chapter 9 - muscular system; part 4

Question 1

what does energy from muscle contraction come from?

Answer 1

it comes from ATP

Question 2

aerobic respiration

Answer 2

ATP synthesized by this respiration produces energy for muscle contractions under resting conditions or during exercises such as long distance running. although ATP is produced more efficiently, it is produced more slowly

Question 3

anaerobic respiration

Answer 3

ATP synthesized by this respiration provides energy for a short time during intense exercise; anaerobic respiration produces ATP less efficiently but more rapidly than aerobic respiration; lactic acid levels increase because of anaerobic respiration

Question 4

what is 2 ADP converted to?

Answer 4

two ADP are converted to one ATP and one AMP during intense exercise

Question 5

what is muscle fatigue?

Answer 5

it is the decreased ability to do work, can be caused by the central nervous system, depletion of ATP in muscles, or depletion of acetylcholine in the neuromuscular junction; physiological contracture and rigor mortis result from inadequate amounts of ATP

Question 6

what is soreness caused by?

Answer 6

caused by inflammation in the muscle

Question 7

what happens after anaerobic respiration?

Answer 7

after anaerobic respiration, aerobic respiration is higher than normal, as the imbalances of homeostasis that occurred during exercise become rectified

Question 8

what happens when phosphate is removed?

Answer 8

if phosphate is removed while the cross-bridge are not attached, relaxation occurs rapidly

Question 9

visceral smooth muscle fibers

Answer 9

contract slowly, have gap junctions (and thus function as a single unit), and can be autorhythmic

Question 10

multiunit smooth muscle fibers

Answer 10

contract rapidly in response to stimulation by neurons and function independently

Question 11

what do spontaneous contractions result from?

Answer 11

they result from Na+ and Ca2+ leakage into cells; Na+ and Ca2+ movement into the cell is involved in depolarization

Question 12

what can the ANS, hormones, and chemicals produce locally?

Answer 12

these can inhibit or stimulate action potentials (and thus contractions); hormones can also stimulate or inhibit contractions without affecting membrane potentials

Question 13

what are the functional properties of smooth muscle?

Answer 13

1. they can contract auto rhythmically in response to stretch or when stimulated by the autonomic nervous system or hormones
2. maintains a steady tension for long periods
3. the force of smooth muscle contraction remains nearly constant, despite changes in muscle length
4. does not develop an oxygen deficit

Question 14

why are hormones important?

Answer 14

they are important in regulating smooth muscle; certain hormones can increase the Ca2+ permeability of some smooth muscle membranes and therefore cause contraction without a change in the resting membrane potential

Question 15

smooth muscle is innervated by what?

Answer 15

by the autonomic nervous system and it is involuntary

Question 16

cardiac muscle fibers

Answer 16

they are striated, have a single nucleus, are connected by intercalated disks (thus function as a single unit), and are capable of autorhythmicity

Question 17

what are the effects of aging skeletal muscle?

Answer 17

1. reduced muscle mass
2. increased time that muscle takes to contract in response to nervous stimuli
3. less precise muscle control
4. longer recovery period