Muscular System

Question 1

What is the main function of the muscular system?

Answer 1

Contractibility - muscles attached to bones, internal organs + blood vessels are responsible for movement

Muscles attached to bones or internal organs and blood vessels are responsible for movement.

Question 2

What type of muscles are skeletal muscles?

Answer 2

Voluntary

Skeletal muscles respond to voluntary messages from the nervous system.

Question 3

Describe the shape and appearance of skeletal muscle fibres.

Answer 3

Cylindrical shape, striated appearance, lots of nuclei

These fibres are organized into bundles supplied by blood vessels.

Question 4

How are skeletal muscles attached to bones?

Answer 4

Through tendons

Question 5

How does skeletal muscle move bone?

Answer 5

By contracting and relaxing in response to voluntary messages from the nervous system

Question 6

How are skeletal muscle fibres organised?

Answer 6

In bundles supplied by blood vessels and innervated by motor neurons

Question 7

What is the shape and nucleus count of smooth muscle fibres? Where are they found?

Answer 7

Spindle shaped, single nucleus, involuntary muscles, in walls of internal organs such as bladder and uterus.

Smooth muscles are involuntary and found in the walls of internal organs.

Question 8

Where is cardiac muscle found?

Answer 8

In the heart

Question 9

What is unique about the shape and nucleus count of cardiac muscle fibres?

Answer 9

Branch shaped, 1 nucleus, striated appearance

Question 10

What is the function of connective tissue?

Answer 10

Supports and connects parts of the body

Question 11

What type of cells are fibroblasts and what do they produce?

Answer 11

Cells that produce extracellular material needed in connective tissue

This includes ground substance and fibres.

Question 12

What are adipocytes and what do they contain?

Answer 12

Large cells containing lipids stored in droplet formation

Question 13

What is the role of leukocytes?

Answer 13

To provide immune defence responses

Question 14

What are the two types of connective tissue?

Answer 14

Connective tissue proper and specialized connective tissue

Question 15

What does loose adipose connective tissue do?

Answer 15

Protects organs, located beneath skin, around organs, in breasts

Question 16

What is the function of loose aerolar connective tissue?

Answer 16

Binds organs

Question 17

Where are dense regular fibroblasts found?

Answer 17

In tendons and ligaments

Question 18

What does dense irregular fibroblasts connective tissue protect?

Answer 18

Organs, dermis of skin, surrounds organs/bones

Question 19

What is the role of bone in specialized connective tissue?

Answer 19

Provides support for body and movement

Question 20

What do blood cells transport?

Answer 20

Nutrients, gases, and waste products

They are part of the cardiovascular system.

Question 21

What is the function of cartilage?

Answer 21

Softens joint movements, provides shape in airways and structure to body parts

Question 22

What are the characteristics of Slow Twitch (Type 1) muscle fibres?

Answer 22

Aerobic, red colour, contract slowly over long periods, lots of mitochondria, lots of capillaries, fatigue slowly - used in marathons

Examples include marathon and cycling.

Question 23

What are the characteristics of Fast Twitch (Type 2a) muscle fibres?

Answer 23

Anaerobic, pale colour, fast contraction speed, fatigue slowly, low number of capillaries and mitochondria - used in weight training and 400m sprint

Used in weight training and 400m sprint.

Question 24

What are the characteristics of Fast Twitch (Type 2b) muscle fibres?

Answer 24

Anaerobic, very fast contraction speed, fatigue very quickly - used in 100m sprint

Used in 100m sprint.

Question 26

What theory explains muscle contractions?

Answer 26

Sliding filament theory - when thin filaments slide past thick ones

Question 27

What is the definition of muscle contraction?

Answer 27

Process leading to the shortening and development of tension in muscle tissue, triggered by nerve conduction

Question 28

What are muscle fibers made of?

Answer 28

Myofibrils

Question 29

What do myofibrils consist of?

Answer 29

Sarcomeres with actin and myosin

Question 30

What forms cross bridges in muscle contraction?

Answer 30

Binding of actin and myosin

Question 31

What is the first step in the process of muscle contraction?

Answer 31

Nerve impulse arrives at the neuromuscular junctions, releasing acetylcholine - depolarisation causes calcium release

Question 32

What happens after calcium is released during muscle contraction?

Answer 32

Calcium binds to troponin, moving tropomyosin off actin binding sites

Question 33

What forms the cross-bridge during muscle contraction?

Answer 33

Myosin heads binding to actin

Question 34

What does the hydrolysis of ATP allow during muscle contraction?

Answer 34

Releases energy allowing myosin to 'cock' its head and pull actin to create an overlap (a muscle contraction)

Question 35

What happens when ATP binds to the myosin head?

Answer 35

The cross bridge is broken

Question 36

What is required for the continuation of muscle contraction?

Answer 36

ATP binding to myosin head to bind to another actin site

Question 37

What causes the contraction to stop?

Answer 37

Depletion of ATP and calcium

Question 38

What happens to actin binding sites when contraction stops?

Answer 38

Covered again with tropomyosin

Question 39

Where is the pelvic floor located and what it's main functions?

Answer 39

Across base of the core connecting coccyx and pubic bone. Functions - support (bladder, bowel, uterus), control (of bladder and bowel), sex

Question 40

What is an isometric contraction?

Answer 40

When the muscle contracts and stays the same length e.g. in a plank

Question 41

What is an isokinetic contraction? Where is it possible?

Answer 41

When the movement takes place at a constant speed and the muscle changes length during contraction. Only in specialist settings

Question 42

What is an isotonic contraction?

Answer 42

When the muscle either shortens or lengthens during contraction

Question 43

What are the 2 types of an isotonic contraction?

Answer 43

Concentric and eccentric

Question 44

Describe the difference between concentric and eccentric contractions (give and example)

Answer 44

Concentric = when the muscle shortens during contraction e.g. biceps in lifting phase of bicep curl. Eccentric = when the muscle lengthens during contractions e.g. biceps in downwards phase of bicep curl.