CHAPTER 14 THE AUTONOMIC NERVOUS SYSTEM AND HOMEOSTASIS

Question 1

1) Visceral reflex arcs do NOT control: A) blood pressure.
B) heart rate.
C) digestion.
D) voluntary muscle functions.

Answer 1

D) voluntary muscle functions.

Question 2

2) Sally sustained damage to some autonomic ganglia. What part of the visceral reflex arc is interrupted?
A) sensory reception
B) initiation of a motor impulse in the central nervous system (CNS)
C) motor response in a target cell
D) integration

Answer 2

C) motor response in a target cell

Question 3

3) Autonomic motor neurons do NOT innervate: 
A) skeletal muscle cells.
B) smooth muscle cells.
C) glands.
D) cardiac muscle cells.

Answer 3

A) skeletal muscle cells.

Question 4

4) Somatic motor neurons innervate: A) skeletal muscle cells.
B) cardiac muscle cells.
C) glands.
D) smooth muscle cells.

Answer 4

A) skeletal muscle cells.

Question 5

5) Control of skeletal muscle is the responsibility of: 
A) a somatic motor neuron.
B) a preganglionic neuron.
C) an autonomic ganglion.
D) a postganglionic neuron.

Answer 5

A) a somatic motor neuron.

Question 6

6) Where are autonomic ganglia located? 
A) brain
B) central nervous system (CNS)
C) peripheral nervous system (PNS)
D) spinal cord

Answer 6

C) peripheral nervous system (PNS)

Question 7

7) Where does the cell body of the preganglionic neuron originate? 
A) peripheral nervous system (PNS)
B) postganglionic neuron
C) central nervous system (CNS)
D) target cell

Answer 7

C) central nervous system (CNS)

Question 8

8) What is found between the preganglionic neuron and postganglionic neuron of a visceral reflex arc?
A) target cell
B) central nervous system (CNS)
C) spinal cord
D) autonomic ganglion

Answer 8

D) autonomic ganglion

Question 9

9) Where do the cell bodies of preganglionic neurons of the sympathetic nervous system originate?
A) thoracic and upper lumbar regions of the spinal cord
B) cervical region and sacral region of the spinal cord
C) cranial nerves and the sacral region of the spinal cord
D) cranial nerves and the lumbar region of the spinal cord

Answer 9

A) thoracic and upper lumbar regions of the spinal cord

Question 10

10) Which division of the autonomic nervous system (ANS) promotes homeostasis when the body is engaged in any type of physical work?
A) sensory nervous system
B) somatic nervous system
C) parasympathetic nervous system
D) sympathetic nervous system

Answer 10

D) sympathetic nervous system

Question 11

11) As Lisa drove home, she was suddenly alerted to the sound of a blaring horn and realized she had drifted off to sleep. Which nervous system division dominated when she was startled awake? 
A) sensory nervous system
B) sympathetic nervous system
C) parasympathetic nervous system
D) somatic nervous system

Answer 11

B) sympathetic nervous system

Question 12

12) Which of the following innervates target cells or organs of the autonomic nervous system (ANS)?
A) preganglionic neuron
B) autonomic ganglion
C) somatic motor neuron
D) postganglionic neuron

Answer 12

D) postganglionic neuron

Question 13

13) Which branch of the autonomic nervous system (ANS) includes the vagus nerves, which innervate the thoracic and abdominal viscera?
A) sensory nervous system
B) parasympathetic nervous system
C) somatic nervous system
D) sympathetic nervous system

Answer 13

B) parasympathetic nervous system

Question 14

14) After eating a large meal, Mr. Davis felt sleepy. Which nervous system dominates and is often called our "rest and digest" division of the autonomic nervous system (ANS)?
A) systemic nervous system
B) somatic nervous system
C) parasympathetic nervous system
D) sympathetic nervous system

Answer 14

C) parasympathetic nervous system

Question 15

15) Which nervous system division works antagonistically to the sympathetic nervous system? 
A) sensory nervous system
B) central nervous system
C) parasympathetic nervous system
D) somatic nervous system

Answer 15

C) parasympathetic nervous system

Question 16

16) What do the parasympathetic and sympathetic nervous systems share in common?
A) Both systems are called the “rest and digest” division of the autonomic nervous system (ANS).
B) Both systems are divisions of the autonomic nervous system.
C) Both systems have short preganglionic neurons and long postganglionic neurons.
D) Both systems trigger the same motor response in target organs.

