Test 3 (Final) Flashcards
This deck was created by combining two or more decks
Parasympathetic NS
Rest and digest
Vegetative functions
Decrease HR, decrease BP, increase digestive function
Conserves energy
Almost all viscera is innervated by ________ the parasympathetic and the sympathetic systems
Both
Myelin
Fatty protien that coats the axon
Functions to speed the conduction of the APs
Gaps between the myelin are called nodes of panvier
The AP jumps from node to node via saltatory conduction
Axon
Conducting zone
Conducts/propagates the APs
Peripheral nervous system (PNS)
All neural tissue outside of the CNS
Consists of cranial nerves and spinal nerves
Sensory and motor
Soma
Cell body of a neuron
Contains the nucleus and all other organelles
CNS= nuclei
PNS= ganglia
Somatic NS
System of motor neurons that conduct AP from CNS to skeletal muscle
Dendrites
Input zone
Receive signals
Axon hillock
Trigger zone
Sums incoming signals (inhibitory and excitatory)
Generates AP if threshold is reached
Sensory/afferent system
Carries signals from sensory receptors to CNS (input)
Central nervous system (CNS)
Brain and spinal cord
Command center that receives information form sensory receptors
Propogate
To reproduce and spread
Axonal/terminal branches
Carry the AP to several extensions
The AP remains the same strength in all the branches
Sympathetic NS
Fight or flight
Energetic functions
Increase HR, increase BP, decrease digestive function
Autonomic NS
Visceral nerve fibers that conduct AP from CNS to smooth muscle, cardiac muscle, and glands
Parasympathetic and sympathetic
Neurons/nerve cells
Highly specialized to conduct APs throughout the body
Lose the ability to divide and reproduce at maturity (have extreme longevity)
Very high metabolic rate therefore they need a constant supply of oxygen and glucose to prevent irreversible damage
Axon terminals
Secretory zone
Release of neurotransmitters/neurohormones to communicate with another neuron, muscle, or gland
Motor/efferent
Carries signals from the CNS to effector organs
Results in the contraction of muscle or glandular secretion
Somatic NS and autonomic NS
Anticholinergics
Ah receptor antagonist
Ex. Atropine
Curare
Curare
N2 receptor antagonist
Decrease in skeletal muscle activity
Best know for its uses as an arrow poison in south America
Drug causes paralysis
Neostigmine
Used to treat myasthenia gravis
Autoimmune disease where N2 receptors on skeletal tissue are destroyed
Drug allows Ach to increase stimulation of functioning N2 receptors
Antiadrenergics
Adrenergic receptor antagonists
Blocks sympathetic response
Ex. Propranolol
Hytin
Physostigmine
Used to treat digestive disorders that result in a decrease in gut motility
Increase gut activity (M3)
Propranolol
Beta1 receptor blocker
Treatment for high blood pressure
Drug causes a decrease I’m HR, which leads o a decrease in BP
Parasympathomimetics
Muscarinic receptor agonists
Similar in structure to Ach
Cause parasympathetic response
Ex. Pilocarpine
Ach-esterase inhibitors
Pent the breakdown of Ach allowing it to exert its effects for a longer period of time
Ex. Physostigmine
Neostigmine
Agonist
Binds to a receptor and elicits a response
Pilocarpine
Used to treat glaucoma
Condition caused by The compression of the optic nerve by excess fluid
Drug induces contraction of the muscle in the eye (ciliary) which aids the fluid drainage (M3)
Atropine
Muscarinic receptor blocker
Blocks the parasympathetic response
Used to reduce salivation Nd mucus production in surgical patients
Drug decreases glandular secretory activity (M3)
Hytin
Alpha1 receptor blocker
Treatment for tissue hypoxia
Drug causes vasodilation of blood vessels, increase blood flow
Sympathomimetics
Adnergic receptor agonists
Similar in structure to epinephrine and neuroepinephrine
Elicit a sympathetic response
Ex. Ventolin
Antagonist
Binds to a receptor and blocks a response
Ventolin
Used as a treatment for asthma
Drug causes relaxation of smooth muscle surrounding the bronchioles (Beta2)
Postsynaptic cell
The receiving structure
Each AP is _______, APs _______ decrease on intensity during propagation
Identical
Do not
Neuro- neuronal synapse
One neuron to another neuron
Chemical synapses
Much more common
Specialized for the release and reception of neurotransmitters and neurohormones
Convert electrical signals into chemical signals
Neuro-glandular synapse
One neuron to a gland
Chemical synapse
Convert electrical to chemical
The chemical signal travels across the synapse to the post synaptic structure
And then is converted back into electrical signals
Neuro- muscular synapse
One neuron to a muscle
Functional types of synapses
Electrical
Chemical
During repolarization the membrane is in
A relative refractory period
The post synaptic structure can be……..
