Quiz III, Nervous System Flashcards
Basic unit of nervous system
neuron
Carries impulses toward the CNS
sensory
Carries impulses from neuron to neuron
associative
Carries impulses away from CNS
Motor
Parts of a neuron (3)
cell body, dendrite, axon
Main functions (3)
sensory, intergrative (analysis), motor (action)
CNS is composed of the
Brain & spinal cord
Peripheral Nervous System is composed of which (2) division
afferent & efferent
Carries nerve impulses from peripheral receptors to CNS
Afferent
Carries nerve impulses to muscles/glands
Efferent
What is the CNS connected with?
Glands, muscles & receptors
The CNS is also subdivided into
The Somatic NS & Autonomic NS
Somatic NS is made up of
- Made of efferent that carry impulses from the CNS to skeletal muscles
- Voluntary or conscious control
- Has 1 neuron that carries impulses to target structure
Autonomic NS is made up of
- Consists of efferent nerve cells that carry information from the CNS to cardiac muscles, glands and smooth muscles
- Involuntary or unconscious control
- Has 2 neurons that carry impulses to target structures
What nervous system is involved with:
- Smooth muscle, cardiac muscle, salivary glands, & other viscera
- GI motility, rate & force of heartbeat, secretions of glands & size of pupils
Autonomic NS
Subdivisions of ANS (2)
Sympathetic & Parasympathetic
Sympathetic
Regulates energy-expending activities
Parasympathetic
Regulates energy-conserving activities
What type of action does parasympathetic have, its definition & where does its first neuron arise?
- Cholinergic
- An action or receptor that is activated by acetylcholine
- craniosacral cord (parasympathetic)
What type of action does sympathetic have, its definition & where does its first neuron arise?
- Adrenergic
- An action or a receptor that is activated by epinephrine or norepinephrine
- thoracolumbar cord (sympathetic)
Epinephrine
Stimulates alpha and beta receptors = a potent stimulator of the heart and powerful dilator of the bronchioles. Acatecholaminehormoneoftheadrenalmedullathatisthemost potentstimulantofthesympatheticnervoussystem,resulting
in increasedheartrateandforceofcontraction,vasoconstriction
or vasodilation,relaxationofbronchiolarandintestinalsmooth
muscle,glycogenolysis,lipolysis,andothermetaboliceffects.
Alsocalledadrenaline.
Norepinephrine
is a neurotransmitter that is important for attentiveness, emotions, sleeping, dreaming, and learning. Norepinephrine is also released as a hormone into the blood, where it causes blood vessels to contract and heart rate to increase.
Acetylcholine
a very widely distributed excitatory neurotransmitter that triggers muscle contraction and stimulates the excretion of certain hormones. In the central nervous system, it is involved in wakefulness, attentiveness, anger, aggression, sexuality, and thirst, among other things.
Dopamine
a neurotransmitter involved in controlling movement and posture. It also modulates mood and plays a central role inpositive reinforcementand dependency.
GABA (gamma-aminobutyric acid)
an inhibitory neurotransmitter that is very widely distributed in the neurons of the cortex. GABA contributes to motor control, vision, and many other cortical functions.It also regulates anxiety.
Serotonin
contributes to various functions, such as regulating body temperature, sleep, mood, appetite, and pain
Glutamate
a major excitatory neurotransmitter that is associated withlearning and memory.
How do axons travel in the ANS
The axon of the first neuron leaves the CNS –> to ganglion which synapses with dendrite of the second neuron
Axons of the first neuron are called ?
preganglionic
Preganglionic fibers of the Sympathetic (length)
short (end adjacent to spinal cord)
Preganglionic fibers of the Parasympathetic (length)
long (travel to ganglia in the wall of the target organ)
Axons of the second neurons are called
Postganglionic
Postganglionic Sympathetic (length)
long
Postganglionic Parasympathetic (length)
short
Ganglion (def.)
Nerve cell cluster or group of nerve cell bodies located in the ANS
SNS - Preganglions are? function?
short (end adjacent to spinal cord) except in adrenal medulla
- Releases neurotransmiters, epinephrine/norepinephrine directly
SNS - Postganglions are
long (epi/norepi)
Sympathetic NS- Stimulations:
Increases HR & RR
Decrease GI activity
Pupil dilation
Constricts blood vessels to smooth muscle
Dilation of blood vessels to skeletal muscle
Dilation of bronchioles
Increase blood glucose levels
Fight or flight response
Receptors : alpha (stimulatory) & beta (inhibitory)
Receptors for the Sympathetic (adrenergic)
Alpha 1 & Alpha 2
Alpha 1
smooth muscles of blood vessels
– constriction of arterioles to increase BP
Except GIT
Alpha 2
postganglionic nerve endings
– inhibition of norepi release
Decreases BP & constriction of skeletal mm
Alpha receptors are generally
stimulatory
The synapse between the preganglionic neuron and the postganglionic neuron is called?
ganglionic synapse
The primary neurotransmitters for adrenergic sites are?
norepinephrin, epinephrine and dopamine
Direct-Acting Cholinergic: This product has been used to treat atony of the GI tract and to stimulate uterine contractions in swine
Carbamylcholine
Direct-Acting Cholinergic: Used to control vomiting and to promote gastric tract emptying
Metoclopromide (Reglan)
Indirect-Acting Cholinergic: Used to diagnose myasthenia gravis
Edrophonium (Tensilon)
Indirect-Acting Cholinergic: Used to treat urine retention and GI atony, are also used as an antidote to neuromuscular blocking agents
Neostigmine (Prostigmine, Stiglyn)
Indirect-Acting Cholinergic: Commonly used as insecticide dips and may results in toxicity if used inappropriately.
Organophosphate Compounds
Anticholinergic: Used as a pre-anesthetic to dry secretions and prevent bradycardia; to counteract organophosphates poisoning.
Atropine
Anticholinergic: Used to control diarrhea. Also an ingredient of Biosol-M
Methscopolamine
Anticholinergic: Similar to atropine, provide longer duration of action than atropine and is used as a pre-anesthetic
Glycopyrrolate (Robinul-V)
Anticholinergic: Used to treat diarrhea, urinary incontinence, and bradycardia and to produce colonic peristalsis in horses to allow rectal exam.
Propantheline (Pro-Banthine)
Anticholinergic: A cholinesterase reactivator used to treat organophosphate intoxication.
Pralidoxime (Protopam, 2-PAM)
Some fibers are surrounded by an insulating substance called
myelin
If the impulse travels around the arc without going to the brain for analysis, the sequence of events is called ?
spinal reflex
Reflex arc is composed of the following:
A receptor A sensory neuron A center in the CNS for a synapse A motor neuron An effector
