Unit 4_Autonomic Nervous System

Question 1

What nervous system presents as the following:
- Maintains homeostasis
- Vegetative (digestive) & visceral (organs) functions
- Generally, an involuntary system
Minimal voluntary control

Answer 1

Autonomic Nervous System (ANS)

Question 2

What are the following associated with?

General sensations: Pain, temp, touch

Special senses: vision, auditory, vestibular, etc.

Visceral afferents: through nucleus of solitary tract (CNs IX &X)

Answer 2

Sensory Afferents Stimulate Reactions to the ANS

Question 3

What do the following make up:
Efferents (the True ANS system)

Two functional systems
1. Sympathetic (SNS)
2. Parasympathetic (PNS)

Innervate smooth muscle, the heart, glands, and organs
*NO direct innervation of skeletal muscle

Answer 3

ANS

Question 4

What kind of neurons sit within the brainstem and spinal cord inside the cns?

Answer 4

preganglionic

Question 5

What kind of neurons include cells situated in ganglion outside cns?

Answer 5

postganglionic

Question 6

What neuron includes:

Sympathetic: T1-L2 or L3 (Lateral Horn)

Parasympathetic: CN nuclei 3,7,9,10 (autonomic nuclei) and sacral spinal cord S2-S4 (lateral horn)

Answer 6

Preganglionic Neurons

Question 7

What neuron includes:

Sympathetic:
A. Sympathetic trunks
B. three specialized prevertebral areas past the trunk:
1. celiac ganglion
2. superior mesenteric ganglion
3. inferior mesenteric ganglion
Axons go to the organs

Parasympathetic: various ganglions are located very near the target organ; very far from the spinal cord and brainstem

Answer 7

Postganglionic Neurons

Question 8

What kind of neurotransmitters include the following:

Preganglionic cells release ACH onto postganglionic cell
Postganglionic cells release epinephrine and norepinephrine except on sweat glands where they release ACH
There also co-transmitters

Answer 8

Sympathetic

Question 9

What kind of neurotransmitters includes the following:

Both pre & postganglionic cells use ACH

There can also be co-transmitters

Answer 9

Parasympathetic

Question 10

What ANS includes the following:

• AKA thoracolumbar division
• preganglionic neurons located in T1-L3 (Lateral Horn)
• axons exit spinal cord through ventral root
• can do one of 2 things:
  1. enter synaptic chain on either side of the cord
  *synapses on postganglionic neuron in chain and release ACH
  *axon of postganglionic cell travels in peripheral nerves to target organs where it synapses and releases norepinephrine (except sweat glands where they release ACH)
  2. go directly to neurons in prevertebral ganglion
  *synapse on postganglionic neuron in ganglion and release ACH
  *axons from postganglionic neurons go direct to target organ and release norepinephrine

The target tissue or target organ receives norepinephrine from the postganglionic cell (except sweat glands). The receptors on the target organ are divided into 2 classes:
1. alpha adrenergic receptors - when these receive norepinephrine they excite the target tissue except in the GI system where they inhibit the target tissue.
2. beta adrenergic receptors - when these receive norepinephrine they inhibit the target tissue except in the heart where it excites the heart

Answer 10

Sympathetic

Question 11

What organ has sympathetic innervation only and includes the following:

• There is only one efferent neuron
• When stimulated, this organ releases epinephrine
• This serves as a mechanism to release hormones quickly into the blood; “FIGHT OR FLIGHT”

Answer 11

adrenal medulla

Question 12

What do the following organs have in common?

• Adrenal medulla
• sweat glands
• piloerector muscles
• peripheral blood vessels (in skin)

Answer 12

sympathetic innervation only

Question 13

What do most organs contain?

Answer 13

both sympathetic and parasympathetic innervation

Question 14

What kind of ANS innervation includes the following:
- follows 2 neuron pathway rules
- preganglionic neuron sits in thoracic cord axons, leave the spinal cord, and travel to postganglionic neurons either in the stellate or superior cervical ganglion
- Axons from these cells ascend and go to blood vessels and glands of the face through cranial nerves
- Goes to the eye to dilate the pupil through CN V (ophthalmic division)
- This is controlled via descending axons from the hypothalamus

Answer 14

Sympathetic innervation of face and head

Question 15

What ANS is involved in catabolic responses (energy expediting)?

Answer 15

Sympathetic

Question 16

What includes the following:
- aka cranio-sacral division
- cranial division consists of brainstem CN autonomic nuclei and their axons
- sacral division innervates urinary system, the lower colon, anal sphincter, and the reproductive system

Answer 16

Parasympathetic Nervous System

Question 17

What includes the following:
- located in CN 3,7,9,10 and lateral gray horn of S2-S4
- CN nuclei include Edinger Westphal (III), lacrimal and superior salivatory (VII), inferior salivatory (IX) and dorsal vagal (X)
- axons are long; exit cranial nerves or S2-S4 and travel to synapse on postganglionic neurons where they release ACH

Answer 17

Preganglionic Neurons

Question 18

What is located in ganglia near target organs and axons leave the ganglia to innervate structures and release ACH?

Answer 18

Postganglionic Neurons

Question 19

What conserves energy (anabolic system) and features opposite actions of sympathetic?

