Chapter 16: The Autonomic Nervous System
Muscarinic; produces longer lasting effects by coupling G-protein receptors
@ cholinergic neuromuscular or neuroglandular junctions that are stimulated by a mushroom toxin; how does it produce longer lasting effects?
ACh
All parasympathetic use what neurotransmitter?
Alpha-2; has a inhibitory effect on the cell
Alpha receptor that helps coordinate sympathetic and parasympathetic activities and decreases cAMP levels. What kind of effect does it have on the cell?
Enteric nervous system (ENS); extensive network in digestive tract walls of roughly 100 million neurons; complex visceral reflexes coordinated locally
Briefly describe the 3rd division of the autonomic nervous system
1. Secondary memory 2. Tertiary memory
Components of long term memory 1. May take you longer to retrieve but you will remember this information for a long time 2. Something you will never forget like your name
Parasympathetic innervation dominates under resting conditions; crisis accelerates heart rate by stimulating the sympathetic innervation and inhibiting parasympathetic innervation
Describe how the heart receives dual innervation
Craniosacral (2 parts) Cranial: mesencephalon, pons, medulla oblongata (brainstem) associated with cranial nerves III, VII, IX, X Sacral: later gray horns of spinal segments S2-S4 nerve X
Describe how the parasympathetic division is organized
Supports digestion and nutrient absorption by cells
Describe the activation of the parasympathetic system
very short post-ganglionic fibers that release neurotransmitters into the bloodstream (not at synapse); they function as hormones to affect target cells throughout body
Describe the adrenal medullae
1. Increased Neurotransmitter release: frequently active synapse increases neurotransmitter storage, releasing more and having a greater effect on postsynaptic neuron 2. Facilitation at synapse: frequently active synapse begins continuously releasing neurotransmitter, bringing membrane closer to depolarization 3. Formation of additional synaptic connections: Axon tips can branch and form additional synapses on postsynaptic neuron. So presynaptic neuron has greater effect on postsynaptic neuron.
How are memories made/ stored? (3 steps)
Different receptor types; if it binds to inhibitory receptor it will inhibit stimulus
How does one neurotransmitter (Norepinephrine) have different effects? Inhibitory on some organs and excretory on others?
1. Can only increase activity 2. Can increase or decrease activity
In regards to autonomic tone what happens to activity when 1. A nerve is inactive under normal conditions 2. If a nerve maintains a background level of activity
Preganglionic neurons and ganglionic neurons
In the sympathetic division what is involved in using energy and increasing metabolic rate?
They are located near the spinal cord; Preganglionic fibers (release NE at neuroeffector junctions) release ACH stimulating ganglionic fibers
In the sympathetic division where are ganglia located ? What stimulates them?
Lateral gray horns of spinal segments T1 - L2
In the sympathetic division where are preganglionic neurons located ?
Cholinergic (ACh) sympathetic terminals; stimulates sweat gland secretion and dilates blood vessels
Innervates sweat glands of skin and blood vessels of skeletal muscles and brain. What does this stimulate?
Short term memory
Memory where you can retrieve information quickly and that will not stay very long
Alpha-1; has an excitatory effect on target cell
More common type of alpha receptor that increases intracellular calcium. What type of effect does it have on the target cell?
1. cerebral cortex: interacts with other parts of brain 2. conscious and unconscious information processing 3.Not part of programmed wiring of brain, can adjust over time.
Name 3 things needed for higher order functions
sympathetic synapses closer to the spinal cord and have short pre ganglionic neuron and longer post ganglionic fiber (ACh, nonephinephrine, epinephrine) parasympathetic synapses closes to the effector organ (ACh only)
Name anatomical differences between sympathetic and parasympathetic nervous system
1. stimulates visceral activity 2. conserves energy 3. promotes sedentary activity 4.decreased metabolic rate, heart rate and blood pressure 5.increased salivary and digestive glands secretion 6.increased mortility and blood flow in digestive tract 7. urination and defection stimulation
Name functions of the parasympathetic division of the ANS?
Thoracolumbar
Name the location of sympathetic division
Sympathetic and Parasympathetic Nervous Systems; 2 divisions can work together or separately
Name the two division of the Autonomic Nervous System? How do these two systems work in relation to one another?
alpha (NE preference) and beta receptors; E binds equally to A and B. They activate enzymes on the inside of the cell membrane via G proteins
Name the two types of adrenergic membrane receptors that Norepinephrine (NE) and Epinephrine (E) act on? How do they activate enzymes on the inside of the cell membrane?
Vagus Nerve (X) Innervates: neck, thoracic, abdominopelvic cavity Ex: large intestine
Nerve that carries 75% of parasympathetic outflow? Innervates? Ex?
