bio cards part 2 Flashcards
(188 cards)
1
Q
where do the different components of aerobic respiration occur
A
glycolysis - in the cytoplasm
krebs, etc, oxidative phosphorylation - in mitochondria
2
Q
what are phospholipid molecules made of?
A
glycerol backbone attached to two fatty acids and a phosphate group.
3
Q
glycoproteins
A
proteins that contain carbohydrate components. they extend out of the plasma membrane and help out with adhesion and recognition
4
Q
acetylcholine
A
one of the principal neurotransmitters involved in the transmission of the nerve impulse
5
Q
subunits of ribosomes
A
made up of 40S and 60S subunits with additional proteins
6
Q
endocytosis
A
used to transport materials that are too big for a transport protein from the exterior of a cell to the interior. requires ATP. involves the rearrangement of the cytoskeleton to form vesicles.
7
Q
shape of growth curves of microorganisms
A
sigmoidal - S shaped
8
Q
basic virus facts - common features
A
contain either DNA or RNA, not both. so not have metabolic machinery for ATP production or protein synthesis. Rely on the machinery of their host. unable to reproduce directly. rely on host. have no membranes to regulate entry or exit of material some have a lipid membrane-like outer coat
9
Q
Facts about fungi
A
eukaryotic typically filamentous, sometimes unicellular filamentous - made of continuous hyphae that form a mycelium have chitin containing cell walls
10
Q
***correspondence between frequency of recombination and distance between genes on a chromosome
A
one to one correspondence can determine gene order if given frequencies one map unit equals 1% recombination frequency
11
Q
how is a lethal in infancy sex-linked recessive gene passed on?
A
carried on x chromosome. only from fathers to daughters and from mothers to both sons and daughters. if it is lethal in infancy, all the sons receiving the gene from their mother will die (because they only have one x chromosome and that comes from their mother)/. males can’t be carriers of the gene because they would die at birth. A female can never be homozygous because she can’t get an allele from her dad. therefore, there will be no female deaths as a result of the allele.
12
Q
where is a sex linked recessive gene carried
A
on the x chromosome
13
Q
how to do a test cross to determine genotype
A
must be able to tell the unknown parental genotype from the gross. if homozygous dominant crossed with homozygous recessive → get 100% phenotypically dominant. hetero dominant with homo recessive → 50% pheno dominant, 50% pheno recessive using a homozygous recessive as testcross allows us to distinguish between genotypes
14
Q
recombinant chromosomes
A
arise through crossing over of CNA between homologous chromosomes during meiosis.
15
Q
degree of genetic linkage
A
measure of how far apart two genes are on the same chromosome.
16
Q
what is the probability of a crossover and exchange happening between two points
A
generally it is directly proportional to the distance between the points. ex. genes that are far apart have higher probability of crossing over than pairs of genes that are close together.
17
Q
penetrance
A
the percentage of individuals in the population carrying the allele who actually express the phenotype associated with it.
18
Q
expressivity
A
degree to which the phenotype associated with the genotype is expressed in individuals who carry the gene.
19
Q
incomplete dominance
A
occurs when the phenotype of the heterozygote is an intermediate of the phenotypes and homozygotes.
20
Q
codominance
A
occurs when multiple alleles exist for a given gene and more than one of them is dominant.
21
Q
color - blindness genetics
A
sex linked recessive trait
22
Q
shape for male and female on tree of genetic inheritance
A
female - circle. male - square
23
Q
translocation
A
chromosomal fragment joins with a nonhomologous chromosome, it the fragment joins with its homologous chromosome, the event is called duplication.
24
Q
digestion in mouth
A
mechanical and chem digestion begins salivary glands produce saliva which has salivary amylase (ptyalin and lipase). salivary amylase digests starch to maltose (disaccharide) tongue forms food into a bolus
25
digestion in esophagus
food moves down esophagus to the stomach via cardiac sphincter by means of peristalsis (smooth muscle contraction)
26
peristalsis
smooth muscle contractions
27
digestion in stomach
gastric glands make HCl which makes pH of stomach very acidic stomach protected from acid by mucosal lining proteins are digested in stomach by pepsinogen (activated to pepsin by HCl)
28
chyme
mixture of digested proteins and pepsin in stomach
29
how do ulcers form
when a portion of mucosal lining in stomach is digested and a hole forms.
