Muscle Tissues

Question 1

What is epimysium?

Answer 1

Fibrous elastic tissue that surrounds a muscle

Question 2

What is endomysium?

Answer 2

Loose connective tissue that surrounds each muscle cell/muscle fibre

Question 3

What is perimysium

Answer 3

Surrounds. A bundle of muscle fibres eg a fascicles

Question 4

In skeletal muscles , are nuclei central or peripheral ?

Answer 4

Peripheral

Question 5

What are the three different types of muscle fibres ?

Answer 5

1) slow twitch
2) fast twitch

3 intermediate twitch

Question 6

What type of respiration do Type 1( slow twitch) , Type 2A and type 2b ( fast twitch) fibres undergo?

Answer 6

Type 1 and type 2A- aerobic which means they have many mitochondria , many cytochromes , have a rich capillary supply

Type 2B - anaerobic - which means they have few cytochromes, few mitchondria , poor capillary supply

Question 7

What colour do each muscle fibres appear ?

Answer 7

Slow twitch - red ( high myoglobin levels)

Type 2A - red to pink ( high myoglobin levels)

Type 2B - white

Question 8

What type of activity would you expect to use type 1 fibres ?

Answer 8

Endurance type

Question 9

What type of activity would you expect type 2B to be used?

Answer 9

• strength activities

Question 10

What does slow oxidative mean and what type of fibres produce ATP through this method?

Answer 10

• type 1
• produce many ATP through oxidative phosphorylation
• 36 mol / glucose ATP to allow low power contractions over long periods.

Question 11

What does fast oxidative glycolytic fibres mean?

Answer 11

• produce ATP through aerobic and anaerobic respiration.

- type 2A fibres use this

Question 12

What fibres use fast glycolytic ?

Answer 12

Type 2B - generate ATP through anaerobic respiration , produce lactate.

• generate ATP at a slow rate.

Question 13

What are a few similarities between cardiac muscles and skeletal muscles ?

Answer 13

• both striated

- contraction mechanisms are the same

Question 14

What are a few differences between cardiac and skeletal muscle?

Answer 14

• cardiac have intercalated discs which have low electrical resistance.
• cardiac are involuntary whereas skeletal are voluntary
• cardiac are uninucleated whereas skeletal are multinucleated.
• in skeletal muscles , nuclei are peripheral whereas in cardiac they are central
• in cardiac muscles , there is only one type of contractile cell- this being the cardiomyocyte.

Question 15

How does the heart conduct electricity ?

Answer 15

1) action potentials are originated at the SAN in the right atria. This is sent across the atria causing them to contract. There is a non-conducting collagen fibre which prevents ventricles from contracting at this point.
2) action potentials are sent to the AVN .
3) action potentials then travel slowly across the AV bundle , then to bundle of his
4) then descends to Apex - then to purkyne fibres which conduct action potentials RAPIDLY

Question 16

What are a few characteristics of purkyne fibres ?

Answer 16

• they conDuct electricity very quickly
  2) have large cells
  3) lots of glycogen
  4) have extensive gap junctions to let ions pass through quickly .

Question 17

What are a few characteristics of smooth muscles ?

Answer 17

• non striated
• involuntary
• uninucleated
• spindle shaped
• no sarcomeres , no T tubules
• nuclei are in the centre
• contraction is slower , requires less ATP

Question 18

What would you expect from a TEM u,trastructure of smooth muscle ?

Answer 18

• fewer mitochondria
• gap junctions formCa2+ to enter
• caveolae

Question 19

What are a few examples of where smooth muscle is found ?

Answer 19

• gut
• respiratory tract
• reproductive and urinary systems

Question 20

What are a few illnesses that smooth muscle is responsible for ?

Answer 20

• asthma
• painful menstruations
• high blood pressure
• abnormal gut mobility eg diorreah and constipation

Question 21

Is muscle repair possible in skeletal muscle ?

Answer 21

• muscle cells themselves cannot divide , but satellite cells which are a type of stem cells can divide by mitosis resulting in hyperplasia .
• they can also fuse with existing skeletal muscles cells to increase muscle mass ( hypertrophy)

Question 22

Is muscle repair possible in cardiac muscle ?

Answer 22

• only on children , not adults
• in adults , fibroblasts invade and divide and lay down scar tissue

-

Question 23

Can smooth muscle repair itself ?

Answer 23

Yes , they retain their mitotic ability , for example during pregnancy muscle wall expands and in asthma.

Question 24

Where in the body would you find many type 1 muscle fibres ?

Answer 24

Postural muscles such as those in the spine and neck.

Question 25

Where would you find type 2A muscle fibres ?

Answer 25

• muscles of the arms

Question 26

What do,our does the endomysium and perimysium stain with trichrome?

Answer 26

Blue/cyan

Question 27

What donintercalated discs comprise of ?

Answer 27

Gap junctions

Desmosomes

Fascia adherens

Question 28

What is the role of calveoli on the sarcolemma surface of smooth muscle cells ?

Answer 28

• constantly sample the external environment and use the contents to initiate some forms of contraction.

Question 29

Why are purkyne cells usually stained pale white ?

Answer 29

• high glycogen content

Question 30

Where is the sinoatrial node located ?

Answer 30

• in the wall of the heart (myocardium) of the right atrium , in a region called sinus venarum.

Question 31

During skeletal muscle damage what components would be found in blood ?

Answer 31

• tropnin C , I, T
• creatine kinase
• K+ ( because high intracellular concentration)

Question 32

During cardiac muscle damage an increase of what components would be found in blood ?

Answer 32

k+

• troponin I
• creatine kinase

Question 33

In smooth muscle damage , what components would be found in the blood

Answer 33

k+ only