocytosis
phagocytosis and pinocytosis
cell eating
cell takes in liquid
opposite of endocytosis and secretes substances out of the cell
sugar chain attached to a protein
Glycoprotein function
Anchors cells/cell to cell recognition
carbohydrate attached to a lipid
a lipid that contains phosphorus and that is a structural component in cell membranes
1 glucose -> 2 pyruvate
simplified overall reaction of glycolysis
how many net ATP are formed from glycolysis?
how many net NADH molecules are formed in glycolysis
Glucose 6-phosphate
Reaction 1/10: Glucose -->
fructose 6-phosphate
Reaction 2/10: Glucose 6-phosphate -->
dihydroxyacetone phosphate and glyceraldehyde-3-phosphate
Reaction 4/10: fructose-1,6-phosphate -->
Reaction 5/10: dihydroxyacetone -->
Reaction 6/10: glyceraldehyde-3-phosphate -->
Reaction 7/10: 1,3-bisphospho=glycerate -->
Reaction 8/10: 3-phosphoglycerate -->
reaction 10/10: phosphoenol-pyruvate -->
last molecule before splitting in glycolysis
last molecule before pyruvate
glucose cannot leave cell after the first step of glycolysis because it is _______
where does glycolysis occur?
The coenzyme must be regenerated to allow glycolysis to proceed
acetyl CoA
fate of pyruvate in aerobic conditions?
Citric Acid Cycle, The Kreb Cycle, and TCA (tricarboxylic acid)
What are the different names for the Kreb Cycle?
In the mitochondrial matrix
Where does the Kreb Cycle occur?
Acetyl Co A and oxaloacetate
What starts the Krebs cycle?
Is separates from the Acetyl and leaves before the Acetyl joins the cycle
What happens to the Co-A in Krebs cycle?
A CO2 leaves citrate while a NAD+ is reduced, oxidizing the citrate
What happens in step 2 of the Kreb Cycle?
An alpha-ketoglutarate
What is the product of step 2 in the Kreb Cycle?
Succinate is formed
What happens in step 3 of the Kreb Cycle?
Malate is made
What happens in step 4 of the Kreb Cycle?
The step makes oxaloacetate
What happens in step 5 of the Kreb Cycle?
Oxaloacetate is the final compound which is then added to the 2 carbon compound, restarting the cycle
Why does the Kreb cycle repeat?
It is the CO2 that is released in the Kreb Cycle. It is toxic to our body so we have to breath it out.
Why do we breath out CO2?
The high amount of electron carriers (NADH and FADH2) made. They are used in the electron transport chain to make ATP.
What is the most important use of the Kreb Cycle?
Aerobic uses oxygen
Anaerobic doesn't use oxygen
What is the difference between anaerobic and aerobic respiration?
What type of respiration is the Kreb Cycle?
The inner membrane of the mitochondria is impermeable
In the space between the inner and outer membrane
Where is the proton gradient?
The Krebs Cycle
What reactions occur in the matrix of the mitochondria?
False. It is almost 80% protein
The inner membrane is mainly composed of phospholipid rather than protein
In order to capture the energy. If we did it in one jump, FADH2 or NADH to oxygen, we would lose more energy to heat as per the second law of thermodynamics
Why is the ETC linked up in a series of oxidation/reduction reactions?
Molecules that drives the ETC
NADH dehydrogenase
What is the formal name for complex I?
Succinate dehydrogenase
The formal name of complex II
Cytochrome b-c1 complex
The formal name for complex III
Complex IV
This complex is known as the cytochrome oxidase
Complex II does not do this
Pump protons
Complex I
This complex transfers 2 electrons
two electrons
How many electrons does succinate dehydrogenase (Complex II) transfer to ubiquinone?
Complex III
This complex transfers electrons from ubiquinone to cytochrome C?
*4* protons and *2 O2* are used to make *2* H2O and 42 O2otons and *2 O2* are used to make 2 H2O and 4 protons are pumped into the intermembrane space
In complex IV, or cytochrome c oxidase, ____ protons and ___ O2 are used to make _____ H2O and _____ protons are pumped into the intermembrane space
process by which cells produce energy in the absence of oxygen
anerobic respiration
glycolysis and fermentation are together referred to as _______________ ____________
pyruvic acid+NADH-alcohol+CO2+NAD
simple equation of alcoholic fermentation
lactic acid fermentation
most organisms carry out what type of fermentation?
pyruvic acid+NADH-lactic acid+NAD
simple equation for lactic acid fermentation
process that does not require oxygen
first set of reactions in cellular respiration in which a molecule of glucose is broken into two molecules of pyruvic acid
gross number of ATPs produced in glycolysis:
net number of ATPs produced in glycolysis:
What are the purpose of light reactions?
