part 1

Question 1

What are the three types of muscle tissue?

Answer 1

Skeletal - striated - for support and movement
Smooth - non striated - found in GIT and intestines
Cardiac - striated - To pump blood around the body and regulates BP

Question 2

What are the functions of muscle tissue?

Answer 2

For protection and movement
Generates heat
Stabilizing body position
Storing and moving substances

Question 3

What are the properties of muscles?

Answer 3

Excitability
Elasticity
Contractility
Electric excitability

Question 4

Muscle fibers are formed during the development of myobLasts. TRUE OR FALSE?

Answer 4

TRUE

Question 5

Muscle growth is via hypertrophy. TRUE OR FALSE?

Answer 5

TRUE

Question 6

Where is calcium stored?

Answer 6

In sarcoplasmic reticulum

Question 7

Sarcoplasm does not contains glycogen for ATP and myoglobin for oxygen. TRUE OR FALSE?

Answer 7

FALSE

Question 8

What is myofibrils?

Answer 8

It is a contractile organelle

Question 9

What are filaments and how are they arranged?

Answer 9

Filaments are thin and long and are directly involved in contractile of the muscles, they are arranged in sacromeres

Question 10

Describe the basic functional units of muscle

Answer 10

Z-discs - separate the sacromeres
A-band - Darker middle part which extends the length of thick filaments
End of A-band - zone of overlap with thin filaments
H-band - Within the overlap - center of A-band with thick but no thin filaments
M-Line - is the middle of the sacromere
I-band - is lighter area with thin filaments only

Question 11

What are the two muscle proteins?

Answer 11

Actin and myosin

Question 12

Myosin is the thick filaments, it functions as a protein molecule converting chemical energy ATP into mechanical energy. STATEMENT TRUE OR FALSE?

Answer 12

TRUE

Question 13

Actin is the main component of thin filaments and it joins to form a helix, each actin molecule has a myosin binding site. TRUE OR FALSE?

Answer 13

TRUE

Question 14

Tropomyosin is a component of thin filaments and troponin is thin filament that binds calcium. STATEMENT TRUE OR FALSE?

Answer 14

TRUE

Question 15

What does titin do?

Answer 15

It connects Z disc to M-line

Question 16

What does alpha actinin do?

Answer 16

Z disc protein that binds actin and titin

Question 17

What does myomesin do?

Answer 17

M-line protein that binds titin

Question 18

What does nebulin do?

Answer 18

it wraps around thin filaments

Question 19

What does dystrophin do?

Answer 19

it binds to thin filaments

Question 20

Calcium concentrations in the cytosol does not regulate contraction and relaxation. TRUE OR FALSE?

Answer 20

FALSE

Question 21

Describe the events of muscle contraction?

Answer 21

1. Myosin head hydrolyzes ATP into ADP +Pi
2. Myosin head binds to actin forming a crossbridge
3. Myosin head rotates towards center of the sarcomere (known as a power stroke)
4. As myosin head binds ATP , crossbridge detaches from myosin and back to start.

Question 22

AP propagates into t-tubules and induces ca release from sarcoplasmic reticulum, ca binds troponin which alters the conformation, tropomyosin uncovers myosin binding sites on actin. TRUE OR FALSE?

Answer 22

TRUE

Question 23

After termination of AP, ca is pumped back into the SR . TRUE OR FALSE?

Answer 23

TRUE

Question 24

Describe the different stages of twitch contraction?

Answer 24

Latent period - Action potential occurs and ca is released from Sarcoplasmic reticulum
Contraction period - Formation of crossbridges and tension development (lasts 10-100msec)
Relaxation period - Ca is brought back to Sarcoplasmic reticulum (lasts 10-100msec)
Refractory period - Resistant to re-stimulation

Question 25

What are the two types of skeletal muscle fibres?

Answer 25

Red muscle fibres - Have high myoglobin, mitochondria concentration and are rich in capillaries White muscle fibres - Are low in myoglobin concentration.

Question 26

What are the three main types of muscle fibres? (that can cause fatigue)

Answer 26

Slow oxidative Fast oxidative glycolytic Fast glycolytic

Question 27

Describe slow oxidative muscle fibres

Answer 27

The least powerful and shortest in diameter, has slow contraction twitch and resistant to fatigue (used to maintain posture and for long endurance activities)

Question 28

Describe fast oxidative glycolytic muscle fibres

Answer 28

Have high concentration of myoglobin and capillaries, they generate ATP by aerobic cellular respiration, they also generate ATP from glycogen They have faster twitch contraction and are used for activities such as walking

Question 29

Describe fast glycolytic fibres

Answer 29

Longest in diameter, and most powerful Low myoglobin, mitochondria and few capillaries Strong fast contractions ATP is produced via glycolysis using glycogen Meant for quick anaerobic movement for short durations for example weight lifting

Question 30

Length of sarcomere determines the rate of contraction. TRUE OR FALSE?

Answer 30

TRUE

Question 31

What is the Neuromuscular junction?

Answer 31

Site between synapse and muscle cell

Question 32

Synaptic cleft - AP cannot jump across so needs NT Axon terminal - synaptic vessicles containing ACh molecules Motor end plate - ACh receptors - ligand gated ion channel ARE ALL THESE TRUE OF FALSE?

Answer 32

TRUE

Question 33

Describe the events of NT at neuromuscular junction

Answer 33

1. ACh is released from synaptic vessicles 2. Ach binds to ACh receptors 3. Muscle action potential is produced 4. ACh is broken down

Question 34

Botulinum toxin , blocks exocytosis so muscle contraction does not occur and breathing stops (can also be used for treatment of botox and wrinkles) Curare - Blocks ACh receptors - so no ion channels open Anticholinesterase agents - slows ACh removal and prolongs its action. ARE ALL THESE STATEMENTS TRUE OR FALSE?

Answer 34

TRUE

Question 35

What are the different types of ways for making ATP for muscles?

Answer 35

1. From creatine phosphate 2. ATP from anaerobic glycolysis 3. ATP from aerobic cellular respiration

Question 36

What is proprioception input?

Answer 36

It allows the brain to know where limbs are and it allows for distribution of weight for example muscle spindles

Question 37

What do muscle spindles do?

Answer 37

They monitor changes in skeletal muscle length, it consist of nerve endings wrapped around in intrafusal muscle fibres and is surrounded by a connective tissue capsule

Question 38

What is muscle fatigue?

Answer 38

The inability of muscles to maintain force of contraction after prolonged period of time.

Question 39

What are the mechanisms that cause muscle fatigue?

Answer 39

1. Oxygen insufficiency - glycogen depletion 2. Production of lactic acid 3. Creatine phosphate levels also decrease 4. inadequate release of ca from SR 5. Decreased Ach release

Question 40

What is polymositis and how can it be treated?

Answer 40

It is an inflammatory autoimmune disease, leads to destruction of muscle fibres, gradually obtain muscle weakness. It can be treated with steroid glucocorticoids

Question 41

What is muscle dystrophy and how can it be treated?

Answer 41

It is a group of inherited diseases, which causes mutation in different genes/the severity of it can vary as it can appear in childhood. Treatments include providing medication to help with cardiac complications, corticosterioids in duchenne MD and pace maker in emerydreifuss MD.

Question 42

What is myasthemia gravis?

Answer 42

It is an autoimmune disease where the body produces antibodies against Ach, it causes muscle weakness after prolonged use. It is treated with acetylcholinesterase inhibitor, steroids, immunosuppressants and in emergency IV ig