Final Flashcards
1
Q
Electron
A
atomic particle with a negative charge
2
Q
free radical
A
particle with an unnatural number of electrons
3
Q
dimer
A
molecule composed of two monomers
4
Q
rough er
A
synthesizes lipids
5
Q
covalent bond
A
sharing of electrons between atoms
6
Q
(CH2O)n
A
molecular formula of a carbohydrate
7
Q
Cilia
A
moves material over surface of a cell
8
Q
Mitochondrion
A
ATP-producing organelle
9
Q
catalyst
A
speeds up chemical reactions
10
Q
amino acid
A
has a carbocyl, amino, and r-group
11
Q
solute
A
particles disolved in solvent
12
Q
ribosome
A
binds to RNA and synthesizes proteins
13
Q
isotonic
A
equal osmotic pressure on both sides
14
Q
matrix
A
material between cells in a tissue
15
Q
lysosome
A
vesicle containing digestive enzymes
16
Q
How many electrons are found in only the second shell of an atom? a. one b. two c. eight d. eighteen
A
c. eight
17
Q
What tissue type has superficial cells connected to a basement membrane? a. epithelial b. connective c. muscle d. nervous
A
a. epithelial
18
Q
Which organelle is responsible for the synthesis of ATP molecules? a. mitochondria b. golgi apparatus c. smooth er d. rough er
A
a. mitochondria
19
Q
Which atomic bond involves the transfer of electrons from one atom to another? a. ionic bond b. covalent bond c. hydrogen bond d. James Bond
A
a. ionic bond
20
Q
Which molecule is organic? a. H2O b. CO2 c. NH3 d. CH4
A
d. CH4
21
Q
Which type of tissue has the ability to contract? a. epithelium b. connective c. muscle d. nervous
A
c. muscle
22
Q
Which concept is part of cell theory? a. all cells came from pre-existing cells b. cells were derived from non-living molecules billions of years ago c. all cells possess a nucleus with genetic material d. all cells perform photosynthesis
A
a. all cells came from pre-existing cells
23
Q
What is the function of cholesterol in the body? a. energy source b. main component of steroid hormones c. membrane transport d. thermal insulation
A
b. main component of steroid hormones
24
Q
Which cell transport method does not need ATP? a. active transport b. exocytosis c. receptor mediated endocytosis d. osmosis
A
d. osmosis
25
WHich of the following substances is a charbohydrate? a. sucrose b. maltase c. keratin d. cholesterol
a. sucrose
26
Which molecule is made of a large lipid and a small protein? a. Lipoglycan. b. Proteolipid. c. Lipoprotein. d. Glycolipid.
b. proteolipid
27
Which of these organelles has a double phospholipid bilayer? a. Rough ER. b. Nucleus. c. Golgi apparatus. d. Flagella.
b. nucleus
28
Which organelle is responsible for the synthesis of cellular carbohydrates? a. Endoplasmic reticulum. b. Ribosomes. c. Golgi Apparatus. d. Lysosomes.
c. golgi apparatus
29
Which property of water allows humans to lose large quantities of heat through the evaporation of sweat? a. Solvency. b. Thermal stability. c. Chemical reactivity. d. Adhesion.
b. thermal stability
30
What is the name of the organelle that organizes the shape of the cytoskeleton? a. Cristae. b. Cisternae. c. Centrioles. d. Cytoskeleton.
c. centrioles
31
True or False: Stratified squamous epithelial tissue is often used for secretion
false
32
True or False: Substances that dissolve in water are hydrophobic
false
33
True or False: A cell that grows to twice its former volume has twice its former surface area
false
34
True or False: A mole is a number equal to 5.02x 10^23
false
35
True or False: Cytosol is the gelatinous fluid component of cytoplasm
true
36
True or false: Proteins are responsible for cellular movement
true
37
True or False: RNA molecules are smaller than DNA molecules
true
38
True or false: for a triglyceride to be saturated, all three fatty acids in it have to be saturated
true
39
True or false: in osmosis, solute particles move from lw to high concentrations
false
40
true or false: particles in a colloidal mixture are less than 1 nm in size
false
41
Carbon has an atomic number of 6, oxygen has number 8, and hydrogen has number 1. Calculate the weight of one mole of the triglyceride C55 H101 O6.
