The PNS and ANS Flashcards
(187 cards)
The ________ is composed of nervous system structures outside the brain and spinal cord; nerves, ganglia, sensory receptors and efferent nerve endings.
PNS
A nerve is a cordlike organ composed of numerous nerve fibers (________) bound together by connective tissue.
axon
A nerve may contain a few nerve fibers or
hundreds of thousands
Spinal nerve axons are grouped within connective tissue, what are these 3 layers
endoneurium, perineurium, epineurium
delicate layer of loose connective tissue
endoneurium
connective tissues around the nerve fascicles
perineurium
whole nerve is surrounded by a tough fibrous sheath
epineurium
Are these nerves innervated with numerous blood vessels?
Yes
Peripheral nerves, either cranial or spinal, are classified according to the __________ in which they transmit impulses.
direction
Most nerves contain both sensory and motor fibers, these are called what
mixed nerves
transmitting sensory from the body to the brain, these are called
Sensory, or afferent, nerves
transmit signals from the brain to the muscles and glands, these are called
Motor, or efferent, nerves
Ganglia associated with afferent nerve fibers are cell bodies of _________ neurons
sensory
ganglia associated with efferent nerve fibers are mostly cell bodies of _________ motor neurons.
autonomic
what is the difference between the regeneration of PNS vs CNS nerve fibers
PNS: if cell body remains intact, axons can regen
CNS: no chance
so what cells help rebuild fibers / support them for each the PNS and CNS
PNS: schwann cells, help regen
CNS: oligodendrocytes, do not support regrowth
What do sensory receptors do?
collect info about the environment and send it to the brain
what are the ways to classify sensory receptors?
(a) stimulus modality
(b) origin of the stimulus
(c) dist of receptors in the body
what are some examples of the stimulus modality
thermoreceptors, photoreceptors, nociceptors, chemoreceptors, mechanoreceptors
respond to temperature changes
thermoreceptors
in the eye respond to light
photoreceptors
respond to harmful stimuli that result in pain
nociceptors
respond to chemicals in solution and changes in blood chemistry
chemoreceptors
respond to mechanical forces such as touch, pressure, stretch, and vibrations
mechanoreceptors