Chapter 14 Flashcards
Automatic Nervous System (65 cards)
1
Q
what does the ans do
A
Oversees vital functions such as heart rate, blood pressure, and digestive and urinary functions, without conscious control, through
2
Q
what does ans stand for
A
autonomic nervous system
3
Q
what are visceral reflex arcs
A
The reflex of the ANS that affects the visceral organs
- Sensory signals from viscera and skin are sent by afferent sensory neurons to the brain or spinal cord
- Stimuli are integrated by the C N S
- Motor impulses from the C N S are sent via efferent motor neurons in cranial and spinal nerves to autonomic ganglia
- Autonomic ganglia send impulses via other efferent motor neurons to target organs, where they trigger a motor response in the target cells
4
Q
pns motor division is divided into
A
- somatic motor division
- visceral motor division
5
Q
what is somatic motor division
A
Somatic motor neurons directly innervate skeletal muscle fibers; voluntary control; acetylcholine (A C h); excitatory
6
Q
visceral motor division aka
A
autonomic nervous system
7
Q
what kinds of neurons are in ans
A
- preganglionic
- postganglionic
8
Q
what is a preganglionic neuron
A
Cell body in the C N S; synapses on the cell body of postganglionic neuron
9
Q
what is a postganglionic neuron
A
Cell body in the P N S autonomic ganglion; axon synapses on the target cell; often A C h and norepinephrine; excitatory and inhibitory
10
Q
*figure 14.1
A
11
Q
ans aka
A
visceral motor division
12
Q
figure 14.2
A
13
Q
figure 14.3 - big one
A
14
Q
length of axons in the sympathetic ns
A
preganglionic axons are often short
postganglionic axons are long
15
Q
parasympathetic nervous system is responsible for
A
“rest and digest”
16
Q
sympathetic nervous system is responsible for
A
“fight or flight”
17
Q
length of axons in the parasympathetic ns
A
postganglionic axons are often short preganglionic axons are long
18
Q
what is the balance between the parasympathetic ns and the sympathetic ns
A
- Actions of the parasympathetic nervous system directly antagonize those of the sympathetic nervous system
- For example, parasympathetic neurons decrease the rate of the heart’s contractions; sympathetic neurons increase the rate of the heart’s contraction
- The two divisions maintain a delicate balance to ensure homeostasis is maintained at all times
19
Q
figure 14.4
A
20
Q
what are the types of sympathetic neurotransmitters
A
- Acetylcholine
- Norepinepherine
- epinephrine
21
Q
what do the postganglionic axons of the sympathetic ns release
A
releases norepinephrine, epinephrine, or Acetylcholine
22
Q
what do the preganglionic axons of the sympathetic ns do
A
communicate with the postganglionic neurons at an excitatory synapase using acetylcholine
23
Q
what are the classes of sympathetic receptors
A
- adrenergic receptors
- alpha receptors
- alpha-1
- alpha-2 - beta receptors
- beta-1
- beta-2
- beta-3
- alpha receptors
24
Q
what are beta receptors - sympathetic
A
A type of adrenergic receptor which can excite or relax cells during a sympathetic response
25
what type of neuron is attached to the target muscle - ans
postganglionic neurons in the sympathetic
26
what are adrenergic receptors
Bind to norepinepherine or epinephrine; include different types
27
what are alpha receptors - sympathetic
A type of adrenergic receptor which can excite or inhibit cells during a sympathetic response
28
what type of neuron is attached to the spine - ans
preganglionic neurons
29
what are alpha-2 receptors - sympathetic
found in the plasma membranes of certain sympathetic target cells in the pancreas and adipose tissue; most in the plasma membranes of preganglionic sympathetic neurons where hyperpolarization occurs, and slows or cancels the action potential; dampens or shuts off sympathetic response to prevent excessive activity
30
what are alpha-1 receptors - sympathetic
Located on all smooth muscles, glands and organs of the sympathetic nervous system (on the plasma membranes of smooth muscle cells including blood vessels of skin, organs of the gastrointestinal system, the kidneys, the arrector pili muscles in the dermis, smooth muscle cells around the pupil of the eye, the uterus (during pregnancy), and certain organs of the genitourinary system)
31
somatic ns is voluntary or involuntary
voluntary
32
autonomic ns is voluntary or involuntary
involuntary
33
where are sympathetic ganglia
generally near the spinal cord
34
where do the preganglionic neurons in the sympathetic ns originate
originate in the thoracic and upper lumbar spinal cord
thoracolumnar division
35
what is the thoracolumnar division
thoracic and upper lumbar spinal cord
sympathetic ns
36
what is the craniosacral division
The cranial nerves and the sacral region of the brainstem
parasympathetic ns
37
what does the sympathetic ns prepare the body for
emergencies
38
figure 14.6
39
what are neurotransmitters
a chemical substance that is released at the end of a nerve fiber by the arrival of a nerve impulse and, by diffusing across the synapse or junction, causes the transfer of the impulse to another nerve fiber, a muscle fiber, or some other structure
40
where are alpha-1 receptors
- blood vessels
- eye