To produce ATP and NADPH to for the Calvin Cycle
NADP+ is used as a....
Hydrogen and electron acceptor
energy used to make electrons move to higher orbit
Photosystems II
the first electron transport chain makes ATP and uses electrons from light
Photosystem I
the second electron transport chain in the light reactions in electron movement, but it's called #1 since it was discovered first.
Products of light reaction
What are the electrons used for after the photosystems and the electron transport chain?
Eventually, they will be used to reduce NAD to NADPH
Absorbs light in chloroplasts
Antenna pigment molecules
Source of electrons to replace Photosystem II
Splitting of Water
Source of Oxygen Plant gives off
Production of ATP
ATP Synthase
Where do light reactions take place?
Thylakoid Membranes
H+ movement down concentration gradient
Turns/Powers the ATP Synthase
Two Reactants of Light Reactions (One is Energy)
Water and Light
Production of ATP using light
reaction in which rubisco attaches oxygen instead of carbon dioxide to ribulose bisphosphate
process by which plants use the sun's energy to convert water and carbon dioxide into sugars
the enzyme that catalyzes the first step of the Calvin cycle
Light response curve
Rate of photosynthesis:
Increases proportionally with increase in irradiance
Higher CO2 levels
increase in rate of photosynthesis
Higher levels of O2
inhibit photosynthesis
Oxygen competes with CO2 for active site on
Photorespiration produces _____ instead of 2 PGA
PGA & phospholycolate
Amount of fixed carbon lost to photorespiration
As temperature increases rate of photosynthesis decreases because
stomata cloase to regulate water loss, causing decrease in CO2 concentration
Photosynthesis is more effiecienct in _____ temperatures
Shade plant leaves
thinner, broader, increased chlorophyll
-Mild climate
-Alabama plants
-C3 plants
-C3 pathway
-RUBISCO is the enzyme
Plants in a cooler & low stress environment
-Plants in the tropics
-Tropical grasses (ex: sugarcane)
-More sun, higher temps
-C4 plants
-C3 and C4 pathway
-No photorespiration
-PEP carboxylase and RUBISCO are the enzymes
Plants in a warm & medium stress environment
-Desert plants: cacti
-Even more sun, higher temps, and less precipitation
-CAM plants
-C3 and C4 pathway
-No photorespiration
-PEP carboxylase and RUBISCO are the enzymes
Plants in a hot/desert & high stress environment
-Just as many on top as on bottom of leaf
-Ex: blade of grass stands straight up, so it needs them on both sides, not just one
Stomates in C4 plants
never more than 3 cells away from bundle sheath cell
Describe the mesophyll in C4 plants
-Only place where glucose is made (during the C3 pathway) in these plants, so they have to be big
-(In C3 plants, all cells/mesophyll can make glucose)
Describe the bundle sheath cells in C4 plants
C4 pathway starts in the ____________ cells
When do C3, C4, and CAM plants open their stomates?
-CO2 combines with 3-C PEP, with the help of the PEP carboxylase enzyme, to form a 4-C oxaloacetate
1st step of C4 pathway
-First form of stable organic carbon
-How the C4 pathway gets its name
4-C oxaloacetate
-It won't accept O2 even during drought
PEP carboxylase only accepts ____
-The 4-C oxaloacetate becomes a 4-C malate
2nd step of C4 pathway
-The 4-C malate moves to bundle sheath cells from the mesophyll cells
-CO2 comes off of malate and enters the C3 pathway to make glucose
-There is a 3-C leftover, which is PEP, and the process starts over again
3rd step of C4 pathway
-The bundle sheath cells are right around the vein, so the glucose can be dumped directly into the phloem in the form of sucrose
-It doesn't have to travel from the mesophyll cells
What is efficient about the fact that in C4 and CAM plants, glucose is only made in bundle sheath cells?
-Crassulacean Acid Metabolism
What does CAM stand for?
-To take in CO2
-This conserves water, but it delays their growth rates because they can't take in sunlight at the same time
Why do CAM plants open their stomates at night?
When do CAM plants undergo C4 and C3 pathways?
-Temporal (time)
The separation of C3 and C4 pathways is ___________ in CAM plants
Shape of DNA
a double helix.
Nitrogenous base
A nitrogen containing molecule that is a part of nucleotides
Complementary Base to Adenine
Complementary Base to Cytosine
Backbone of DNA is made of
Deoxyribose sugar and phosphate
Rungs of ladder are made of
Nitrogen bases
The complimentary DNA strand of the following is:
The complimentary DNA strand of the following is:
DNA molecules contains
ATCG, A Deoxiribose Sugar, and is double stranded
A section of DNA that codes for a trait
The Base Pair A matches with
The Base Pair G matches with
DNA Back Bone
Made from Phosphate and Deoxiribose
origin of replication
a particular sequence in a genome at which replication is initiated
replication fork
A Y-shaped region on a replicating DNA molecule where new strands are growing.
replication bubble
an unwound and open region of a DNA helix where DNA replication occurs
separate double-stranded DNA into single strands allowing each strand to be copied; unzips dna
gyrase (topoisomorase)
relieves strain while double-stranded DNA is being unwound by helicase. This causes negative supercoiling of the DNA
single-stranded binding protein
prevent ssDNA from re-forming a double helix; speeds up replication
functions by synthesizing short RNA sequences that are complementary to a single-stranded piece of DNA; primer for dna polymerase
a short strand of RNA that serves as a starting point for DNA synthesis
deoxynucleoside triphosphate
individual nucleotides with three phosphate groups
5 to 3 direction
direction new DNA is formed. The 5' carbon has a phosphate group attached to it and the 3' carbon a hydroxyl (-OH) group
dna polymerase III
enzyme that builds new DNA strand
dna polymerase I
removes the RNA primer and fills in the nucleotides which are necessary for the formation of the DNA in the direction- 5' to 3'. It also helps in proof reading to see if there is any mistake done while replication and while matching base pairs
okazaki fragments
short, newly synthesized DNA fragments that are formed on the lagging template strand during DNA replication.
seals repairs in the DNA, it seals recombination fragments, and it connects Okazaki fragments
The process by which the message from DNA is written down into RNA
mRNA (messenger RNA)
The form of RNA which is created as a blueprint from DNA; carries instructions for making a protein
Uracil (U)
The base found only in RNA (replaces thymine in DNA)
The location where transcription takes place
RNA editing
A process that takes place before the mRNA is sent to the ribosome; some RNA bases are removed in order to create a final draft of the mRNA
The sections of RNA removed from the final draft of mRNA that remain in the nucleus
The sections of RNA that make up the final draft of mRNA which is sent out of the nucleus to the ribosome
RNA polymerase
The main enzyme that transcribes DNA into mRNA
Number of strands RNA is made of
5' to 3'
The direction mRNA is synthesized
DNA 3' ATG CGT TAG 5' transcribes to
rho protein
RNA binding protein responsible for terminating transcription
5' cap
a methylated guanine nucleotide added to the 5' end of eukaryotic mRNA
Poly-A tail
Prevents mRNA from being degraded in cytoplasm
100-250 A's at 3' end
complex of enzymes that serves to splice out the introns of a pre-mRNA transcript
Small nuclear ribonuclear peptide
Process by which mRNA is decoded and a protein is produced
A three base sequence on the mRNA use to code for one amino acid
A three base sequence on the tRNA used to recognise and bind to the codon as each amino acid is added
Produce of translation
A linked chain of amino acids created in the ribosome
The location where translation takes place
Start Codon
A first 3 base sequence that starts all genes; AUG
Stop Codon
A 3 bases sequence found at the end of each gene; UAA, UAG or UGA
Amino Acids
The units that make up a protein; each amino acid is coded for by one codon
A difference between RNA and DNA bases
RNA us "U" instead of "T"
Induced mutations
Result from the influence of an unrelated factor or agent, either natural or artificial
Spontaneous mutations
Happen naturally and randomly, arising from replication error and base modifications
Somatic mutations
occur in any cell except germ cells and are not heritable
Germ-like mutations
Occur in gametes and are inherited
Missense mutations
Change a codon resulting in altered amino acid
Nonsense mutation
changes a codon into a stop codon and results in premature termination of translation
Silent mutation
Alters a codon but does not result in a change in the amino acid at that position of the protein
Point mutations
Fibrodysplasia Ossificans Progressiva - point mutation in a bone morphogenetic protein type I receptor
Frame shift mutation
Result from insertions or deletions of a base pair. Eg. Muscular dystrophy results from a frame shift mutation in the dystrophy gene on X chromosome.
