The PNS and ANS Flashcards
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
what are some examples of classifying by origin of stimulus
exteroceptors, interoceptors, proprioceptors
sensory end organ that responds to stimuli from the external world
exteroreceptors
Nerve ending situated in a visceral organ; responds to changes and stimuli within the body’s internal environment
interceptors
Receptor that senses moment in the musculoskeletal system; more specifically, proprioceptors sense stretch in muscles, tendons, and joint capsules
proprioceptors
give an example of distribution of receptors in the body
general (somatic) senses, special senses
touch, pain, pressure, temperature, and proprioception is that general or special?
general (somatic) senses
taste, vision, hearing, and equilibrium is that general or special?
special senses
Are general sense receptors complex or simple?
simple, one or a few sensory nerve fibers
on a mircoscoping level what can you see in a sensory receptor
free nerve ending, cilia, encapsulated nerve endings at the dendrites of a-order sensory neurons, or separate cells that synapse w/ 1st order sensory neurons
what are the nerve endings that are wrapped in glial cells or CT that are mechanoreceptors for touch, pressure, and stretch
encapsulated nerve endings
__________ sensations are : sense of touch
tactile
________ touch refers to : general, vague sense of touch (ie something made contact)
crude
_____ touch provides specific information about : details -> location, size, shape, and texture
fine
_________: sense of continuous mechanical force
pressure
________ : perception of rapidly oscillating stimuli
vibration
_______ Receptors: specialized structures in the skin and other tissues that respond to specific stimuli and initate nerve impulses to the brain
sensory
_______ nerve endings: detect pain, temp, and light touch (epidermis)
free
________ ______: sustained pressure and texture (epidermis), fine touch discrimation
merkel’s (tactile) discs
_____ _____ plexuses : detect movement of hair or light touch
hair root plexuses
__________ (lamellated) _________: deep pressure and vibration (dermis)
Pacinian (lamellated) corpuscles
___________ _________: continuous pressure and stretch
Ruffini’s corpuscle
___________ Sensations : bodys ability to sense its position, movement, and orientation in space, even without visual input
proprioceptive
what are the 3 proprioceptors
Pacinian corpuscles, muscle spindles, Golgi tendon organs
which proprioceptor is the speed of joint movement
Pacinian corpuscles
which proprioceptor is for muscle length and stretch
muscle spindles
which proprioceptor is tendon tension and force
golgi tendon organs
In addition to tactile, touch, pressure/vibration sensations and proprioceptive sensations, what is the last one?
temperature - detect changes in temperature
_______ is a vital sensation because it provides us with information about tissue-damaging stimuli and with signs that may be used for diagnosis of disease or injury.
Pain
___________: Pain receptors in the body that detect potentially harmful stimuli, triggering the sensation of pain to protect the body from injury
nociceptors
What are the 2 types of pain recognized by the parietal lobe of the cortex
somatic and visceral
what is the difference between somatic and visceral pain
- somatic (superficial and deep)
- visceral: felt just under the skin, overlying an organ (associated w/ referred pain)
T or F: Projection pathways for pain are diverse and complex, and the sensation can originate anywhere along any of the routes.
T
How many main pathways does pain have, but it also has multiple subroutes
2
Pain signals from the head travel to the brainstem by way of four cranial nerves:
trigeminal (V), facial (VII), glossopharyngeal (IX) and vagus (X)
Okay so these 4 from the head are 2nd order and arise at the medulla, where to next
thalamus > cerebral cortex
Pain signals from the neck down travel by way of three of the ascending spinal cord tracts:
spinothalamic tract, the spinorecticular tract, and the gracile fasciculus
These from the neck down, thalamus relays most pain signals through 3rd order neurons to their final destination of
postcentral gyrus of the cerebrum
_______ ________ : A phenomenon in which pain is perceived in a location different from the site of the actual injury or underlying problem
Referred pain
how many pairs of cranial nerves attach to the brain and innervate the head and neck
12
the ________ nerves are the only pair that “wanders” into the thorax and abdomen.
vagus
T or F: C. