Muscles

Question 1

What is a muscle?

Answer 1

pieces of soft tissue throughout the human body

Question 2

What is the dominant tissue throughout the heart and walls of other hollow organs?

Answer 2

muscle

Question 3

What moves and supports body organs?

Answer 3

muscle

Question 4

How much of the body mass does muscle form?

Answer 4

nearly half

Question 5

How many muscles are there in the human body?

Answer 5

over 600

Question 6

what are the four properties of muscle?

Answer 6

excitability
contractility
elasticity
extensibility

Question 7

What is electrical excitability?

Answer 7

The ability to respond to stimuli from neurotransmitters

Question 8

What are neurotransmitters?

Answer 8

chemicals by which neurons translate

Question 9

What can stimulation from neurotransmitters to muscles eclicit?

Answer 9

an action potential or nerve impulse

Question 10

What is contractibility?

Answer 10

The ability of a muscle to shorten in response to an action potential

Question 11

What is extensibility?

Answer 11

The ability of a muscle to stretch without injury

Question 12

What is elasticity?

Answer 12

The ability of a muscle to recover its original shape after contracting or extending

Question 13

What are the 7 functions of the muscular system?

Answer 13

1. body movements
2. stabilizing joints
3. maintaining body posture
4. storing substances
5. movement of substances
6. thermogenesis
7. communication

Question 14

What is thermogenesis?

Answer 14

The production of heat as a by-product of contraction

Question 15

How does the muscular system allow body movements?

Answer 15

by contracting and releasing around joints

Question 16

What substances does the muscle move around the body? name 3

Answer 16

1. blood
2. air
3. food

Question 17

What are the three types of muscle?

Answer 17

1. cardiac muscle
2. Skeletal muscle
3. smooth muscle

Question 18

Where is cardiac muscle found?

Answer 18

only in the heart

Question 19

What forms the bulk of the heart wall (myocardium)?

Answer 19

cardiac muscle

Question 20

What does the cardiac muscle do?

Answer 20

contracts rhythmically and continuously to provide the pumping action necessary for life

Question 21

What other muscle type is cardiac muscle similar to in structure?

Answer 21

skeletal muscle

Question 22

What are the two names for a cardiac muscle cell?

Answer 22

1. cardiac muscle fibre
2. cardiomyocyte

Question 23

What is the structure of cardiac muscle?

Answer 23

does not taper but forms intercalated discs

Question 24

What is a syncytium?

Answer 24

a unit of combined cardiac muscle cells

Question 25

What kind of mitochondria does cardiac muscle have? why?

Answer 25

large mitochondria for a constant supply of energy

Question 26

What are smooth muscles?

Answer 26

unstriated involuntary muscles found in internal organs

Question 27

Where are smooth muscles found? (3)

Answer 27

internal organs blood vessels the intrinsic muscle of the eye

Question 28

What do smooth muscles enable? give an example

Answer 28

involuntary visceral contraction such as vasoconstriction

Question 29

Do smooth muscles have striations or T-tubules?

Answer 29

no

Question 30

How are smooth muscles organised?

Answer 30

loosely in the sarcoplasmic reticulum

Question 31

How are the thick and thin filaments in smooth muscle arranged? what happens when they contract?

Answer 31

they are arranged differently and when contracted pull the cell into a ball

Question 32

which muscle cells can be single unit or multi unit?

Answer 32

smooth muscle cells

Question 33

How do single-unit muscle cells contract?

Answer 33

as one unit

Question 34

How do multi unit muscle cells contract?

Answer 34

they contract on the cell stimulated

Question 35

Where are single unit muscle cells found?

Answer 35

on the walls of hollow organs

Question 36

Are single or multi unit muscle cells more common?

Answer 36

single unit muscle cells are more common

Question 37

Where are multi unit muscle cells found? (3)

Answer 37

around large blood vessels, in the respiratory airways and in the eyes

Question 38

In the structure of a skeletal muscle, what is the endomysium?

Answer 38

a thin layer of delicate connective tissue that surrounds each individual muscle fiber

Question 39

In the structure of a skeletal muscle, what is the perimysium?

Answer 39

a layer of collagenous connective tissue that separates the muscle tissue into bundles (fascicles)

Question 40

In skeletal muscle structure, what is a fascicle?

Answer 40

a bundle of skeletal muscle fibers

Question 41

In skeletal muscle structure, what is the epimysium?

Answer 41

a dense layer of connective tissue that surrounds the entire muscle

Question 42

Where in the muscle does the tendon anchor the bone to the muscle?

Answer 42

at the epimysium

Question 43

Instead of a tendon, what else can anchor muscle to bone?

