Exam1Lec8Muscle

Question 1

What are the striated muscles?

Answer 1

skeletal and cardiac

Question 2

Which muscles are voluntary and what are involuntary?

Answer 2

• voluntary: skeletal
• involuntary: smooth and cardiac

Question 3

What does the endomysium surround?

Answer 3

each single muscle fiber

Question 4

What does the perimysium surround?

Answer 4

each fasicle

Question 5

What does the epimysium surround?

Answer 5

the entire muscle

Question 6

What are the 3 connective tissue layers of muscle (outside to in)?

Answer 6

epimysium> perimysium> endomysium

Question 7

Which connective tissue layers are made from dense irregular tissue?

Answer 7

epimysium and perimysium

Question 8

Which connective tissue layers are made from reticular connective tissue?

Answer 8

endomysium

Question 9

What band stays consistent with its length during a contraction?

Answer 9

A band (actin + myosin)

Question 10

Which bands get smaller during a contraction?

Answer 10

I (actin) and H (myosin) bands

Question 11

What is the triad of a muscle fiber? What does it align with?

Answer 11

2 profiles of of SR, and 1 profile of T-tubules. It aligns with the A-I junction

for cardiac. it aligns with z-line

Question 12

What is needed to have the muscle relax after each stroke?

Answer 12

ATP

Question 13

Where are the nuclei located in skeletal muscle?

Answer 13

on both sides of the fiber (periphery)

Question 14

What is myomesin?

Answer 14

cross-links thick filaments that are next to each other at M line

Question 15

What is titin?

Answer 15

forms elastic lattice that anchors thicK filaments to Z disks

Question 16

What is troponin?

Answer 16

• binds Ca
• binds to tropomyosin
• binds to actin (inhibitibg actin-mysosin interact)

Question 17

What is tropomyosin?

Answer 17

occupies grooves of the thin filaments

Question 18

What is C protein?

Answer 18

binds thick filaments at the M line

(anchors thick @M)

Question 19

What are the 2 types of muscle fibers?

Answer 19

red and white muscle fibers

Question 20

What is a muscle spindle?

Answer 20

sense what the contraction level is of a muscle

Question 21

What occurs during Ca depolarization?

Answer 21

1. membrane depolarizes
2. L-type Ca channel located in transverse tubule changes conformation
3. ryanodine-sensitive Ca channel becomes present in sarcoplasmic reticulum to open and release Ca
4. ryanodine channel releases Ca into sarcomere
5. released Ca binds to troponin C and initiates contraction

Question 22

What is rigor mortis?

Answer 22

continued contraction of muscle due to lack of ATP

Question 23

What is the process of a contraction?

Answer 23

1. need ATP for muscle contraction
2. ATP broken down to ADP
3. release of phosphate group
4. release ADP to bind ATP for muscle relaxation

Question 24

What is a powerstroke in regards to a contraction?

Answer 24

conformation change leads to the release of ADP

Question 25

What is the vascularization of red and white muscle fibers?

Answer 25

• red: rich vascular supply
• white: poor vascular supply

Question 26

What is the contractiontion of red and white muscle fibers?

Answer 26

• red: slow but repetitive; NOT easily fatigued; weaker contraction
• white: fast but easily fatigued; stronger contraction

Question 27

What is the mitochondria composition in red and white muscle fibers?

Answer 27

• red: numerous
• white: few

Question 28

What is the myoglobin composition of red and white muscle fibers?

Answer 28

• red: rich
• white: poor

Question 29

What is the relationship between intrafusal and extrafusal fibers?

Answer 29

when intrafusal contracts, extrafusal relaxes

when intrafusal relaxes, extrfusal contracts

Question 30

What is needed to stimulate a skeletal muscle contraction?

Answer 30

Ach release at NMJ

Question 31

What is myasthenia gravis?

Answer 31

autoimmune disease where antibodies are produced against Ach receptors

Question 32

Where are intercalated disks located?

Answer 32

between cardiac muscle cells

Question 33

What are the components of the intercalated disk?

Answer 33

fascia adherens, desmosomes, and gap junctions

Question 34

What type of muscle has the least amount of sarcoplasmic reticulum?

Answer 34

smooth muscle

Question 35

What regulates the smooth muscle contraction?

Answer 35

Ca/calmodulin

Question 36

What is the smooth muscle contraction system bound to?

Answer 36

the membrane and dense bodies made of alpha-actinin

Question 37

What are the 2 things unique to smooth muscle for a contraction?

Answer 37

1. myosin lightchain kinase (MLCK)
2. calmodulin

Question 38

What is the purpose of the calveola?

Answer 38

brings in Ca via pinocytosis to initiate contraction

Question 39

What are the 3 layers of smooth muscles?

Answer 39

1. muscularis mucosa
2. muscularis externa inner circular
3. muscularis externa outer longitudinal