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Flashcards in Muscle Tissue Deck (40)
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1
Q

What are the functions of muscle tissue?

A

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

2
Q

What are the three types of muscle?

A

Skeletal, cardiac, smooth

3
Q

Which muscle types have voluntary control?

A

Skeletal muscle

4
Q

Which muscle types have involuntary control?

A

Cardiac and smooth muscle

5
Q

Which muscle types appear striated?

A

Skeletal and cardiac

6
Q

Which muscle types appear non-striated?

A

Smooth

7
Q

What is the purpose of skeletal muscle?

A

Body movements and maintain posture

8
Q

What is the purpose of cardiac muscle?

A

Pump blood through cardiovascular system

9
Q

What is the purpose of smooth muscle?

A

Maintain visceral organ tone and movement; vasodilation and vasocontraction

10
Q

What are the names for a single muscle cell?

A

Myocyte, myofiber, muscle fiber

11
Q

What surrounds a single myofiber?

A

Endomysium - loose CT

12
Q

What surrounds a fasicle?

A

Perimysium

13
Q

What surrounds a collection of fasicles?

A

Epimysium - dense irregular CT

14
Q

Describe the organization into a muscle?

A

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

15
Q

What is the purpose of the CT in muscle?

A

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

16
Q

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

A

Myofibrils - contain actin and myosin filaments known as sarcomeres

17
Q

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

A

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

18
Q

What sleeves cover each myofibril?

A

Sarcoplasmic reticulum that houses calcium

19
Q

What forms the triad?

A

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

20
Q

What is the terminal cisternae?

A

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

21
Q

What is a sarcomere?

A

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

22
Q

Z line to Z line

A

1 sarcomere

23
Q

M line

A

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

24
Q

Z line

A

Attachment site for thin actin microfilaments

25
Q

I band

A

Space containing only actin microfilaments

26
Q

H zone

A

Space containing only myosin filaments

27
Q

A band

A

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

28
Q

Do thick and thin filaments change length?

A

NO!! Only change degree of overlap!

29
Q

Describe the process of a sarcomere contracting

A
  • 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
30
Q

What is the power stroke?

A

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

31
Q

Rigor Mortis

A

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

32
Q

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

A

Acetylcholine

33
Q

Describe how a myofiber releases calcium to the myofibrils

A

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

34
Q

What is different about cardiac muscle?

A

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

35
Q

What are the three types of intercalated discs?

A

Fascia adheren, desmosomes, gap (nexus) junctions

36
Q

Which intercalated discs runs perpendicular to the striations?

A

Fascia adheren, desmosomes

37
Q

What replaces the triad in cardiac muscle?

A

Diad - 1 t tubule and 1 terminal cisternae

38
Q

What is different about smooth muscle?

A

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

39
Q

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

A

Smooth muscle

40
Q

What anchors smooth muscle?

A

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