Unit 6: ANS Flashcards
What structures in the body are controlled by the ANS?
The ANS (Autonomic Nervous System) controls involuntary structures such as:
-Smooth muscle (e.g., in the digestive tract, blood vessels, respiratory tract)
-Cardiac muscle (the heart)
-Glands (sweat, salivary, digestive, adrenal)
-Visceral organs (like the bladder, intestines, stomach)
Describe the components of a visceral reflex and be able to give a specific example.
Components of a visceral reflex arc:
1) Receptor – detects stimulus (e.g., stretch, chemical change)
2) Sensory neuron – sends info to the CNS
3) Integration center – often in the brainstem or spinal cord
4) Motor neurons – preganglionic and postganglionic neurons
5) Effector – smooth muscle, cardiac muscle, or gland
Example:
Baroreceptor reflex
-Baroreceptors in arteries detect high BP
-Sensory signals sent to brainstem
-Parasympathetic output slows heart rate
-BP lowers to normal
Compare and contrast the parasympathetic division to the sympathetic division. Be sure
to discuss anatomy and physiology.
Compare and contrast somatic pathways to autonomic pathways.
Describe the basic structure of a neural pathway in the ANS. How many neurons are in
each pathway? Where are ganglia? What are the possible effectors?
Two-neuron chain:
-Preganglionic neuron (cell body in CNS) → releases ACh -Postganglionic neuron (cell body in ganglion) → releases ACh or NE
Ganglia are clusters of cell bodies located either near the spinal cord (sympathetic) or near/in target organs (parasympathetic).
Effectors include: smooth muscle, cardiac muscle, and glands.
6.Describe the enteric nervous system.
A semi-autonomous system in the GI tract
Regulates digestion (motility, secretion, blood flow)
Contains millions of neurons in two plexuses (myenteric and submucosal)
Can function independently but is modulated by the ANS
What neurons in the ANS are cholinergic (release ACh) and which neurons are
adrenergic (release NE)?
Cholinergic neurons (release ACh):
-All preganglionic neurons (sympathetic and parasympathetic) -All parasympathetic postganglionic neurons -Some sympathetic postganglionic neurons (e.g., sweat glands)
Adrenergic neurons (release NE):
-Most sympathetic postganglionic neurons
What two receptor types does ACh bind to? What is the response of the post-synaptic
neuron?
Nicotinic receptors → always excitatory, found on postganglionic neurons and adrenal medulla
Muscarinic receptors → can be excitatory or inhibitory, found on parasympathetic effectors
Be able to describe the various types of receptors found on neurons and effectors in the
ANS. What neurotransmitters do they respond to? What is the response? Where are
they located?
Define dual innervation.
Most organs receive input from both sympathetic and parasympathetic divisions, allowing fine-tuned control.
Give examples of how the parasympathetic and sympathetic divisions can be
antagonistic with each other.
Heart rate:
Sympathetic ↑ HR
Parasympathetic ↓ HR
Pupil size:
Sympathetic dilates (mydriasis)
Parasympathetic constricts (miosis)
GI activity:
Sympathetic inhibits
Parasympathetic stimulates
Give examples of how the parasympathetic and sympathetic divisions can be
cooperative with each other.
Be able to discuss the effects of sympathetic and parasympathetic innervation for a
variety of visceral organs
Explain what transducers do.
Name the type of receptors that detect pain and explain how fast pain is different from
slow pain.
Briefly describe the projection pathway for somesthetic/general senses.
Describe the various ways that receptors can be classified.
List the 5 primary taste sensations. What is the sensory transduction mechanism for
each (what is the specific stimulus for each taste and how does it affect the receptor)?
Where in the cerebrum are taste sensations processed?
What is found within the olfactory foramina of the cribriform plate? What bone is the
cribriform plate part of?
Do olfactory receptors adapt quickly or slowly? Explain.
What is the function of the pinna (auricle)?
Describe and follow the sequence of events from a sound wave entering the pinna all
the way to the information being processed in the brain.
What are the three regions of the ear and what structures are located within each
region and what is happening in each region?
Explain the relationship between K+ gates and cochlear hair cells.
Describe the location and function of the conjunctiva and the lacrimal apparatus.
Explain how the semicircular canals provide the brain with information about body
position (equilibrium/balance)
Name the three tunics/layers of the eye and briefly describe their functions. Be sure to
include the location and function of the following parts of the eye: cornea, sclera,
choroid, retina, optic disc, lens and iris as it relates to these three tunics.
Describe the path of a photon of light and the subsequent nerve impulse through the
parts of the eye and to the cerebral cortex.
Define emmetropia, hyperopia and myopia
Where are the two humors of the eye and what are their functions?
Name and describe the optical components.
How does your eye respond when looking at something close up versus something that
is far away? In other words, describe the near response of the eye.
Compare and contrast rods and cones. Where in the retina are they located? What is
their function?
Color blindness is a sex-linked trait – explain what this means.
What two components make up the neural apparatus?
24.Review the eye lab notes. Be able to identify and spell each of the bolded structures on
the lab notes.
