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Flashcards in Muscle systems Deck (32)
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1

Which muscle groups are striated & unstriated?

Striated: skeletal & cardiac, unstriated: smooth

2

Characteristics of skeletal muscle

multiple peripheral nuclei, elongated, visible striations, voluntary

3

Characteristics of smooth muscle

single central nuclei, spindle-shaped, no visible striations, involuntary

4

Characteristics of cardiac muscle

single central nucleus, branching cell, visible striations, involuntary

5

List the 4 primary functions of skeletal muscle

Movement & posture, blood circulation, heat production, protein source

6

At what level does contraction occur?

Protein level (actin & myosin)

7

What are the 5 connective tissues in muscle?

Sarcolemma, endomysium, perimysium, epimysium, tendon

8

Which connective tissue surrounds the muscle body?

Epimysium

9

Which connective tissue surrounds the muscle fibres?

Endomysium

10

Which connective tissue surrounds the fibre bundles?

Perimysium

11

What are myofibrils?

Actin (thin) & myosin (thick) filaments

12

Myofibrils make up what?

Skeletal muscle fibres

13

Muscle fibres make up what?

Fibre bundles

14

Fibre bundles make up what?

Muscle body

15

What are sarcomeres?

Functional units of skeletal muscle (From Z line - Z line)

16

Properties of A band?

Dark striations (myosin/thick filaments). Remains same thinkness upon contraction (see diagram)

17

Properties of I band?

Light striations (actin/thin filaments). Shortens upon contraction (see diagram)

18

Properties of H band?

Myosin/thick only - no overlap (see diagram). Shortens

19

What 3 proteins make up the thin filament?

Actin, tropomyosin, troponin

20

What role does the M line play?

Links thick filaments

21

Role of troponin?

Holds tropomyosin in place

22

Describe the process of muscle contraction from AP to contraction in detail at the molecular level out loud

...

23

ATP is sources from..? (3 different sources)

1. Phosphorylation of ADP by creatine phosphate, 2. Ox. phos. of ADP (mitochondria)
3. Anaerobic glycolysis

24

Difference in fast & slow twitch fibres depends on..?

myosin ATPase activity (ATP hydrolysis)

25

Factors affecting muscle contraction? (fibre-related)

Fibre diameter, change in fibre length, extent of fatigue, no. of fibres recruited (more AP's -> more fibres)

26

Causes of muscle fatigue?

High intensity activity (+lactic acid, ACh depletion), Low intensity activity (energy depletion), +Pi, changes in ion distribution, psychological

27

In which muscle type are gap junctions found?

smooth muscle

28

Smooth muscle cell characteristics?

Activated by autonomic neuron varicosity, spindle-shaped, smaller than skeletal by 1/10, unstriated (no sarcomeres), contain actin & myosin (more actin), . Contract together as single unit using gap junctions.

29

Multi unit SM characteristics?

Found in large airways, arteries & eye, few to no gap junctions, own innervation, no tone

30

Cardiac muscle cell characteristics?

Striated (sarcomeres), troponin & tropomyosin regulation, T tubules, SR not as well developed, slow to fatigue, gap junctions, pacemaker cells, ANS, hormone & paracrine influences, Ca+ from ECF & SR

31

3 things that influence skeletal muscle growth/atrophy?

change ATP-synthesising capacity (+mitochondria ox. phos., +capillaries), change myosin isoforms (ie contaction speed/fibre type), diameter (hypertrophy of fast glycolytic, +actin/myosin, endurance not affected)

32

Which 2 fibres can convert to the other type & how?

Endurance training -> fast oxidative
Weight training -> fast glycolytic (more ATPase)