Answer 16

B) Both systems are divisions of the autonomic nervous system.

Question 17

17) Preganglionic neurons of the sympathetic nervous system originate in the: 
A) gray rami communicantes.
B) sympathetic chain ganglion.
C) collateral ganglion.
D) lateral horns of the spinal cord.

Answer 17

D) lateral horns of the spinal cord.

Question 18

18) Gene's parachute did not open when he jumped out of the airplane. He injured his back in the thoracic and lumbar regions, damaging the autonomic ganglia found close to his spinal cord. What neurons did he likely damage?
A) parasympathetic preganglionic neurons
B) sympathetic preganglionic neurons 
C) sympathetic postganglionic neurons 
D) somatic motor neurons

Answer 18

B) sympathetic preganglionic neurons

Question 19

19) What do the white rami communicantes contain? 
A) preganglionic parasympathetic neurons
B) sympathetic chain ganglia
C) preganglionic sympathetic neurons
D) postganglionic sympathetic neurons

Answer 19

C) preganglionic sympathetic neurons

Question 20

20) What neurotransmitter is released by the axon of a sympathetic preganglionic neuron to communicate with the sympathetic postganglionic neuron?
A) adrenalin
B) norepinephrine
C) acetylcholine
D) epinephrine

Answer 20

C) acetylcholine

Question 21

21) Receptors that bind norepinephrine and epinephrine are known as: 
A) cholinergic.
B) muscarinic.
C) adrenergic.
D) nicotinic.

Answer 21

C) adrenergic.

Question 22

22) If a drug is administered to block the heart’s adrenergic receptors, how is heart rate affected during exercise?
A) Heart rate will be unable to increase in response to exercise.
B) Heart rate will increase in response to the drug.
C) The heart will stop beating.
D) The drug has no effect on heart rate during exercise.

Answer 22

A) Heart rate will be unable to increase in response to exercise

Question 23

23) What effect does a β2 agonist have on the diameter of respiratory passages?
A) The diameter of the respiratory passageways will increase.
B) The diameter of the respiratory passageways will decrease.
C) The drug will have no effect on passageway diameter.
D) The diameter of the respiratory passageways will decrease first, and then increase.

Answer 23

A) The diameter of the respiratory passageways will increase.

Question 24

24) Receptors that bind acetylcholine are known as: 
A) alpha.
B) adrenergic.
C) beta.
D) cholinergic.

Answer 24

D) cholinergic.

Question 25

25) Which receptor hyperpolarizes the axon terminal to slow or cancel the action potential when norepinephrine binds?
A) β3 receptor
B) α2 receptor 
C) α1 receptor 
D) β2 receptor

Answer 25

B) α2 receptor

Question 26

26) Nicotinic and muscarinic receptors are classified as: 
A) alpha receptors.
B) beta receptors.
C) cholinergic receptors.
D) adrenergic receptors.

Answer 26

C) cholinergic receptors.

Question 27

27) Drugs known as beta-blockers may be useful in treating: 
A) a fast heart rate.
B) benign prostatic hyperplasia.
C) asthma.
D) opiate withdrawal.

Answer 27

A) a fast heart rate.

Question 28

28) Which drug binds receptors on the smooth muscle of airways and causes bronchodilation? 
A) α2-agonist
B) β2-agonist
C) α1-blocker (antagonist)
D) beta-blocker (antagonist)

Answer 28

B) β2-agonist

Question 29

29) A drug decreases heart rate by blocking a receptor on cardiac muscle cells. This drug probably binds to:
A) β2 receptors.
B) nicotinic cholinergic receptors. C) α1 receptors.
D) β1 receptors.

Answer 29

D) β1 receptors.

Question 30

30) What receptor present on smooth muscle cells of blood vessels to digestive and urinary organs binds norepinephrine?
A) β2 receptor
B) α2 receptor 
C) α1 receptor 
D) β1 receptor

Answer 30

C) α1 receptor

Question 31

31) Stimulation of α1 receptors present on smooth muscle cells of blood vessels to the skin by norepinephrine results in:
A) sweating.
B) vasodilation.
C) vasoconstriction.
D) bronchodilation.

Answer 31

C) vasoconstriction.

Question 32

32) A drug known as a beta-blocker should primarily affect: 
A) heart rate.
B) dilation of the pupils.
C) sweating.
D) bronchodilation.

Answer 32

A) heart rate.