Eg2. ABO blood system
DNA replication errors
DNA polymerase occasionally insets incorrect nucleotides, generally due to base mispairing
- Lead to point mutations
Elements that can move within the genome and insert themselves into various positions within the genome, potentially causing mutations
binding site of RNA polymerase
regulatory switch controlling the operon
repressor protein
binds to operator to prevent transcription of genome
regulatory gene
makes the repressor protein
repressible system
usually turned on such as tryptophan operon
inducible system
usually turned off such as lactose operon
turns tryptophan operon off
turns on lactose operon
how do prokaryotes (E.coli) regulate the expression of lactose specific genes
lac operon
what does E.coli do when there is no glucose and there is lactose available?
it switches so that its is able to metabolise lactose
genes function as single transcription unit
what controls the transcription of eukaryotic genes?
transcription factors located in nucleus
role of transcription factors?
they activate or repress RNA polymerase
it also contains a binding site specific to a sequence of DNA bases found in promoter region of gene)
The body's ability to maintain relatively stable internal conditions even though the outside world is continuously changing.
monitors changes then sends information to the control center
Control Center
Determines the levels to be maintained, analyzes information, and determines the appropriate response
causes a response to change conditions
result of the stimulus
Negative Feedback
-depresses or stops the conditions to return toward set point
-Most conditions in the body
Positive Feedback
-enhances or continues the response away from set point
-Examples: childbirth, blood clotting
signal molecule released into the bloodstream that triggers particular responses.
Interstitial Fluid
aqueous solution that fills the gaps between cells in a tissue.
the maintenance of a relatively stable internal body temperature.
Negative feedback loop
when a system responds to a change by returning to its original state
Negative feedback loops: What happens when a human's internal temperature increases?
We sweat and blood rises to the surface of the head
Negative feedback loops: What happens when a human's internal temperature decreases?
We get goosebumps ( pulling our skin in)
Biological systems use to both maintain homeostasis and to amplify, or increase, the sending of a biological signal
Control their internal body temperature with very strict limits - independent of external environment
Not able to regulate their own body temperature - dependent on external environment
Endotherms positive
Fairly constant temperature
Remain active despite cold
Can live in cold areas
Endotherms negative
Significant part of intake energy used to regulate body temperature
Need more food
Less energy for growth
May overheat in hot weather
Ectotherms positive
Less food energy used in respiration
More used for growth
Can survive longer without food
Ectotherms negative
Must gain heat in cold
Less active in cold
Example - horned lizard
Expands/contracts rib cage accordingly to adjust surface area to volume ratio
all or nothing response
A neuron either reaches threshold and generates an action potential or not. Action potentials are always the same size.
action potential
A momentary reversal in electrical potential across the membrane of a neurone that occurs when the cell has been activated by a stimulus.
The level of stimulation required to trigger an impulse in a neurone.
The change from a negative resting potential to a positive action potential (caused by opening of sodium channels).
The change from a positive potential difference back to a negative resting potential (caused by opening of potassium channels).
When resting potential is restored too many potassium ions may diffuse out of the cell (it overshoots) which causes the potential difference to be slightly lower than usual.
refractory period
The period following an action potential, in which another action potential cannot be generated. This means action potentials are unidirectional and allows the cell to restore ions on the correct side of the membrane.
sodium-potassium pumps
pump positive ions out from the inside of the neuron, making them ready for another action potential
all or none
referring to the fact that a neuron either fires completely or does not fire at all
sodium channel
a protein channel in the nerve cell membrane that controls the movement of sodium ions into the cell
potassium channel
leak channel - remains open
saltatory conduction
the rapid skipping of an action potential from node to node on myelinated neurons
resting membrane potential
-70 mV
a difference in electrical potential across the membrane of a nerve cell during an inactive period
Long slender projection of a nerve cell
Central Nervous System
Brain and spinal cord
Peripheral Nervous System
Cranial and peripheral nerves (everything other than brain and spinal cord)
Process of renewal, restoration and growth
White Matter
Contains axons that are surrounded by myelin
Grey Matter
Darker areas of the brain and spinal cord consisting mainly of nerve cell bodies
Reflex Arc
The nerve pathway involved in a reflex...The pathway is this stimulus, sensory neuron, dorsal root of spinal cord, motor neuron, and effector organ
Chemical transmitters that help nerve impulses move through a synapse
Sensory Receptors
A sensory receptor that will respond to a stimulus
Something that causes a reaction
Somatic Nervous System
Part of the nervous system that controls voluntary movements like skeletal muscles
Autonomic Nervous System
Part of the nervous system that controls involuntary movements like heart rate, heart beat, respirations, digestion, and smooth muscle
Action Potential
Nerve Impulse
Permits a neuron to pass an electrical signal from one neuron to another
Sympathetic Nervous System
A major division of the autonomic nervous system that controls the "fight or flight" response, increased blood pressure and heart rate, decreased digestion, and dilation of pupils.
