Muscle Physiology Flashcards
1
Q
Bicarbonate buffer system equation
A
H+ + HCO3- <-> H2CO3 <-> CO2+H2O
2
Q
4 tissue types in the body
A
muscle, connective, epithelial, nervous
3
Q
What is histology
A
the study of tissues
4
Q
What is the largest tissue by mass in the body
A
muscle tissue
5
Q
What tissue do we really have the most of though, not by mass
A
connective tissue
6
Q
What are the 3 types of muscle tissues
A
Sleletal: Voluntary control
Cardiac: Involuntary control
Smooth: Involuntary control
7
Q
What is a fasicle synonymous with
A
muscle cell
8
Q
What does the epimysium cover
A
the muscle itself
8
Q
What does the perimysium cover
A
individual fasicles
9
Q
What does endomysium cover
A
Individual muscle fiber, covers SR and nerve
10
Q
Thick filament vs thin filament
A
Thick: Myosin
Thin: F-actin (tropomyosin and troponin on them)
11
Q
Function of myosin2
A
has heads, ATP ase creates power stroke
12
Q
Function of actin
A
Myosin binding site, actually what does the sliding
13
Q
Tropomyosin function
A
Blocks myosin binding site with troponin I
14
Q
Troponin I Function
A
blocks myosin binding site
15
Q
Troponin T Function
A
Connect troponin to tropomyosin
16
Q
Troponin C Function
A
Calcium binding site
17
Q
Actinin function
A
binds actin to Z-lines
18
Q
Titin function
A
Connects z lines to M lines
19
Q
Desmin function
A
Binds Z lines to plasma membrane
20
Q
Dystrophin function
A
Binds actin to dystroglycan complex
21
Q
What is the largest protein in the body
A
titin
22
Q
What is duchenne muscular dystrophy
A
Dystrophin protein is absent (anchors sarcomere to plasma membrane)
(tear cell membrane when muscles contract)
Death before age 30 usually
23
Q
Becker muscular dystrophy
A
Dystrophin is malformed. Sarcomere not anchored well to plasma membrane
(tear cell membrane when muscles contract)
24
Describe the activation at the NMJ
1. Motor neuron sends an action potential to soma
2. causes snare proteins to release Ca, which causes acetylcholene release into the synaptic cleft. AcH binds to muscle cell receptors causing Na and K release.
3. Na enters the muscle plasma membrane, depolarizing cell and creating graded potentials.
4. Muscle cell reaches threshold, action potential travels to T-tubules and activates sarcoplasmic reticulum which is the release of Ca into sarcomeres
5. Ca binds to troponin C, changing shape of complex
6. Moves tropomyosin, exposing myosin binding sites on actin
25
Cross bridge cycling steps
1. When energized, a Myosin head attaches to actin, forming a crossbridge.
2. ADP and Pi are released and the myosin head pivots and bends, pulling actin towards M line
3. After ATP attaches to myosin, myosin head detatches
4. ATP is hydrolyzed to ADP and Pi, and myosin head is in pre-stroke position
26
What breaksdown extra AcH
Acetylcholine esterase
27
Mechanism of botulinum toxin
blocks AcH release from neuron
28
Mechanism of myasthenia gravis
autoimmune disorder destroys AcH receptors
29
How many actin per myosin
6
30
What causes power stroke
dephosphorylation- phospate comes off
31
What type of protein is responsible for re-uptake of calcium
SERCA
32
What type of transport is SERCA transport
primary active
33
When is the muscle the strongest
When there is myosin atin connection, mid range, where there is optimal overlap to shorten the muscle but not too much that the muscle can't shorten more.