857 grams
42
What are the three types of subatomic particles and what charges do they have
proton- positive
neutron- no charge
electron - negative
43
Draw an atom with atomic number 12 and atomic weigt 24. Fill in the electron shells and label the number of protons and neutrons. (2n^2)
12 protons
| 12 neutrons
44
What is the matrix of a tissue and what is it composed of?
a
45
What is the fluid mosaic theory of cell membranes?
a
46
Name and describe the three shapes of cells found in epithelial tissue.
simple- flat cells with a nucleus. can be found in simple or stratified. found mostly in skin cells.
cuboidal - usually found in cubed shapes but always have equal height, width, and depth. found in the kidneys
columnar- cells that are taller than they are wide with a nucleus
47
Define the conformation of a protein and denaturation of a protein
a
48
What is the name of the structure that anchors cilia and flagella to a cell?
basal body
49
What are the 3 most common elements in the body?
carbon, hydrogen, oxygen
50
What are the three types of cartilage and how tough or elastic are they?
elastic- elastic
hyaline- mid-grade
fibro- tough
51
What is the difference between intergral and peripheral proteins?
a
52
Define hydrophilic, hydrophobic, and amphiphilic
hydrophilic- binds to water
hydrophobic- does not bind to water
amphiphilic- both hydrophilic and hydrophobic
53
What are the 3 protein filaments that make up the cytoskeleton and which is the thickest?
intermediate filaments
microfilaments
microtubules- are the thickest
54
What do the prefixes mono-, poly-, and oligo- mean?
mono- one
poly- many
oligo- fewer than 15
55
Why are saturated fats solid and unsaturated fats liquid at room temperature?
a
56
Explain why a large surface are-to-volume ratio is good for a cell and how that limits cell size. (3)
a
57
How many amino acid types are found in human proteins and how many amino acids in a chain make up a protein (3)
There are 20 amino acid types found in human proteins. There needs to be 50 or more amino acids in a chain to make up a protein
58
What are the differences between symports, antiports, and uniports? (3)
a
59
What is a hydration sphere and how is it formed? (3)
A hydration shere is when water binds to a compound breaking it appart. The hydrogen in water is attracted to the negative element in the compound and the oxygen is attracted to the positive element in the compound.
60
What is the difference between synthesis, decomposition, and exchange reactions? (3)
In synthesis, two reations combine to form a new product. A+B --> AB.
In decomposition, a reactant breaks down into two or more products. AB --> A+B
In exchange reations, two or more elements are "exchanged" to form two new compounds. AB+CD --> AD+BC
61
Describe the cell actions during pinocytosis, phagocytosis, and excocytosis. (5 points)
a
62
List the 6 physical properties of water. (5 points)
```
solvency
cohesion
adhesion
temperature stability
chemical reactivity
polarity
```
63
Explain the differences in shape and function of microvilli, cilia, and flagella. (5 points)
a
64
List the 7 functions of proteins in the body (5 points)
a
65
Compare and contrast diffusion and osmosis, describe how particles flow in each, why they move the way they do, and under what conditions they both reach equalibrium (10 points)
a
66
Describe the 4 levels of protein structure including what bonds are formed in each and why it makes those bonds (10 points)
a
67
hematoma
j. a blood clot
68
stratum corneum
s. epidermal layer of dead keratinized cells
69
endosteum
l. lines the medullary cavity of long bones
70
tendon
w. connects muscle to bone
71
excrine
q. gland that secretes through a duct
72
hair shaft
i. portion of the hair outside the epidermis
73
haversian canal
b. carries blood vessels and nerves through compact bone
74
hyperplasia
a. tissue growth through cell multiplication
75
hypodermis
o. mostly composed of adipose tissue
76
synarthrosis
c. a non-movable joint
77
gomphosis
f. tooth socket joint
78
multiaxial
m. allows movement in 3 planes
79
solubility product
y. necessary for calcium deposition
80
bursae
z. contains synovial fluid and cushions outside of joints
81
fibrosis
d. replacement of damaged cells with FCT
82
1. Which bone shape do the vertebrae have? a. Flat. b. Short. c. Long. d. Irregular.
d. irregular
83
2. Which layer of the epidermis is only found in thick skin? a. Stratum corneum. b. Stratum lucidum. c. Stratum granulosum. d. Stratum basale.
b. stratum lucidum
84
3. What are fibers of collagen that extend into bone matrix from the periosteum called? a. Perforating fibers. b. Chondroblasts. c. Osteoid tissue. d. Trabeculae.
b. chondroblasts
85
4. What type of tissue change involves sudden death due to loss of blood supply? a. Apoptosis. b. Atrophy. c. Hypertrophy. d. Infarction.