30
digestion in small intestine
the chyme moves into small intestine via pyloric sphincter. digestion and absorption happen in small intestine produces lipase (lipid digestion), aminopeptidases (for polypeptide digestion), disaccharidases (for digestion of maltose, lactose, and sucrose). secretes secretin - stimulates release of sodium bicarbonate from pancreas lined with villi which increase the surface area for absorption of nutrients into the blood.
31
what are the three sections of the small intestine?
duodenum, jejunum, and ileum. most Digestion occurs in the Duodenum. absorptive process mostly happens in the jejunum and ileum Dow Jones Index - to remember order.
32
villi
line the small intestine. made of capillaries and lacteals - increase surface area for absorption of nutrients into the blood
33
what are the functions of the liver?
storage of certain nutrients, detox of chemicals and drugs from the bloodstream formation of urea formation of glycogen from glucose or vice versa depending on body’s needs production of bile which is stored in the gallbladder and secreted into the small intestine.
34
what does bile do?
emulsifies fats
35
what does the pancreas do in digestion?
secretes pancreatic juices into small intestine that contain hydrolytic enzymes: amylase (starch), trypsin (protein), chymotrypsin (protein), pancreatic lipase (lipids), and sodium bicarbonate. sodium bicarbonate ions neutralize the acidic chyme from the stomach.
36
what does the large intestine do in digestion?
water reabsorption. the e. coli that live in the large intestine produce vitamin K
37
what does the rectum do in digestion?
storage of feces
38
what are some properties of maltose?
it is a disaccharide and can be hydrolyzed into 2 glucose molecules.
39
where does the signal to breathe originate?
in the medulla oblongata and travels to the diaphragm via the phrenic nerve
40
axial skeleton
consists of skull, vertebral columns, and ribcage. basic central framework of the body.
41
appendicular skeleton
arms, lets, pelvic, and pectoral girdles that are attached to the axial skeleton for stability.
42
cartilage
think pipe cleaners made of chondrin - secreted by cells called chondrocytes. relatively avascular (without blood and lymphatic vessels) not innervated softer and more flexible than bone fetal skeleton has a lot of cartilage - hardens into bone in places on adult bodies that need more flexibility
43
types of bone
compact, spongy, and cancellous
44
spongy bone
looks like a sponge, made of bony points called trabeculae (honeycomb) cavities filled with bone marrow (red or yellow)
45
long bones
have cylindrical shafts called diaphyses and dilated ends called epiphyses diaphysis are full of marrow epiphyses has spongy bone core
46
epiphyseal plate
separates epiphysis and diaphysis cartilaginous structure, site of longitudinal bone growth
47
periosteum
surrounds long bone to protect it as well as serve as site for muscle attachment
48
osteons/Haversian systems
structural units of the bony matrix encircle Haversian canal surrounded by concentric circles of bony matrix called lamellae (think tree stump with growth rings) space between lamellae called lacunae - house mature bone cells called osteocytes
49
canaliculi
little canals that allow for exchange of nutrients and waste between them and Haversian canals.
50
endochondral ossification
hardening of cartilage into bone
51
intramembranous ossification
undifferentiated embryonic connective tissue is transformed into and replaced by bone. no cartilage template
52
osteoclasts
reabsorb bone - bone ingredients (like Ca and P) are release as ions into the bloodstream
53
osteoblasts
build bone using Ca and P obtained from the blood.