Parasympathetic Nervous System
A major division of the autonomic nervous system that controls rest and relaxation
Afferent Neuron
Another name for a sensory neuron
Efferent Neuron
Another name for a motor neuron
Synaptic Vesicle
Store and release neurotransmitters at a synapse.
Neurotransmitter that helps in muscle contraction
Neurotransmitter that gives the sensation of pleasure "natural high"
Neurotransmitter that functions in mood
Neuromuscular Junction
Where nervous system and muscular system meet
Receives information and transmits to cell body
axon hillock
cell body
made up of protoplasm containing nucleus
myelin sheath
white fatty sheath that wraps around the axon
sends information via excitatory or inhibitory neural impulses
Node of Ranvier
gap in myelin sheath between adjacent Schwann cells
How does an axon work?
- Conducts impulse away from cell body via sodium-pottassium pump
-Depolarization begins the degeneration of an action potential which travels toward the terminal button
-AP is the "neural impulse"
Sheath is formed by neuroglial cells (oligodendrocytes in CNS: Schwann cells in PNS)
a specialized cell transmitting nerve impulses; a nerve cell.
neuroglia (glue) cells
supportive cells
1. provide stuctural support and insulation
2. contribute to neural metabolism
3. aid in repair when neurons are damaged.
The synapse
Space between presynaptics terminal button and post synaptic cell membrane. The button contains contains synaptics vesicles filled with neurotransmitters.
Thyroid Releasing Hormone
Stimulates secretion of thyroid stimulating hormone
Growth Hormone
Stimulates tissue and organ growth by promoting cellular growth, mitosis, and cellular differentiation
Adrenocorticotrpic Hormone
Stimulates secretion of adrenal cortex hormones
Thyroid Stimulating Hormone
Stimulates activity of thyroid gland to release hormones
Follicle Stimulating Hormone
Stimulates ovarian follicle maturity and spermatogenesis
Luteinizing Hormone
Stimulates ovulation and corpus luteum formation
Stimulates uterine contractions and milk-let-down by mammary glands
Antidiuretic Hormone
Regulates water reabsorption by kidneys and raises BP by constricting arterioles
T4 and T3
Increases basal metabolic rate and body heat production
Retains calcium in the bones, lowers blood calcium levels
Parathyroid Hormone
Increases release of calcium from bone, raises blood calcium levels.
Promotes fat and protein catabolism, gluconeogensis, and inhibits inflammation
Reabsorption of sodium and excretion of potassium in kidneys
Increases awareness through the sympathetic N.S
Returns body to normal function after secretion of adrenaline
Promotes glucose uptake and synthesis of glycogen to glucose to lower blood sugar levels
Stimulates growth of uterine lining
Pituitary gland
1. Tiny structure size of grape
2. Connected to hypothalamus
3. makes ADH
Endocrine gland
a. Secrete hormones directly into bloodstream
b. Ductless
Exocrine gland
a. Secrete substance through a duct
b. Sweat, salivary and pancreas
Function of endocrine system
1. To secrete hormones that coordinate and direct target cells and organs
Thyroid gland
1. Main hormone, thyroxine, is controlled by secretion of TSH
2. Thyroxine controls the rate of metabolism
Adrenal glands
Adrenalin - hormone from adrenal medulla, powerful cardiac
stimulant, "fight or flight" hormone
1. insulin production
2. Insulin promotes utilization of glucose by the cells
Diseases - Gigantism
1. Hyperfunction of pituitary - too much growth hormone
2. In preadolescence - overgrowth of long bones leads to excessive tallness
nervous system
fast response that doesnt last long. electric message
endocrine system
slow response with long lasting effects, chemical message
• anterior pituitary
• stimulates breast milk production

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