Question 33

33) During sympathetic nervous system activity, what is NOT an effect of norepinephrine?
A) The pancreas releases a hormone called glucagon.
B) Blood glucose levels decrease.
C) Lipids are broken down from adipocytes.
D) Glucose is broken down from glycogen.

Answer 33

B) Blood glucose levels decrease.

Question 34

34) To increase sweat production from sweat glands, acetylcholine binds: 
A) muscarinic receptors.
B) beta receptors.
C) nicotinic receptors.
D) adrenergic receptors.

Answer 34

A) muscarinic receptors.

Question 35

35) The adrenal medulla serves to supplement:
A) the somatic nervous system.
B) the parasympathetic nervous system.
C) the sympathetic nervous system.
D) both the sympathetic and parasympathetic nervous systems.

Answer 35

C) the sympathetic nervous system.

Question 36

36) What two systems are interfaced by the adrenal medulla?
A) somatic nervous system and autonomic nervous system
B) parasympathetic nervous system and endocrine system
C) sympathetic nervous system and endocrine system
D) parasympathetic nervous system and sympathetic nervous system

Answer 36

C) sympathetic nervous system and endocrine system

Question 37

37) Which nervous system dilates the pupils and allows more light to enter the eyes? 
A) somatic nervous system
B) sympathetic nervous system
C) parasympathetic nervous system
D) sensory nervous system

Answer 37

B) sympathetic nervous system

Question 38

38) Which neurotransmitter ensures skeletal muscles receive the supply of nutrients needed to make ATP by stimulating the release of more fatty acids and glucose into the blood stream? 
A) acetylcholine
B) aldosterone
C) norepinephrine
D) epinephrine

Answer 38

C) norepinephrine

Question 39

39) What best characterizes the function of the parasympathetic nervous system?
A) The parasympathetic nervous system maintains homeostasis when the body is at rest.
B) The parasympathetic nervous system prepares the body for emergency situations.
C) The parasympathetic nervous system is the “fight or flight” system.
D) The parasympathetic nervous system prepares the body for physical activity.

Answer 39

A) The parasympathetic nervous system maintains homeostasis when the body is at rest.

Question 40

40) The axons of parasympathetic postganglionic neurons are: 
A) situated within terminal ganglia.
B) long.
C) found close to the spinal cord.
D) short.

Answer 40

D) short.

Question 41

41) Which cranial nerve is NOT involved in the parasympathetic nervous system? 
A) vagus nerve (CN X)
B) oculomotor nerve (CN III)
C) hypoglossal nerve (CN XII)
D) facial nerve (CN VII)

Answer 41

C) hypoglossal nerve (CN XII)

Question 42

42) Which plexus is NOT served by the vagus nerve? 
A) brachial plexus
B) esophageal plexus
C) cardiac plexus
D) pulmonary plexus

Answer 42

A) brachial plexus

Question 43

43) Damage to the splanchnic nerves would affect functioning of the: 
A) heart.
B) lungs.
C) urinary bladder.
D) eye.

Answer 43

C) urinary bladder.

Question 44

44) Where are the ganglia of the parasympathetic nervous system located?
A) close to the brain
B) near the cells or organ being innervated by parasympathetic postganglionic neurons
C) close to the spinal cord
D) near the parasympathetic preganglionic neuron

Answer 44

B) near the cells or organ being innervated by parasympathetic postganglionic neurons

Question 45

45) What organ is served by the parasympathetic sacral nerves? 
A) last portion of the large intestine
B) esophagus
C) heart
D) lungs

Answer 45

A) last portion of the large intestine

Question 46

46) Due to an accident, Lori’s sacral nerves are severed. What do you expect to be affected by this injury?
A) production of saliva
B) urinary bladder and the last portion of the large intestine
C) heart and lungs
D) blood pressure and heart rate

Answer 46

B) urinary bladder and the last portion of the large intestine

Question 47

47) What does the vagus nerve (CN X) innervate? 
A) blood vessels
B) cardiac muscle cells
C) adipocytes
D) sweat glands

Answer 47

B) cardiac muscle cells

Question 48

48) What type of receptor is located in the membranes of all parasympathetic target cells? 
A) beta receptor
B) alpha receptor
C) nicotinic receptor
D) muscarinic receptor

Answer 48

D) muscarinic receptor

Question 49

49) What neurotransmitter is released by both preganglionic and postganglionic parasympathetic neurons at their synapses?
A) both epinephrine and norepinephrine
B) epinephrine
C) norepinephrine
D) acetylcholine

