Exam 1- Chapter 9 Flashcards
Autonomic motor nerves innervate what organs?
Organs not under voluntary control
What do the effectors of the autonomic motor nerves include?
- Cardiac muscle
- Smooth muscle of visceral organs and blood vessels
- Glands
Describe the dependance of visceral effector organs on autonomic motor nerves.
Somewhat independent of innervation and will not atrophy if a nerve is cut (unlike skeletal muscle)
What will cardiac muscle, and some smooth muscle do without nerve stimulation? What can autonomic innervation do to these intrinsic (natural) contractions?
- Contract rhythmically
2. Speed up or slow down
Unlike somatic motor neurons autonomic motor neurons can do what? How exactly is this different from somatic motor neurons?
- Stimulate or inhibit
2. Somatic motor neurons are always stimulatory)
The autonomic system has how many neurons?
2
Preganglionic neurons originate where?
1. Midbrain or 2. Hindbrain or 3. Thoracic, lumbar, or sacral spinal cord
Where do postganglionic neurons originate?
Ganglion
Where can the autonomic ganglia be located?
- Head
- Neck
- Abdomen
- Parallel chains along either side of the spinal cord
What are the two divisions of the autonomic nervous system?
- Sympathetic
2. Parasympathetic
Which division of the ANS is involved in “fight or flight”?
Sympathetic
How does the sympathetic division of the ANS activate the bodies fight or flight system?
- Release of norepinephrine from postganglionic neurons
2. Secretion of epinephrine from the adrenal medulla
How do the norepinephrine, and epinephrine secretions prepare the body for intense physical activity?
- Increasing heart rate
- Increasing blood glucose levels
- Diverting (changing course) blood to skeletal muscles
In the sympathetic division where do preganglionic neurons come from?
Thoracic/Lumber regions of spinal cord (thoracolumbar division of spinal cord)
What is the thoracolumbar division of the spinal cord?
Thoracic and Lumbar regions
In the sympathetic division where do preganglionic synapse?
sympathetic ganglia
In the sympathetic division where are the ganglia located? What are they called? How are they connected?
- Parallel chains along either side of the spinal cord
- Paravertebral ganglia
- By forming a sympathetic chain of ganglia
Because preganglionic neurons can branch and synapse in ganglia at any level, there is what?
- Divergence
2. Convergence
What is divergence?
One preganglonic neuron synapses on postganglionic neurons at different levels
What is convergence?
Several preganglionic neurons at different levels synapse on one postganglionic neuron
What does divergence, and convergence allow the sympathetic division to do?
act as a single unit through mass activation
Many of the sympathetic neurons that exit the spinal cord below the diaphragm do not do what?
synapse in the sympathetic chain of ganglia
Sympathetic neurons that exit the spinal cord below the diaphragm and do not synapse in the sympathetic chain of ganglia form what? Where do they synapse?
- Splanchnic nerves
2. Synapse in collateral ganglia
What does collateral ganglia include?
- Celiac ganglia
- Superior mesenteric ganglia
- Inferior mesenteric ganglia
Postganglionic neurons of collateral ganglia (don’t synapse in the sympathetic chain) innervate what?
innervate organs of the:
- Digestive
- Urinary
- Reproductive systems
What does the adrenal medulla of the adrenal glands secrete when stimulated by the sympathetic nervous system?
- Epinephrine
2. Norepinephrine
The parasympathetic division is _______ to the sympathetic division.
antagonistic
The parasympathetic division allows the body to do what?
“Rest and Digest”
How does the parasympathetic division allow the body to “rest and digest”?
through the release of ACh from postganglionic neurons
When the parasympathetic division releases ACh, what does this cause?
- Slows heart rate
- Dilates visceral blood vessels
- Increases digestive activities
In the parasympathetic division where do preganglioic neurons come form?
brain or sacral region of the spinal cord (Also called the craniosacral division)
What is the craniosacral division?
brain/sacral region of the spinal cord
In the parasympathetic division where do preganglioic neurons synapse on?
Ganglia located near or in effector organs (terminal ganglia)
What are terminal ganglia?
Ganglia located near or in effector organs
What is the tract the vagus nerve (CN X) takes in the parasympathetic division?
- Preganglionic fibers exit medulla
- Branch into several plexi and nerves
- Travel to ganglia within effector organs
What are the effector organs of the vagus nerve (CN X)?
- Heart
- Lungs
- Esophagus
- Stomach
- Pancreas
- Liver
- Intestines
What is the NT used by all preganglionic neurons in the parasympathetic division?
ACh
What is the NT released by MOST postganglionic neurons in the parasympathetic division?
ACh
Some sympathetic postganglionic neurons (those that innervate sweat glands and skeletal muscle blood vessels) release what NT?
ACh
What sympathetic postganglionic neurons release ACh?
Those that innervate:
- Sweat Glands
- Skeletal Muscle
- Blood vessels
The synapses in the PNS that use/release ACh are called what?
Cholinergic
What is the NT released by MOST postganglionic neurons in the sympathetic division? What are the synapses called?
- Norepinephrine
2. Adrenergic
Axons of postganglionic neurons have various swellings called what?
