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MCAT Biology
MCAT biology review
217
Medical
Undergraduate 3
06/20/2014

Additional Medical Flashcards

 


 

Cards

Term
abductor
Definition
a muscle that moves a limb away from the center of the body
Term
acrosome
Definition
the large vesicle at the head of a sperm cell containing enzymes hat degrade the ovum cell membrane to allow fertilization
Term
actin
Definition
principle constituent of thin filament in muscle cells
Term
adductor
Definition
a muscle that moves a limb toward the center of a body
Term
Where is epinephrine synthesized?
Definition
adrenal medulla
Term
epinephrine
Definition
AKA adrenaline
stimulates fight-or-flight response
neurotransmitter in the sympathetic nervous system
Term
ACTH
Definition
adrenocorticotropic hormone
Term
Where is ACTH secreted from?
Definition
anterior pituitary
Term
ACTH (adrenocorticotropic hormone)
Definition
stimulates hormone production in the adrenal cortex
Term
afferent neuron
Definition
AKA sensory neuron
picks up impulses from sensory receptors and transmits them toward CNS
Term
allantois
Definition
one of four embryonic membranes
contains growing embryo's waste products
Term
amnion
Definition
the innermost fluid-filled embryonic membrane
forms protective sac surrounding embryos
Term
amylase
Definition
enzyme found in saliva and pancreatic juices
hydrolyzes starch to maltose
AKA ptyalin, diastase, or amylopsin
Term
analogous structures
Definition
similar in function but from different evolutionary origins (e.g., whale flippers and fish fins)
Term
androgen
Definition
any male sex hormone
includes testosterone and dihydrotestosterone
Term
anterior
Definition
front of an organism
Term
immunoglobulin
Definition
antibody
binds to specific antigen in an immune response
Term
ADH
Definition
antidiuretic hormone
AKA vasopressin
Term
ADH (antidiuretic hormone) / vasopressin
Definition
inhibits urine excretion by increasing water reabsorption in the kidneys
Term
Where is ADH synthesized?
Definition
hypothalamus
Term
archenteron
Definition
the central cavity in the gastrula stage of embryological development
lined by endoderm and ultimately gives rise to the digestive tract
Term
atrioventricular node (AV node)
Definition
a small mass of nodal tissue that serves as an electrical bridge between the atria and the ventricles
located in the lower portion of the wall that separates the atria
Term
bacillus
Definition
rod-shaped bacterium
Term
bile
Definition
solution of salts, pigments, and cholesterol
emulsifies large fat droplets when secreted into the small intestine via the bile duct
Term
where is bile produced, stored, and used?
Definition
produced by liver
stored in gall bladder
secreted into small intestine
Term
blastocoel
Definition
fluid-filled central cavity of the blastula
Term
blastopore
Definition
opening of the archenteron to the external environment in the gastrula stage of embryonic development
Term
blastula
Definition
the early embryonic stage during which the embryo is a hollow fluid-filled sphere of undifferentiated cells
Term
Bundle of His
Definition
part of the conducting system of the heart
carries impulses from the AV node to the ventricles
Term
calcitonin
Definition
polypeptide hormone
causes deposition of calcium and phosphate in bones and thus lowers their concentration in the blood
Term
where is calcitonin secreted from?
Definition
thyroid
Term
cecum
Definition
a cavity open only at one end
such as the diverticulum at the junction of the large and small intestines
Term
centriole
Definition
organizes spindle apparatus during mitosis or meiosis
Term
centromere
Definition
area of chromosome where sister chromatids are joined
the point of attachment to the spindle fiber during mitosis and meiosis
Term
cerebellum
Definition
controls muscle coordination and equilibrium
part of hindbrain
Term
cerebral cortex
Definition
part of forebrain
consisting of gray matter
site of higher cognitive functions in humans
neurons of the cerebral cortex initiate voluntary muscle action and constitute the final reception area for sensory impulses
Term
chiasmata
Definition
site at which crossing over occurs between homologous chromosomes during meiosis
Term
chondrocyte
Definition
differentiated cartilage cell that synthesizes cartilage matrix
Term
cleavage
Definition
a series of mitotic divisions of the zygote, immediately following fertilization, resulting in progressively smaller cells with increased nucleus-to-cytoplasm ratios
Term
coccus
Definition
spherically shaped bacterium
Term
cochlea
Definition
coiled tube that comprises the auditory sensory organ of the inner ear
Term
codominance
Definition
heterozygote reflects both alleles
(red and white spots)
Term
coenocytic
Definition
cells consisting of many nuclei housed within the same cytoplasm (ie. skeletal muscle)
Term
coenzyme
Definition
organic cofactor required for enzyme activity
Term
cofactor
Definition
nonprotein molecules required by enzymes for activity
Term
conjugation
Definition
temporary joining of two organisms via a pilus, through which genetic material is exchanged
done by baceria, fungi, algae, and protozoans
Term
convergent evolution
Definition
process by which unrelated organisms living in a similar environment develop analogous structures
Term
corpus luteum
Definition
the remnant of the ovarian follicle, which after ovulation continues to secrete progesterone
degeneration leads to menstruation
maintains uterine lining during pregnancy
Term
cortex
Definition
outer layer of organs
(brain, adrenal glands, and kidney)
Term
adenylate cyclase
Definition
synthesizes cAMP from ATP
Term
cytochromes
Definition
iron-containing proteins that function in the ETC in mitochondria and in photophosphorylation in chloroplasts
Term
dendrite
Definition
portion of neuron that receives stimuli and conveys them toward the cell body
Term
diastole
Definition
period of relaxation of cardiac muscle during which the atrioventricular valves open and the ventricles fill with blood
Term
diencephalon
Definition
posterior forebrain containing the thalamus and hypothalamus
Term
divergent evolution
Definition
process of change whereby organisms with a common ancestor evolve dissimilar structures
Term
dorsal
Definition
situated towards the back of an organism
Term
duodenum
Definition
first segment of the small intestine
site of digestion and some absorption
contents of stomach and the pancreatic and bile ducts empty into it
Term
ectoderm
Definition
outermost embryonic germ layer

