Muscles ILO's

Question 1

Myalgia

Answer 1

Muscle pain

Question 2

Myasthenia

Answer 2

Muscle weakness

Question 3

Myopathy

Answer 3

Disease of the muscles

Question 4

Myoclonus

Answer 4

A sudden spasm of the muscles

Question 5

Myocardium

Answer 5

Muscular component of the heart

Question 6

Which of the 3 types of muscle are striated?

Answer 6

Cardiac and skeletal

Question 7

In which of the 3 types of muscle tissue is myoglobin absent?

Answer 7

Smooth muscle

Question 8

Which of the 3 types of muscle tissue are under involuntary control?

Answer 8

Cardiac and smooth

Question 9

Type of nerve-muscle communication in skeletal muscle

Answer 9

Direct nerve-muscle communication

Question 10

Which types of muscle cells have indirect nerve-muscle communication?

Answer 10

Cardiac and smooth

Question 11

What is myoglobin?

Answer 11

A red protein that is structurally similar to a single subunit of haemaglobin

Question 12

Function of myoglobin

Answer 12

Stores oxygen and provides O2 to working striated muscles

Question 13

What are the 3 types of muscle fibre types?

Answer 13

Type 1 (slow oxidative fibres)
Type 2a (fast oxidative glycolytic fibres)
Type 2b (fast glycolytic fibres)

Question 14

Differences between Hb and myoglobin

Answer 14

• myoglobin doesn’t bind to CO2
• myoglobin has a higher affinity for O2 (that’s why Hb gives up its O2 to myoglobin at the muscles at low pH)

Question 15

What is Rhabdomyolysis?
What will be released into the blood stream?

Answer 15

Striated muscle damage
- Myoglobin released into bloodstream (myoglobinaemia)
- K ions will be released too - show lysis

Question 16

Describe the significance of myoglobin in the blood stream

Answer 16

• Can cause renal damage so kidney remove it from blood into the urine (myoglobinuria)
• Tea- coloured urine

Question 17

What are the different muscle contraction speeds? Describe the colours
What does each fascicle have?

Answer 17

• Slow twitch (red/dark)
• Intermediate (mix of slow twitch and fast twitch fibres)
• Fast twitch (white/light)
• Each fascicle has at least one of each

Question 18

What does continued contraction depend on?

Answer 18

• Amounts of ATP
  AND
• Ca2+ ions

Question 19

Compare and contrast fast and slow twitch fibres

Answer 19

In addition to diagram:

Type 1: Fatty acids
Type 2a: Fatty acids and glycogen
Type 2b: Glycogen

Type 1: Lots of ATP/Co2
Type 2a: Initially lots of CO2 then lots of lactate
Type 2b: Lots of lactate, little ATP

Question 20

Contrast the histology of slow and fast twitch muscle fibres (3)

Answer 20

Question 21

Where is an example of where fast twitch fibres can be found?

Answer 21

Eye muscles

Question 22

Where is an example of where slow twitch fibres can be found?

Answer 22

Soleus in the lower leg

Question 23

Describe the reparation of skeletal muscle (3)

Answer 23

• Cannot divide but can regenerate by mitotic activity of satellite cells (they divide to produce another satellite cell and a muscle cell)
• So hyperplasia follows muscle injury.
• Satellite cells can also fuse with existing muscle cells to increase mass (skeletal muscle hypertrophy)

Question 24

Reparation of cardiac muscle

Answer 24

• Regeneration is impossible so following muscle injury fibroblasts invade, divide and lay down scar tissue

Question 25

Reparation of smooth muscle

Answer 25

- Retain mitotic activity and can form new smooth muscle cells - Very good at repairing themselves

Question 26

Give an example of smooth muscle cell hypertrophy and hyperplasia

Answer 26

- Pregnant uterus where the muscle wall (myometrium) becomes thicker by hypertrophy (cell enlargement) - hyperplasia (cell division/mitosis) of individual cells, thus to increase muscle mass

Question 27

Describe the order from skeletal muscle to sarcomere

Answer 27

- Skeletal muscles surrounded by epimysium - Fasicles surrounded by perimisum - Muscle fibres/cells surrounded by endomysium - Each muscle fibre contains myofibrils - Sarcomeres are small contraction units from z line to z line

Question 28

Muscle cell component terminology (5)

Answer 28

Sarcolemma - outer membrane Sarcoplasm - cytoplasm Sarcoplasmic reticulum - smooth endoplasmic reticulum Sarcosome - mitochondria Sarcomere - contraction unit ONLY IN STRIATED

Question 29

a striated muscle cell is called a ... it's plasma membrane is called the ...

Answer 29

muscle fibre; sarcolemma

Question 30

each striated muscle cell fibre is made up of many ... which contain many ...

Answer 30

myofibrils; sarcomeres

Question 31

What length is a sarcomere?

Answer 31

Z line/disc to z line/disc

Question 32

actin filament is ... and found in the ... ... band and ... disc, whereas myosin filament is ... and found in the ... ... band and ... zone

Answer 32

actin filament is thin and found in the light I-band and Z-disc, whereas myosin filament is thick and found in the dark A-band and H-zone

Question 33

Is actin thick or thin? Is myosin thick or thin? Describe the bands present in a muscle fibre and their staining, if applicable

Answer 33

Actin - thin Myosin - thick I band - just actin so stains lighter H zone - just myosin (stains darker) A band is overlap of myosin and actin so stains DARK

Question 34

What is the M line and what does it act as?

Answer 34

- In the centre of the A band - Marks the centre of the sarcomere - Attachment site for myosin filaments

Question 35

Features of skeletal muscle fibres/cells(2)

Answer 35

Abundant mitochondria between myofibrils Nuclei are peripheral

Question 36

3 connective tissue layers in muscle Where are they found?

Answer 36

Epimysium - around whole muscle Perimysium - around fascicles Endomysium - between muscle fibres/cells Continuous to tendon

Question 37

What is the epimysium, perimysium and endomysium ?

Answer 37

Fibrous connective tissue surrounding muscle, fascicle and between muscle fibres/cells, respectively

Question 38

What does the epimysium, perimysium and endomysium do? (5)

Answer 38

- Lubricate (mainly perimysium) - Protect - Strengthen - Separate - Bind

Question 39

What do the epimysium, perimysium and endomysium contain ?

Answer 39

- Blood vessels - Lymphatic vessels - Nerves ... Supplying the muscles

Question 40

a bundle of muscle fibres is called a ... and is surrounded by ...

Answer 40

fascicle; perimysium

Question 41

What's the difference between epimysium and endomysium and perimysium?

Answer 41

epimysium covers the whole muscle body endomysium covers individual muscle fibres (perimysium covers fascicles)

Question 42

How do different fibres require different amounts of blood?

Answer 42

Thin fibres need less blood, thick fibres need more blood

Question 43

Which band contains actin only? What colour is it?

Answer 43

I band It is light

Question 44

Which band contains myosin only?

Answer 44

H zone (It is part of the dark A band)

Question 45

Which band contains actin and myosin? What colour is it?

Answer 45

A band It is dark

Question 46

What is a sarcomere?

Answer 46

The contractile unit of striated muscle

Question 47

What are the similarities between cardiac and smooth muscle cells histology?