Answer 19

Parasympathetic Nervous System

Question 20

What tissue/organ features the following:

Sympathetic Stimulation Causes: Dialation
Parasympathetic Stimulation Causes: Constriction (CN III and Edinger Westphal nucleus in the midbrain)

Answer 20

Pupil of the Eye

Question 21

What tissue/organ features the following:

Sympathetic Stimulation Causes: Increased sweat production
Parasympathetic Stimulation Causes: NONE

Answer 21

Sweat Glands

Question 22

What tissue/organ features the following:

Sympathetic Stimulation Causes: Increased heart rate
Parasympathetic Stimulation Causes: Decreased heart rate (CN X and Dorsal vagal nuclei in medulla)

Answer 22

Heart

Question 23

What tissue/organ features the following:

Sympathetic Stimulation Causes: Stimulation causes constriction and removal of stimulation causes dilation
Parasympathetic Stimulation Causes: NONE

Answer 23

Blood vessels

Question 24

What tissue/organ features the following:

Sympathetic Stimulation Causes: Relaxation-bronchal dilation
Parasympathetic Stimulation Causes: Constriction (CN X)

Answer 24

Lungs

Question 25

What tissue/organ features the following: Sympathetic Stimulation Causes: Little effect Parasympathetic Stimulation Causes: Contraction (sacral cord)

Answer 25

Bladder: detrusor muscle

Question 26

What tissue/organ features the following: Sympathetic Stimulation Causes: Contraction Parasympathetic Stimulation Causes: Relaxation (sacral cord)

Answer 26

Bladder: Sphinctors

Question 27

What are critical for normal physiological functions? These include baroreceptor reflex, the micronutrition reflex and the reflexes important for defecation and sexual function.

Answer 27

Autonomic Reflexes

Question 28

What controls short term blood pressure changes? Increased blood pressure is sensed by visceral afferent nerve fibers in the carotid sinus and aortic arch this sensation is carried back to CN IX (from carotid sinus) and X (from aortic arch). The information synapse on reticular cells in the medulla responsible for cardiovascular regulation. These cells send axons down to the presympathetic ganglia cells lateral horns to reduce the stimulation to the smooth muscle of blood vessels and cause them to relax or dilate which will reduce the blood pressure.

Answer 28

Baroreceptor Reflex

Question 29

What is the effect of autonomic reflexes?

Answer 29

To reduce sympathetic activity

Question 30

What controls the filling and emptying of the bladder? This reflex comes under our conscious control only up to an extent. As the bladder fills with urine, the PNS reduces the amount of contraction and the SNS activates the sphincter to keep the urine from flowing out. As it continues to fill mechanoreceptors in the bladder walls sense the stretch on the bladder and send this to two locations: 1. The micronutrition reflex center in the pons 2. The cerebral cortex sensory area to sense that the bladder is full consciously The micturition center in the pons then sends descending signals down to cause relaxation of the sphincter (inhibits SNS) and contraction of the bladder detrusor muscle (excites PNS). This microturition center is controlled by the cortex which can inhibit the reflex and stop urination or excite the reflex and allow urination.

Answer 30

Micturition Reflex

Question 31

Damage to the spinal cord above the sacral cord often damages what and bladder control is lost?

Answer 31

The ascending and descending connections to the micturition center

Question 32

What are organized from anterior to posterior, and midline to lateral?

Answer 32

Regions of the hypothalamus

Question 33

What does the (lateral) hypothalamus project to the (lateral) medulla, where the cells that drive autonomic systems are located? These include the Parasympathetic Vagal Nuclei and a group of cells that descend to the Sympathetic System in the Spinal Cord. With access to these systems, the hypothalamus can control heart rate, vasoconstriction, digestion, sweating, etc.

Answer 33

Neural signals to the autonomic system

Question 34

What features magnocellular neurons sending axons directly to the posterior pituitary and secrete oxytocin and vasopressin directly into the bloodstream? Parvocellular neurons secrete peptides that regulate release of anterior pituitary hormones.

Answer 34

Endocrine signals to/through the pituitary

Question 35

Where do the descending autonomic pathways originate from?

Answer 35

the hypothalamus and various brain stem nuclei

Question 36

What is the major hypothalamic nucleus for controlling sympathetic and parasympathetic functions?

Answer 36

the paraventricular nucleus

Question 37

What other hypothalamic sites contribute axons to the descending visceromotor pathways?

Answer 37

- neurons in the lateral hypothalamic zone - the dorsomedial hypothalamic nucleus - the posterior hypothalamus

Question 38

What is on the lateral horn of spinal cord?

Answer 38

a hypothalamic projection

Question 39

What have descending inputs the ANS spinal cord? Spinal cord injuries can disrupt that control.

Answer 39

Both the hypothalamus and brainstem areas

Question 40

What clinical implication of ANS includes visceral afferents coming from the gut through dorsal root ganglion? It sets up reflex connections. Treatment: heat

Answer 40

Irritated gut

Question 41

What clinical application of ANS includes the following: - pain felt at a site distant to the cause of pain - has to do with visceral afferents (and is related to) - It is the convergence of somatosensory and visceral afferents on a single pain tract cells that causes referred pain - distinguish between shoulder pain and referred pain from heart *reproduction of pain in shoulder *vital sign

Answer 41

Referred pain

Question 42

What clinical application of ANS includes sympathetic innervation to the face is interrupted by a lesion in the descending sympathetic innervation to the face? Ptosis Anhidrosis Miosis

Answer 42

Horner's Syndrome

Question 43

What clinical application of ANS includes a lesion in high thoracic or cervical cord (SCI) - life threatening?

Answer 43

Autonomic Dysreflexia