-
Located on all smooth muscles, glands and organs of the sympathetic nervous system (on the plasma membranes of smooth muscle cells including blood vessels of skin, organs of the gastrointestinal system, the kidneys, the arrector pili muscles in the dermis, smooth muscle cells around the pupil of the eye, the uterus (during pregnancy), and certain organs of the genitourinary system)
41
where are alpha-2 receptors
plasma membranes of certain sympathetic target cells in the pancreas and adipose tissue;
42
alpha-1, alpha-2, beta-1, beta-2
which stimulate and which inhibit
stimulate:
alpha-1
beta-1
inhibit:
alpha-2
beta-2
43
where are beta-3 receptors
cells of adipose tissue, smooth musclecells in walls of digestive tract
44
where are the beta-2 receptors
membranes of smooth muscle cells in the bronchioles, skeletal muscle fibers, smooth muscle cells of the urinary bladder, smooth muscle cells of blood vessels of skeletal muscle, cells of the liver and pancreas, and salivary glands
45
what is hyperpolarization
after peak action potential (most positive), the cell will repolarize - go back to its rest potential. for a amall amount of time, it overcorrects and goes too negative. that is hyperpolarization
46
where are beta-1 receptors
membranes of cardiac muscle cells and certain cells of the kidney
47
what is the sympathetic nervous system's most basic function
ensure survival and maintain homeostasis during times of physical or emotional stress
48
what are antagonists
drugs which block the receptor, preventing neurotrnansmitters from binding to it
49
what are agonists
drugs which bind to the receptor and mimic the effects of neurotransmitters
50
what do a1 blockers do
- antagonists
- bind to smooth muscle cells lining blood vessels
- prevent vasoconstriction (lowers blood pressure)
- bind to smooth muscle cells in the prostate gland to relax and treat benign prostatic hyperplasia
51
what do a2 agonists do
- decrease output of pre- and postganglionic sympathetic neurons
- used to treat hypertension and opiate withdrawal
52
- what do b1 blockers do
- antangonists
- bind to the heart and decrease the rate and force of contraction
- used to treat hypertension and other cardiovascular diseases
53
what do b2 agonists do
- bind to smooth muscle cells of the bronchioles to cause bronchodilation
- used to treat asthma
54
what is the parasympathetic ns
- body's maintenance function (digestion/urine formation)
- functions carried out during rest
55
what is the organization of the parasympathetic ns
- sacral nerveswith parasympathetic preganglionic neurons aare S2-S4
56
parasympathetic ns most basic function
maintain homeostasis when the body is at rest
57
effects on cardiac muscle cells - parasympathetic ns
heart rate and blood pressure lower
preganglionic parasympathetic neurons travel to heart via the vagus nerves and stimulate postganglionic neurons which REDUCE the rate of contraction of the heart and LOWER heart rate and blood pressure
58
effects on smooth muscle cells - parasympathetic ns
- **constriction of the pupil**
the oculomotor nerve in the ciliary ganglion innervate the sphincter pupillae muscle, which DILATE the pupil, allowing MORE light into the eye
- **constriction of bronchioles**
Vagal neurons stimulate mild contraction of the smooth muscle cells of the linings of the airways, resulting in Bronchoconstriction
- **contraction of the smooth muscle lining the digestive tract**
Vagal neurons trigger contracts of the smooth muscle producing rhythmic contractions known as peristalsis that propel digested food through the tract
- **relaxation of digestive and urinary sphincters**
Vagal neurons and pelvic splanchnic nerves stimulate relaxation of smooth muscle cells of the sphincters; promotes urination and movement of digestive food through the tract, ultimately resulting in defecation
59
effects of the parasympathetic ns on other cells (not smooth muscle or cardiac)
- No direct effect on metabolic rate, mental alertness, force generated by skeletal muscle contractions, blood clotting, adipocytes, or most endocrine secretions
- Instead, each of these factors returns to a “resting” state during times of parasympathetic activity because the sympathetic nervous system is not dominant
- Important time for the body to store glucose and other fuels for the next round of sympathetic activity
60
What does dual innervation mean
most organs are innervated by neurons from both the sympathetic and parasympathetic ns
61
when is sympathetic ns dominant
during exercise or emergency
62
when is parasympathetic ns dominant
during rest
63
what is autonomic tone
the balancing of the sympathetic and parasympathetic systems.
constant amount of activity forom each system, different degrees in different organs
64
what is sympathetic tone
the continuous activity of the sympathetic system
dominant in blood vessels and keeps them partially constricted at all times
65
what is parasympathetic tone
the continuous activity of the parasympathetic ns
dominant in
the heart and keeps heart rate at an avg of 72 beats/min
stronger in athletes who recover more quickly from intense bursts of sympathetic activity
digestive and urinary systems