Answer 49

D) acetylcholine

Question 50

50) Maddie planned to go for a swim after dinner. But, after a large meal, she decided to rest rather than swim. What neurotransmitter promotes rest by binding muscarinic receptors after her meal?
A) epinephrine
B) adrenalin
C) norepinephrine
D) acetylcholine

Answer 50

D) acetylcholine

Question 51

51) What effect does the parasympathetic nervous system have on heart rate?
A) no effect on heart rate
B) increases heart rate
C) decreases heart rate
D) at first decreases, then increases heart rate

Answer 51

C) decreases heart rate

Question 52

52) The parasympathetic nervous system prepares the eye for: 
A) age-related deterioration.
B) near vision.
C) changing light levels.
D) distance vision.

Answer 52

B) near vision.

Question 53

53) Which of the following is NOT an effect of the parasympathetic nervous system? 
A) constriction of the pupil
B) decreased heart rate
C) increased sweat secretion
D) bronchoconstriction

Answer 53

C) increased sweat secretion

Question 54

54) Decreased parasympathetic stimulation could cause: 
A) a slow heart rate.
B) diarrhea.
C) a dry mouth.
D) frequent urination.

Answer 54

C) a dry mouth.

Question 55

55) What receptor is found in the membranes of all postganglionic parasympathetic neurons? 
A) beta
B) nicotinic
C) muscarinic
D) alpha

Answer 55

B) nicotinic

Question 56

56) Which system works opposite to the sympathetic nervous system? 
A) sensory nervous system
B) somatic nervous system
C) parasympathetic nervous system
D) central nervous system

Answer 56

C) parasympathetic nervous system

Question 57

57) What is responsible for keeping blood vessels partially constricted at all times? 
A) parasympathetic tone
B) cerebral cortex control
C) sympathetic tone
D) somatic control

Answer 57

C) sympathetic tone

Question 58

58) Which nervous system usually maintains a heart rate of 72 beats per minute? 
A) sympathetic nervous system
B) parasympathetic nervous system
C) somatic nervous system
D) central nervous system

Answer 58

B) parasympathetic nervous system

Question 59

59) What part of the brain largely controls homeostatic functions? 
A) pineal gland
B) hypothalamus
C) cerebellum
D) occipital lobe

Answer 59

B) hypothalamus

Question 60

60) Most organs are innervated from both the sympathetic and parasympathetic nervous systems, referred to as:
A) sympathetic tone.
B) dual innervation.
C) antagonism.
D) parasympathetic tone.

Answer 60

B) dual innervation.

Question 61

61) The somatic motor division consists of somatic motor neurons that innervate cardiac, smooth, and skeletal muscle cells.

Answer 61

FALSE

Question 62

62) The sympathetic nervous system has short preganglionic axons and long postganglionic axons, with the sympathetic ganglia located near the spinal cord.

Answer 62

TRUE

Question 63

63) The parasympathetic nervous system is often known as the “rest and digest” division of the ANS.

Answer 63

TRUE

Question 64

64) Sympathetic chain ganglia extend from the superior cervical ganglion to the inferior sacral ganglion.

Answer 64

TRUE

Question 65

65) Alpha and beta receptors are classified as cholinergic receptors.

Answer 65

FALSE

Question 66

66) Acetylcholine binds α1 receptors on the smooth muscle cells of blood vessels serving the organs of the digestive, urinary, and integumentary systems and causes them to contract.

Answer 66

FALSE

Question 67

67) The basic function of the parasympathetic nervous system is to maintain homeostasis when the body is at rest.

Answer 67

TRUE

Question 68

68) The sympathetic nervous system, or craniosacral division, involves four cranial nerves and sacral nerves S2 - S4.

Answer 68

FALSE

Question 69

69) Both preganglionic and postganglionic parasympathetic neurons release acetylcholine at their synapses.

Answer 69

TRUE

Question 70

70) Ejaculation is accomplished by the parasympathetic nervous system.

Answer 70

FALSE

Question 71

71) Most organs experience dual innervation from the sympathetic and parasympathetic nervous systems.

Answer 71

TRUE

Question 72

72) The reticular formation can exercise control over autonomic centers if its connection with the hypothalamus is severed.

