Ch 14-The Autonomic Nervous System Flashcards
The stability of our internal environment depends largely on what?
Autonomic nervous system (ANS)
What does ANS innervate?
smooth and cardiac muscle and glands
ANS is also called what?
involuntary nervous system and general visceral motor system
How does ANS differ from the somatic nervous system?
It can stimulate or inhibit its effectors
All somatic motor neurons release this at their synapses with skeletal muscle fibers
acetycholine (ACh)
Released onto visceral effector organs by autonomic fibers
norepinephrine and ACh
ACh and norephinphrine are what?
neurotransmitters
Norepinephrine is secreted by?
sympatetic fibers
ACh is secreted by?
parasympathetic fibers
Depending on the type of receptors on the organ, the effect may be?
excitatory or inhibitory
ANS consists of what type of divisions?
parasympathetic and sympathetic divisions
T or F. Parasympathetic and sympathetic divisions serve the same visceral organs but with opposite effects.
T
Promotes maintenance functions and conserves body energy
parasympathetic
Mobilizes the body during activity
sympathetic
What is the parasympathetic division sometimes called?
rest and digest system
What is the role of the parasympathetic division?
keeps body energy use as low as possible
The parasympathetic division involves the D activities. What are they?
digestion, defecation, diuresis
What is the sympathetic division sometimes called?
fight or flight system
The sympathetic division involves the E activities. What are they?
exercise, excitement, emergency, embarassment
What are 3 things the sympathetic division promotes adjustments for during vigorous physical activity?
- Visceral blood vessels constrict, blood is shunted to active skeletal muscles, vigorously working the heart
- Bronchioles in lungs dilate, increasing oxygen, the liver releases more glucose into blood
- at same time, temporarily nonessential activities are damped
Why is the parasympathetic division also called the craniosacral division?
Because preganglionic fibers spring from opposite ends of the CNS (brain stem and sacral region of spinal cord)
Pregaglionic fibers in the cranial part of the parasympathetic division run in the following?
oculomotor, facial, glossopharyngeal. and vagus cranial nerves
What cranial nerves supply the entire parasympathetic innervation of the head?
Cranial nerves III (oculomotor), VII (facial), IX (glossopharyngeal)
The parasympathetic fibers of the oculomotor nerves do what?
innervate smooth muscles in the eye that cause pupils to constrict and lenses to bulge (to focus on close objects)
The parasympathetic fibers of the facial nerves do what?
stimulate large glands in the head
Where are the fibers located that activate the nasal gland and the lacrimal gland of the eye
Lacrimal nuclei of the pons
The parasympathetic fibers of the glossopharyngeal nerves do what?
activate the parotid salivary glands
Provide fibers to the neck and nerve plexuses serving virtually every organ in the thoracic and abdominal cavities
vagus nerves
As the vagus nerves pass into the thorax, they send branches to the ____ ____, supplying fibers to the heart to slow heart rate, ___ ____ serving the lungs and bronchi, and ___ ____ supplying the esophagus.
cardiac plexuses
pulmonary plexuses
esophageal plexuses
When the main trunks of the vagus nerves reach the esophagus, their fibers intermingle, forming what?
anterior and posterior vagal trunks
The vagal trunks ____ the esophagus down to the___ ____
ride; abdominal cavity
In the abdominal cavity, vagal trunks do what?
Send fibers through the large abdominal aortic plexus before giving off branches to abdominal viscera
Vagus nerves innervate what?
liver, gallbladder, stomach, small intestine, kidneys, pancreas, proximal half of large intestine
The rest of the large intestine and the pelvic organs are served by
sacral outflow
Serves the distal half of the large intestines, urinary bladder, ureters, reproductive organs
sacral outflow
T or F. Sympathetic division innervates more organs
T
How does the sympathetic division provide pathways to the head?
