A: Histology of muscle

Question 1

Types of skeletal muscle connective tissue:

Answer 1

• Epimysium: surrounds entire muscle
• Perimysium: surrounds each fascicle
• Endomysium: surrounds each fibre/muscle cell.

Question 2

Structure of skeletal muscle fibre

Answer 2

• Long unbranched cylindrical shape
• Multinucleated
• Nuclei positioned peripherally
• Striated

Question 3

Thin (actin) filaments

Answer 3

From from Z disc to centre of sarcomere

Question 4

Thick (myosin) filaments

Answer 4

In the centre of the sarcomere, contain ATPase enzymes.

Question 5

A bands

Answer 5

Full length of thick filament (including parts of thin filament)

Question 6

H zone

Answer 6

Centre part of A band, no thin filament.

Question 7

M line

Answer 7

Centre of H zone

Question 8

L band

Answer 8

Only thin filaments, lies within 2 adjacent sarcomeres.

Question 9

T tubules

Answer 9

Runs around myofibrils in sarcolemma, makes sure all myofibrils contract simultaneously.

Question 10

Sarcoplasmic reticulum

Answer 10

Interconnecting tubules surrounding each myofibril. Contains Ca2+

Question 11

Nerve impulse direction in muscle

Answer 11

T-tubule –> release of Ca2+ from sarcoplasmic reticulum –> Ca2+ into cytoplasm –> contraction.

Question 12

Sliding filament theory

Answer 12

1. Thin filaments are pulled towards the centre of the sarcomere
2. Sarcomere shortens

Question 13

Smooth muscle cell structure

Answer 13

• Fibres are shorter than skeletal
• Spindle shaped
• Single nucleus in centre.
• No myofibrils or sarcomeres, so not striated
• Thin + thick filaments are scattered + attached to dense bodies throughout the sarcoplasm
• Have calveolae

Question 14

Dense bodies

Answer 14

noncontractile intermediate filaments

Question 15

Caveolae

Answer 15

Indentations in sarcolemma that act like T tubules.

Question 16

Types of smooth muscle

Answer 16

Unitary/ tonic
Phasic

Question 17

Unitary smooth muscle

Answer 17

• Cells arranged in sheets in hollow viscera
• Cells contract spontaneously (no need for nerves to contract)
• Have gap junctions which allow the spread of excitation and for ions to move between cells.
• Influenced by Autonomic nervous system

Question 18

Cardiac muscle cell structure

Answer 18

• Long + cylindrical
• One central nucleus
• Branching cells
• Have intercalated discs: cells join end to end which facilitates spread of excitation along row of cells.
• Striated (have myofibrils with sarcomeres)
• T-tubules associated with single small cistern of SR

Question 19

Identify

Answer 19

Cardiac

Question 20

Identify

Answer 20

Cardiac cell

Question 21

Identify

Answer 21

smooth muscle

Question 22

Identify

Answer 22

Skeletal muscle

Question 23

Identify

Answer 23

Intercalated discs

Question 24

In which muscle types are intercalated discs absent?

Answer 24

Smooth + skeletal

Question 25

Identify

Answer 25

Skeletal

Question 26

Which muscle types are satellite cells found at?

Answer 26

Skeletal

Question 27

Identify muscle type

Answer 27

Skeletal

Question 28

How do arteries enter muscle

Answer 28

with nerves

Question 29

how to capillaries enter muscle

Answer 29

parallel to muscle fibres

Question 30

If connective tissue is very short + hard to see –> _____ attachments.
If there is a tendon or aponeurosis –> ____ attachments.

Answer 30

fleshy
indirect

Question 31

Example of parallel fusicles

Answer 31

1. Strap like - SCM
2. Fusiform - biceps brachii

Question 32

Example of convergent fascicle

Answer 32

pectoralis major

Question 33

Sesamoid bone

Answer 33

bone within a tendon

Question 34

sesamoid fibrocartilage

Answer 34

cartilage in tendon