54
sacromete
basic contractile unit of muscle. put end to end to build myofibrils made of thick and thin filaments
55
sarcoplasmic reticulum
surround myofibrils - it is a modified endoplasmic reticulum which contains a lot of Ca2+
56
myocyte
muscle cell - may contain many myofibrils. most cells are multinucleate due to fusion of several embryonic cells
57
red and white fibers in muscle
red - slow twitch, have high myoglobin content, primarily anaerobic energy white- fast twitch, anaerobic, less myoglobin, contract more rapidly, get tired faster, mitochondria poor
58
myoglobin
protein similar to hemoglobin - binds to oxygen more tightly
59
thick filaments
organized bundles of myosin
60
thin filaments
made up of actin and troponin and tropomyosin
61
Z-lines
define boundaries of each sarcomere - responsible for striated look of skeletal and cardiac muscle
62
M-line
runs down center of sarcomere
63
I-band and H-zone
I → contains only thin filaments H → contains exclusively thick filaments
64
A-band
contains thick filaments in their entirety including any overlap with thin filaments
65
what happens to the zones, band and lines during contraction?
H-zone, I-band, and distance between z-lines all become smaller. A-band’s size remains constant.
66
functions of the skeletal system
protection and support movement (muscles use bones as levers) maintenance of calcium ion homeostasis - when calcium ion concentration in blood decreases, Ca is drawn in from the bones. formation of blood cells (in the bone marrow)
67
what is bone made out of
organic compounds: proteins, lipids, and carbohydrates. inorganic compounds: calcium, phosphate, hydroxide → form hydroxyapatite crystals
68
osteon
Haversian canal plus surrounding lamellae
69
red and yellow marrow
red - contains stem cells which form blood and immune cells. yellow - used to store fat.
70
parathyroid hormone
raises plasma calcium levels by stimulating calcium release from the bone. also regulate osteoblasts
71
calcitonin
lowers blood calcium levels by inhibiting calcium release form bone
72
osteoblasts
produce collagen, which forms bone when mineralized. osteoBlasts - Build bone osteoClasts - Crush bone
73
osteoclasts
involved in bone resorption. activity regulated by osteoblasts
74
types of joints
immovable - ex. skull bones → don’t move. partly movable - limited flexibility, usually no cartilage. ex. joint between 2 vertebrae synovial - wide range of movement, lubricated by synovial fluid. ex. hip bone.
75
antagonistic pairs of muscles
one muscle in pair contracts, the other relaxes. muscles can only contract, so extension takes place passively.
76
function of immune system
protects the body against foreign cells and foreign substances. also protects against abnormal cells that could turn cancerous.
77
bone marrow and immune system
produces cells such as lymphocytes, monocytes, leukocytes, B cells, and T cells
78
what does thymus secrete?
secretes thymosin - a hormone that stimulates pre-T cells to mature
79
spleen and immune system
storage area for blood. filters blood and lymph.
80
complement immune system
series of proteins secreted in the blood that defend against infection in a general manner. complement proteins bind to the surface of many pathogens and attract white blood cells to destroy the infecting cells.
81
neutrophils and macrophages
white blood cells that see out and ingest infections agents via phagocytosis
82
interferons
released in response to viral infection. stimulate the production of proteins that interfere with viral replication
83
inflammatory response
initiated in response to cell damage. injured cells release histamine which causes blood vessels to dilate and increased blood flow to area. often accompanied by a fever which retards bacterial growth.
84
2nd level of immune defense
directed against specific pathogens. B and T cells are types of white blood cells that recognize and remove foreign materials
85
B-cell response
production of antibodies (humoral response - antibodies circulate through “humors” (fluids) of the body.
86
T-cell response
cellular response - involves direct action of T cells.
87
cytotoxic t-cells
kill cells that are infected by a pathogen that the T cell recognizes.
88
helper T cells
coordinate immune response of other cells against specific antigens through the secretion of lymphokines (signaling molecules)
89
suppressor T cells
regulate other T and B cells to decrease their activity
90
where do T and B cells mature?
T cells mature in the Thymus. B cells mature in the Bone marrow
91
what do immune cells recognize?
specific parts of pathogen (not whole). antigens are foreign substances and they are defended against.
