APHY LO1-nerve tissue Flashcards
CNS consists of
brain
spinal cord
PNS
connect CNS with body walls, cavities, organs, and extremeties
cranial nerves
spinal nerves
ganglia-masses of nervous tissue
sensory function
gathering environmental info by sensory receptors at ends of peripheral neurons
integrative function
info is brought together creating sensations (perceptions) adding to memory or helping to produce thoughts in the CNS
motor function
impulses that have specific effects on body parts called effectors
two types of effectors
muscles and glands
motor functions of the PNS
somatic nervous system(voluntary)
autonomic nervous system(unvoluntary)
autonomic nervous system
sensory neurouns (relay info from autonomic sensory receptors; found in visceral organs) motor neurons (send info from CNS to cardiac muscle, smooth muscle and glands)
2 branches on autonomic motor neurons
sympathetic nervous system - fight of flight
parasympathetic nervouse system - rest & digestion
neuron
has cell body and tubular processes calles nerve fibers
types of nerve fibers
axon
dendrites
dendrites
finction as neurons main receptor & transmits impulses to cell body
axons
single fiber extension from neuron of cell body to transmit inpulese away.
may be encased in lipid covering - myeline sheath
myeline sheath
white mater
cover axon and increase speed of nereve impulses
produced in schwan cells on PNS
nerolema
thin nucleus containing membrae that covers myelin sheath
only found surrounding the myelin sheath in the PNS
myelin sheath in CNS
produced by oligodendrocytes (type of neuroligical cell)
oligodendrocytes
resposible for adding layers of myelin sheath around multiple axons at the same time.
DO NOT have neurolema (unable to naturally generate)
types pf neurons
sensory (afferent)
interneurons (association)
motor (efferent)
sensory (afferent) neurons
recieve info from sensory receptors
carry it from PNS toward CNS via cranial or spinal nerves
specialized nerve endings which respond to environmental stimuli
interneurons (association) neurons
located in brain or spinal cord & form links between other neurons
1) sensory -> motor = reflex
2) carry impulse from sensory up spinal cord to brain
3) in thought patterens from one interneuron to another
4) carry impulse down spinal cord to motor neuron
motor (efferent) neuron
carry info from CNS to effectors in PNS via cranial or spinal nerves
when stimulated by motor impulses, effectors will cause response.
muscle will contract - glands will secrete
SAME
Sensory = Afferent Motor = Efferent
neurological cells CNS
structural support for neurons
insulating layers on myelin
phagocytize bacterial cells & cell debris
form cerebrospinal fluid
form innner linings that enclose spaces within the brain
synaptic transmission
junction between two neurons - synapse
gap between two neurons - synaptic cleft
process of nerve impulse
travels from axion of presynaptic neuron to dendrites or cell body of postsynaptic neuron.
synaptic knobs conatins synaptic vessicles which are stimulated to release nerotransmitter into synaptic cleft
for another impulse to be transmitted, nurotransmitter that was released needs to be removed
neurotransmitter can be removed by
diffusing in synaptic cleft
decomposing enzymes in synaptic cleft removes it
reuptake(return) of neurotrasmitter to the presynaptic neuron
nerves
many nerve fibers in a bundle
in CNS bundles of nereve fibers are TRACTS
SENSORY NEREVE- only afferent neurons
MOTOR NEREVE- only efferent neurons
most nreves contain BOTH and are called mixed
nerve pathways
once change is detected, electrical impulse is generated
impulse goes to brain for interpretation and contiunues to effectors so response can be generated
types of stiumuli
mechanical -pin prick chemical- tasting thermal- change in temp stretch- change in BP sound- turning head toward noise
complete afferent pathway
extends from receptor to brain
carries nerve impulses to spinal cord
interneuron carries impulse up spinal cord to brain
complete efferent pathway
from brain to effector
interneuron from brain to appropriate level of spinal cord
then an efferent neuron from the cord to the effector
pathway from receptor ro effector
SENSORY (afferent) - cell body outside
MOTOR (efferent) - cell body inside
INTERNEURONS - entore neron inside
5 componesnt of reflex
receptor sensory neuron interneuron motor neuron effector
withdrawl reflex
3 neurons involved