gives rise to skin and nervous system
Term
efferent neuron
Definition
AKA motor neuron
transmits nervous impulses from spinal cord to an effector
Term
effector
Definition
an organ, muscle, or gland used by an organism to respond to a stimulus
Term
embryo
Definition
in humans, the first two months after fertilization
Term
endocrine
Definition
ductless glands that produce or secrete hormones
Term
endoderm
Definition
innermost embryonic germ layer

gives rise to linings of the alimentary canal and of the digestive and respiratory organs
Term
endoplasmic reticulum
Definition
transports proteins and lipids to varies parts of the cell
Term
endotherms / homeotherms
Definition
organisms that maintain a constant internal temperature
Term
epididymis
Definition
the coiled tube in which sperm gains motility and is stored after its production in the testes
Term
erythrocyte
Definition
red blood cell
biconcave disk-shaped cell that contains hemoglobin and has no nucleus
Term
estrogen
Definition
female se hormone that stimulates the development of secondary sexual characteristics and is secreted by the ovarian follicle
Term
estrous cycle
Definition
the regular changes in the behavior and physiology of a female mammal throughout her fertile life
Term
exocrine glands
Definition
release their secretions into ducts
(e.g., liver, sweat glands)
Term
extensor
Definition
muscle used in the straightening of a limb
Term
faculatative anaerobes
Definition
prokaryotes that can exist with or without oxygen
Term
fetus
Definition
in humans from third month of pregnancy until birth
Term
fibrin
Definition
the insoluble protein that forms the bulk of a blood clot
Term
flexor
Definition
a muscle used in the bending of a limb
Term
follicle
Definition
a set of cells surrounding a developing or mature ovum

secretes nutrients and estrogen and atrophies into the corpus luteum after ovulation
Term
FSH
Definition
follicle-stimulating hormone
Term
where is FSH secreted from?
Definition
anterior pituitary hormone
Term
follicle-stimulating hormone (FSH)
Definition
stimulates spermatogenesis and the maturation of ovarian follicles
Term
fovea
Definition
an area in the center of the retina containing the greatest concentration of cones, and therefore, the area of sharpest vision
Term
ganglion
Definition
a mass of neuron cell bodies

ganglia integrate and coordinate impulses
Term
gastrula
Definition
embryonic stage characterized by the presence of endoderm, ectoderm, the blastocoel, and the archenteron