Varicosities
What do varicosities do?
release neurotransmitter along the length of the axon
What do varicosities form in passing?
synapses en passant
Do sympathetic and parasympathetic neurons innervate different tissues?
NO, THEY INNERVATE THE SAME TISSUES
Adrenergic stimulation can _____ or _____. What does the depend on?
- Stimulate or Inhibit
2. Receptors
What does adrenergic stimulation stimulate?
- Heart
- Dilatory muscles of the iris
- Smooth muscles of some blood vessels (causes vessel constriction)
What does adrenergic stimulation inhibit? What does it do to these structures?
1.
1. Bronchioles in lungs 2. Other blood vessels 2. Inhibits contraction and causes dilation of these structures
What are the types of adrenergic receptors?
- α adrenergic receptors
1. α1
2. α2 - β adrenergic receptors
1. β1
2. β2
How many adrenergic receptors are there total?
4
All adrenergic receptors act using what? What secondary system do α receptors use? What secondary system do β receptors use?
- G-proteins and second messenger systems
- α receptors use a Ca2+ second messenger system
- β receptors use cAMP
Where are α2 receptors located?
Located on presynaptic axons
When α2 receptors are stimulated what happens? What might these be?
- Inhibition of norepinephrine release in the synapse
2. Negative-feedback system
Some drugs that lower blood pressure act on what receptors? What do these drugs do? What is a negative side affect of this?
- α2 receptors
- Inhibit presynaptic neurons in the brain
- inhibiting of the whole sympathetic nervous system
When ACh is released from preganglionic neurons of both the sympathetic and parasympathetic division is it stimulatory, inhibitory or both?
Stimulatory
When ACh is released from postganglionic neurons of the parasympathetic division is it stimulatory, inhibitory or both?
Both; can be stimulatory or inhibitory, depending on receptors
Nicotinic Acetylcholine (cholinergic) receptors are found where?
Autonomic ganglia
What are Nicotinic Acetylcholine (cholinergic) receptors stimulated by? What do they also serve as? This makes them what?
- ACh
- Ion channel
- Ligand-gated ion channels
Muscarinic receptors are found where?
visceral organs
How many types of muscarinic receptors are there? Stimulatory/Inhibitory/Both? Ligand-gated ion channels, if not then what? How do they work?
- 5
- Both; can be ether (opening K+ or Ca2+ channels)
- No; separate receptor and ion channel
- Use G-proteins and second messenger system
What are nonadrenergic, noncholinergic fibers? Is this common?
- Postganglionic autonomic neurons that are not inactivated by drugs that block ACh or norepinephrine activity
- Only “some”
What are some of the proposed NT’s for nonadrenergic, noncholinergic fibers?
- ATP
- Vasoactive intestinal peptide
- Nitric oxide
Nonadrenergic, noncholinergic fibers are important for what?
Erection of the penis
How is erection of the penis accomplished? What NT is said to be used?
- Parasympathetic neurons innervate blood vessels, causing relaxation and vasodilation
- NO
What can NO also produced?
Smooth muscle relaxation in the:
- Stomach
- Intestines
- Urinary bladder.
Most visceral organs are innervated by ____ sympathetic and parasympathetic neurons.
both
When organs are dual innervated (sympathetic and parasympathetic) most of the time they are _____.
antagonist
What are some examples of organ functions that are dual innervated (sympathetic and parasympathetic) antagonistically?
- Heart rate
- Digestive functions
- Pupil diameter
When do complementary effects occur?
when both divisions produce SIMILAR effects on the same target
What is an example of complementary effects? What does the parasympathetic division do? What does the sympathetic division do?
- Salivary gland secretion
- Stimulates secretion of watery saliva
- Constricts blood vessels so the secretion is thicker.
When do cooperative effects occur?
Occur when both divisions produce DIFFERENT effects that work together to promote a SINGLE action
What are two example of cooperative effects?
- Erection and ejaculation
2. Urination
In the cooperative effect of erection and ejaculation, what does the parasympathetic division do? What does the sympathetic division do?
- Causes vasodilation and erection
2. Causes Ejaculation
In the cooperative effect of urination, what does the parasympathetic division do? What does the sympathetic division do?
- Aids in urinary bladder contraction
2. Helps with bladder muscle tone to control urination
Which organs are only innervated by the sympathetic division and thus are not dual innervated?
- Adrenal medulla
- Arrector pili muscles in skin
- Sweat glands in skin
- Most blood vessels
How are the organs that are not dually innervated regulated? What is this important for?
- Regulated by increase and decrease in sympathetic nerve activity
- Body temperature (shivering, and sweating from glands)
Many visceral functions are regulated by__________.
Autonomic reflexes
How is autonomic regulation of visceral functions achieved?
- Sensory input is sent to brain centers (usually by the vagus nerve)
- Brain centers integrate the information and modify the activity of preganglionic neurons
The medulla oblongata controls what?
Medulla oblongata controls many
- Cardiovascular
- Pulmonary
- Urinary
- Reproductive
- Digestive functions
What regulates the medulla oblongata?
Higher brain regions
What part of the brain is the major regulatory center of the ANS?
Hypothalamus
In regards to the ANS what is the limbic system responsible for?
Responsible for autonomic responses during emotional states (blushing, pallor, fainting, sweating, racing heart rate)