Muscle Tissue

Question 1

What are the functions of muscle tissue?

Answer 1

Movement of body and fluids, maintain posture and position, maintain body temperature, support soft tissues and sphincters

Question 2

What are the three types of muscle?

Answer 2

Skeletal, cardiac, smooth

Question 3

Which muscle types have voluntary control?

Answer 3

Skeletal muscle

Question 4

Which muscle types have involuntary control?

Answer 4

Cardiac and smooth muscle

Question 5

Which muscle types appear striated?

Answer 5

Skeletal and cardiac

Question 6

Which muscle types appear non-striated?

Answer 6

Smooth

Question 7

What is the purpose of skeletal muscle?

Answer 7

Body movements and maintain posture

Question 8

What is the purpose of cardiac muscle?

Answer 8

Pump blood through cardiovascular system

Question 9

What is the purpose of smooth muscle?

Answer 9

Maintain visceral organ tone and movement; vasodilation and vasocontraction

Question 10

What are the names for a single muscle cell?

Answer 10

Myocyte, myofiber, muscle fiber

Question 11

What surrounds a single myofiber?

Answer 11

Endomysium - loose CT

Question 12

What surrounds a fasicle?

Answer 12

Perimysium

Question 13

What surrounds a collection of fasicles?

Answer 13

Epimysium - dense irregular CT

Question 14

Describe the organization into a muscle?

Answer 14

Myofiber surrounded with endomysium then congregate to form fasicles (multiple myofibers) surrounded by perimysium and then multiple fasicles create a muscle that is surrounded by epimysium

Question 15

What is the purpose of the CT in muscle?

Answer 15

CT sheaths are continuous with muscle tendons in order to transmit their contractile force to bone and they allow for passage of blood and nerves to the myofibers

Question 16

Within a myofiber, the nuclei are located in the periphery of the cell, what houses the majority of the cytoplasm?

Answer 16

Myofibrils - contain actin and myosin filaments known as sarcomeres

Question 17

What is the plasma membrane that surrounds the myofiber called and what is unique about it?

Answer 17

Sarcolemma, it has invaginations known as T-tubules that run between myofibrils in the cell

Question 18

What sleeves cover each myofibril?

Answer 18

Sarcoplasmic reticulum that houses calcium

Question 19

What forms the triad?

Answer 19

One T-tubule and 2 terminal cisternae that will cause muscle contraction

Question 20

What is the terminal cisternae?

Answer 20

Dilated ends of the sarcoplasmic reticulum that release calcium in order for muscle to contract

Question 21

What is a sarcomere?

Answer 21

Basic contractile unit consisting of thin actin microfilaments and thick myosin filaments

Question 22

Z line to Z line

Answer 22

1 sarcomere

Question 23

M line

Answer 23

Attachment site for thick myosin filaments ( in between z lines)

Question 24

Z line

Answer 24

Attachment site for thin actin microfilaments

Question 25

I band

Answer 25

Space containing only actin microfilaments

Question 26

H zone

Answer 26

Space containing only myosin filaments

Question 27

A band

Answer 27

Space where thin actin microfilaments overlap the thick myosin filaments and includes the H zone in between

Question 28

Do thick and thin filaments change length?

Answer 28

NO!! Only change degree of overlap!

Question 29

Describe the process of a sarcomere contracting

Answer 29

- Calcium comes in and binds troponin C, which causes tropomyosin to move the troponin complex (specifically troponin I off of myosin binding site) - Myosin head binds the binding site on actin and power stroke invoked - ATP binds myosin and hydrolyzes to release energy for myosin to release from actin and recock head - Myosin binds actin, powerstroke, releases ADP and Pi

Question 30

What is the power stroke?

Answer 30

When the myosin head moves actin filament toward M line and releases ADP & Pi

Question 31

Rigor Mortis

Answer 31

When ATP source is lost, myosin cannot bind it, thus it is stuck bound to the actin filament and muscle is locked in place

Question 32

What neurotransmitter is released from the axon terminal at the neuromuscular junction?

Answer 32

Acetylcholine

Question 33

Describe how a myofiber releases calcium to the myofibrils

Answer 33

Motor neuron fires, the axon terminal releases vesicles containing acetylcholine across the synaptic cleft where they will bind to receptors on the sarcolemma and travel down the t-tubules. This will cause the terminal cisternae of the sarcoplasmic reticulum to release calcium to the myofibrils and cause muscle contraction

Question 34

What is different about cardiac muscle?

Answer 34

One nucleus in center of cytoplasm, involuntary, straited but has intercalated discs, cells branch, not innervated, can be under hormonal control

Question 35

What are the three types of intercalated discs?

Answer 35

Fascia adheren, desmosomes, gap (nexus) junctions

Question 36

Which intercalated discs runs perpendicular to the striations?

Answer 36

Fascia adheren, desmosomes

Question 37

What replaces the triad in cardiac muscle?

Answer 37

Diad - 1 t tubule and 1 terminal cisternae

Question 38

What is different about smooth muscle?

Answer 38

Involuntary, non-striated, under control of ANS and hormones, one elliptical shaped nucleus

Question 39

Which muscle type has a slow and sustained contraction/relaxation and is resistant to fatigue?

Answer 39

Smooth muscle

Question 40

What anchors smooth muscle?

Answer 40

Dense bodies made of desmin and vimentin intermediate filaments Cells communicate via gap junctions