d. infarction
86
5. What type of movement can be performed with a ball-and-socket joint? a. Inversion. b. Pronation. c. Circumduction. d. Retraction.
c. Circumduction
87
6. Which cell does NOT come from an osteogenic cell? a. Osetoblasts. b. Osteoclasts. c. Fibroblasts. d. Chondroblasts.
b. Osteoclasts
88
7. Which is NOT a pigment found in the integument? a. Hemoglobin. b. Carotene. c. Melanin. d. Myoglobin.
d. myoglobin
89
8. In bone tissue, what is the name of the chambers the osteocytes sit in? a. Haversian canal. b. Lacunae. c. Canaliculi. d. Osteon.
b. lacunae
90
9. Which is an example of a cartilaginous joint?
| a. Skull sutures b. Hip socket and femur. c. Between vertebral bodies. d. Finger joints.
c. between vertebral bodies
91
10. Where will you find the Zone of Hypertrophy?
| a. In the epiphysis. b. In the metaphysis. c. In the diaphysis. d. In California.
b. in the metaphysis
92
11. Which of the following is not one of the formed elements of blood? a. Adipocytes. b. Erythrocytes. c. Leukocytes. d. Platelets.
a. adipocytes
93
12. Which gland type produces earwax? a. Ceruminous. b. Sudoriferous. c. Endocrine. d. Sebacious.
a. ceruminous
94
13. Which hormone reduces blood calcium by stimulating osteoblasts? a. Parathyroid hormone. b. Calcitonin. c. Calcitriol. d. Oxytocin.
b. calcitonin
95
14. Which is NOT a feature of a synovial joint?
| a. Synarthrosis. b. Meniscus. c. Joint capsule. d. Synovial fluid.
a. synarthrosis
96
15. What is the smooth muscle bundle that causes hairs to stand on end? a. Follicle. b. Arrector pili. c. Cuticle. d. Cerumen.
b. arrector pili
97
1. TRUE/FALSE Skin and bones are constantly growing new tissue.
true
98
2. TRUE/FALSE The periosteum of a bone and the tendon of a muscle are made of the same tissue.
true
99
3. TRUE/FALSE In thin skin there are no sweat glands.
false
100
4. TRUE/FALSE Eumelanin produces red/blond colored hair.
false
101
5. TRUE/FALSE Third class levers have a high mechanical advantage.
false
102
6. TRUE/FALSE Inversion and eversion are motions of the hands.
false
103
7. TRUE/FALSE All synovial joints are diarthroses.
false
104
8. TRUE/FALSE Lanugo hair is found on fetuses.
true
105
9. TRUE/FALSE Yellow marrow is found only in the epiphyses of bones.
false
106
10. TRUE/FALSE All diarthroses are synovial joints.
true
107
1. Put the following in chronological order: osteoblast, spongy bone, osteogenic cell, osteoid tissue, compact bone. (3 points)
osteogenic cells, osteoblast, osteoid tissue, spongy bone, compact bone
108
2. Draw a hair in lateral view and in cross-section and label the following parts: shaft, root, and bulb on the first; medulla, cortex, and cuticle on the second. (3 points)
see test
109
3. Define abduction, adduction, flexion, and extension. (3 points)
abduction- movement of a body part in the frontal plane away from the middle of the body
adduction- movement in the frontal plane back to midline
flexion- a movement that decreases a joint angle
extension- straightens a joint and generally returns a body part to the zero position
110
4. Name the 3 stages of hair growth and what occurs in each stage. (3 points)
conagen - stem cells form the bulge in follicle and multiply and travel downwards
catagen - mitosis in the hair matrix ceases and sheath cells below the bulge die
telogen - when the papillae reaches the bulge
111
5. Name the 4 cutaneous glands and what they secrete. (3 points)
mammory- milk
ceruminous - ear wax
sudoriferous - sweat
sebacious - oil
112
6. In what organs are calcitriol, calcitonin, and parathyroid hormone made? (3 points)
m
113
7. Name the three cell types found in the stratum basale of the epidermis and what their functions are. (3 points)
m
114
8. What are the three types of cartilage and the three types of muscle tissue? (3 points)
cartilage - hyaline, fibro, elastic
| muscle - smooth, skeletal, cardiac
115
9. What are the organic and inorganic components of bone matrix? (3 points)
m
116
10. What is the difference between amphiarthroses, diarthroses, and synarthroses? (3 points)
synarthroses - little to no movement
amphiarthrosis - some movement
diarthrosis - much movement occurs
117
11. Describe or draw and label the 3 lever types. (3 points)
lever 1 - has fulcrum in the middle between effort and resistance
lever 2 - has resistence between fulcrum and effort
lever 3 - effort is between resistance and fulcrum
118
