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BIO 225 > Exam 3 > Flashcards

Exam 3 Flashcards

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1
Q

specialized cytoplasm of muscle cell/fiber

A

Sarcoplasm

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2
Q

Surround each myofibril and transmits APs deep in the muscle fibers

A

t-tubules

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3
Q

Storage site of Ca2+

A

Sarcoplasmic reticulum

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4
Q

Located at ends of sarcoplasmic reticulum, calcium storage sites, where Ca2+ is released from

A

terminal cisternae

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5
Q

Unit of muscle contraction

A

Sarcomeres

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6
Q

Depolarization of the plasma membrane opens DHPR, while Ca2+ enters the cell, changes in DHPR structure triggers opening of RYR

A

Excitation of AP in skeletal muscle fiber

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7
Q

RYR opening allows Ca2+ to escape sarcoplasmic reticulum. Elevated Ca2+ concentration triggers actino-myosin ATPase

A

Calcium release of AP in a skeletal muscle fiber

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8
Q

After repolarization, ion pumps begin returning Ca2+ to resting locations, outside the cell and in the sr

A

Relaxation of AP in a skeletal muscle fiber

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9
Q

Actin filaments anchored here

A

Z-line

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10
Q

Actin filaments and Z-line

A

I-band

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11
Q

Area of myosin not overlapping

A

H-zone

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12
Q

Myosin filaments composed of actin and myosin

A

A-band

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13
Q

Middle of myosin filament

A

M-line

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14
Q

Sarcomere shortens

A

Z-lines move closer together, I band decreases in length, H-zone dissapears

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15
Q

Myofibrils

A

composed of actin and myosin

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16
Q

Muscle belly shortens

A

actin + myosin filaments slide past each other without changing length

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17
Q

How does actin and myosin contribute to cellular movements

A

Cytoskeleton contains a branched network of actin microfilaments, controlled polymerization of actin can cause cell movement

Myosin motors catalyze ATP hydrolysis

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18
Q

Cross Bridge Cycle

A
  1. ATP binds causing myosin to detach from actin
  2. Detachment of myosin causes ATP to hydrolyzed to ADP and Pi which still remain bound by myosin
  3. Hydrolysis causes myosin to attach to actin
  4. Release of phosphate from actin-myosin complex promotes power stroke
  5. ADP is released
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19
Q

Troponin composition

A

TnI, TnC, and TnT

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20
Q

Regulation of muscle contraction by troponin and tropomyosin

A

TnC binds to calcium, one calcium is bound to TnCm there is conformational change that pulls on TnI that pulls on TnT that pulls on tropomyosin

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21
Q

Excitation of skeletal muscle coupled to contraction

A
  1. Release of Ca2+ from SR exposes binding sites on thin filament
  2. Allows muscle contraction cycle to occur
  3. Cross-bridge actin to myosin
  4. Cross-bridge pulls actin filaments (power stroke) ADP and P released
  5. New ATP binds to myosin causing linkage to release
  6. ATP splits which provides power to cock myosin cross-bridge
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22
Q

what types of muscles are striated

A

cardiac and skeletal

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23
Q

structure and function of circulatory systems

A
  • one or more pumps/structures that apply force to drive fluid flow
  • system of tubes through which fluid can flow
  • a fluid that circulates through the system
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24
Q