serves the skin and blood vessels
Fibers stimulate the dilator muscles of the irises of the eyse
sympathetic division
Inhibit nasal and salivary glands
sympathetic division
innervate the smooth muscle that lifts the upper eyelid
sympathetic division
How does the sympathetic division provide pathways to the thorax?
originates at T1-T6
The sympathetic division, pathway to the thorax, innervates what?
the heart via the cardiac plexus, some innervate the thyroid gland, but most serve the skin
Sends information concerning chemical changes, stretch, and irritation of the viscera and are the first link in autonomic reflexes
visceral sensory neurons
Have essentially the same components as somatic reflex arcs-receptor, sensory neurons, integration center, motor neuron, effector
visceral reflex arcs
What are the 2 differences between somatic reflex arcs and visceral reflex arcs?
visceral reflex arc has 2 consecutive neurons in its motor component and the afferent fibers are visceral sensory neurons
Neurons on the visceral reflex arcs make up the ____ nervous system, which plays an important role in controlling gastrointestinal tract activity
enteric
T or F. Visceral pain afferents travel along the same pathways as somatic pain fibers helps explain the phenomenon of referred pain
T
Pain stimuli arising in one part of the body are perceived as coming from another part
referred pain
Major neurotransmitters released by ANS neurons
ACh norepinephrine
Fibers that release ACh
cholinergic fibers
Most sympathetic postgaglionic axons release NE and are called?
adrenergic fibers
Response of visceral effectors depends on
neurotransmitters and the receptors they attach
T or F. The effects of ACh and NE on their effectors are not consistently excitatory or inhibitory
T
2 types of receptors that bind ACh are named for drugs that bind to them and mimic acetylcholine’s effects
cholinergic receptors
What are the two types of cholinergic receptors?
nicotinic receptors and muscarinic receptors
Are all ACh receptors nicotinic, muscarinic, or both
either nicotinic or muscarinic
When ACh binds to nicotinic receptors, the effect is always what?
stimulatory
The effect of ACh binding to muscarinic receptors can be either inhibitory, stimulatory, or both
inhibitory or stimulatory
ANS has two arms (divisions). What are they?
parasympathetic and sympathetic divisions
T or F. Most visceral organs receive dual innervation
T
Where are most antagonistic interactions seen?
heart, respiratory system, and gastrointestinal organs
Which division is the major actor in controlling blood pressure
sympathetic division
Division that normally dominate the heart and the smooth muscle of digestive and urinary tract organs
parasympathetic
Can the sympathetic division override parasympathetic effects during times of stress
Yes
Except for the adrenal glands and sweat glands of the skin, most glands are activated by what?
parasympathetic fibers
Mediates reglexes that regulate body temperature
sympathetic division
Division that increases the metabolic rate of body cells
sympathetic division
Division that raises blood glucose levels
sympathetic division
Division that mobilizes fats for use as fuels
sympathetic division
Division that increases mental alertness by stimulating the reticular activating system of the brain stem
sympathetic division
All parasympathetic fibers release this
ACh
Which division produces longer lasting effectis
sympathetic activation
What makes sympathetic nerve impulses linger?
hormonal effects
What oversees ANS activity?
hypothalamus
ANS is regulated by what?
CNS control in the spinal cord, brain stem, hypothalamus and cerebral cortex
What is considered the boss of the ANS system and main integration center?
hypothalamus
What appears to exert most direct influence over autonomic functions in the ANS
brain stem reticular formation
Control muscles concerned with pupil diameter and lens focus
midbrain center (oculomotor nuclei)
Defecation and micturition (urination) reflexes that empty the bladder are integrated where?
Spinal cord
Medial and anterior hypothalmic regions direct which division?
parasympathetic function
Lateral and posterior areas direct which division?
sympathetic function
Through the ANS, the hypothalamus coordinates what?
heart rate, BP, body temp, h2o balance, endocrine activity
Serves as the keystone of the emotional and visceral brain
hypothalamus
T or F…The hypothalamus influences ANS functioning and behavior
T
