Myology

Question 1

Define Myology

Answer 1

the study of muscles, their function, and their structure

Question 2

What are the 3 muscle system functions?

Answer 2

1. Movement
2. maintain posture
3. produce heat

Question 3

what are the 3 muscle types?

Answer 3

1. skeletal muscle
2. smooth muscle
3. cardiac muscle

Question 4

number of nuclei in a skeletal muscle cell

Answer 4

multiple (located at the periphery)

Question 5

what muscle cells are voluntary?

Answer 5

skeletal muscle

Question 6

what muscle cells are in voluntary?

Answer 6

smooth muscle
cardiac muscle

Question 7

what is a smooth muscle responsible for?

Answer 7

digestion

Question 8

what are the 2 myofilament components?

Answer 8

actin
myosin

Question 9

what are myofibrils composed of?

Answer 9

myofilaments

Question 10

how many nuclei does a smooth muscle cell have?

Answer 10

1 (centrally located)

Question 11

where are smooth muscle cells found?

Answer 11

hollow organs
wall of: blood vessels, urinary bladder, uterus, digestive
tract, respiratory tract

Question 12

what are the 2 types of smooth muscle cells?

Answer 12

single unit / visceral smooth muscle (found in sheets)

Multiunit smooth muscle (found are individual fibers)

Question 13

What do single-unit smooth muscle cells form?

Answer 13

walls of hollow organs

Question 14

What are multiunit smooth muscle cells found as?

Answer 14

individual fibers

Question 15

what muscle is used in piloerection?

Answer 15

multi-unit smooth muscle cells
(autonomic nervous system)

Question 16

what cells are branched?

Answer 16

cardiac muscle cells

Question 17

what connects the ends of cardiac muscle cells?

Answer 17

intercalated discs

Question 18

what aids in the conduction of the nervous impulse to coordinate contraction?

Answer 18

intercalated discs

Question 19

how many nuclei does the cardiac muscle have?

Answer 19

1 (central)

Question 20

describe voluntary muscles

Answer 20

conscious ability to contract a muscle
e.g skeletal muscle

Question 21

describe involuntary muscles

Answer 21

muscle contraction without conscious thought
e.g. smooth muscle and cardiac muscle

Question 22

what are the 4 properties of muscle?

Answer 22

1. Plasticity: the ability to increase volume without increasing pressure (prominent in smooth muscle)
2. Contraction (shortening)
3. Relaxation (return to normal length)
4. Irritability (transmit an electrical wavelength along its length, cardiac muscle)

Question 23

Flexors

Answer 23

Antagonist: extensors

bends limbs
decrease joint angle

Question 24

Extensors

Answer 24

Antagonist: Flexor

bends limbs
Increase joint angle

Question 25

Abductors

Answer 25

Antagonis: Adductors Moves limb AWAY from the midline

Question 26

Adductors

Answer 26

Antagonist: Abductors Moves limb TOWARDS the midline

Question 27

cutaneous muscles

Answer 27

used for piloerection

Question 28

Levators

Answer 28

antagonist: depressors produce a DORSALLY directed movement lift

Question 29

Depressors

Answer 29

antagonist: levators Produce a VENTRALLY directed movement lower

Question 30

Sphincters

Answer 30

antagonist: dilators decrease the size of the opening eg. pupil, bladder

Question 31

dialators

Answer 31

antagonist: sphincters increase the size of the opening

Question 32

Pronators

Answer 32

antagonist: supinators move the paw inward

Question 33

supinators

Answer 33

antagonist: pronators move paw outwards

Question 34

what are the 2 types of muscle attachment?

Answer 34

direct attachment indirect attachment

Question 35

describe direct muscle attachment

Answer 35

muscle attaches directly to the periosteum of the bone

Question 36

describe indirect muscle attachment

Answer 36

muscle is first attached to a connective tissue (a tendon or aponeurosis) which in turn is attached to the bone

Question 37

origin

Answer 37

-the end of the skeletal muscle that is the most stable -usually the end closer the the medial plane

Question 38

insertion

Answer 38

-the end of the skeletal muscle that is most mobile - usually most distal end

Question 39

aponeurosis

Answer 39

-broad, flat, white connective tissue band that connects skeletal muscle to bone - different from tendon because it's flat (not round)

Question 40

fascia

Answer 40

white connective tissue sheath that covers muscle bundles

Question 41

name the muscle contractile proteins

Answer 41

actin and myosin

Question 42

Where are actin molecules attached?

Answer 42

the ends of the sarcomere (z lines)

Question 43

what causes muscle relaxation?

Answer 43

the removal of Ca (when the nerve impulse stops, Ca is actively transported back into the SER)

Question 44

define Sarcomere

Answer 44

- the basic contractile unit of muscle fiber. - the length of a myofibril between 2 successive z-lines

Question 45

describe skeletal muscle

Answer 45

- striated (light-dark alternating bands parallel to each other) - voluntary - cells are long (1-40 microns) - multinucleated (found at the cell periphery) - rounded/tapered ends

Question 46

each skeletal muscle fiber is a muscle cell consisting of

Answer 46

many myofibrils

Question 47

describe smooth muscle

Answer 47

- visceral - non-striated - involuntary (digestion) - cells elongated with tapered ends (spindle-shaped) - 1 central nucleus - myofilaments are not well organized - cells tightly packed with indistinct borders - location: blood vessels, urinary bladder, uterus, digestive tract, respiratory tract - can be single or multi-unit

Question 48

neuro-muscular junction

Answer 48

where synapsis occurs

Question 49

synaptic vesicles contain which neurotransmitter?

Answer 49

acetylcholine

Question 50

synaptic cleft (5)

Answer 50

- is where the neurotransmitter is released - space separating the nerve and muscle - has transmitter attachment sites - changes the permeability of the muscle cell, allowing sodium to enter - creates an action potential that moves along the muscle cell membrane

Question 51

muscle contraction has what principle?

Answer 51

all or nothing (full contraction or no contraction at all)