chapter 8- intro. to muscles

Question 1

what are the 5 functions of the muscular system?

Answer 1

1. Movement - all movements rely on muscle contraction
2. Stabilization = maintaining position
3. Movement of substances= blood, food, urine, babies
4. Heat generation = heat in muscle keeps body warm
5. Communication = speaking, writing, facial expressions

Question 2

this type of muscle has visible striations under a microscope

Answer 2

striated muscle

Question 3

this type of muscle occupies voluntary muscle and allows some subconscious control

Answer 3

skeletal muscle

Question 4

this muscle is only found in the heart and is involuntary (autorhythmic)

Answer 4

cardiac muscle

Question 5

this type of muscle lacks striations and is also involuntary

Answer 5

smooth muscle

Question 6

each skeletal muscles contains how many nerves, veins, arteries?

Answer 6

one nerve
one artery
one or 2 veins

Question 7

whole muscles consist of bundles of fibres called

Answer 7

fascicles

Question 8

fascicles consist of many

Answer 8

fibers = cells

Question 9

each fiber (cell) consists of smaller fibers called

Answer 9

myofibrils

Question 10

a myofibril consists of tiny filaments called

Answer 10

actin and myosin

Question 11

what gives skeletal muscle a striated appearance?

Answer 11

actin and myosin

-boundaries of sarcomeres make up the striations

Question 12

actin is referred to as ____filaments and myosin is referred to as _____ filaments

Answer 12

actin = thin filaments 
myosin = thick filaments

Question 13

this structure is the basic unit of muscle contraction

Answer 13

sarcomere

Question 14

what is the muscular heart wall called?

Answer 14

myocardium

Question 15

how does cardiac muscle differ from skeletal muscle?

Answer 15

cardiac = only single cells

similar to skeletal = also striated and contains many sarcomeres

Question 16

in cardiac muscle, cells are branched and join together at ____?

Answer 16

intercalated discs

Question 17

where is smooth muscle found?

Answer 17

walls of visceral organs

- urinary bladder, uterus, intestines, eyes, walls of circulatory vessels and respiratory tubes

Question 18

how does the actin and myosin differ in smooth muscle?

Answer 18

similar contraction but actin and myosin not arranged in neat rows but lined in a way where striations are not visible

Question 19

what shape is each smooth muscle fiber and how many nuclei?

Answer 19

spindle -shaped with one central nucleus

Question 20

external force that opposed the force of the muscle

Answer 20

load

Question 21

what is an isotonic contraction?

Answer 21

load less then the force of the muscle

Question 22

what is a isometric contraction?

Answer 22

load is greater then the force of the muscle

Question 23

when a muscle contracts, it generates ______ that is ______ at both ends

Answer 23

tension

equal

Question 24

this is where attachment to more stationary element (usually proximal)

Answer 24

origin

Question 25

this is where attachment to more mobile element (usually distal)

Answer 25

insertion

Question 26

a muscle shape that shortens the entire muscle by about 30%

Answer 26

parallel

Question 27

a muscle shape that narrow tendons at each end and exerts great force at each end

Answer 27

fusiform

Question 28

a muscle shape that is useful for closing an oriface

Answer 28

circular

Question 29

a muscle shape where muscle fibres are over a broad area and come together at a common attachment site but can pull in different directions

Answer 29

convergent

Question 30

a muscle shape that is characterized by having one or more tendons running thru body of muscle and contains more muscle fibres per unit area
- generate more force

Answer 30

pennate

Question 31

a muscle coordination where muscles whose contraction is responsible for a particular movement

Answer 31

prime movers (agonists)

Question 32

a muscle coordination where muscles whose actions oppose that of the agonist

Answer 32

antagonist

Question 33

a muscle coordination that assists the prime mover in performing the action

Answer 33

synergists

Question 34

what are the 6 criteria used to name muscles?

Answer 34

1. specific body region
2. orientation of muscle fibers
3. origin and insertions
4. function
5. muscle shape
6. size (major/minor, maximusm/medius/minimus)