the early gastrula is two layered; later a third layer, the mesoderm develops
Term
where is gastrin secreted from?
Definition
it is released by the pyloric mucosa of the stomach when food enters the stomach
Term
gastrin
Definition
stimulates the secretion of gastric juices
Term
genetic drift
Definition
variations in the gene pool caused by chance
Term
gene flow
Definition
the movement of alleles into and out of a population's gene pool
Term
glottis
Definition
the opening to the trachea
Term
glucagon
Definition
hormone that ncreases the concentration of blood glucose
Term
where is glucagon made?
Definition
alpha cells of the pancreas
Term
glycogen
Definition
the principal storage form of glucose in animals
Term
glycolysis
Definition
anaerobic catabolism of glucose to pyruvic acid
Term
golgi bodies
Definition
packaging and secretion of proteins and other molecules produced intracellularly
Term
gray matter
Definition
any region in the central nervous system that consists largely of neuron cell bodies, dendrites, and synapses
Term
Hardy-Weinberg principle
Definition
gene ratios and allelic frequencies remain constant through the generations in a non-evolving population
Term
Haversian system
Definition
the structural unit of compact bone

consists of a hard, inorganic matrix surrounding a central canal
Term
hepatic
Definition
of or pertaining to the liver
Term
histone
Definition
structural protein found in eukaryotic chromosomes
Term
homologous structures
Definition
structures that are similar in function and are of the same evolutionary origin
Term
hyperplasia
Definition
an increase in the number of cells in a tissue or organ
Term
hypertrophy
Definition
an increase in the size of individual cells within a given site or tissue
Term
hyphae
Definition
branched filaments of a fungus
Term
hypothalamus
Definition
the region of the vertebrate forebrain that controls the autonomic nervous system and is the control center for hunger, thirst, body temperature, and other visceral functions. Also secretes factors that stimulate or inhibit pituitary secretions
Term
ileum
Definition
the terminal portion of the small intestine
Term
incomplete dominance
Definition
heterozygote is mixture of the two parental phenotypes
(i.e. pink instead of red or white)
Term
in situ
Definition
at the site (origin) of
Term
induction
Definition
the initiation of cell differentiation in a developing embryo due to the influence of other cells
Term
insulin
Definition
hormone that lowers blood glucose concentration
Term
where is insulin produced?
Definition
produced by the beta cells of the pancreas
Term
interneuron
Definition
a neuron that has its cell body and nerve terminals confined to one specific area
Term
interphase
Definition
includes G1, S, and G2 stages

when cell growth and DNA replication occurs
Term
jejunum
Definition
the middle portion of the small intestine
Term
Krebs cycle / Citric Acid cycle / TCA cycle
Definition
metabolic pathway used in cellular respiration in which acetyl-CoA combines with oxaloacetic acid to form citric acid, which then undergoes a series of reactions to yield NADH, FADH, ATP, and CO2

occurs in aerobes
Term
latent period
Definition
the short interval between the application of a stimulus to a muscle and the contraction of the muscle
Term
leukocyte
Definition
white blood cell

4 main types: granulocytes, macrophages, monocytes, and lymphocytes
Term
ligament
Definition
connective tissue that joins two bones
Term
lipase
Definition
enzyme that specifically cleaves the bonds of lipids
Term
lumen
Definition
the space within a tube or a sac
Term
luteinizing hormone (LH)
Definition
In females, it transforms a follicle into a corpus luteum and triggers ovulation.

In males, it stimulates testosterone secretion
Term
LH
Definition
luteinizing hormone
Term
where is LH made?
Definition
secreted by anterior pituitary
Term
lymphocyte
Definition
type of white blood cell involved in an organism's immune response
Term
lysosome
Definition
organelle that stores hydrolytic enzymes
Term
macrophage
Definition
a phagocytic white blood cell
Term
medulla
Definition
the internal section of an organ
(e.g., the adrenal glands and the kidney)
also the medulla oblongata of the mammalian hindbrain
Term
medulla oblongata
Definition
the part of the brainstem closest to the spinal cord

controls functions such as breathing and heartbeat
Term
Mendel's first law
Definition
alleles segregate during meiosis
Term
Mendel's second law
Definition
alleles of unlinked genes independently assort during meiosis
Term
meninges
Definition
the three membranes that envelop the brain and spinal cord

the dura, arachnoid, and pia mater
Term
mesoderm
Definition
the middle embryonic germ layer

it gives rise to the muscular, skeletal, urogenital, and circulatory systems
Term
metencephalon
Definition
the anterior portion of the hindbrain of vertebras

includes cerebellum and the pons
Term
microtubule
Definition
a small, hollow tube composed of two types of protein subunits

