Muscle

Question 0

What can be found in the deep fascia?

Answer 0

Large blood vessels, nerves and small amounts of fat

Question 1

What is the deep fascia?

Answer 1

Dense connective tissue which surrounds adjacent muscles, in between muscles and bends them into functional groups.

Question 2

Describe and explain the appearance of skeletal muscle

Answer 2

Pink due to pigmentation, myoglobin and vascularisation

Question 3

In skeletal muscle what does the power output depend on?

Answer 3

Number of muscle fibres which can be increased by increased exercising

Question 4

Where is the T tubule located in skeletal muscle?

Answer 4

AI junction

Question 5

Describe the layers of skeletal muscle

Answer 5

Fascicles, myofibres, myofibrils, microfilaments. Epimysium surrounds muscles/organs, perimysium surrounds fascicles and endomysium surrounds individual muscle cells/fibres

Question 6

What types of fascicles can there be?

Answer 6

Architectural patterns - parallel, circular, pennate etc. the pattern determines the range and power.

Question 7

Describe red muscle in skeletal muscles.

Answer 7

Slow - lots of myoglobin, rich vascularisation, numerous mitochondria, fatigue slowly, rich in oxidative enzymes, poor in ATPase, fewer NMJ

Question 8

Describe white muscle in skeletal muscles

Answer 8

Fast - poor vascularisation, few myoglobin, few mitochondria, faster and stronger contractions, poor oxidative enzymes, more NMJs

Question 9

What are cross bridges?

Answer 9

HMM - contraction via breakdown of ATP by myosin ATPase

Question 10

Describe the banding in skeletal muscle

Answer 10

Myosin filament, H zone, A band, Z line and I band

Question 11

Describe the effects of contraction on the bands in skeletal muscle

Answer 11

I and H become smaller in length whereas A remains the same

Question 12

Describe the structure of actin

Answer 12

Double helical, tropomyosin lies in a groove

Question 13

Describe the structure of troponin

Answer 13

Attached through tropomyosin, one is a Ca2+ receptive protein

Question 14

Out of myosin and actin which is thick and which is thin?

Answer 14

Myosin = thick
Actin = thin

Question 15

What is a tendon?

Answer 15

Fibrous cord that extends from the muscle to connect it to bone

Question 16

What is aponeurosis?

Answer 16

Broad, flat structure that attaches bone or other adjoining structures

Question 17

What are the functions of smooth muscle?

Answer 17

Slow contraction, hormonal stimulation, gap junction, less ordered interaction of myosin and actin

Question 18

Describe the structure of smooth muscle

Answer 18

Fusiform, long cells. Only a few exhibit nuclei when transversely sectioned

Question 19

Where would you find smooth muscle?

Answer 19

Contractile part of wall of GI tract, respiratory tract, ducts/glands, urinary and genital ducts, veins/arteries, muscles of iris in eye

Question 20

Can skeletal muscle regenerate?

Answer 20

Yes, to a degree. In gross damage scar tissue will be formed

Question 21

What do purkinje fibres do?

Answer 21

Spread impulse to the heart

Question 22

Describe the structure and location of purkinje fibres

Answer 22

Fewer myofilaments, fibrils and Fewer intercalated discs. Beneath endocardium on internal surface of the heart. Commonly found along the inter-ventricular septum.

Question 23

Describe intercalated discs

Answer 23

They are specialised junctions. Facing membranes have grooves and reciprocal pits. They have strong horizontal components (Z bands). Weaker vertical components contain gap junctions

Question 24

What is brown atrophy of heart?

Answer 24

Atrophy of heart caused by lipofuscin pigment

Question 25

Where are the T tubules in cardiac muscle?

Answer 25

Lie at the Z band

Question 26

What are the main characteristics of cardiac muscle?

Answer 26

Elongated nuclei, fibres may bifurcate, cells joined by intercalated discs, fibres contain large numbers of sarcosomes with many cristae

Question 27

Does cardiac muscle regenerate?

Answer 27

Does not regenerate when injured. Cardiac muscle is more resistant to injury than the other types of muscle. Damage is contained by formation of fibro-connective scar tissue

Question 28

What is the role of calcium in muscle contraction?

Answer 28

Triggers contraction via troponin. Sarcoplasmic reticulum forms vesicles which in the presence of ATP reversibly take up Ca2+. Release of Ca2+ under control of T tubule membrane depolarisation triggers contraction via troponin.

Question 29

How does smooth muscle recuperate after injury?

Answer 29

Proliferation and differentiation of primitive smooth muscle into new muscle fibres

Question 30

How does skeletal muscle recuperate after injury?

Answer 30

Connective tissue of endomysium and perimysium divides and differentiates into myoblasts which fuse to form new muscle fibres

Question 31

What is myopathy?

Answer 31

Muscle weakness that is not a result of NS or emotional disorders. Causes impaired muscles, cramps etc.

Question 32

What is atrophy?

Answer 32

Wasting of muscle tissue as a result of lack of use, immobilisation, loss of nerve supply

Question 33

What is dystrophy?

Answer 33

Defective muscular nutrition

Question 34

What is hypertrophy?

Answer 34

Increased number of myofibrils, increased exercise, in pregnancy the uterus increases in size.