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205 terms

Biology 621A - Midterm Review

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chromosomes
rod shaped cell structures that direct the activities of a cell and passes on the traits of a cell to new cells
cytokinesis
division of the cytoplasm, usually at the end of nuclear division.
cytoplasm
gel-like substance in which all cellular components outside the nucleus are immersed.
daughter cell
one of two cells resulting from the division of a single cell.
diploid
a cell that contains two of each type of chromosome, such as a human somatic cell.
chromatin
The loose and uncoiled form of DNA seen during interphase
G1 stage
first stage in interphase, during which cellular growth and development takes place
G2 stage
third stage of interphase during which organelle replication and protein synthesis takes place
gametes
reproductive cells; sperm and egg cells in animals.
hereditary material
the information which is passed from one cellular generation to the next (encoded in DNA in humans).
homologous chromosome
A member of a chromosome pair, both of which are similar in shape, size, and the genes they carry
interphase
the portion of the cell cycle where the cell is not dividing; includes G1, S and G2 stages.
metaphase
the stage in mitosis or meiosis in which the replicated chromosomes line up along the equatorial plate of the cell
mitosis
process of cellular division in which the daughter cells are genetically identical to themselves and to the parent cell.
nucleus
organelle in the center of the cell which contains the chromosomes.
prophase
the first stage of mitosis /meiosis in cell division; characterized by the condensation of the chromosomes and the dissolution of the nuclear envelope
replicated chromosomes
chromosomes which have undergone DNA replication and contain two sister chromatids.
S-phase
second stage of interphase ; period of DNA replication.
sister chromatids
two identical copies of a parent chromosome which are attached to one another at the centromere.
somatic cell
any cell in the body that is not a germ cell (reproductive cell).
spindle fibers
protein structures which move the chromosomes during cell division.
telophase
the final stage of mitosis or meiosis, during which a nuclear membrane forms around each set of new chromosomes
clones
A group of cells derived from a single ancestor.
histones
protein molecules around which DNA is tightly coiled in chromatin
anaphase
the stage of meiosis or mitosis when chromosomes move toward opposite ends of the poles
centrioles
specialized organelles that facilitate cell division
centromere
the region of the chromosome that holds the two sister chromatids together during mitosis
cleavage furrow
contractile ring of microfilaments in animal cell where the cell membrane is divided
cell plate
the precursor of a new plant cell wall that forms during cell division and divides a cell into two
cancer
any malignant growth or tumor caused by abnormal and uncontrolled cell division
radiation therapy
treatment using x-rays to destroy cancerous tissue
chemotherapy
the use of chemical agents to treat or control some types of cancer (destroys cells or prevents them from dividing)
binary fission
a form of asexual reproduction in single-celled organisms by which one cell divides into two cells of the same size
budding
a process of asexual reproduction in which a new individual develops from an outgrowth of the parent
spore formation
single, specialized cells that are units of reproduction that can be formed asexually or sexually (ex. bread mold)
regeneration
the ability for an organism to regrow and replace a body part
meiosis
cell division that occurs in sex cells in which the number of chromosomes is reduced by half.
synapsis
the pairing of homologous chromosomes during meiosis
disjunction
The separation of homologous chromosomes during meiosis
crossing over
exchange of genetic material between homologous chromosomes during prophase I of meiosis
gametogenesis
The formation of haploid gametes (sperm or ova) via meiosis.
oogenesis
the meiotic process that results in the formation of eggs
spermatogenesis
the meiotic process that results in the formation of sperm cells
endocrine system
a collection of glands and groups of cells that secrete hormones that regulate growth,development, and homeostasis
hormones
chemical "messengers" of the endocrine system that are released into the blood
protein hormones
class of hormones that cannot pass through the cell membrane; less likely to be stored in the body
steroid hormone
class of hormones that can pass through the cell membrane; can be stored in the body
prostaglandins
local hormones that do not enter the bloodstream
positive feedback
Process that amplifies a small change (Reinforce change)
negative feedback
a response that opposes the original stimulus
one messenger model
mechanism of hormone action used by steroid hormones which bring their message directly into the cell
two messenger model
mechanism of hormone action used by protein hormones; attach to cell membrane receptors which activate enzymes in the cell to produce the desired effect
hypersecretion
excessive hormone production by an endocrine gland
hyposecretion
deficient hormone production by an endocrine gland
pituitary gland
the master gland of the endocrine system
growth hormone
hormone secreted by anterior pituitary gland that stimulates growth of bones
luteinizing hormone
A protein hormone secreted by the anterior pituitary that stimulates ovulation in females and androgen production in males.