92
antibodies
aka immunoglobulins - proteins that recognize and bind to antigens. can attract other cells to phagocytize antigens or cause the antigens to clump together to form big, insoluble complexes that can be removed by phagocytic cells.
93
T-cell receptors
antigen recognition proteins found in the membrane of T cells. only recognize antigens that are on the surface of other cells in a specific context. to stimulate a T cell receptor, antigen must be part of MHC found in plasma membrane of cells.
94
MHC (major histocompatibility complex)
complex of proteins found in the plasma membrane of cells. class I - proteins are present on the surface of all cells class II - proteins are only present on immune cells including macrophages, B cells, and T cells.
95
what happens o the fragments of a pathogen phagocytized by a macrophage?
the pathogen proteins are broken down into short polypeptide fragments that are displayed on the surface of the macrophage via MHC class II proteins
96
interleukins
activate cytotoxic T cells to kill infected cells and stimulate B cells to secrete antibodies.
97
plasma cells
specialized B cells that produce and secrete antibodies
98
structure of antibodies
2heavy chains joined by disulfide bridges to light chains. one end is called the constant region and the other is called the variable region. they bind to antibodies at the variable region sequence of variable regions determines antibody specificity - fold into complex structure that forms the binding site for antigens. variable region contains large number of amino acid sequences, provides vast repertoire of antigen specificity. broad range of variable regions is created during b cell differentiation
99
epitope
specific part of the antigen that is recognized by the immune system (ex. bact. cell wall or viral protein coat)
100
immunological memory
ability of body to recognize an antigen to which it has previously been exposed. based on memory cells produced during primary immune response
101
memory cells
produced during primary immune response. survive for long periods and quickly proliferate if exposed to antigen that caused their creation.
102
active immunity
development of antibodies in response to exposure to an antigen
103
vaccination
injection of a killed or weakened antigen; immune system mounts an immune response against the antigen and produces memory cells. example of artificially acquired immunity.
104
passive immunity
transfer of pre-formed antibodies - happens from mom to fetus. example of naturally acquired immunity. only lasts as long as antibodies remain in the bloodstream.
105
primary function of activated B cells
produce antibodies to be secreted. contain a lot of endoplasmic reticulum because they have to produce a lot of secretory proteins.
106
troponin
protein making up sarcomeres.
107
sarcoplasmic reticulum
the endoplasmic reticulum of a muscle cell; envelops microfibrils
108
osteocytes
mature osteoblasts that eventually become surrounded by their matrix and whose primary role is bone maintenance
109
chondrocytes
cells that secrete chondrin, an elastic matrix that makes up cartilage
110
frequency summation in muscle
when a muscle fiber is subjected to very frequent stimuli, the muscle cannot fully relax. the contractions begin to combine, becoming stronger and more prolonged.
111
what is the ossification process that occurs in the skull?
intramembranous ossification. mesenchymal cells directly create bone matrix. fills in where the fontanelles were.
112
what is the part of the muscle attached to the stationary bone and the bone that moves during contraction?
the origin is attached to the stationary bone. in limbs, this corresponds to the proximal end. the part of the muscle connected to the bone that moves during contraction is call the insertion (distal end in limbs)
113
what is the only type of muscle that is always multinucleated?
skeletal muscle.
114
chief cells
“chiefs of digestion” in the stomach. secrete pepsinogen which is the zymogen of the protein-hydrolyzing enzyme pepsin.
115
zymogen
an inactive enzyme precursor that is converted into an active enzyme
116
parietal cells
in stomach. secrete HCl. HCl activates pepsin which is most active in pH 2
117
pyloric glands
secrete gastrin in stomach. gastrin is a hormone that induces stomach to secrete more HCl and mix it with the contents of the stomach. This produces chyme which has an increased surface area and makes it easier to the nutrients to be absorbed in the small intestine
118
gastric glands
respond to signals from brain activated by sight, taste, and smell of food. composed of mucous cells, chief cells, and parietal cells
119
what is stomach’s primary function?
digestion, not absorption.