34
Concentric, eccentric, and isometric contraction
1. Concentric: Shortening the muscle
2. Isometric: No movement of muscles
3. Eccentric: Lengthening muscles
- Eccentric fully stretches and uses the least electrical activation
35
Which muscle contraction is strongest
eccentric
36
What are the naming of muscle fibers based on
- Myosin, ATP ase, Slow acting or fast acting (how fast they work)
- Dominant energy system used (oxidative or glycolytic)
37
What are type 1 muscle fibers used for
Endurance
slow-twitch, oxidative
38
What are type 2 muscle fibers used for
2a: fast twitch, oxidative, glycolitic (2-4 minutes of activity)
2b: Fast twitch, glycolytic (sprinting 30 seconds or less)
39
What is a motor unit
one motor neuron and all the fibers it innervates
40
All or nothing princapal of muscle contraction
Once an AP reaches a muscle, all the motor units will contract when the siganl reaches (not just some of the parts in the unit)
41
What is the size princapal of muscle contraction
small units are recruited before the large units are in muscles
42
What are the characteristics of cardiac muscle
branched, gap junction, intercalated disks connecting cells with the gap junctions
Lots of mitochondria (more than skeletal muscle)
Only 1 nucleus per cell (skeletal have many)
All cells in chamber contract at same time
43
Describe calcium-induced calcium release
Ca enters cardiomyocyte through L-type Ca channel
Ca activates ryanodine receptors to open SR
Triggers Ca release from SR to increase availability in the cell
SERCA pump returns to normal limits
44
What does cardiac muscle rely on extracellularly
Calcium extracellularly to induce SR Ca release
45
Are cardiac muscles anaerobic or aerobic
aerobic 100%
46
What does cardiac muscle primarily metabolize
lipids (60%)
Carbs (35%)
47
Cardiac muscle resting AP
-90
48
What is stretch dependent on in the heart
diastolic filling
- When we stretch out the heart, it has a large elastic bouncing back
49
What is sympathetc activation of the heart dependent on and what is the MOA
Beta 2 adrenergic increases contractility via:
- Cyclic AMP and protein Kinase A opens CA2 and activates Ca 2 pumping back into SR via SERCA pump
50
What is diastolic heart failure
can't relax heart muscle
51
What does sympathatic activation of the heart lead to
- Increase contractile force in the heart and the releaxation speed (caffine does this too)
52
What are neuroeffector junctions/nerve endings in smooth, cardiac, and skeletal muscle
- skeletal muscle has endplate
- Smooth muscle: Noradrenergic neurons have varicosities that contain synaptic vesicles.
- In cardiac muscle, SNS and PNS neurons innervate SA node, AV node, Bundle of HIS
53
Smooth muscle features
- Gap junction between cells, very very few mitochondria
- multiunit (iris, not connected to other cells ) or unitary(uterus, gi tract, interconnected in large sheets).
54
What type of muscles are blood vessils
smooth muscles
55
Does smooth muscle have actin and myosin
yes
56
Smooth muscle contraction steps
1. AP leads to Ca influx
2. Calcium binds to calmodulin protein
3. Calmoduline activates myosin light chain kinase enzymes
3. Phyosphorylates myosin, mypsin forms cross bridges with actin and contracts muscles
Relaxation occurs via MLCP(myosin light chain phosphetase) dephosphorylating myosin
57
What neurotransmitter/ion activates MLCP
NO
58
What causes tone in smooth muscles
--Latch bridge mechanism leads to extra force of contraction after myosin head already exerts force.
--Continuous electrical activity, keeps blood vessil functioning.
59
What primarily consumes ATP in skeletal muscle?
Myosin ATPase (70%)
25% used by CA pumps
60
How much ATP is stored in muscles
enough to last 5 secodnds of sprinting or 15 secs of aerobic exercise
61
How long is the energy that creatine gives us ? does it need oxygen?
10-15 seconds
Does not need oxygen
Good for extra sprints or single powerful exercises (one more rep)
62
What does exercise lasting more than 1 second produce
lactic acid
63
How long does CP system take to recharge
2-3 minutes
64
What stimulates the creatine phosphate system
ADP and Pi
65
How much ATP does the CP system provide in 10 seconds
3 times the amount of stored ATP
66
Glycolosys takes what and makes what
takes 1 glucose and makes 2 pyruvate
67
Glycolytic system
Glucose-> 2 pyruvate-> go through LDH and done with 2 pyruvate
68
Oxidative system
2 pyruvate--> PDH--> Acetyl COA (2)--> krebs cycle, ETC and ATP
69
Glycolytic system ATP increase
4 produced
2 or 1 used (2 atp used with glucose, 1 atp used with glycogen)
Net gain of 2 or 3
70
What enzyme breaks down glycogen and kickstarts glycolytic system?
Glycogen phosphorylase (PHOS)
71
What does PHOS do
Break down glycogen and kickstart system
72
What does PFK do
Rate limiting enzyme in glycolytic system, make ATP to ADP
73
What does LDH do
turn pyruvic acid to lactic acid
74
What do PDH do
Turn pyruvic acid to acetyl coa to start krebs cycle
75
In the glycolytic system:
1. An increase in what leads to an increased concentration of what (that activates glycolytic system)
2. Causes an increase in
3. Which stimulates which enzyme?
1. Increased ATP or AMP activates PHOS
2. Glucose 6 phosphate
3. PFK(rate limiting step)
76
What are the most important products of krebs cycle
ATP, NADH, FADH2
77
What is the byproduct of krebs cycle
CO2
78
What is the rate limiting enzyme in krebs cycle
Isocitrate dehydorgense
79
What is NAD+
Niacin, B3, drive energy production
80
What is FADH
Riboflavin, B5, energy production
81
What type of transport is the ETC
secondary active
82
of ATP made from ETC
28
83
important byproducts of ETC
Oxygen, H2O
84
What drives atp synthase
the chemical/electrical gradient of H+
ADP and Pi conversion Makes rotors on synthase spin, create ATP
85
Which muscles have gap junctions
smooth and cardiac
86
Which muscle tissues have 1 cell
Cardiac muscle and smooth muscle
87