Prolactin
Peptide hormone released by anterior pituitary which promotes lactation.
follicle stimulating hormone
secreted in increasing amounts during puberty, by the anterior pituitary gland, to stimulate development of reproductive cell follicles
adrenocorticotropic hormone
A peptide hormone released from the anterior pituitary, it stimulates the production and secretion of steroid hormones by the adrenal cortex.
oxytocin
A hormone produced by the hypothalamus and released from the posterior pituitary. It induces contractions of the uterine muscles during labor.
antidiuretic hormone
hormone secreted by the posterior pituitary gland which aids in water reabsorption by the kidney
hypothalamus
part of the brain which links the endocrine and nervous system, and controls the pituitary gland.
acromegaly
Hypersecretion of the GH in adults which causes an overgrowth of bones in the hands, feet, and face
thyroid gland
gland found in neck that regulates rate of metabolism; produces thyroxine
calcitonin
Produced by the thyroid gland and decreases the blood calcium levels by stimulating calcium deposit in the bones. The antagonist of the parathyroid hormone.
parahormone
secreted by parathyroid glands and controls calcium and phosphate metabolism
tetany
condition affecting nerves causing muscle spasms as a result of low amounts of calcium in the blood caused by a deficiency of the parathyroid hormone
osteoporosis
a condition in which the body's bones become weak and break easily; may be caused by hypersecretion of parahormone
adrenal gland
one of a pair of ductless glands, located above the kidneys, consisting of a cortex, which produces steroidal hormones, and a medulla, which produces epinephrine and norepinephrine.
cortex
outer part of kidney which produces corticosteroids; helps body deal with long term stress
medulla
inner part of kidney which produces epinephrine and norepinephrine
cortisol
secreted from the adrenal cortex, aids the body during stress by regulating glucose, carbohydrates, and fat levels
aldosterone
a corticosteroid hormone that is secreted by the cortex of the adrenal gland, regulates mineral balance in blood and controls fluid volumes
Cushing syndrome
excessive production of cortisol by adrenal cortex with symptoms of abnormal fat deposits and wasting away of muscle
pancreas
located partially behind the stomach in the abdomen, and it functions as both an endocrine and exocrine gland. It produces digestive enzymes as well as insulin and glucagon
insulin
a hormone secreted by the beta cells of the Islets of Langerhans of the pancreas responsible for regulating the metabolism of glucose
glucagon
hormone secreted by alpha cells of the pancreas; raises blood glucose levels
diabetes
a condition in which the pancreas fails to produce enough insulin or the body's cells cannot use it properly, characterized by excessive thirst, weight loss/gain, frequent urination.
estrogen
a general term for female steroid sex hormones that are secreted by the ovary and responsible for typical female sexual characteristics
progesterone
A hormone produced by the ovaries which acts with estrogen to bring about the menstrual cycle.
testosterone
The male sex hormone produced by the testes which promotes the maturation of the reproductive system accessory structures, and development of the male secondary sex characteristics.
pineal gland
A small mass of tissue near the center of the brain; it secretes the hormone melatonin.
melatonin
Hormone secreted by the pineal gland, used to regulate sleep patterns.
Thymus gland
Gland located near the heart; it aids in the body's defense against infection by making antibodies
neuron
a nerve cell; the basic building block of the nervous system.
brain
specialized group of nerve cells that controls & coordinates activities of the nervous system
cns
the portion of the vertebrate nervous system consisting of the brain and spinal cord
pns
subdivision of the nervous system that brings information to the cns
autonomic nerves
serves the internal organs of the body
nerve impulse
message that travels from the dendrites of a neuron to the axon
axon
long nerve fiber that conducts away from the cell body of the neuron
dendrite
the branching extensions of a neuron that receives messages and conducts impulses toward the cell body
schwann cell
large nucleated cells that form myelin around the axons of neurons
node of ranvier
small gap between myelinated segments where axonal membrane is exposed; increase speed of impulses
synapse
the space between two neurons through which neurotransmiters travel
receptor
receives information about changes in the environment (stimuli)
effector
muscles or glands that respond to impulses
stimulus
something that causes a response
cell body
contains major concentration of the cytoplasm and the nucleus of the neuron
myelin
an electrically-insulating phospholipid (fat) layer that surrounds the axons of many neurons
reflex
A relatively simple, involuntary response to a stimulus.
