Muscle and Nervous Tissue

Question 1

What are the 4 qualities of muscle tissue?

Answer 1

• Excitability - ability to respond to stimuli
• Contractibility - ability to contract e.g.
  shorten
• Extensibility - ability to stretch without
  tearing
• Elasticity - ability to return to original shape

Question 2

Is cardiac muscle striated or involuntary?

Answer 2

Both - its is striated and involuntary

Question 3

Is skeletal muscle striated or involuntary?

Answer 3

Striated

Question 4

Is smooth muscle striated or involuntary?

Answer 4

Involuntary

Question 5

What is the structure of smooth muscle cells?

Answer 5

• Short and spindle shaped - no striations -
  Unstriated
• Single centrally located nuclei
• Gap junctions between cells
• Able to regenerate by mitosis
• Slow, partial contractions

Question 6

Where is smooth muscle found?

Answer 6

Found in vessels, organs and walls of hollow organs.

Question 7

What type of innervation is smooth muscle under?

Answer 7

Under autonomic (involuntary, unconscious) control

Question 8

What does smooth muscle look like histologically?

Answer 8

Made up of:
- outer longitudinal smooth muscle
- inner circular muscle
- collagen

Question 9

What does a cardiac muscle cell look like?

Answer 9

Short and narrow

Question 10

Where is cardiac muscle found in the body?

Answer 10

In the heart and adjacent veins.

Question 11

Is cardiac muscle striated?

Answer 11

Yes - has striations due to dense arrangement on actin + myosin - its cylindrical with branches

Question 12

Is cardiac muscle striated?

Answer 12

Yes - has striations due to dense arrangement on actin + myosin - its cylindrical with branching fibres

Question 13

How many nuclei are present in cardiac muscle?

Answer 13

Has a single central nucleus

Question 14

What type of cell to cell junctions are present in cardiac muscle ?

Answer 14

Intercalated disks containing gap junctions
- joining cells to allow cell-cell communication for a coordinated output

Question 15

What type of innervation is cardiac muscle under?

Answer 15

Autonomic control (spontaneous contraction)

• Vagus nerve and sympathetic chain provide parasympathetic and sympathetic innervation to the cardiac muscle and heart rate (Visceral Motor Efferent)

Question 16

What type of contractions are present in cardiac muscle?

Answer 16

All or none

Question 17

Does mitosis occur in cardiac muscle?

Answer 17

No

Question 18

Does regeneration occur in cardiac muscle?

Answer 18

No

Question 19

What does a skeletal muscle cell look like?

Answer 19

Large and elongated - long cylindrical cells

Question 20

Where is skeletal muscle located in the body?

Answer 20

Found throughout the body attached to bones via tendons
(voluntary muscle)

Question 21

Is skeletal muscle striated?

Answer 21

Yes
- has fine black lines running perpendicular to
the fibres

Question 22

How many nuclei does skeletal muscle have?

Answer 22

Many peripheral nuclei - has long multinucleated parallel cells

Question 23

What type of control is skeletal muscle under?

Answer 23

Under voluntary (conscious) control - by general somatic efferent (GSE) fibres in the nerves

Question 24

What type of innervation is skeletal muscle under?

Answer 24

somatic

Question 25

What type of contraction occurs in skeletal muscle?

Answer 25

All or nothing

Question 26

Can skeletal muscle undergo mitosis?

Answer 26

No

Question 27

Can skeletal muscle undergo regeneration?

Answer 27

a limited amount

Question 28

What is dispersed within skeletal muscle cells to aid recovery?

Answer 28

Satellite cells

Question 29

What are the 4 components of a myofibril?

Answer 29

- Muscle fiber - Nuclei - Sarcolemma - Mitochondria

Question 30

What are the 3 components of a muscle ?

Answer 30

- Epimysium - Perimysium - Endomysium

Question 31

What causes muscle contraction?

Answer 31

Overlapping actin and myosin myofilaments - At rest actin and myosin don't touch - Before they contract thick actin filaments slide past thicker myosin so they overlap more

Question 32

What is required for muscle contraction?

Answer 32

ATP and Calcium - proteins can become unblocked

Question 33

What causes muscle contraction?

Answer 33

- Chemical energy converted to kinetic energy - Mitochondria makes ATP - Sarcoplasmic reticulum loaded with calcium pumps - and stores calcium - Action potential opens calcium channels - calcium floods into the cell - Calcium binds with troponin - Deforms tropomyosin, meaning the myosin heads can bind to the newly revealed sites on troponin - ATP --> ADP and P => releases energy - Myosin heads bind to actin - Calcium stops flooding into fibre: - nerve impulse stops - calcium has been depleted - Calcium unbinds from troponin

Question 34

How does rigor mortis occur?

Answer 34

There is no ATP to unbind the myosin from the troponin Muscle remains contracted - fixed in position rigor mortis = bridge made

Question 35

What is the nervous system?

Answer 35

A complex network of neurones and associated support cells. Peripheral vs Central Autonomic vs Somatic Motor vs Sensory

Question 36

What is a neruon?

Answer 36

Nerve cells, specialised cells that conduct electrical impulses

Question 37

What is the structure of a neurone?

Answer 37

Dendrites - extend from the cell body. They are short with many branches, the points at which nerve impulses are received by the cell. ( the listening part of the cell) Cell body - located in the central nervous system or arranged in the ganglia of peripheral nervous system Axon - single nerve fibre which transmits impulses to the distal end. (Talking part of the cell)

Question 38

What are the 4 types of neurone?

Answer 38

- Multipolar neurone - Bipolar neurone - Pseudo - unipolar neurone - Unipolar neurone

Question 39

What are supporting cells called and what do they do?

Answer 39

Glial Cells Provide support, nutrition, insulation and help with signal transmission in the nervous system

Question 40

What are the 4 types of glial cells in the central nervous system and their function?

Answer 40

- Astrocytes - Microglial cells - Ependymal cells - Oligodendrocytes

Question 41

What are the 2 types of glial cells in the peripheral nervous system and their functions?

Answer 41

Satellite cells Schwann cells

Question 42

What do Schwann cells do?

Answer 42

- provide a lipid rich insulating barrier - the myelin sheath (In peripheral nervous system)

Question 43

What is the function of satellite cells?

Answer 43

Layer of small cuboidal cells - surround and support neuron cell bodies (In peripheral nervous system)

Question 44

What is the function of oligodendrocytes?

Answer 44

Produce an insulating barrier - the myelin sheath (In peripheral nervous system)

Question 45

What is the function of oligodendrocytes?

Answer 45

- Engulf and destroy debris - part of the immune defence against invading microorganisms (In central nervous system)

Question 46

What is the function of ependymal cells?

Answer 46

- Create, secrete and circulate cerebrospinal fluid - Line ventricles of the brain - line cavities (In central nervous system)

Question 47

What is the function of astrocytes?

Answer 47

- communicate between neuron and capillary - most numerous, cover surfaces - support, regulate ions - blood brain barrier - blood to brain - involved in metabolic exchange between neurons and blood (In central nervous system)

Question 48

What is a neuromuscular junction and where are they located?

Answer 48

Originate at spinal cord or brain stem Richly innervated by motor neurons Branch near the muscle and end on individual fibres Neuromuscular junction / motor end plate