Answer 72

TRUE

Question 73

Match the following with the effects of the sympathetic nervous system or parasympathetic nervous system.
A) sympathetic nervous system
B) parasympathetic nervous system

73) Increased heart rate

Answer 73

A) sympathetic nervous system

Question 74

74) Contraction of digestive tract smooth muscle

Answer 74

B) parasympathetic nervous system

Question 75

75) Relaxation of the urinary sphincter

Answer 75

B) parasympathetic nervous system

Question 76

76) Vasoconstriction of blood vessels

Answer 76

A) sympathetic nervous system

Question 77

77) Secretion of saliva

Answer 77

B) parasympathetic nervous system

Question 78

78) Increased secretion from sweat glands

Answer 78

A) sympathetic nervous system

Question 79

Match the following to the correct receptor.
A) muscarinic receptor 
B) nicotinic receptor 
C) beta receptor
D) alpha receptor

79) Located in the plasma membranes of cardiac muscle cells

Answer 79

C) beta receptor

Question 80

80) Located in the membranes of all postganglionic parasympathetic neurons

Answer 80

B) nicotinic receptor

Question 81

81) Found on arrector pili muscles in the dermis

Answer 81

D) alpha receptor

Question 82

82) Found in the membranes of all parasympathetic target cells

Answer 82

A) muscarinic receptor

Question 83

83) Discuss the target cells of the somatic and autonomic nervous systems.

Answer 83

Somatic motor neurons innervate skeletal muscle cells for the somatic nervous system. Autonomic motor neurons innervate smooth muscle cells, cardiac muscle cells, and glands.

Question 84

84) Explain where the cell bodies of the preganglionic neuron and the postganglionic neuron are located in the autonomic motor pathway.

Answer 84

The preganglionic neuron is the initial efferent neuron whose cell body resides within the CNS. The cell body of the postganglionic neuron resides within an autonomic ganglion in the PNS.

Question 85

85) Explain why the sympathetic nervous system is often call the “fight or flight” division of the ANS.

Answer 85

The sympathetic nervous system is often referred to as the “fight or flight” division of the ANS due to its role in preparing the body for emergency situations in which one may fight off an attack or flee from danger. This system prepares the body for physical activity associated with either the fight or the flight.

Question 86

86) Briefly explain the role of the sympathetic nervous system in maintaining homeostasis.

Answer 86

The sympathetic nervous system, or “fight or flight” division of the ANS, is responsible for preparing the body for emergency situations and physical activity. It is active when we experience emotion, or even during minor physical activities such as standing up.

Question 87

87) Explain the three places where a preganglionic sympathetic neuron may synapse with a postganglionic sympathetic neuron.

Answer 87

A preganglionic sympathetic neuron may synapse with a postganglionic neuron in one of three ways:

1) The axon synapses with a postganglionic neuron in the sympathetic chain ganglion.
2) The axon descends or ascends and synapses with a postganglionic neuron in a different chain ganglion.
3) The axon passes through the chain ganglion and synapses with a postganglionic neuron in a collateral ganglion.

Question 88

88) List the two classes of sympathetic receptors and the neurotransmitter(s) each binds.

Answer 88

The two classes of sympathetic receptors are the cholinergic and adrenergic receptors. The neurotransmitter acetylcholine (ACh) binds to cholinergic receptors while neurotransmitters norepinephrine or epinephrine bind to the adrenergic receptors.

Question 89

89) Pauline takes a medication known as a β-blocker to decrease the rate and force of contraction of her heart. Predict the neurotransmitter this medication prevents from binding and determine the specific type of β receptor being blocked by this medication.

Answer 89

A drug known as a β-blocker is an antagonist that binds β1 receptors to block the
effects of norepinephrine and epinephrine. Beta-1 (β1) receptors are found in the plasma membranes of cardiac muscle cells. This medication prevents epinephrine and norepinephrine from binding those β1 receptors.

Question 90

90) Determine the effects of norepinephrine when its binds receptors on blood vessels serving smooth, skeletal, and cardiac muscle cells.

Answer 90

Vasoconstriction results when norepinephrine binds α1 receptors on the smooth muscle cells of blood vessels serving the organs of the digestive, urinary, and integumentary systems and causes them to contract. Although norepinephrine constricts most of the body’s blood vessels, when it binds to β2 receptors on the smooth muscle cells of blood vessels serving skeletal and cardiac muscle, it causes them to relax. This opens the blood vessels, an action called vasodilation, which increases the blood flow and the delivery of oxygen and nutrients to the skeletal and cardiac muscle cells.