Answer 43

the aponeurosis

Question 44

What is the aponeurosis?

Answer 44

a flat sheet of connective tissue that can connect muscle to bone

Question 45

what are the three general functions of skeletal muscle tissue?

Answer 45

1. movement 2. Heat production 3. posture

Question 46

What are the three main characteristics of skeletal muscle tissue?

Answer 46

1. excitability or irritability 2. Contractability 3. Extensibility

Question 47

What is excitability or irritability in skeletal muscle tissue?

Answer 47

the ability to respond to stimulus

Question 48

What is contractibility in skeletal muscle tissue?

Answer 48

the ability to shorten in length

Question 49

What is extensibility in skeletal muscle tissue?

Answer 49

the ability to extend in length

Question 50

A skeletal muscle cell is an individual _______

Answer 50

fibre

Question 51

Each muscle fibre is composed of several hundred to several thousand _________

Answer 51

myofibrils

Question 52

What are myofibrils in skeletal muscle cells?

Answer 52

a contractile structure within a muscle fibre containing protein filaments called thick and thin myofilaments

Question 53

What do myofilaments do in skeletal muscle cells?

Answer 53

they slide against each other when the muscle contracts

Question 54

What is the sarcolemma of skeletal muscle cells?

Answer 54

the tubular sheath that encases each muscle fibre, it is plasma membrane or wall

Question 55

What is the sarcoplasm of a skeletal muscle cell?

Answer 55

the cytoplasm

Question 56

What is cytoplasm?

Answer 56

the gelatinous liquid that fills the inside of a cell

Question 57

What are transverse tubules in skeletal muscle cells?

Answer 57

the entry point for action potential into the muscle cell

Question 58

What is the sarcoplasmic reticulum in skeletal muscle cells?

Answer 58

a network of tubules and sacs involved in the storage of calcium

Question 59

what are the 7 general skeletal muscle shapes?

Answer 59

1. parallel muscles 2. Convergent muscles 3. Unipennate 4. bipennate 5. multipennate 6. Fusiform muscles 7. Circular muscles

Question 60

What are the 3 subcategories of pennate muscles?

Answer 60

1. unipennate 2. bipennate 3. multipennate

Question 61

Describe the shape of parallel skeletal muscles. Give an example.

Answer 61

Long, strap like muscles such as the sartorius muscle (runs from thigh to knee)

Question 62

Describe the shape of convergent skeletal muscles. Give an example.

Answer 62

fanning fibres from a narrow to a wider point, such as the pectoralis.

Question 63

Describe the shape of pennate skeletal muscles. Give an example.

Answer 63

featherlike in appearance, eg rectus femoris

Question 64

Describe the shape of fusiform skeletal muscles. Give an example.

Answer 64

have fibres that are parallel in the centre but taper on the ends to form one or two tendons. strap like. Such as biceps brachii.

Question 65

Describe the shape of circular skeletal muscles. Give an example.

Answer 65

circular in shape. Also known as sphincters such as the orbicularis oris (around the mouth).

Question 66

what is the origin of a muscle?

Answer 66

the point of attachment which does not move when the muscle contracts

Question 67

what is the insertion of a muscle?

Answer 67

the point of attachment that moves when contracts

Question 68

what is meant by the term prime mover when referring to muscles?

Answer 68

the muscle that directly performs movement

Question 69

What is the other name of prime movers?

Answer 69

agonists

Question 70

What is the antagonist in mucles?

Answer 70

the muscle that does the direct opposite of the agonist, relaxes to allow movement

Question 71

What are the syngergists in muscles?

Answer 71

muscles that contract at the same time as the prime mover

Question 72

what are fixators in muscles?

Answer 72

the muscles that stabilize the joint

Question 73

Describe the structure of fibers in skeletal muscle?

Answer 73

striated, tubular and multi nucleated

Question 74

Are skeletal muscles voluntary?

Answer 74

yes

Question 75

Where are skeletal muscles usually attached in the body?

Answer 75

the skeleton

Question 76

describe the structure of fibers in smooth muscle.

Answer 76

non-striated, spindle-shaped and uni(one)nucleated

Question 77

Is smooth muscle voluntary or involuntary?

Answer 77

involuntary

Question 78

where is smooth muscle usually located in the body?

Answer 78

covering walls of internal organs

Question 79

Describe the structure of fibres in cardiac muscle? (3)

Answer 79

striated, branched and uni nucleated

Question 80

are cardiac muscles voluntary or involuntary?

Answer 80

involuntary

Question 81

Where are cardiac muscles found in the body?

Answer 81

only covering the walls of the heart