Muscle tissue i

Question 1

When is skeletal muscle somewhat involuntary?

Answer 1

breathing (diaphragm) and posture

Question 2

functions of muscle tissue

Answer 2

body movement
stabilizing position
moving stuff in body (blood/ intestine stuff)
generate heat (shivering)

Question 3

cell to cell connections in each muscle type

Answer 3

skeletal = none
cardiac = intercalated discs = gap junc. and desmosomes
smooth muscle = sometimes gap junc.

Question 4

skeletal muscle function

Answer 4

support/protection = abdominal wall / pelvic floor
movement
nutrients = AA for liver to make glucose
posture
heat = 85%

Question 5

fascia

Answer 5

dense sheet/ broad band of irregular ct that surrounds muscles

Question 6

epimysium

Answer 6

outermost layer surrounding multiple fasicle bundles

Question 7

perimysium

Answer 7

separates 10-100 muscle fibers into fascicle bundles

Question 8

endomysium

Answer 8

separates muscle fibers from each other

NOT plasma membrane

Question 9

tendon

Answer 9

cord attaching muscle to bone (dense CT)

Question 10

Aponcurosis

Answer 10

broad, flattened tendon

Question 11

filament to muscle

Answer 11

filament
myofibril
muscle fiber
fascicle bundle
muscle

Question 12

skeletal muscle attachment to bone

Answer 12

Direct: epimysium fuses to periosteum of bone

Indirect: CT wrappings extend beyond muscle tissue as tendon

Series Elastic Component : CT wrappings have elastic properties
- when muscle contracts, SEC streches b4 bone movement

Question 13

skeletal muscle nerve supply

Answer 13

somatic motor neurons

-motor unit = axon of somatic motor neuron and the muscle fibers it enervates –> all contract at once

Question 14

How do muscles grow? what hormones are involved?

Answer 14

• # of fibers stay the same
• hypertrophy = enlargement of existing muscle fibers
• Testosterone and HGH stimulate hypertrophy
• satellite cells retain capacity to regenerate damaged muscle fibers

Question 15

sarcolemma

Answer 15

plasma membrane of muscle cells

Question 16

Transverse tubules

Answer 16

deep invagination in sarcolemma

-ap tracels thru them

Question 17

Sarcoplasm

Answer 17

cytoplasm of muscle fiber

• contains glycogen for ATP synthesis
• contains myoglobin which binds O2
• Myoglobin releases O2 when needed to make ATP

Question 18

SR

Answer 18

membranous sacs encircling each myofibril

• stores calcium
• release of calcium triggers muscle contraction

Question 19

myofibrils

Answer 19

thread-like structures with contractile funciton

Question 20

filament-componenets of myofibrils

Answer 20

• function in contractile process
• thick and thin
• 2 thin for every thick

Question 21

sarcomeres

Answer 21

• compartments of arranged filaments

- basic functional unit of a myofibril

Question 22

Z disc

Answer 22

• separates 1 sarcomere from another

- anchors actin filaments

Question 23

A band

Answer 23

dark middle part of sarcomere

-area of thick filaments whether or not they overlap

Question 24

I band

Answer 24

lighter –> only thin filaments

-Z disc passes thru middle of I band

Question 25

H zone

Answer 25

Center of each A band with only thick filaments

Question 26

M line

Answer 26

supporting proteins that hold the thick filaments together in the H zone

Question 27

3 types of proteins that make up myofibrils

Answer 27

contractile, regulatory, and structural

Question 28

Contractile proteins

Answer 28

1. Myosin = thick filaments that function as motor proteins to achive motion
   - converts ATP to energy of motion
   - projections of each molecule protrude outward (myosin head)
2. Actin = thin filaments providing site for myosin head attachment
   - tropomyosin and troponin are part of thin filament
   - tropomyosin covers myosin binding sites
   - Ca binds to troponin, moving tropomyosin off the site

Question 29

Regulatory Proteins

Answer 29

Tropomyosin = strand blocking binding site

Troponin = Globular with 3 subunits

1. Troponin T = binds to tropomyosin
2. Troponin I = binds to actin
3. Troponin C = binds to calcium

Question 30

Structural proteins

Answer 30

1. Actinin = cross links thin filaments at z line
2. Connectin (titin) = big elastic proteins from z disc to m line
   - stabilizes thick filaments and provides elasticity to muscles
3. Nebulin = big protein along thin filaments at z disc
   - stabilizes thin filaments
4. Dystrophia = links thin filaments to sarcolemma
   - get fucked up in muscular dystrophy