120
pyloric sphincter
food leaves stomach through here o enter the duodenum of the small intestine
121
pancreatic peptidases
responsible for protein digestion. includes trypsinogen, chymotrypsinogen, elastinogen, and carboxypeptidase
122
enterokinase
produced by the small intestine → is the master switch. it activates trypsinogen to trypsin which activates other zymogens.
123
lipase
hydrolyzes lipids.
124
sucrase
secreted by the intestinal glands. hydrolyzes sucrose to glucose and fructose.
125
pH of stomach and small intestine
stomach = low pH - acidic small intestine = high pH - basic
126
chylomicrons
protein coated droplets of large fatty acids and glycerol combined to form triglycerides, with phosphoglycerides and cholesterol. these are absorbed into tiny lymph vessels within villi called lacteals which lead to the lymphatic system.
127
where do the intestinal capillaries transport nutrients?
from the intestines to the liver where they get processed, repackaged, and distributed.
128
erythrocytes
red blood cells. produced in red bone marrow, circulate in blood for about 120 days and are then phagocytized by the spleen and liver. disk shaped, lose their membranous organelles during maturation. can’t multiply on their own. anaerobic main role is transport of oxygen to the tissues. use hemoglobin to do this
129
path of cardiac impulse
SA node → atria (both contract simultaneously) → AV node (slows conduction to allow for completion of atrial contraction and ventricular filling)→ bundle of His → Purkinje fibers (in the walls of both ventricles)→ ventricles (contract)
130
Bohr effect
decreasing the pH in blood decreases hemoglobin’s affinity for O2 . decrease in pH generally happens during heavy exercise when a lot of lactic acid is produced. the decreased affinity for O2 facilitates unloading of O to tissues in need.
131
Circulatory pathway
superior vena cava → right atrium→ tricuspid valve → right ventricle → pulmonary valve → pulmonary artery → lungs → pulmonary veins → left atrium → mitral valve → left ventricle → aortic valve → aorta → body
132
hydrostatic pressure in capillaries
osmotic pressure of surrounding tissues remains constant, hydrostatic pressure at the arterial end is greater than the hydrostatic pressure at the venous end of the capillaries. results in fluid moving out of the capillaries at the arterial end and back in at the venous end.
133
cardiac output
heart rate\*stroke volume
134
pressure in aorta vs. superior vena cava
usually 120-80 mmHG in aorta. very low in superior vena cava.
135
how do arteries vs. veins transport blood
arteries use the pumping of the heart and the snapping back of their elastic walls to transport blood. venous blood is pumped by skeletal muscle contractions.
136
what is the blood’s most important buffer
carbon dioxide produced from metabolism. CO2 combines with water to form bicarbonate.
137
primary function of lymphatic system
collect excess interstitial fluid and return it to the circulatory system, maintaining the balance of body fluids. Also absorbs chylomicrons from the small intestine and delivers them to the cardiovascular circulation.
138
how are antibodies produced?
by plasma cells derived from B lymphocytes. antibodies recognize and bind to specific antigens, marking them so they can be recognized by phagocytes. They may also cause antigens to agglutinate to facilitate their removal.
139
what does resting membrane potential depend on?
the polarization of the neutron at rest is the result of an uneven distribution of ions between the inside and outside of cell. This difference happens by active pumping ot ions in and out of the neuron and the selective permeability of the membrane.
140
myelin in the nervous system
white, lipid containing material surrounding axons of many neurons in the central and peripheral nervous systems. produced by glial cells and arranged discontinuously on the axon. gaps between segments of myelin are called nodes of Ranvier. myelin increases conduction velocity by insulation segments of the axon, so membrane only permeable to ions at nodes of Ranvier action potential jumps from node to node
141
saltatory conduction
when the action potential jumps from node to node in a neuron.
142
all or none law of action potential
whenever the threshold membrane potential is reached, an action potential with a consistent size and duration is produced. neuronal information is coded by the frequency and number of action potentials and not their size
143
functions of the cerebellum
helps modulate motor impulses important in maintaining balance, hand-eye coordination, and timing of rapid movements. alcohol affects the cerebellum - person will transiently show signs of cerebellar lesion.
