peripheral & autonomic nervous system Flashcards
cns
- center of all mental activity (thoughts, learning, memory, sensory, perceptions, voluntary and involuntary motor control)
- keeps us in touch with external and internal environment
- regulate and maintain homeostasis with endocrine system
sensory receptors
- detect internal or external stimuli and relay info toward CNS
- afferent neurons
integrative receptors
- analysis, storage, decision making, perception
- interneurons
motor receptors
- muscular contraction
- glandular secretion
- efferent neurons
pns divisions
- afferent (sensory) division
- efferent (motor) division
afferent division of pns
- sensory
- trasmits impulses from receptors to cns
- somatic and visceral afferent fibers
somatic afferent fibers
- carry impulses from skin, skeletal muscles, and joints
- general senses: touch, pain, pressure, vibration, temp, proprioception
- special senses: hearing, equilibrium, vision
visceral afferent fibers
- transmit impulses from visceral organs
- general senses: stretch, pain, temp, chemical changes, irritation in viscera, nausea, hunger
- special senses: taste smell
efferent division of pns
- motor
- transmits impulses from cns to effector organs
- 2 subdivision: somatic and autonomic nervous system
efferent somatic nervous system
- pns efferent (motor) division
- provides conscious control of skeletal muscle
efferent autonomic nervous system
- pns afferent (sensory) division
- parasympathetic and sympathetic
- regulates cardiac and smooth muscle, secretory glands
pns definition
nervous structures outside the brain and spinal cord that are not covered in meningeal layers
which cranial nerves are in the midbrain
- CNI (olfactory)
- CN2 (optic)
which cranial nerves are in the pons
CN4 (trochlear)
how many cranial nerves are there
12
where do all cranial nerves (except 1 and 2) attach
brainstem
? pairs of spinal nerves
31
spinal nerve pair name and number
- cervical (8)
- thoracic (12)
- lumbar (5)
- sacral (5)
- coccygeal (1)
where do cervical spinal nerves exit
from the vertebral foramen above their respective cervical vertebrae
where do thoracic spinal nerves exit
from the vertebral foramen below their respective thoracic vertebrae
parasympathetic division
- rest and digest
- autonomic nervous system (efferent)
- routine maintenance
- acetylcholine
sympathetic division
- fight, flight, freeze
- autonomic nervous system (efferent)
- mobilization
- increased metabolism
- norepinephrine
difference between somatic and visceral sensory system (afferent)
- somatic: receptors are specifically localized
- visceral: receptors widely scattered (poor localization)
ganglia
synaptic relay stations between neurons
preganglionic neurons
- presynaptic neurons
- located in CNS gray matter
- axons synapse with postganglionic neurons
postganglionic neurons
- postsynaptic neurons
- located in autonomic ganglia
- axons terminate in effector organs (smooth/cardiac muscle, glands)
preganglionic axons exist spinal cord through ventral root and enter spinal nerve, exit spinal nerve via while matter communicating ramus, enter sympathetic trunk/chain, then ? (3 options)
- synapse on postganglionic neuron in chain ganglion, return to spinal nerve and follow branch to the skin
- ascend or descend within sympathetic trunl, synapse with a postganglionic neuron within a chain ganglion, return to spinal nerve at that level and follow branches to skin
- enter sympathetic chain, pass through without synapsing, form a splachnic nerve that passes toward thoracic or abdominal organs; synapse in prevertebral ganglion in front of aorta; postganglionic axons follow arteries to organs
types of ganglia
- sensory ganglia
- autonomic ganglia
sensory ganglia location
- in the dorsal root ganglia of spinal nerves
- on the ganglia of some cranial nerves
dorsal root ganglia of spinal nerves
- found on dorsal root of spinal nerves
- transmit messages relating to pain, touch, temp from PNS to CNS
sensory ganglia of cranial nerves
- found on ganglia of some cranial nerves
- special sensory functions
3 groups of autonomic ganglia
- sympathetic chain ganglia
- prevertebral ganglia
- parasympathetic ganglia
sympathetic chain ganglia
- sympathetic trunk or paravertebral ganglia
- 23 pairs
sympathetic chain ganglia location
ventral and lateral to the spinal cord that extend from upper neck to coccyx
sympathetic chain ganglia input from ?
lateral horn of thoracic and lumbar spinal cord
sympathetic chain ganglia relay info about ?
stress and danger
prevertebral ganglia
- between sympathetic chain and target organ
- carry sympathetic function but are NOT part of the sympathetic chain
- innervate all abdominal and pelvic organs (excluding adrenal gland)
parasympathetic ganglia location
in the cranial nerve nuclei and lateral horn of sacral spinal cord
thoracolumbar system
- sympathetic nervous system
- preganglionic neuronal cell bodies are located in the lateral horn of gray matter from T1-L2
- postsynaptic neurons are in the paravertebral and prevertebral ganglia
- short preganglionic fibers
- long postganglionic fibers
- supplies every part of the body
- causes: dry mouth, pupil dilation, increased hr and respiratory rate to increase O2 to skeletal muscle
- when nervous, sweat and when excited, bp rises
in thoracolumnbar system acetylcholine released by ?
preganglionic fibers
in thoraculmnbar system, norepinephrine released by ?
postganglionic fibers
craniosacral system
- parasympathetic nervous system
- preganglionic neuronal cell bodies are in brain stem or sacral levels of the spinal cord
- in lateral horn of grat matter from S2-S4
- long preganglionic fibers
- short postganglionic fibers
- supplies head, visceral cavities of the trunk, erectile tissues of the external genitalia
- postsynaptic cell bodies are in the wall of the target organ
craniosacral system cranial nerves
CNIII, VII, IX, X
craniosacral system acetylcholine secreted by ?
preganglionic and postganglionic fibers
cranial outflow (craniosacral system)
- increases motility of smooth muscle of digestive tract, decreases hr, causes bronchial constriction
- CNIII constrict pupuls
- CNVII tears, nasal mucus, saliva
- CNIX parotid salivary gland
- CNX stimulates digestive gland
sacral outflow (craniosacral system)
- form pelvic splachnic nerves
- supply 2nd half of large intestine
- supply all pelvic (genitourinary) organs