12. What is the difference between serous, mucous, and cytogenic glands? (3 points)
serous- watery, low-protein fluid
| mucous- composed of epithelium, CT and often smooth muscle
119
13. What is the difference between appositional and interstitial growth? (3 points)
appositional - bones continue to grow throughout life in diameter and thickness
interstitial - growth of cartilage from within the metaphyses
120
14. Name the pairs of bones that form a condyloid joint, a hinge joint and a pivot joint. (3 points)
condyloid- ankles and wrists
hinge joint - ulna/ hummerus and tibia/femer
pivot joints - ball and socket
121
15. Define pronation, supination, opposition, and reposition. (3 points)
pronation- a rotational movement of the forearm that turns the palm downwards or upward
supination- rotational movement of the forearm
opposition- a movement of the thumb in which it touches any finger tip of the same hand
reposition- returning to the zero position
122
16. What do the prefixes chondro-, osteo- and fibro- refer to? (3 points)
chondro - cartilage
osteo - bone
fibro - fibers
123
17. What is the difference between endocrine, exocrine, holocrine and merocrine glands? (3 points)
endocrine- glands secrete into the blood
exocrine- glands secrete into a duct leading to an organ surface
halocrine- cell death
merocrine- perspiration
124
18. Draw and label the following parts of an osteon: Haversian canal, lamellae, osteocytes, canaliculi. (3 points)
see test
125
19. Where are the primary and secondary ossification centers found? (3 points)
a
126
20. Define atrophy, apoptosis, and necrosis. (3 points)
atrophy- shrinkage of tissue due to age, disuse, or disease
apoptosis- programmed cell death
necrosis- premature cell death
127
1. (5 pts.) List the 6 functions of the skeletal system.
1. support
2. protection (from)
3. movement
4. electrolyte balance
5. acid base balance
6. blood formation
128
2. (5 pts) List the 6 functions of the integumentary system.
1. protection
2. body temperature regulation
3. excretion
4. blood reservoir
5. metabolic functions
6. cutaneous functions
129
3. (5 pts.) List in order of depth all the strata and layers of tissue in the epidermis and dermis.
1. stratum corneum
2. stratum lucidum
3. stratum granulosum
4. stratum spinosum
5. stratum basale
6. papillary layer
7. reticular layer
130
4. (5 pts.) List the 3 types of fibrous joints, the two types of cartilaginous joints, and the 6 types of synovial joints.
k
131
5. (10 pts.) Name all the zones of the metaphysis and describe in detail what is happening in each of the zones, until osteons are formed.
1. Reserve Cartilage - hyaline has not yet begun to transform into bone.
2. Cell Perilification - chondrocytes multiply and arrange themselves into longitudinal columns of flattened lacunae
3. Cell Hypertrophy - the chondrocytes cease diving and enlarge
4. Calcification - Ca^2+ minerals are deposited in the matrix and calcify the cartilage
5. Zone deposition - walls between lacunae break down and chondrocytes die; osteoblasts line up along the walls of the channels and begin depositing concentric lamallae
132
6. (10 pts.) Describe in detail how a fractured bone is repaired. Include the types of tissue formed, where they are formed, what cells formed them, and in what order.
(not as important)
- clot
- invaded by osteogenic cells
- then cartilage
- hard cartilage?
osteoclast - remove excess one also are done top sheath
133
1. action potential
z. voltage change on the axon
134
2. fusiform
q. spindle-like muscle shape
135
3. trigger zone
n. dominated by voltage gated ion channels
136
4. Actin
c. thin filament in a sarcomere
137
5. lactic acid
j. byproduct of anaerobic fermentation
138
6. IPSP
r. makes a neuron less likely to fire
139
7. endoneurium
e. sheath surrounding each axon in PNS
140
8. motor unit
u. motor neuron and its muscle fibers
141
9. Reverberating
l. neuronal circuit that stimulates itself
142
10. tetanus
w. smooth prolonged contraction of muscle
143
11. synapse
s. junction of a neuron and a target cell
144
12. Treppe
b. muscle cells go to full relaxation but next twitch has higher tension
145
13. Isometric
a. change in tension but no change in length
146
14. ganglion
t. cluster of neuron cell bodies outside the CNS
147
15. Calcium
g. ion pumped outside of smooth muscle
148
1. Which of the following is a function of the muscular system? a. Integration. b. Heat production. c. Conduction. d. Electrolyte balance.