Nicotonic
On ganglion cells of both sympathetic and parasympathetic. ACH causes excitation of ganglionic neuron on chemically gated channels; stimulated by nicotine
1. brain stem and lateral portion of anterior gray horns of S2-S4; release ACh stimulating ganglionic neurons 2. near the target organ 3. Postganglionic fibers release ACh @ neuroeffector junctions
Parasympathetic location of the following: 1. Preganglionic neurons? 2. Ganglion? 3. Target organs
Somatic Nervous System (SNS)
Part of the nervous system that operates under conscious and unconscious control; controls skeletal muscles; it seldom affects long term survival
Autonomic Nervous System
Part of the nervous system that operates with conscious instruction; controls vital systems and coordinates vital system functions: cardiovascular, respiratory, digestive, urinary or reproductive
Nitroxidergic synapses; produces vasodilation and increased blood flow
Releases nitric oxide as neurotransmitter; neurons innervate smooth muscles in the walls of blood vessels in skeletal muscles and in the brain. What does it produce?
Beta receptors; they are stimulated by increasing intracellular cAMP levels
Type of receptor that affects membranes in many organs (blood vessels of skeletal muscles, lungs, heart and liver) that triggers metabolic changes in target cells; how is it stimulated?
a. Beta-1 b. Beta- 2 c. Beta-3 Lipolysis
Types of Beta receptors: a. increase metabolic activity b. relaxation of smooth muscles along the respiratory tract c. breakdown of triglycerides in adipocytes
Skeletal Muscles
What are the target organs of the autonomic nervous system ?
Nicotine and Muscarinic
What are the two types of parasympathetic neurotransmitter receptors?
Compounds that enhance serotonin cause hallucinations (Ex: LSD) Blocking serotonin causes depression, blocking its breakdown used as antidepressants (Ex: Prozac)
What do compounds that enhance serotonin cause? What does blocking serotonin cause?
Exhilaration
What do drugs that stimulate Norepinephrine (NE) cause?
Varicosities that are scattered across the cell surface that are filled with neurotransmitter vesicles
What do ganglionic neurons release neurotransmitters from?
Release norepinephrine called adrenergic
What do most sympathetic ganglion release? What is this called?
effectors in body wall, thoracic cavity, head and limbs
What do neurons in ganglia control?
They release ACh and are called Cholinergic synapses
What do preganglionic neurons release? What are they called?
Reduces metabolic rate and promotes digestion
What does the parasympathetic division reduce?
Heightened mental alertness Increased metabolic rate Reduced digestive and urinary functions Energy reserves activated Increased respiratory rates Respiratory Passageways dilate Increased heart rate and blood pressure Sweat glands activated
What happens when their is increased sympathetic activity in this division of the autonomic nervous system? (8 things)
Inherited depression
What is caused by defective Norepinephrine (NE) synthesis?
Rest and Digest
What is the parasympathetic division also called?
Schizophrenia (Parkinsons)
What is the result of having excessive dopamine?
Tracts between the amygdala and hypothalamus
What links memory to emotion
Visceral Reflexes Ex: When light is shone into 1 eye the pupil in BOTH eyes constrict (consensual light reflex)
What regulated autonomic function? Example?
Amphetamines
What stimulates dopamine secretion?
The fight or flight response; sweaty palms; nausea; sweaty palms (are all part of the activation of the sympathetic nervous system
What system in your body is activated when you are anxious or nervous ?
Amygdala and hippocampus
What two parts of the limbic system are essential to memory consolidation?
During exertion, stress or emergency; increases alertness, metabolic rate and muscular abilities
When is the sympathetic division activated ? What does this increase?
Fight or flight
When is the sympathetic division also called?
Dual innervation; ex: heart, digestive tract & lungs
When sympathetic and parasympathetic divisions can innervate the same organ and have the opposite effect. Provide an example
Vasovagal response
When the parasympathetic nervous system goes into overdrive; when you faint
In the cerebral cortex in appropriate association areas
Where are long term memories stored?
They join in bundles called autonomic plexuses; Ex: cardiac plexus and pulmonary plexus
Where do parasympathetic nerves join? Provide an example.
1. Sympathetic Chain Ganglia 2. Collateral Ganglia 3. Adrenal Medullae
Where do ventral root nerves carry myelinated preganglionic fibers to? 1. near vertebral column 2. abdominopelvic viscera receive innervation 3. preganglionic fibers synapse on neuroendocrine cells and secrete hormones into the blood
Originates in the brain stem or sacral region of the spinal cord; synapses in ganglia close to (or within) target organs
Where does the parasympathetic division originate? Synapse?
out of the ventral root; they send post ganglionic nerves to visceral organs in the thoracic cavity
Where does the preganglionic nerve travel? What is the job of these nerves?
Craniosacral
Where is the parasympathetic division located ?
Autonomic Tone
autonomic neurons showing resting levels of spontaneous activity
Preganglionic fibers
fibers that are long
Postganglionic
fibers that are short
serotonin
neurotransmitter that affects sensory interpretation
Collateral Ganglia
structure that is anterior to vertebral bodies and that contain ganglionic neurons that innervate tissues and organs in the abdominopelvic cavity