Histology - 514-8 Flashcards Preview

Tim's Cards > Histology - 514-8 > Flashcards

Flashcards in Histology - 514-8 Deck (67)
Loading flashcards...
1
Q

What is the connective tissue component that surround a muscle cell?

A

Endomysium

2
Q

What is the specialized plasma membrane of muscle cells called?

A

Sarcolemma

3
Q

What is the cytoplasm of a muscle cell called?

A

Sarcoplasm

4
Q

What is the specialized series of interconnected tubules throughout the sarcoplasm connected to storage sacs of Calcium called?

A

Sarcoplasmic Reticulum

5
Q

Myofibrils are made up of…

A

myofilaments

6
Q

Myofilaments are made of…

A

Actin and Myosin

7
Q

What protein anchors myofibrils inside a muscle cell?

A

Dystrophin

8
Q

What is a disease caused by abnormalities in dystrophin?

A

Muscular Dystrophy

9
Q

What are T-tubules?

A

Perpendicular invaginations of the sarcolemma.

10
Q

What connective tissue fibers surround the sarcolemma and connect muscle cells together?

A

Endomysium

11
Q

What type of CT is continuous with the ends of a muscle cell to tendon?

A

Dense Regular

12
Q

What type of cells are found between the Endomysium and Sarcolemma?

A

Satellite Cells.

13
Q

A resting muscle cell membrane is______ and has a ______ charge

A

Polarized

Net postitive outside the cell

14
Q

What defines a sarcomere?

A

Z- lines

15
Q

Where does depolarization of a cell occur after it leaves the NMJ?

A

Sarcolemma and T-tubules

16
Q

What are A bands?

A

The entire length of Myosin

17
Q

What is the H band?

A

Myosin without actin overlap

18
Q

What is the I band

A

Only actin with no myosin overlap

19
Q

At rest, what covers the active site on the actin filaments?

A

Tropomyosin

20
Q

What begins at the ACh receptors at the terminal button?

A

Depolarization

21
Q

Upon depolarization, what do T-tubules induce the sarcoplasmic reticulum to release?

A

Calcium through channels.

22
Q

What does Calcium bind to release tropomyosin from the actin filament?

A

Troponin

23
Q

What is the key process of anabolic steroid use?

A

Stimulation of satellite cells. (Incorporation in fibers)

24
Q

What is the functional unit of a muscle?

A

Sarcomere

25
Q

Where is the calcium reservoir in sarcoplasmic reticulum?

A

Terminal Cisternae

26
Q

Where are terminal cisternae positioned?

A

Over actin/myosin overlap

27
Q

What structure is located between two terminal cisternae?

A

T-tubule

28
Q

What does the t-tubule combined with lateral cisternal structures comprise?

A

Triad

29
Q

Where are triads found in an transmission electron micrograph?

A

On border of myosin/actin, often next to mitochondria

30
Q

What are the two regulatory proteins on Actin?

A

Tropomyosin (big)

Troponin (small - Ca binding site)

31
Q

How many heads does one myosin contain?

A

Two

32
Q

How many actin subunits make up an actin filament?

A

6 or 7

33
Q

What is the elastic component in a sarcomere?

A

Titin - aka connectin

34
Q

Where is Titin found?

A

Z-disk to M-line

35
Q

How many muscle fibers can a small motor unit innervate?

Large motor unit?

A

3-6 fibers per nerve

1000 fibers per nerve

36
Q

What is the synapse between a nerve fiber and muscle cell called?

A

NMJ

37
Q

What is the folded and specialized region of sarcolemma under the terminal bouton called?

A

Motor End Plate

38
Q

What enzyme breaks down ACh in the synaptic cleft?

A

Acetylcholinesterase

39
Q

What is a cell membrane potential?

A

0.06 volts / 60 millivolts

40
Q

What main ion is outside the cell?

Inside the cell?

A

Na

K

41
Q

What helps create negative charge inside the cell?

A

Anionic proteins

42
Q

What ion enters the synaptic bulb (bouton)

A

Calcium

43
Q

What does entry of Calcium trigger?

A

ACh release

44
Q

What moves more in depolarization, Na or K?

A

Na

45
Q

Is the motor end plate ligand gated or voltage gated?

A

Ligand (ACh)

46
Q

What do ACh receptors allow?

A

binding of ACh, opening of channel, which allows Na to rush into the cell

47
Q

What does Calcium bind?

What does this do?

A

Troponin

Exposes Actin active site

48
Q

What breaks the cross-bridge between actin and myosin?

A

ATP

49
Q

What removes calcium from the sarcoplasmic reticulum?

A

Active transport pumps (use ATP)

50
Q

What causes rigor mortis?

A

Sarcoplasmic reticulum breaks down - releases Calcium
Ca activated actin/myosin cross bridging
No ATP to remove myosin heads

51
Q

How does botox work?

A

blocks ACh release

52
Q

How does curare work?

A

blocks ACh receptors

53
Q

How does tetrodotoxin work?

A

blocks Na movement in nerves

54
Q

How does Black Widow venom work?

A

causes mass release ACh

55
Q

How does Tetanus work?

A

blocks glycine (inhibitor preventing overstimulation)

56
Q

How do many pesticides work?

A

By inhibiting acetylcholinesterase

57
Q

What is Myasthenia Gravis and how does it work?

A

Autoimmune

Degrades ACh receptors - muscles no longer work

58
Q

What are 2 ways to regenerate ATP from ADP?

A

Myokinase

Creatine kinase

59
Q

What type of muscle fiber is fast twitch?

A

White

IIb

60
Q

What is the main difference between cardiac and skeletal muscle?

A

Intercalated disks

also gap junctions and desmosomes

61
Q

Is smooth muscle multi-nucleated?

A

No

62
Q

What are the neurotransmitters for smooth muscle?

A

Norepinepherine and ACh

63
Q

What to dense bodies do in smooth muscle?

A

create triangulation contraction between thin and thick filaments.

64
Q

How are calcium channels often stimulated in smooth muscle?

A

Mechanically

65
Q

What is a primary regulatory protein in smooth muscle?

A

Calmodulin

66
Q

What does Calmodulin activate?

A

MLCK

67
Q

Why is smooth muscle contraction slow?

A

ATPase act slowly

Ca pumps also slow

Decks in Tim's Cards Class (140):