Excited or inhibited
Excitatory post synaptic potential
NT/NH binding causes channels that allow depolarization to open
Becomes more positive on the inside
Brought closer to threshold
Usually chemically gated Na+ ion channels (influx)
As the AP travels down the length of the axon
It is newly generated at each patch of the membrane
Gap junctions
Specialized cellular adhesions
Relative refractory period
A 2nd AP can be generated on top of the first if the stimulus is strong enough
Inhibitory post synaptic potential
NT/NH binding causes channels that induce hyperpolarization to open
Becomes more negative on he inside
Taken further from threshold
Can be chemically gated K+ ion channels (eflux) or chemically gated Cl- ion channels (influx)
Electrical synapses
Joined by gap junctions
Allow electricity to flow quickly from cell to cell
Ex. In the heart
Presynaptic cell
The neuron conducting signals toward the synapse
Info sender
Absolute refractory period
Cannot respond to further stimulation
No matter how strong
Once threshold is reached a _______ AP is generated. It _______ possible to produce a partial AP
Complete
Is not
Synapse
The junction where information is transferred from
During depolarization the membrane is in
An absolute refractory period
Postganglionic fiber
Neuron whose cell body lies in the PNS
Binds to the NT released from the postganglionic fiber
Axon extends to the effector organ
Releases NT that bind to the effector organ
Function of the parasympathetic NS
Rest and digest
Vegetative and Maintance activities
Conservation of ATP
Ex. Decrease HR, decrease BP, increase digestive function
Location of ganglia (origin of postganglionic fiber)
Sympathetic- sympathetic ganglionchain
Collateral ganglion
Adrenal medulla
Parasympathetic- terminal ganglion
Digestive tract smooth muscle
P- increase in motility (M3)
S- decrease in motility (Alpha2, Beta2)
Increase contraction of sphinctors (Alpha1)
N2
On sarcolemma of skeletal tissue (depolarization)
Muscatinic receptors
Receptor stimulation by ch can result in an excitatory or inhibitory response depending on the receptor and the target organ
M1
M2
M3
Neurotransmitters
Somatic- Ach
Autonomic- Ach, epinephrine, neuroepinephrine
Esophageal plexus
Innervates the esophagus
Preganglionic sympathetic fiber releases Ach which binds to N1 receptors on medullary tissue
This causes a release of epinephrine and neuroepinephrine into the blood stream
(system wide sympathetic response)
Cardiac plexus
Innervates the heart
Adrenal medulla
Internal portion of the adrenal gland
Nicotinic receptor
Receptor stimulation by Ach is always excitatory
N1
N2
Glassopharyngeal (9)
Parotid salivary gland
Vagus (10)
90% of the parasympathetic supply Branches into the Cardiac plexus Pulmonary plexus Esophageal plexus Descending aortic plexus
Cholinergic receptors
Bind and respond to Ach
Nicotinic 1&2
Muscarinic 1,2,&3
Origin sites of preganglionic fibers
Sympathetic- thoracolumbar region of the spinal cord (T1-L2)
Parasympathetic- cranial and spinal nerves
Some preganglionic fibers synapse
With the adrenal medulla
Sympathetic ganglionchainq
Close to the spinal cord
M3
Located on smooth muscle and glands
Excitatory
Facial (7)
Nasal glands
Lacrimal glands
Submandibular and sublingual salivary glands
M1
Located on neural tissue
Excitatory
Cholinergic fibersq
Fibers that release Ach
Adrenerhic fibers
Neurons that release epinephrine and neuroepinephrine
Descending aortic plexus
Innervates most abdominal viscera
Heart
P- decrease in HR (M2)
S- increase in HR (Beta1)
Eye
P- pupil constriction via contraction of the circular muscle of the iris (M3)
S- pupil dilation via the contraction of the radial muscle of the iris (Alpha1)
Sphinctor
Cuff of smooth muscle between one organ and the next
Dual innervation
Most viscera is innervated by both the parasympathetic and the sympathetic NS
Alpha