144
how is neuronal information coded?
by the frequency and number of action potentials., not the size of the potential. increasing the intensity of the stimulus will increase the action potential. nervous system distinguishes by the frequency of the action potential.
145
sensory neurons
bring info from the outside to the nervous system. aka afferent neurons. synapse in the dorsal spine.
146
motor neurons
take info from nervous system to effector organs --- aka efferent
147
rods in the retina
detect low intensity illumination; important in night vision. rhodopsin absorbs one wavelength.
148
rhodopsin
rod pigment
149
hyperpolarization in nervous system
when the potential across the axon membrane is more negative than the normal resting potential , the neuron is referred to as hyperpolarized. occurs right after an action potential and is caused by too much potassium exiting the neuron.
150
cochlea
in the ear. includes the organ of Corti, with specialized sensory cells called hair cells. vibration of the ossicles exerts pressure on the fluid in the cochlea and stimulates the hair cells to transduce pressure into action potentials. action potentials travel via the auditory nerve to the brain for processing.
151
smooth muscle
responsible for involuntary action. found in digestive tract, bladder, uterus, blood vessel walls, etc. capable of longer more sustained contractions. can contract without nervous system input
152
skeletal vs. cardiac vs. smooth muscle
skeletal: striated, voluntary, somatic innervation, many nuclei per cell, Ca2+ required for contraction cardiac: striated, involuntary, autonomic innervation, 1-2 nuclei per cell, Ca2+ required for contraction smooth: nonstriated, involuntary, autonomic innervation, one nucleus per cell, Ca2+ required for contraction
153
what 6 products does the stomach secrete?
H+ - kills microbes, denatures proteins, converts pepsinogen to pepsin. pepsinogen - pepsin partially digests proteins. Mucus - protects mucosa. bicarbonate - protects mucosa. water - dissolves and dilutes digested material. intrinsic factor - required for normal absorption of vitamin B12
154
how are nutrients absorbed
absorptive process mostly happens in jejunum and ileum. dimple sugars and amino acids are absorbed by active transport and facilitated diffusion into the epithelial cells lining the gut and move into intestinal capillaries. concentration gradient between capillaries and blood cause nutrients to pass into blood. then they go to the liver. fats also pass through membrane into capillaries. reform into larger fat molecules after they are in the intestinal cells. triglycerides are packed into chylomicrons and enter lymphatic circulation through lacteals. chylomicrons processed directly into low density lipoprotein and processed by liver into good HDL cholesterol
155
vitamin absorption
all are either fat or water soluble vitamins A,D,E, and K are fat soluble they are absorbed with fat water soluble vitamins are absorbed across endothelial cells and go directly into blood plasma.
156
parts of the large intestine
cecum- connects large and small intestine, has appendix attached colon - absorbs water and salts - pulls out last bits of nutrients from food rectum- stores poop
157
what are the valves between the atria and ventricles
LAB RAT left atrium bicuspid right atrium tricuspid
158
parasympathetic and sympathetic nervous systems
parasympathetic - rest and digest. - slow the heart via the vagus nerve sympathetic - fight or flight. - speed up the heart part of the autonomic nervous system. control the heart
159
components of blood
plasma - liquid portion of blood erythrocytes - red blood cells leukocytes- white blood cells platelets - blood clotting
160
B-cells
type of lymphocyte that matures in the spleen or lymph nodes. responsible for antibody generation . exposure to an antigen stimulates the B cells to produce many antibodies
161
T-cells
type of lymphocyte that matures in the thymus. kill virally infected cells and activate other immune cells
162
ABO system genotypes
blood type system - based on 3 alleles for blood type A and B are codominant O is recessive to both genotype for A: IAIA or IAi genotype for B: IBIB or IBi genotype for O: ii
163
universal recipients and donors
AB - universal recipients O - universal donors - have no ABO antigens on the surface
164
ABO blood types
blood type → antigen in RBC → Antibodies Produced A → A → anti-B B → B → anti-A AB → A and B → none O → none → anti-A and anti-B
165
Rh factor
surface protein expressed on red blood cells. Rh+ means individual has the protein on their RBC, Rh- means they don’t. Presence is dominant
166
hemoglobin
composed of 4 subunits interaction of subunits changes binding affinity for oxygen quaternary structure.
