nervous system Flashcards
_________ neurons are important in reflex regulation and influence efferent action
Afferent
_______ neurons carry impulses from CNS to effector organs
Efferent
these neurons are Short and end in ganglia
Sympathetic Preganglionic neurons
these neurons Originate in CNS and emerge from thoracic and lumbar regions
Sympathetic Preganglionic neurons
these neurons Originate in ganglia
Sympathetic Postganglionic neurons
these neurons are
Long and end at effector organs
Sympathetic Postganglionic neurons
this only gets preganglionic innervation and secretes hormones in blood
adrenal medulla
these neurons Originate in CNS (CN III, VII, IX, X) and sacral region
Parasympathetic Preganglionic neurons
these neurons are Long and terminate on or near effector organs
Parasympathetic Preganglionic neurons
these neurons Originate in ganglia and are
Short and terminate at effector organs
Parasympathetic Postganglionic neurons
what Innervate the GIT, pancreas, and gallbladder
Enteric Neurons
Enteric Neurons Functions independently of the ____
CNS
Enteric Neurons controls
Motility
Exocrine secretion
Endocrine secretion
Microcirculation
Enteric Neurons are Modulated by both________.
sympathetic and parasympathetic systems
Sympathetic Nervous System stimulation
Increase HR and BP
Mobilize energy stores
Increase blood flow to skeletal muscle and heart
Divert blood from skin and internal organs
Dilation of pupils
Dilation of bronchioles
Other in GIT and sex organs
nervous system that Adjusts for stressful situations
Sympathetic Nervous System
The sympathetic system tends to function as a___ and often discharges as a complete system
unit
Sympathetic Nervous System -Reactions triggered by direct stimulation of sympathetic activation and _____
adrenal medulla
does the PNS discharge as a complete system
never
what system does the following:
Maintains homeostasis
Usually opposes/balances the sympathetic system
“Rest and digest” response
Parasympathetic Nervous System
ANS is a “motor” system and requires _____ input.
This feedback comes from viscera and other autonomically innervated structures
sensory
in ANS, Most reflex responses do not require _______ control
conscious
Most organs have___ innervation (i.e., sympathetic and parasympathetic)
dual
Do both the sympathetic and parasympathetic provide equal stimulation in a given situation?
One system usually predominates in any given situation
examples that only have sympathetic innervation
Adrenal medulla Kidney Pilomotor muscles Sweat glands Vascular pressure (virtually no participation by parasympathetic system)
Sympathetic sites of origin
thoracic and lumbar region of the spinal cord
parasympathetic sites of origin
brain and sacral areas of the spinal cord
Sympathetic length of fibers
short preganglionic
long postganglionic
parasympathetic length of fibers
long preganglionic
short postganglionic
location of ganglia in sympathetic system
close to spinal cord
location of ganglia in parasympathetic system
within or near effector organs
preganglionic fiber branching in the sympathetic nervous system
extensive
preganglionic fiber branching in the parasympathetic nervous system
minimal
sympathetic nervous system distribution
wide
parasympathetic nervous system distribution
minimal
sympathetic nervous system type of response
diffuse
parasympathetic nervous system type of response
discrete
Hormones are
Secreted into blood via _____ cells- Action is widely distributed
endocrine
these are
Chemical secreted by tissues.
Action is on immediate environment surrounding secreting tissues–Do not enter blood
Local mediators
______ are distinct anatomical units with no structural continuity
Neurons
neurons Require release of ______ at nerve terminals to communicate with other neurons or effector organs
neurotransmitters
NT Release is triggered by ______ which leads to membrane depolarization
action potential
Increase in intracellular Ca2+ initiates fusion of vesicles (containing neurotransmitters) and release of their contents into _____.
synaptic cleft
Once the neurotransmitter is released, it diffuses across the ______.
synaptic cleft
Once the neurotransmitter is released, it diffuses across the synaptic cleft.
It can then react with receptors on the _______.
postsynaptic OR presynaptic neuron
neurotransmitters do not diffuse through cell membranes…they need _____ to have an action
receptors
common Neurotransmitters
Norepinephrine (NE) [and closely related epinephrine (Epi)] Acetylcholine (ACh) Dopamine (DA) Serotonin (5-HT) Histamine γ-aminobutyric acid (GABA) Glutamate
ANS fibers can be divided into 2 groups based on _____of the neurotransmitter released
chemical nature
If mediated by ACh: neuron termed ______.
cholinergic
When NE or Epi is transmitter, the neuron is termed ____.
adrenergic
