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A&P Exam III > Smooth and Cardiac Muscle > Flashcards

Smooth and Cardiac Muscle Flashcards

(64 cards)

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1
Q

How does smooth muscle compare to skeletal muscle

A
  1. It is stronger (per gram muscle)
  2. More efficient
  3. Slower
  4. Uses “latch” mechanism when contracting
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2
Q

What is the speed of skeletal muscle and smooth muscle

A

Skeletal muscle - 0.15ms
Smooth muscle - 0.5-2 seconds

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3
Q

Where does smooth muscle get its Ca++

A

Primarily extracellularly
SR in smooth muscle does not store as much Ca++, so if blood calcium is low smooth muscles ability to contract will be affected

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4
Q

What is the functional unit of smooth muscle

A

Thick Myosin filaments

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5
Q

How many sarcoplasmic reticulum do smooth muscle have

A

It’s location dependent, some smooth muscle will have barely any

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6
Q

What is the ratio of myosin to actin in smooth vs skeletal muscle

A

Smooth muscle - 10:1
Skeletal muscle - 2:1

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7
Q

What are the dense bodies of smooth muscle composed of

A

Collagen and fibrin

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8
Q

What is the speed of smooth muscle cross bridge cycling

A

1/10th-1/300th the speed of skeletal muscle cross bridge cycling

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9
Q

How thick is the endothelium in smooth muscle

A

1 cell thick

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10
Q

What is the outter layer of smooth muscle called

A

Adventitia

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11
Q

What is the middle layer of smooth muscle called

A

Medial muscle fibers

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12
Q

What is the inner layer of smooth muscle called

A

Endothelium

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13
Q

What are smooth muscle examples

A
  1. Eye pupil diameter control
  2. Small/medium airway smooth muscle
  3. Small intestinal muscle
  4. Vascular
  5. Esophagus
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14
Q

How will hypocalcemia affect your cardiovascular system (basic)

A
  1. SVR will be low
  2. CO will be low
  3. BP will be low
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15
Q

Where are SR clustered in smooth muscle

A

Around the caveolae

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16
Q

In smooth muscle, how many myosin light chains are on the myosin filament

A

2 regulatory MLC
2 Essential MLC

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17
Q

How much can smooth muscle and skeletal muscle shorten by

A

Skeletal muscle - 30%
Smooth muscle - 80%

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18
Q

What are the different types of smooth muscle

A

Unitary (visceral)
Multi-unit

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19
Q

Where is unitary smooth muscle

A

In our organs

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20
Q

How do unitary smooth muscle and multi-unit smooth muscle receive signals

A

Multi unit- Each cell receives neurotransmitter signals individually
Visceral - Utilize gap junctions to spread a signal and contract simultaneously

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21
Q

Where are multi-unit smooth muscle usually located

A

Where more fine movement is required such as ciliary muscle

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22
Q

What type of muscle is the esophogus made of

A

Hybrid between smooth and skeletal

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23
Q

What is another name for Adventitia

A

Tunica adventitia/externa

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24
Q

What is another name for medial muscle fibers

A

Tunica media

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25
What is another name for endothelium
Tunica intima
26
Which part of the smooth muscle is composed of a lot of elastin
Adventitia (tunica externa)
27
What is the structural support of the blood vessels
Adventitia
28
How are individual smooth muscle cells connected
Dense bodies
29
What is the vrms of smooth muscle
-50mV Higher resting membrane permeability to Na+ and Ca++
30
Where is oscillating resting membrane potentials found
Gastrointestinal system
31
What happens to a blood vessel when smooth muscle contracts
The diameter of the vessel decreases
32
What part of the nervous system does smooth muscle utilize
Autonomic
33
What are the receptors that we talked about that cause vasoconstriction
1. Alpha 1 2. Angiotensin I 3. Serotonin
34
Where do we not have Alpha 1 receptors
Brain and capillaries
35
What does phospholipase C target
Phosphotidylinositol
36
When cleaved what does phosphotidylinositol split into
DAG and IP3
37
What does protein kinase C do
Opens cell wall Ca++ channels Speeds up myosin light chain kinase
38
What are the 3 ways Ca++ is removed from a muscle cell
1. SERCA pumps back into SR 2. Out via NaCXchanger 3. Out via plasma membrane calcium ATPase (PMCA)
39
Another name for stretch induced contraction
Myogenic vasoconstriction
40
What part of the body utilizes myogenic vasoconstriction
Brain blood vessels autoregulate CBF this way Involves stretch mediated Na+ and Ca++ permeability of smooth muscle
41
What is an example of stretch induced relaxation
Bladder muscles - Sometimes has to relax to fill more, also why will lose sensation to urinate after a while
42
How can smooth muscle have contraction independent of AP
Release of internal Ca++ does not participate in change of resting membrane potential, which can cause contraction without AP
43
What type of muscle is cardiac muscle
hybrid smooth and skeletal
44
what is the vrm of SA node
-55mV
45
What is the vrm of ventricular myocyte
-80mV
46
What receptor does angiotensin II utilize
AT1
47
What type of gates are on Ca++ slow channels
F gate - inactivation gate d gate - activation gate
48
Where does Ca++ in cardiac muscle come from and how much
20% extracellular 80% from SR
49
Where does Ca++ go when the cardiac muscle cell id repolarizing
80% back into SR via SERCA 15% out NaCX 5% out Ca++ATPase
50
What is phospholamban
Regulates uptake of Ca++ through SERCA
51
What takes the brunt of damage in cardiac myocyte from an MI
NaKATPase are most likely to be affected in the event of infarction. Damage to these pumps will cause a complete shut down of the cardiac myocyte
52
What are intercalated discs
Junctions between cardiac cells to add surface area for more gap junctions than other cells Important particularly in ventricular cardiac cells
53
How many nucleus do cardiac muscle have
1 or 2
54
What are the layers of the heart muscle
1. Endocardium 2. myocardium 3. epicardium
55
What is the outter layer of the heart
1. Pericardial space 2. Parietal pericardium 3. Fibrous pericardium
56
Whats different about fibrous pericardium
Much tougher than the rest of the pericardium
57
What happens if you have fluid under the fibrous pericardium
Inhibits the hearts ability to pump due to pressure
58
What is the pattern of the endocardial fibers and why is it useful
Criss cross pattern, allows the heart fibers to twist and squeeze to more efficiently eject blood
59
What is visceral pericardium
Fibrous pericardium
60
What is the threshold potential of the SA node and AV node
-40mV
61
What are purkinje fiber resting membrane potential
-90mV
62
What is the plateau phase caused by in ventricular myocyte
Open L type calcium channel
63
What are T-type calcium channels
Secondary Ca++ channel in the heart that is a fast Ca++ channel
64
In an AP when is K+ channels closed
Phase 0,1,2

A&P Exam III (3 decks)

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