Skeletal, Smooth and Cardiac Muscle Structure and Contraction

Question 1

Muscle fibre structures are…

Answer 1

1. Striated
2. Unbranched
3. Multi-nucleated

Question 2

The 3 different types of Muscle Fibres are…

Answer 2

1. Type 1
2. Type 11A
3. Type 11

Question 3

Contraction is….

Answer 3

Neurogenic

Question 4

Type 1 Muscle Fibres are also called…

Answer 4

Slow Twitch

Question 5

Slow Twitch (Type 1) features are….. (2)

Answer 5

1. Very aerobic
2. Low Fatigue (fibres can contract for a long period)

Question 6

Slow Twitch (1) fibres are used in… (2)

Answer 6

1. Postural Control
2. Repetitive slow locomotion

e.g. Marathon Running

Question 7

Type 11a Fibres are also called….

Answer 7

Fast Twitch (Oxidative) Fibres

Question 8

Fast Twitch Fibres (11a) features are…. (3)

Answer 8

1. Aerobic - somewhat resistant to fatigue
2. Uses oxygen to convert glycogen to ATP (glycolysis)
3. Oxidative

Question 9

Fast Twitch fibres are used in….

Answer 9

Repetitive, fast locomotion

e.g. Sprinting

Question 10

Type 11x Fibres are also called…

Answer 10

Fast-twitch (Glycolytic) Fibres

Question 11

Fast-twitch (11x) Fibres features are… (2)

Answer 11

1. Anaerobic - high power output, fatigue easily
2. Rely on stored ATP to generate energy

Question 12

Fast-twitch (11x) are used for…

Answer 12

1. High output energy

e.g. Weightlifting

Question 13

What are Slow twitch fibres microscopic features? (3)

Answer 13

1. Smaller diameter
2. Darker in colour (due to myoglobin)
3. Numerous Mitochondria and capillaries (to produce ATP)

Question 14

What are Fast twitch Fibres microscopic features? (3)

Answer 14

1. Larger diameter
2. Lighter in colour
3. Less mitochondria (not needed as anaerobic)

Question 15

Skeletal muscle are attached to bones by…

Answer 15

Tendons

Question 16

What is the Skeletal Muscle Anatomy route from largest to smallest… : Myofibril, Fascicle, Muscle Fibre, Deep Fascia

Answer 16

Deep Fascia -> Fascicle -> Muscle Fibre -> Myofibril

Question 17

Actin are _____ filaments

Answer 17

Thin

Question 18

Myosin are ______ filaments

Answer 18

Thicker

Question 19

3 Types of connective tissue in Skeletal Muscle

Answer 19

1. Epimysium (around muscle)
2. Perimysium (around fascicles)
3. Endomysium (around myofibril)

Question 20

Muscle Myofibrils make up a _________

Answer 20

Sarcomere

Question 21

Sarcomeres are found between….

Answer 21

Two Z discs

Question 22

Sarcomeres contain the two proteins….

Answer 22

Actin and Myosin

Question 23

Muscle contraction occurs when ______ pulls ______ to shorten the sarcomere

Answer 23

1. Myosin
2. Actin

Question 24

Actin and Myosin are attached to ___ line by _____ _______

Answer 24

1. Z
2. Alpha Actin

Question 25

What is the role of Titin?

Answer 25

Keeps myosin straight

Question 26

Describe the Process leading up to Muscle Contraction in 7 Steps....

Answer 26

1. AcH is released from an Axon terminal of a motor neurone 2. AcH binds to receptors in the motor end plate 3. This produces an end-plate potential which triggers AP in muscle cell 4. AP travels along sarcolemma of muscle and down T tubules 5. AP triggers Ca2+ release from Sarcoplasmic reticulum 6. Ca2+ binds to troponin and activates power stroke 7. After power stroke, Ca2+ is actively transported back into lumen on SR.

Question 27

Describe the Power stoke Theory in 4 Steps....

Answer 27

1. Calcium from SR floods in and binds to the tropomyosin, moving the tropomyosin away from Actin binding sight. 2. Myosin head binds with the Actin sights producing Actin-Myosin cross-bridges. 3. ATP is converted to ADP + Pi, releasing energy to change Myosin head position (slanted) 4. Actin is pulled past the myosin - Power stroke 5. Actin-myosin cross bridge is broken when an ATP binds to the myosin head.

Question 28

During contraction the I (actin) band....

Answer 28

Gets smaller

Question 29

During contraction the Z band distance...

Answer 29

Gets smaller

Question 30

During contraction the H (myosin) band....

Answer 30

Gets smaller

Question 31

3 Functions of ATP in Skeletal Muscle Contraction....

Answer 31

1. Hydrolysis of ATP for power stroke 2. Allows cross-bridge to be formed between actin and myosin 3. Movement of Ca2+ ions into the SR

Question 31

During contraction the A (actin and myosin) band....

Answer 31

Stays the same

Question 32

Smooth Muscle is....

Answer 32

Involuntary

Question 33

Smooth muscle cells are ______ in shape

Answer 33

Spindle

Question 34

Does smooth muscle contain actin and myosin?

Answer 34

Yes

Question 35

How is actin and myosin linked in smooth muscle?

Answer 35

Intermediate filaments

Question 36

What is the structure of Smooth Muscle? 1. Striated 2. Branched 3. Not striated

Answer 36

3. Not striated

Question 37

What connects adjacent cells....

Answer 37

Gap junctions

Question 38

What are the two types of Smooth Muscle?

Answer 38

1. Single Unit 2. Multi Unit

Question 39

What are examples of single unit SM?

Answer 39

Bronchi, Bladder, Uterus, GIT

Question 40

What are examples of multi unit SM?

Answer 40

Iris muscles, ciliary muscles

Question 41

What controls cross bridge activity?

Answer 41

Calcium Ions - Required to bind to Tropomyosin

Question 42

What is the structure of Cardiac muscle? (2) 1. Striated 2. Non-striated 3. Branched

Answer 42

1. Striated 3. Branched

Question 43

Intercalated discs provide...

Answer 43

Stability

Question 44

What is the function of gap junctions?

Answer 44

Communication, spread of signals between cells