b. heat production
149
1. Which of the following is a function of the muscular system? a. Integration. b. Heat production. c. Conduction. d. Electrolyte balance.
b. heat production
150
2. Which muscle action opposes the prime mover? a. Fixator. b. Synergist. c. Agonist. d. Antagonist.
d. antagonist
151
3. Which neurotransmitter type is made of modified amino acids? a. Neuropeptides. b. Acetylcholine. c. Monoamines. d. Amino acid neurotransmitters.
c. monoamines
152
4. Which of the following is a cuff of connective tissue that holds tendons in place? a. Aponeurosis. b. Retinaculum. c. Insertion. d. Origin.
b. retinaculum
153
5. What type of conduction is permitted by myelinated neurons?
a. Anterograde. b. Saltatory. c. Retrograde. d. Metabotropic.
b. saltatory
154
6. Which type of conduction brings impulses from the body to the CNS? a. Sensory. b. Retrograde. c. Anterograde. d. Motor.
a. sensory
155
7. Which type of neuroglial cell creates a supportive framework in the CNS? a. Oligodendrocytes. b. Astrocytes. c. Microglia. d. Satellite cells.
b. astrocytes
156
8. Which of the following is NOT one of the meninges? a. Fara mater. b. Arachnoid mater. c. Pia mater. d. Dura mater.
a. fara mater
157
9. What is a full cycle of contraction and relaxation of a muscle? a. Tetanus. b. Recruitment. c. Muscle twitch. d. Vacation.
c. muscle twitch
158
10. What type of neuron has only one dendrite and one axon attached to the soma? a. Anaxonic. b. Bipolar. c. Multipolar. d. Unipolar.
b. bipolar
159
11. Which characteristic is common to both nervous tissue and muscular tissue? a. Contractility. b. Elasticity. c. Excitability. d. Extensibility.
c. excitability
160
12. Which method of ATP production does not use oxygen but does use glucose? a. Phosphagen system. b. Anaerobic fermentation. c. Excitation-contraction coupling. d. Aerobic respiration.
b. anaerobic fermentation
161
13. What is the name of the contractile unit of a muscle cell?a. Sarcolemma. b. Sarcoplasm. c. Sarcomere. d. Sarcophagus.
c. sarcomere
162
14. Which part of the muscle cell contains ligand-gated ion channels? a. T-tubule. b. Terminal cisternae. c. Motor end plate. d. Synaptic knob.
c. motor end plate
163
15. Which muscle shape has the weakest of contraction strength? a. Fusiform. b. Circular. c. Parallel. d. Convergent.
b. circular
164
1. TRUE/FALSE Qualitative encoding is based on how many neurons fire and how often they fire.
false
165
2. TRUE/FALSE Ependymal cells filter blood to make cerebrospinal fluid.
true
166
3. TRUE/FALSE Sodium is kept at a high concentration inside neuron membranes.
false
167
4. TRUE/FALSE The time during which a cell cannot be stimulated again is the latent period.
false
168
5. TRUE/FALSE Interneurons communicate between sensory and motor neurons.
true
169
6. TRUE/FALSE Myosin heads bind to actin active sites when exposed.
true
170
7. TRUE/FALSE Superficial fascia lies between muscle surface and skin.
true
171
8. TRUE/FALSE Myofibrils are made up of many sarcomeres.
true
172
9. TRUE/FALSE Actin filaments are connected to dense bodies in smooth muscle.
true
173
10. TRUE/FALSE Sodium gates are slow to open compared to potassium gates
false
174
1. What are all the benefits and disadvantages to aerobic respiration and anaerobic fermentation?
aerobic- produces more ATP and less toxic end products, but requires a continual supply of oxygen
anaerobic- allows the cell to produce ATP in the absence of oxygen, but produces lactic acid, a toxic end product which is a major factor in muscle fatigue
175
2. What are the three characteristics of nervous tissue AND the five characteristics of muscle tissue?
nervous- sensation, communication, integration
| muscle- excitability, contractility, extensibility, conductivity
176
3. Name three of the six neuroglial cell types, and give one function of each.
microglia- clean up cellular debris via phagocytosis
oligodendrocytes- myelinates axons of the neurons in the CNS
schwann cells- myelinates axons of the neurons in the PNS
177
4. What is the difference between a neuron, a nerve and a ganglion?
neuron- a nerve cell
nerve- a card like organ of the peripheral nervous system composed of multiple nerve fibers