167
myoglobin
globular protein responsible for transferring oxygen from hemoglobin to the muscle cells only one subunit lacks quaternary structure.
168
mast cell
releases histamine and other chemicals that promote inflammation
169
granulocyte
three cell types with tiny granules in their interior. neutrophil, eosinophil, and basophil. participate in inflammatory response.
170
dendritic cell
resents antigen - fragments of protein or other molecules from pathogens or cancer cells to adaptive immune cells which induces cells to attach bearers of the displayed antigens.
171
natural killer cell
destroys body’s own cells that have become infected with pathogens. it also goes after cancer cells.
172
anatomy of neuron
cell body - soma. include nucleus, ER, and ribosomes. dendrites - structures to receive info. axon hillock - enlargement at beginning of axon - important in action potential. axon - nerve fiber that carries electrical message. insulated by myelin. nodes of Ranvier - breaks in myelin sheath - help signal conduction. synaptic bouton - transmits to next neuron. synaptic cleft - synapse - space between neurons.
173
action potentials
to relay info to and from central and peripheral nervous systems. cause the release of neurotransmitters into synaptic cleft. resting membrane potential is maintained between inside and outside cell by Na+/K+ ATPase neuron can receive inhibitory or excitatory input to inhibit or cause an action potential voltage gated-ion channels open when action potential is started. Na+ move first and the channels close when the membrane potential reaches +35 mV. then K+ moves down gradient and a negative gradient is created again. the impulse is propagated down the axon with NA+ channels opening and closing in relation to K+ channels signal hops from node to node
174
neurotransmitters and synapses
neurotransmitters are stored at the nerve terminal in vesicles. when an action potential comes, the terminal membrane is depolarized and the neuron will fuse with the presynaptic terminal and release the neurotransmitter into the synaptic cleft. the molecules diffuse across the cleft and bind to receptors on the postsynaptic membrane. this passes a message from one neuron to the next
175
afferent neurons
sensory neurons. carry info from the periphery to the brain or spinal cord
176
efferent neurons
motor neurons. work in opposite direction of afferent. carry info from brain to periphery.
177
nerves
bundles of axons. can be sensory, motor, or mixed.
178
white and gray matter in brain
white - unmyelinated axons. gray- unmyelinated cell bodies and dendrites.
179
forebrain
telencephalon- two hemispheres, each has frontal, parietal, occipital, and temporal lobes. diencephalon - inside telencephalon
180
cerebral cortex
in forebrain. responsible for highest level functioning including creative thought and future planning. integrates sensory movement info and controls movement
181
diencephalon
contains thalamus and hypothalamus. all ascending sensory info is passed through the thalamus before being relayed to cortex
182
midbrain
relay point between peripheral structures and forebrain.
183
hindbrain
responsible for many involuntary functions (ex. respiration). made up of cerebellum, pons, and medulla oblongata (together = brain stem) makes sure motor signal matches sensory info from body.
184
somatic nervous system
responsible for voluntary movement. provides us with reflexes. do not require input or integration from brain to function
185
monosynaptic reflex
ex. knee-jerk reflex. helps protect patellar tendon. single synapse between sensory neuron that received info and motor neuron that responds.
186
polysynaptic
at least one interneuron between sensory and motor neuron. ex. withdrawal reflex.
187
autonomic nervous system
“automatic” requires no conscious control. 1st neuron - preganglionic neuron, 2nd - postganglionic neuron.
188
photoreceptors in the eye
rods - responsible for transmission of black and white images - respond to low intensity light cones - manage color images. 3 types of cones, one absorbs red, green, or blue.