resting potential
the potential difference between the two sides of the membrane of a nerve cell when the cell is not conducting an impulse
action potential
change in electrical potential that occurs between the inside and outside of a nerve or muscle fiber when it is stimulated
refractory period
the time after a neuron fires during which a stimulus will not evoke a response
saltatory conduction
transmission of an impulse by jumping
neurotransmitter
a chemical messenger that travels across the synapse from one neuron to the next and influences whether a neuron will generate an action potential(impulse)
spinal cord
part of central nervous system, links brain to rest of body
cerebellum
responsible for balance and coordination, routine movement
cerebrum
the largest part of the brain, controls thinking, reasoning, and memory
corpus callosum
connects the hemispheres; found deep inside cerebrum; allows hemispheres to share information
pons
relay link between brain and spinal cord
medulla oblongata
Regulates ♥ heart rhythm, blood flow, breathing rate,etc.
endorphins
natural neurotransmitters linked to pain control
sclera
Tough, white outer layer of the eye
autonomic nervous system
The part of the nervous system that controls involuntary action and responses.
Parkinson's Disease
a progressive disease that destroys brain cells and is identified by muscular tremors, slowing of movement, and partial facial paralysis
Alzheimer's Disease
a disease that results in the progressive loss of an individual's memory and mental capacity.
ALS
"Lou Gherig's Disease" - progressive neurological disease in which the motor neurons degenerate to the point of total loss of motor function. The intelligence, memory, and personality is unaffected.
Multiple Sclerosis
disorder in which myelin is destroyed causing loss of motor activity
sclera
Tough, white outer layer of the eye
choroid coat
middle layer of the eye; contains blood vessels
retina
The light sensitive layer of the eye which is composed of receptors (rods and cones).
aqueous humor
anterior cavity of the eye filled with clear, watery fluid
vitreous humor
the clear colorless transparent jelly that fills the posterior chamber of the eyeball
nearsightedness
a condition in which nearby objects are seen more clearly than distant objects
farsightedness
condition in which vision for distant objects is better than for near objects
rods
rod-shaped receptor in the retina of the eye that is sensitive to dim light but not color
cones
Receptor cells in the retina that are sensitive to bright light and produce color vision.
pinna
visible part of the outer ear. It collects sound and directs it into the auditory canal
eardrum
the membrane that separates the outer ear from the middle ear and that vibrates when sound waves strike it (tympanic membrane)
hammer
the bone attached to the eardrum
anvil
the bone between the hammer and the stirrup
stirrup
a tiny U shaped bone that passes vibrations from the anvil to the cochlea
oval window
membrane that covers opening between middle ear and inner ear
cochlea
a coiled tube that is found in the inner ear and that is essential to hearing
semicircular canal
3 loops of fluid filled tubes that that are attached to to the cochlea; maintains equilibrium
olfactory cells
sensitive nerve cells in nasal passages.
eustachian tubes
tube connecting ear to throat; helps to equalize pressure
menstruation
monthly shedding of the lining of the uterus when fertilization does not occur
follicle stage
the stage of the menstrual cycle where the pituitary gland produces FSH which starts the maturation of an egg
corpus luteum
name given to the follicle after ovulation, secretes progesterone
luteinizing hormone
secreted by pituitary; regulates estrogen secretion and ovum development in the female and testosterone production in the male
estrogen
Hormone produced by the ovaries which controls the development of eggs and adult female characteristics.
progesterone
hormone produced by the corpus luteum which promotes uterine lining growth
follicle stimulating hormone
secreted by the anterior pituitary gland to stimulate development of reproductive cell follicles
ovulation
The process by which a mature egg is released from the ovaries into the fallopian tubes.
zygote
the cell resulting from the union of an egg and sperm
embryo
a developing human, from fertilization through the first 8 weeks of development
fetus
the developing organism from the end of the eighth week until birth
morula
the solid mass of cells resulting from the cleavage of the ovum before the formation of a blastula.
blastula
hollow ball of cells formed during the early stages of embryological development; also known as a blastocyst
gastrula
the embryo in the stage of development after the blastula; contains the embryonic germ layers
endoderm
innermost germ layer- forms the digestive tract
ectoderm
outermost germ layer; becomes skin and nervous system
mesoderm
germ layer between ectoderm and endoderm
cleavage
rapid mitotic division of a zygote that occurs immediately after fertilization
differentiation
Process in which cells become specialized in structure and function.
blastocoel
the fluid-filled cavity inside a blastula
blastopore
opening formed when the blastula folds in on itself
primitive gut
cavity within the gastrula
neural tube
The primitive spinal cord that develops from the ectoderm, the top of which swells to form the brain.