ganglion- a cluster of cell bodies in the PNS
178
5. List three ways to increase the strength of a muscle twitch and/or prevent twitch weakness.
1. increase temperature
2. varies cell concentration of Ca ^2+
3. weaker when pH is too low
179
6. Explain how smooth muscle cells are stimulated in a single-unit format.
a
180
7. What is the difference between the CNS and the PNS and what do those acronyms stand for?
CNS- central nervous system, has to do with the brain and spinal cord and their functions
PNS- peripheral nervous system, has to do with all other functions of the body excluding the brain and spinal cord
181
8. What cells create the myelin sheath in the CNS and PNS and what are the two functions of the sheath?
a
182
9. What is the difference in location between endomysium, perimysium and epimysium?
endomysium- surrounds each muscle fiber
perimysium- wraps muscle fibers together in bundles
epimysium- surrounds the muscle
183
10. What are the three ways to remove neurotransmitters from a synaptic cleft?
diffusion, reuptake, degradation
184
11. What is the difference between the somatic and visceral divisions of the PNS?
somatic- pertaining to cells other than germ cells
| visceral- pertaining to the viscera
185
12. What is the function of the troponin/tropomyosin complex?
a
186
13. Draw a multipolar neuron and label the dendrite, soma, axon, terminal arborization, and synaptic knobs.
see laur's test
187
14. Explain the action of an IPSP. (Not just what it is, but how one is formed.)
a
188
15. Name three things that return a muscle cell to its resting size during relaxation.
a
189
16. List the physical differences between a smooth muscle cell and a skeletal muscle cell.
smooth- tapered cells with single nucleus
| skeletal- elongated cells with multiple nuclei
190
17. Explain why the brain is perfused with CSF and not blood.
blood is toxic to the brain
191
18. What is the difference between qualitative and quantitative neural coding?
a
192
19. What is the difference between temporal summation and spatial summation?
a
193
20. Draw a simple sarcomere and label the actin, myosin, z-disc, titin, A-band, and I-band.
see lauren's test
194
1. (5 pts.) Describe the process of regeneration of a severed axon in the PNS.
When a nerve fiber is cut, the part distal to the cut cannot survive. Schwann cells degenerate. Macrophages clean it up. Soma swells. Nissl bodies dispense. Nucleus moves off center. Growth processes grow from axon. Regeneration tube created by Schwann cells. One axon growth process finds tube and grows rapidly. Regeneration tube guides back to target cell. Soma shrinks.
195
2. (5 pts) List the differences in form and function of local and action potentials.
local- dendrite/soma, decremental, graded, reversible, ligand gates
action- axon, all or none, nondecremental, not graded, irreversible, voltage gates
196
3. (5 pts.) List the differences in anatomy and function between slow and fast twitch fibers.
slow- red, aerobic, type I, more mitochondria, more capillaries, more myoglobin, high stamina, low fatigue
fast- white, type II, less mitochondria, less capillaries, less myoglobin, low stamina, high fatigue
197
4. (5 pts.) List the physiological causes of fatigue in muscle cells.
1. Accumulation of K+ in ECF
2. ADP/pi accumulation
3. Lactic acid lowers pH
4. Fuel depletion
5. Electrolyte loss
6. CNS fatigues
198
5. (10 pts.) Describe in detail ONE of the following processes: excitation, excitation-contraction coupling, contraction, relaxation.
Contraction is the step in which the muscle fiber develops tension and may shorten. Myosin ATPase enzyme in myosin head hydrolyzes on ATP molecule. It activates the head "cocking" it in an extended position. ADP + Pi remain attached. Head binds to actin active site forming a myosin-actin cross bridge. Then the myosin head releases ATP and Pi, flexes pulling thin filaments past thick. This is called the power stroke. Upon binding more ATP, myosin releases actin and process is repeated.
199
6. (10 pts.) Describe the transmission of an action potential down an axon in detail, starting from the trigger zone. Describe the motion of sodium and potassium and the change in membrane voltage during the action potential, plus its effects on the next section of the axolemma.
Na+ arrives at the axon hillock and depolarizes membrane as a local potential. Threshold must be reached -55 mV to open voltage gates. Action potential is reached Na+ gates open quickly K+ gates open slower. As it goes past 0 mV, Na+ gates start to shut when they are closed. Voltage is about 35 mV, K+ gates are fully open at this time. K+ leaves and repolarizes membrane more K+ leaves then Na+ enter. mV drops to 1 or 2 mV more negative than RMP therefore hyperpolarizing membrane.
