A&P exam 3

Question 1

major tissue type

typically shortens to create movement

Answer 1

muscle

Question 2

point of muscle attachment that does not move the structure

Answer 2

origin

Question 3

point of muscle attachment where muscle moves the structure

Answer 3

insertion

Question 4

Muscles located on the anterior forearm

Answer 4

flexors

Question 5

muscles located on the posterior forearm

Answer 5

extensors

Question 6

muscles of the shoulder

Answer 6

rotator cuff

Question 7

muscles of the anterior thigh

Answer 7

quadriceps

Question 8

muscles of the posterior thigh

Answer 8

hamstrings

Question 9

muscles of the medial thigh

Answer 9

adductor

Question 10

group of muscles in the lower back

Answer 10

erector spinae

Question 11

What are the levels of muscle organization in order from largest to smallest?

Answer 11

muscle body (epimysium)
muscle fascicles (perimysium)
muscle fibers (endomysium) => cell
myofibrils => organelle
sarcomeres
actin and myosin

Question 12

What’s the name of the connective tissue surrounding muscle fascicles?

Answer 12

perimysium

Question 13

What are the units that make up a myofibril?

Answer 13

sarcomeres

Question 14

What causes sarcomere shortening?

Answer 14

increased overlap of actin and myosin (slides past) [action potential]

Question 15

Are the thick filaments actin or myosin?

Answer 15

myosin

Question 16

Are the dark areas in striated muscle A bands or I bands?

Answer 16

A band= myosin

Question 17

What shape of muscle provides the greatest strength?

Answer 17

convergent or pennate

Question 18

Which type of muscle is not striated?

Answer 18

smooth

Question 19

How is a membrane potential created/maintained?

Answer 19

1. stimulus causes some Na channels to open
2. threshold is reached, ligand-gated Na channels open, depolarization occurs
3. Na channels close and K channels open, repolarization occurs
4. Voltage overshoots, K channels close, voltage returns to normal

Question 20

What is the normal voltage for a resting potential?

Answer 20

-

Question 21

What happens to voltage during an action potential?

Answer 21

becomes positive briefly

Question 22

What happens to potassium channels during hyperpolarization?

Answer 22

they close

Question 23

What is notable about the absolute refractory period?

Answer 23

no new action potentials can start regardless of stimulus

Question 24

What is a T-tubule?

Answer 24

transverse tubules, alleyways in sarcolemma that stretch towards myofibrils

Question 25

Where can one find the sarcoplasmic reticulum?

Answer 25

adjacent to t-tubules

Question 26

What ion is released from the sarcoplasmic reticulum?

Answer 26

Ca2+

Question 27

What part of the sarcomere rotates during contraction?

Answer 27

actin

Question 28

What neurotransmitter is used to initiate contraction?

Answer 28

acetylcholine

Question 29

What is muscle recruitment?

Answer 29

number of motor units

Question 30

Which would you expect to have more motor units--muscle of the hand or the back?

Answer 30

back

Question 31

If a person picks up a ball off the ground, what kind of contraction happened?

Answer 31

isotonic

Question 32

Factors in contraction force and muscle fatigue

Answer 32

number of motor units, diameter of fibers, frequency of stimulation, length of muscle fiber

Question 33

Isotonic vs isometric contraction

Answer 33

isotonic: shortens muscle, moves objects isometric: pulling of the muscle that does not shorten it

Question 34

Fast vs Slow twitch fibers

Answer 34

slow: more mitochondria, aerobic, myoglobin, duration fast: anaerobic, short and intense use

Question 35

Where would you expect muscle that makes the most use of aerobic respiration?

Answer 35

back

Question 36

What molecules can be used to supply muscle with energy once its initial ATP has been used up?

Answer 36

creatine, glucose

Question 37

What causes rigor mortis?

Answer 37

Since ATP is no longer present, there is nothing to make the muscles relax until myofilaments decay

Question 38

smooth muscle

Answer 38

- unconscious control - no myofibrils - activation: neurons or hormones (Ca+) - structure: sigmoidal shape, network of actin and myosin, gap junctions, random nuclei, no striations

Question 39

skeletal muscle

Answer 39

- conscious control - activation: neurons - structure: striated, elongated nuclei pushed to sides

Question 40

cardiac muscle

Answer 40

- unconscious control - activation: neurons - structure: intercalated disks, striated, split cells, random nuclei

Question 41

Location of smooth muscles

Answer 41

internal organs

Question 42

What do gap junctions allow smooth muscle to do?

Answer 42

allows action potential to travel to adjacent cells