embryonic induction
ability of one group of embryonic cells to influence the development of another group
chorion
The outermost of four extraembryonic membranes; contributes to the formation of the mammalian placenta.
amnion
The innermost of four extraembryonic membranes; encloses a fluid-filled sac in which the embryo is suspended.
allantois
One of four extraembryonic membranes; collects embryo's nitrogenous waste.
yolk sac
The membrane that is attached to a vertebrate embryo and that encloses the yolk;stores energy reserves for the developing embryo.
placenta
organ in placental mammals through which nutrients,oxygen, carbon dioxide, and wastes are exchanged between embryo and mother
umbilical cord
In placental mammals, the structure that connects the fetus and the placenta.
teratogens
Harmful agents or substances that can cause malformations or defects in a embryo of fetus
Puberty
the stage in life during which reproductive hormones begin to be formed. Reproductive development occurs during this stage
Seminiferous tubules
long, coiled tubes inside the testes
interstitial cells
cells surrounding the seminiferous tubules in the testes
sertoli cells
cells in the seminiferous tubules that support, regulate, and nourish developing sperm
epididymis
in human males, the tube within the scrotum in which sperm mature and become motile
seminal vesicle
glands that produce a mucus-like fluid containing fructose as energy for sperm
prostate gland
Exocrine gland, in men, at the base of the urinary bladder. It secretes alkaline fluid (part of semen) into the urethra during ejaculation to neutralize the acidity of the female reproductive tract.
cowper's gland
gland in human males that secretes an alkaline fluid that neutralizes the acidity of the female reproductive tract during ejaculation
semen
fluid made of sperm and fluid from the prostrate and Cowper's glands
inhibin
hormone that acts on the hypothalamus to stimulate the production of releasing factors that trigger release of FSH. The interaction of FSH and inhibin controls the rate of formation of sperm.
testosterone
steroid hormone produced in the testicles that is responsible for the development of male secondary sexual characteristics
endometrium
the mucous membrane that lines the uterus and increases in thickness in the latter part of menstrual cycle
ovaries
two glands that are suspended in the abdominal cavity and produce eggs (ova)
oviducts
pair of tubes in the body that transport an egg (ovum) from the ovary to the uterus
fimbriae
finger-like projections that sweep eggs from where they exit the ovaries into the fallopian tubes
menstrual cycle
in a human female, period of 25 - 40 days during which hormones stimulate the development of the uterine lining, and an egg is developed and released from an ovary. If the egg is not fertilized, the uterine lining is shed as the cycle begins again.
follicles
in the female reproductive system, groups of cells held in the ovaries. Each one of these cells contains an ovum (egg) that will develop
luteal stage
stage of the menstrual cycle that begins with ovulation. During this stage, LH stimulates the corpus luteum to produce progesterone, which inhibits the growth of other follicles so that only one ovum is released during each cycle.
menopause
period in women's life during which a decrease in estrogen and progesterone results in an end of menstrual cycle
hormone replacement therapy
administration of low levels of estrogen and/or progesterone to alleviate symptoms of menopause
STI
diseases such as AIDS, chlamydia, or genital herpes that is normally passed from one person to another through sexual activity
sterile
physically incapable of conceiving offspring
infertile
incapable of becoming pregnant or of inducing pregnancy
contraception
a way of avoiding pregnancy, using either artificial methods such as condoms and birth control pills or natural methods such as avoiding sexual intercourse during a woman's none fertile periods
fertilization
first stage in embryonic development, when a sperm and egg interact successfully to form a zygote
blastocyst
stage which follows the morula
trophoblast
thin outer layer (ectoderm) that encloses the embryo of mammals, attaches the fertilized ovum to the wall of the uterus, and absorbs nutrients
implantation
the embryo's attachment of itself to the endometrium, occurs within the first week after fertilization in humans
primary membranes
thin flexible sheets of tissue that are not part of the embryo but that support, nourish and protect it
germ layers
three cellular layers in the gastrula - ectoderm, endoderm and mesoderm
neurula
vertebrate embryo in the stage during which the nervous system begins to develop
differentiation
the process in which each of the three layers of the gastrula develop into different parts of the body
prostaglandins
May cause the release of oxytocin. Prostaglandins together with oxytocin cause the uterus to contract, signaling the beginning of labour
labour
process of giving birth to a baby
lactation
the secretion and formation of breast milk by the mammary glands