Question 91

91) Summarize the role of the parasympathetic nervous system in maintaining homeostasis.

Answer 91

The activities of the parasympathetic nervous system, or “rest and digest” division of the ANS, are often carried out during rest. Activities that are favored during parasympathetic control include digestion and urine formation.

Question 92

92) Discuss the specific nerves involved in the parasympathetic nervous system.

Answer 92

The parasympathetic nervous system is known as the craniosacral division since it involves four cranial nerves and some sacral nerves. The cranial nerves involved are oculomotor nerves (CN III), facial (CN VII), glossopharyngeal nerves (CN IX), and vagus nerves (CN X). The sacral nerves (S2 - S4) make up the pelvic nerves.

Question 93

93) Explain where the two types of cholinergic receptors are located in the parasympathetic nervous system pathway.

Answer 93

The two types of cholinergic receptors in the parasympathetic nervous system are muscarinic and nicotinic receptors. Nicotinic receptors are located in the membranes of all postganglionic parasympathetic neurons. Muscarinic receptors are found in the membranes of all parasympathetic target cells.

Question 94

94) Explain the effect of the parasympathetic nervous system on cardiac muscle cells.

Answer 94

Preganglionic parasympathetic neurons travel to the heart via the vagus nerves (CN X) and stimulate the postganglionic parasympathetic neurons to reduce both the heart rate and the force of contraction. These actions antagonize the sympathetic nervous system and lower blood pressure.

Question 95

95) Explain the concept of autonomic tone.

Answer 95

The parasympathetic and sympathetic nervous systems are active to some degree most of the time, known as autonomic tone. Autonomic tone can be divided into sympathetic tone and parasympathetic tone. Different degrees of tone exist in different organs.

Question 96

96) Heidi arrived home after a long walk with her dog and found that her mom had dinner ready. Why do you think she is not very hungry?

Answer 96

Heidi triggered the sympathetic nervous system to be dominant during exercise (walking her dog). The digestive system is dominated by the parasympathetic nervous system. Heidi needs to rest for a while in order for the parasympathetic nervous system to dominate, allowing her to feel hungry.

Question 97

97) Skyler takes a medication for asthma, known as a β2 agonist, to cause bronchodilation. Determine why this drug should have no effect on his heart rate.

Answer 97

β2 agonists bind β2 receptors on the smooth muscle of the airways and cause bronchodilation to improve breathing for those with asthma. Skyler should not experience an increase in heart rate when he takes his asthma medication since a different type of beta receptor, known as a β1 receptor, is located in the plasma membranes of cardiac muscle cells as well as certain cells of the kidney and adipose tissue.

Question 98

98) A patient was injected with medication that caused a fairly rapid decrease in heart rate and blood pressure. Determine the type of medication that was administered.

Answer 98

β-blockers are antagonists that bind to β1 receptors on the heart and decrease the rate and force of contraction. These drugs are widely used in the treatment of hypertension and other diseases of the cardiovascular system.

Question 99

99) Although Christopher had spinal cord damage, his autonomic nervous system (ANS) was still able to maintain some control over his viscera in the thoracic and abdominopelvic cavities. Which ANS division could still maintain some control? Explain.

Answer 99

The parasympathetic nervous system is the ANS division that could maintain some control over the viscera in his thoracic and abdominopelvic cavities. The parasympathetic cranial nerves supply most of the viscera in these two cavities. Even with a damaged spinal cord, he could still maintain some control over these organs since the cranial nerves originate from the surface of the brain.

Question 100

100) Robin takes an anticholinergic drug to deal with her allergies. Explain why she often experiences constipation.

Answer 100

Anticholinergic medications can block the parasympathetic nervous system’s effect on the smooth muscle of the digestive tract. This causes digested food to move more slowly through the tract and can lead to constipation.

Question 101

101) Determine how the sympathetic and parasympathetic nervous systems achieve homeostasis even though they work antagonistically.

Answer 101

Together, the two divisions of the ANS maintain a balance that ensures the body’s needs are met in an appropriate way at all times. They are able to accomplish this because most organs are innervated by neurons from both systems, referred to as dual innervation. This allows the sympathetic nervous system to become dominant and trigger effects that maintain homeostasis during exercise or emergency, and the parasympathetic nervous system to regulate these same organs and preserve homeostasis when the emergency or exercise has finished.