Stimulation is generally excitatory
Except alpha2 on gut muscle
Alpha1
Alpha2
M2
Located on heart
Inhibitory (decrease muscle contraction)
N1
On all postganglionic cell bodies (at all ganglia in ANS)
On adrenal medulla
Adrenergic receptors
Binds and respond to epinephrine and neuroepinephrine
Alpha 1&2
Beta 1&2
Preganglionic fibers
Neuron whose cell body lies in the CNS
Releases NT that across a Neuro-neuronal synapse and binds with a second neuron
Digestive glands
P- increase in secretory activity (M3)
S- decrease in secretory activity (Beta2)
Function of the sympathetic NS
Fight or flight
Prepares body to deal with an energetic situation
Uses ATP
Ex. Increase HR, increase BP, decrease digestive function
The efferent division is divided into two parts
Somatic
Autonomic
Liver
P- no innervation
S- glycogen breakdown (Beta2)
Terminal ganglion
Close to the effector organ
Pathway
Somatic- single neuron
Autonomic- 2 neuron chain with a synapse in between
Collateral ganglion
Midway between the spinal cord and the effector organ
Affectors
Somatic- skeletal muscle
Autonomic- smooth and cardiac muscle, glands, viscera
Blood vessel smooth muscle
P- no innervation
BV serving the external genetalia (M3)
S- blood vessel vaso-constriction (Alpha1)
Autonomic tone
One division is exhibiting more tone depending on what the body needs
Parasympathetic and sympathetic ______ each other and _______ are active all the time
Oppose
Both
Pulmonary plexus
Innervates the lungs and bronchi
Respiratory system
P- contraction of smooth muscle surrounding the bronchioles (M3)
S- relaxation of the smooth muscle surrounding the bronchioles (Beta2)
Beta
Stimulation is generally inhibitory
Except beta1 on the heart
Beta1
Beta2
Occulomotor (3)
Smooth muscle of the eye that influences pupil size and eyeball movement
Neurotransmitter effect on target cell
Somatic- always excitatory
Autonomic- excitatory or inhibitory
Autonomic NS is divided into two parts
Parasympathetic and sympathetic
Sacral region of the spinal cord Innervates:
Distal half of the large intestine
Urinary bladder
Reproductive organs
Axon diameter
The larger the diameter the faster the speed of the AP conduction
Large diameter offers less resistance to the electrical flow
Two factors that influence the rate of AP conduction
Axon diameter
Degree of myelination
Group C fibers
Slowest
Autonomic NS/visceral
Smallest in diameter
Unmyelinated
Central process
Enter the CNS
Sensory/afferent
Most are unipolar or bipolar
Transmit APs from sensory receptors in the skin and viscera toward the CNS
Degree of myelination
Myelinated axons exhibit “saltatory conduction”
Unmyelinated axons exhibit “continuous conduction”
Functional classification
Baed on the direction the AP travels in relation to the CNS
Sensory/afferent
Internuerons
Motor/efferent
Multipolar neurons
3 or more processes coming from the cell body
Most common type
ALL stomatic efferent types
Bipolar neurons
1 axon and 1 dendrite coming from the cell body (dendrite may branch)
Rare and specialized
Receptors in the retina and olfactory mucosa
Unipolar neurons
1 process coming from the cell body that divides into two branches
Peripheral process
Central process
Most sensory neurons
Group A fibers
Fastest
Somatic fibers tha there the skin, skeletal muscle, and joints
Largest in diameter
Heavily myelinated
Peripheral process
Associated with sensory receptors
Internuerons
Most are multipolar
Live entirely within the CNS
Shuttle signals through e CNS pathways where integration takes place
Make up 99% of the neuronal population
Group B fibers
Autonomic NS/visceral
Intermediate diameter
Lightly/moderately myelinated
Structural classification
Based on the number of processes coming from the cell body
Multipolar neurons
Bipolar neurons
Unipolar neurons
Motor/efferent
All are multipolar
Transmit APs from the CNS to effector organs (muscles and glands)
