Muscle Flashcards

1
Q

How is force produced

A

Produced by movement of actin fibres over myosin fibres

With aid of a number of accessory proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the four muscle cell types

A
Skeletal/voluntary 
Cardiac 
Smooth invol
Myoepthelial 
Myofibroblasts
Pericytes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the non contractile cells in muscle

A

Myofibroblasts
Myoepthelial
Pericytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is myoepthelial

A

Found associated with the secretory units of some exocrine glands
They are flattened cells and hve contractile protein arrangement similar to smooth muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are myofibroblasts

A

Characteristic of both fibroblasts (secrete collagen) and smooth muscle cells
Normally few in number and inconspicuous they enlarge and prolif in injury
Collagen for scaffold for repair they contract the wound

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are pericytes

A

Inconspicuous cells found in around capillaries and venules

Act as stem cells but also contractile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is skeletal muscle

A

Skeletal
Voluntary
Straited

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is muscle tissue

A

Formed from muscle cells and associated connective tissue and forms nulk of muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the features of skeletal muscle

A
Striated 
Unbranched 
Multinucleate 
Fibres long cyclinders 
Nuclei at periphery sarcolemma
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are fascicles

A

Muscle fibres are grouped into bundles called fascicles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the different types of connective tissue associated with skeletal muscle organisation

A

Ct around muscle as a whole - epimysium
Ct around single fascicle - perimysium
Ct around single muscle fibre - endomysium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are sarcomeres

A

Unit of contraction of muscle cell smallest contractile element
Hundreds arranged end to end form myofibril

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does striated mean

A

Fibres have a regular pattern bands running across

True for cardiac muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is a motor unit

A

Motor neurone and all the muscle fibres that it innervates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does a motor neurone end in

A

A motor end plate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What happens at the motor end plate

A

Neuromuscular junction where there is a synapse where the action of acetylcholine occurs and initiates an action potentioa in the sarcolemma

17
Q

What are T-tubules

A

Within muscle fo the cell network of tubules

Extend from sarcolemma into cell surrounding myofibril

18
Q

What is the sarcoplasmic reticulum

A

Muscle cell contains labyrinth of specialised cells sarcoplasmic reticulum
Contains very high conc of calcium

19
Q

What is a triad

A

T tubule with sarcoplasmic reticulum form triad

20
Q

What is the stimulus leading to contraction

A

Action potential arrives at neuromuscular junction acetylcholine released results in action potential in muscle cell
Muscle action potential travels along sarcolemma and invades t tubules at triads release calcium lead to action on myosin fibres shortening sarcomeres and contraction

21
Q

What are the three types of skeletal muscle fibre

A

Type 1 - relatively slow contracting fibres that depend on oxidative metabolism, abundant mitochondria resist fatigue and produce relatively less force red fibres

Type 2A - intermediate between other two and these fibres relatively uncommon

Type 2B - relatively fast connecting fibres that depend on anaerobic metabolism, few mitochondria, fatigue easily and produced greater force called white fibres

22
Q

What su the myotendinous junction

A

Specialised junction where collagen fibres of tendon attaches to end of muscle fibres
Here muscle fibres tightly anchored to collagen by complex interdigitations

23
Q

How is feedback referred

A

Muscle has special sense organs
Muscle spindle contain special muscle fibres referred to as intrafusal fibres
Normal contractile muscle fibres termed as extrafusal fibres

24
Q

What su smooth muscle

A

Involuntary or visceral

No striations

25
What is focal densities
Actin and myosin fibres do not go instant ions or organised like so but do converge on focal densities T periphery of cell
26
What is cardiac muscle
``` Forms major part of walls of heart etc Skeletal muscle, cardiac muscle has striations less prominent Fibres much shorter Single nucleus near centre of fibre Intercalated discs ```
27
What is a dyad
In cardiac muscle t tubule and sarcoplasmic reticulum
28
What are cardiac myocytes
Intrinsic rhythmic contraction Gap junctions in intercalated discs allow for synchronisation of contraction between cells and allow wave of excitation to sweep through tissue Rhythm independant of autonomic nervous system but modulated by it
29
What are satellite cells
Skeletal muscle retains population of myoblasts which are satellite cells Small quiescent cells pressed to sides of sarcolemma under nasal lamina Form new muscle fibres
30
How are cells specialised for contractile force
All cells contain contractile fibres in cytoskeleton | In muscle cells the cytoplasm packed with such fibres and cells highly specialised for contraction force