serves numerous functions in the cell (e.g. comprise the internal structures of cilia and flagella)
Term
monocyte
Definition
a white blood cell that transforms into a macrophage in the presence of foreign invaders
Term
morula
Definition
a solid ball of cells that results from the early stages of cleavage in an embryo
Term
mycelium
Definition
a collection of filamentous hyphae that makes up a fungus
Term
myoglobin
Definition
heme-containing protein that binds molecular oxygen in muscle cells
Term
myosin
Definition
protein in muscle cells that functions in muscle contraction

myosin fibers are thick filaments
Term
NAD (nicotinamide adenine dinucleotide)
Definition
coenzyme that functions in cellular respiration
Term
NADH
Definition
reduced NAD
Term
NADP+/NADPH
Definition
nicotinamide adenine dinucleotide phosphate

an electron acceptor/donator system that functions primarily in biosynthetic processes
Term
neural tube
Definition
embryonic hollow tube that subsequently gives rise to the CNS
Term
Nodes of Ranvier
Definition
points on a myelinated axon that are not covered by myelin
Term
norepinephrine
Definition
hormone that stimulates fight-or-flight response

also neurotransmitter
Term
norepinephrine is secreted by _____
Definition
adrenal medulla
Term
notochord
Definition
a supportive rod running just ventral to the neural tube in lower chordates and in vertebrate embryos
Term
nucleolus
Definition
site of rRNA synthesis
Term
nucleosome
Definition
packaging unit of DNA in eukaryotic cells consisting of DNA and histone proteins complexed together
Term
operon
Definition
segment of DNA with promoter, operator, and structural genes
Term
oviduct
Definition
AKA fallopian tube

generally the site of fertilization
Term
oxidative phosphorylation
Definition
the synthesis of ATP using the energy released from the reactions of the ETC
Term
oxygen debt
Definition
the amount of oxygen needed to reconvert lactic acid to pyruvate following strenuous exercise of muscle tissue
Term
pancreas
Definition
gland that secretes digestive enzymes into the duodenum via a duct and synthesizes and secretes the hormones insulin, glucagon, and somatostatin

between the stomach and duodenum
Term
parasympathetic nervous system
Definition
subdivision of the autonomic nervous system involved in rest or homeostasis

antagonistic to sympathetic nervous system
Term
parathyroids
Definition
two pairs of glands located on the thyroid that secrete hormones that regulate calcium and phosphorus metabolism
Term
parthenogenesis
Definition
form of asexual reproduction yielding progeny without fertilization
Term
passive immunity
Definition
immunity conferred by the transfer or injection of previously formed antibodies
Term
patella
Definition
bone of the kneecap
Term
pepsin
Definition
stomach enzyme that cleaves peptide bonds of proteins
Term
peripheral nervous system
Definition
includes all neurons outside the CNS, including sensory and motor neurons

divided into somatic and autonomic
Term
peristalsis
Definition
rhythmic waves of muscular contraction that move a substance through a tube (i.e. food through digestive tract)
Term
peritoneum
Definition
membrane lining of the abdomen and pelvis that also covers the visceral organs
Term
pituitary
Definition
endocrine gland that lies just below hypothalamus

many of the hormones it releases regulate other endocrine glands --> master gland
Term
placenta
Definition
formed by the wall of the uterus and the chorion of the embryo, containing a network of capillaries through which exchange between maternal and fetal circulation occurs
Term
plasma cells
Definition
derived from B-lymphocytes

have the ability to produce and secrete antibodies
Term
platelets
Definition
small, enucleated, disk-shaped good cells that play an important role in blood clotting
Term
polar body
Definition
a small, nonfunctional haploid cell created during oogenesis
Term
polyploidy
Definition
has more than two alleles per trait

3N, 4N, etc
Term
portal system
Definition
a circuit of blood in which there are two capillary beds in tandem connected by an artery or vein
Term
progesterone
Definition
hormone that prepares the uterine wall for implantation and maintains the thickened wall during pregnancy

secreted by corpus luteum and placenta
Term
progesterone is secreted by _________
Definition
corpus luteum and placenta
Term
prostate
Definition
gland in mammalian male that secretes alkaline seminal fluid
Term
prosthetic group
Definition
a nonpolpeptide unit tightly bound to an enzyme that is essential for that enzyme's activity
Term
purines
Definition
double ringed nitrogenous bases

adenine and guanine
Term
purkinje fibers
Definition
terminal fibers of the heart's conducting system

