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