function of arteries

A

carry oxygenated blood from heart to body

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25
function of arterioles
some diffusion, control blood pressure
26
function of capillaries
site of gas exchange
27
where are continuous capillaries located
brain, muscle, and skin
28
where are fenestrated capillaries located
endocrine organs, kidney, intestines
29
where are sinusoidal capillaries lcoation
liver and bone marrow
30
function of venules
connect capillaries to veins
31
function of veins
carry deoxygenated blood to heart
32
what is the law of bulk flow
fluids flow down pressure gradients from high to low, resistance opposes this movement
33
What is the relationship of blood velocity to pressure and cross-sectional area
Velocity of fluid flow is inversely proportional to cross-sectional area and directly proportional to pressure
34
What happens in systole
ventricles relax, positive pressure, blood flows out, atria relax
34
What happens in diastole
Ventricles relax, negative pressure, blood flows in, and atria contract
35
In diastole what valves open
Mitral and tricuspid
36
In systole what valves open
pulmonary and aortic
37
What is the role of heart valves in the cardiac cycle
To prevent backflow of blood
38
What is the conduction pathway of electrical signals in the heart
The SA node ionic conductances create a self sustaining pacemaker, the depolarization of the pacemaker spreads to the neighboring cardiomyocytes causing APs and contractions
39
Pathway of electrical current in heart
1. SA node depolarizes and depolarization spreads rapidly via internodal pathway 2. AV node delays the signal and the depolarization spreads through atria via gap junctions and causes atria to contract (diastole) 3. Depolarization spreads rapidly through bundles of His and Purkinje fibers 4. Depolarization spreads upward through ventricle causing ventricle to contract (systole_
40
P wave
Depolarization of atria (SA node)
41
QRS complex
depolarization of the ventricles and repolarization of atria (systole)
42
T wave
repolarization of ventricles
43
Relationship of cardiac output to heart rate and stroke volume
Cardiac output = heart rate x stroke volume
44
How does the parasympathetic branch control cardiac output
Slows SA node via muscarinic acetylcholine receptors (hyperpolarizes)
45
How does the sympathetic branch control cardiac output
accelerates SA node pacemaker via B-adrenergic receptors
46
Mean Arterial Pressure
average blood pressure in arteries across the cardiac cycle
47
What is vasoconstriction the result of
Contraction of the smooth muscle of the tunia media
48
Pathway of blood through heart
Superior vena cava -> RA -> RV -> Pulmonary circuit -> LA -> LV -> Aorta
49
Cellular respiration
Conversion of glucose into ATP in the mitochondria
50
External respiration
The sequence of events that result in gas exchange between the external environment and mitochondria
51
dQ/dt
rate of diffusion through a tissue sheet
52
D
diffusion coefficient (area/second)
53
A
area over which diffusion is taking place
54
dC/dx
concentration gradient/distance
55
Bulk flow
air or water can deliver O2 directly to internal cells and tissues
56
Surface area: volume ratio
A higher SA : V is better for diffusion because a larger area is available for exchange relative to organism's ned
57
Boyle's Law
P1V1=P2V2, when volume of a gas-filled space increases, the pressure within it decreases
58
How does the diaphragm work in terms of Boyle's Law
In inhalation the diaphragm contracts which increases the volume of the thoracic cavity which decreases pressure and causes air to move into the lungs, conversely, in exhalation the diaphragm relaxes which decreases the volume of the thoracic cavity and increases pressure and causes air to move to the atmosphere
59
Henry's law
In order to diffuse into a cell, gas molecules must first dissolve in a liquid
60
Tidal bulk flow
What humans do, pick up oxygen in lungs and oxygen diffuses across membrane
61
Unidirectional bulk flow
makes greater energy exchange possible
62
Concurrent flow
Flow of medium in same direction as blood flow (air or water), only exists in temperature
63
Counter current flow
Fish do this, water comes in and their blood flows in opposite directions to draw O2 out of the water
64
Crosscurrent flow
birds do this (most efficient), blood comes in lungs through one tube and vessels cross medium multiple times to get more oxygen than the air they are breathing
65
How do fish gills work
Fish breathe water into their buccal cavity, opercular cavity expands and water gets pushed out
66
How do bird lungs work
Birds breathe in and out of one cavity in a double loop
67
Alveoli
attached to the respiratory bronchiole, alveolar sacs increase SA, highly vascularized by capillaries
68
Type I alveolus
squamous cells where exchange occurs (diffuses gas)
69
Type II alveolus
Respond to damage of type I cells, synthesize and release surfectant that aids in diffusion
70
Hemoglobin
Metalloprotein, 2 alpha units, 2 beta subunits, 4 heme groups, 4 iron atoms
71
Heme molecule
contains iron where oxygen binds, synthesized in mitochondria of bone marrow and liver
72
O2 equilibrium curve for hemoglobin
H increases and increases until it levels off
73
What does a lower P50 indicate
lower affinity
74
How does pH effect oxygen affinity
if pH decreases, pO2 increases, hemoglobin saturation increases
75

BIO 225 (5 decks)

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