located in the walls of ventricles
Term
pyloric sphincter
Definition
valve that regulates the flow of chyme from the stomach into the small intestine
Term
pyrimidines
Definition
single-ringed nitrogenous bases

cytosine, thymine, uracil
Term
reduction
Definition
loss of oxygen
-or- gain of electrons or H
Term
reflex
Definition
an involuntary nervous pathway consisting of sensory neurons, interneurons, motor neurons, and effectors
Term
refractory period
Definition
the period of time following an action potential during which the neuron is incapable of depolarization
Term
releasing hormones
Definition
proteins synthesized and secreted by the hypothalamus that stimulate the pituitary to synthesize and release its hormones
Term
repressor
Definition
protein that prevents attachment of RNA polymerase to the promoter by binding to the operator in an operon

coded for by the regulator
Term
resting potential
Definition
the electrical potential of a neuron at rest

approximately 70 mV across the axon membrane
Term
sarcolemma
Definition
muscle cell membrane capable of propagating action potentials
Term
sarcomere
Definition
the functional contractile unit of striated muscle
Term
sarcoplasmic reticulum
Definition
the endoplasmic reticulum of a muscle cell

envelops myofibrils
Term
seminal vesicle
Definition
gland in males that produces seminal fluid
Term
sinoatrial node (SA node)
Definition
AKA pacemaker

group of cells in the right atrium of the heart that initiates and controls cardiac muscle contraction
Term
spindle
Definition
in dividing cells, composed of microtubules, involved in separation of chromosomes
Term
stem cells
Definition
non-differentiated, rapidly dividing cells in the marrow of long bones that differentiate into red and white blood cells
Term
steroids
Definition
four-ringed organic lipid molecules that make up many hormones and vitamins
Term
sympathetic nervous system
Definition
the subdivision of the autonomic nervous system that produces the "fight-or-flight" response
Term
synapsis
Definition
the pairing of homologous chromosomes during prophase I of meiosis
Term
syngamy
Definition
the union of gametes
Term
systole
Definition
the period of chart contraction during which the ventricles contract and pump blood into the aorta and pulmonary arteries
Term
telencephalon
Definition
anterior portion of the forebrain
Term
tendon
Definition
fibrous connective tissue that connects a bone to a muscle
Term
testis
Definition
sperm-producing organ

also secretes testosterone
Term
tetanus
Definition
sustained muscle contraction that results form continuous stimulation
Term
thalamus
Definition
relay center between brainstem and cerebral cortex

located in the posterior part of the forebrain
Term
thoracic duct
Definition
lymphatic vessel that empties lymph into the bloodstream
Term
threshold
Definition
the lowest magnitude of stimulus strength that will induce a response
Term
thrombin
Definition
enzyme that participates in blood clotting

converts fibrinogen into fibrin
Term
thymus
Definition
ductless gland in the upper chest region of vertebrates

functions in development of the immune system
Term
thyroid
Definition
vertebrate endocrine gland located in the neck

synthesizes thyroxine
Term
thyroxine
Definition
regulates metabolic rate

produced and released by thyroid
Term
thyroxine is secreted from _______
Definition
thyroid
Term
tonus
Definition
a continuous state of muscle contraction
Term
transduction
Definition
the transposition of genetic material from one organism to another via a virus
Term
transformation
Definition
uptake and incorporation of naked DNA by a recipient bacterial cell
Term
urea
Definition
nitrogenous waste product produced in liver from ammonia and CO2
Term
vacuole
Definition
membrane-bound organelle that stores water-soluble nutrients and wastes
Term
vagus nerve
Definition
the tenth cranial nerve

innervates the pharynx, larynx, heart, lungs, and abdominal viscera

maintains homeostatic activity through parasympathetic response
Term
vas deferens
Definition
tube carrying sperm from testis to the urethra in males
Term
vestigial
Definition
an organ or limb that has no apparent function now but was functional at some time in the organism's evolutionary past
Term
villus
Definition
small projection from the wall of the small intestine that increases the surface area for digestion and absorption
Term
white matter
Definition
portion of the CNS consisting primarily of myelinated axons
Term
zymogen
Definition
inactive enzyme precursor that is converted into an active enzyme
Term
vitamin
Definition
organic nutrient that an organism cannot produce itself and that is required by the organism in small amounts to aid in proper metabolic functioning

often serve as cofactors for enzymes
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