The muscle

Question 1

What are the functions of muscle?

Answer 1

• Produce movement
• Maintenance of posture
• Respiration
• Generate heat
• Communication
• Contraction of organs and vessels
• Contraction of heart

Question 2

What are the four functional characteristics of muscle?

Answer 2

• Contractibility - shorten forcefully/contract
• Excitability - ability to respond to stimulus
• Extensibility - ability to stretch
• Elasticity - ability to recoil

Question 3

What are the three muscle types?

Answer 3

• Skeletal
• Smooth
• Cardiac

Question 4

Where are skeletal muscles found?

Answer 4

• Attached to bones
• Some facial muscles attached to the skin

Question 5

Where is smooth muscle found?

Answer 5

• Single-unit muscles found in walls of hollow visceral organs (other than the heart)
• Multiunit muscle in intrinsic eye muscles, air-ways, large arteries

Question 6

Where is cardiac muscle found?

Answer 6

• Walls of the heart

Question 7

Describe appearance and cell shape of smooth muscle

Answer 7

Spindle shape

Question 8

Describe appearance and cell shape of cardiac muscle

Answer 8

Branched, cylindrical

Question 9

Describe appearance and cell shape of skeletal muscle

Answer 9

Long, cylindrical

Question 10

Describe the nucleus in skeletal muscle

Answer 10

Multiple nucleus, peripherally located (on the outside)

Question 11

Describe the nucleus in smooth muscle

Answer 11

Single nucleus, centrally located

Question 12

Describe the nucleus in cardiac muscle

Answer 12

One or two, centrally located

Question 13

What type of muscle has a special intracellular connection?

Answer 13

Cardiac muscle - intercalated

Question 14

Which muscle types have striations?

Answer 14

Skeletal and cardiac

Question 15

How is skeletal muscle controlled?

Answer 15

Mostly voluntary
Involuntary reflexes

Question 16

How is smooth muscle controlled?

Answer 16

Involuntary control
Autonomic nervous system

Question 17

How is cardiac muscle controlled?

Answer 17

Involuntary control
Autonomic nervous system

Question 18

What is the function of skeletal muscle?

Answer 18

Move the whole body

Question 19

What is the function of smooth muscle?

Answer 19

• Move food through digestive system
• Empty urinary bladder
• Regulate blood vessel diameter
• Contract many glands

Question 20

What is the function of cardiac muscle?

Answer 20

Contract heart

Question 21

What are the two points where skeletal muscle attaches to bone called?

Answer 21

Origin aka head and Insertion

Question 22

What attachment point in skeletal muscle moves the most?

Answer 22

The origin

Question 23

What is the skeletal body between the origin and insertion called?

Answer 23

Belly

Question 24

How many origins does the bicep have?

Answer 24

2 origins

Question 25

How many origins does the tricep have?

Answer 25

3 origins

Question 26

What is the process of multiple skeletal muscles working together called?

Answer 26

synergists

Question 27

What skeletal muscle makes the major contribution?

Answer 27

The prime mover

Question 28

What are the skeletal muscles which stabilise structures called?

Answer 28

Fixators

Question 29

What do muscle cells need in order to contract?

Answer 29

Force

Question 30

What is required for a muscle to return to its original position after contraction?

Answer 30

1. Gravity 2. Antagonist - any muscle that opposes the action of the prime mover

Question 31

Give an example of a situation with an antagonist and a prime mover

Answer 31

Extension of elbow Prime mover = Triceps Antagonist = Bicep

Question 32

When naming muscles, brevis is given to what muscle?

Answer 32

Short muscle

Question 33

Longus muscle refers to what type of muscle?

Answer 33

Long muscle

Question 34

What shape is deltoid?

Answer 34

Triangular

Question 35

What shape is quadratus?

Answer 35

Rectangular

Question 36

What shape is teres?

Answer 36

Round and cylindrical

Question 37

In what direction does an abductor move?

Answer 37

Away from

Question 38

In what direction does an adductor move?

Answer 38

Towards midline

Question 39

What do muscles do when there is an impulse to stimulate them?

Answer 39

Contract and shorten

Question 40

What do muscles do when there is no impulse to stimulate them?

Answer 40

Return to original length - requires gravity and an antagonist

Question 41

What is the name of the site where neurons meet the muscle?

Answer 41

The neuromuscular junction

Question 42

What is the outermost layer which encloses the whole muscle called?

Answer 42

The fascia

Question 43

What is the epimysium? Where is it?

Answer 43

- In the deep facia - Dense fibrous connective tissue that surrounds the whole muscle - It lies between neighbouring cells

Question 44

What is the perimysium?

Answer 44

- Connective tissue - Encloses a bundle of muscle cells - Wraps a fascicle

Question 45

What is the endomysium?

Answer 45

- Loose connective tissue - Between each individual muscle fibre

Question 46

Muscle cells are also known as

Answer 46

Muscle fibres

Question 47

What is the name for a plasma membrane in skeletal cells?

Answer 47

sacrolemma

Question 48

What is the name for the cytoplasm in skeletal cells?

Answer 48

Sacroplasm

Question 49

What is the name for the endoplasmic reticulum in skeletal cells?

Answer 49

Sacroplasmic reticulum

Question 50

Where are myofibrils found?

Answer 50

In skeletal muscle

Question 51

What is the contactile unit of myofibrils called?

Answer 51

sarcomere

Question 52

How do a muscles myofilaments provide the mechanisms for movement?

Answer 52

- Skeletal muscles are composed of muscle fibres - Muscle fibres are made up of repeating units sarcomeres (contactile unit) - Each sarcomere contains many overlapping thin actin and thick myosin filaments - The muscle contracts when the filaments slide past eachother resulting in a shortening of the sarcomere and thus the muscle

Question 53

What is the neuromuscular junction?

Answer 53

The synapse between a somatic motor and skeletal muscle - AKA presynaptic button

Question 54

What is between a motor neuron and muscle tissue?

Answer 54

Synaptic cleft (a gap)

Question 55

What are neurotransmitters?

Answer 55

Chemical messengers

Question 56

What is the most common neurotransmitter in muscle contraction?

Answer 56

Acetylcholine (Ach)

Question 57

What happens when a nerve impulse reaches a motor neuron?

Answer 57

Calcium ions flood into the cell

Question 58

What happens when calcium floods into the cell?

Answer 58

The cell (motor neuron) excretes its content via the synaptic cleft - Release of Ach

Question 59

What happens when Ach is released?

Answer 59

Activation of Ach receptors

Question 60

What does the binding of Ach to Ach receptors cause?

Answer 60

Production of a muscle action potential as it allows sodium to flow in

Question 61

What happens after the muscle has been stimulated?

Answer 61

Termination of Ach activity by Aceytlcholinesterase (AChE) enzyme

Question 62

What are skeletal muscle cells called?

Answer 62

Skeletal muscle fiber

Question 63

Describe the composition of a thin filament when muscle is relaxed

Answer 63

Myosin is blocked from binding to actin because of strand of tropomyosin blocking the active sites of actin

Question 64

Explain how thin filaments slide over thick filaments

Answer 64

1. Troponin-ca+ complex pulls tropomyosin away, exposing myosin myosin binding sites 2. ATP is hydrolysed when myosin head is unattached 3. ADP +Pi are bound to myosin as myosin head attaches to actin 4. ADP + Pi release causes the head to change position and actin filament to move 5. Bonding of ATP causes myosin head to return to resting position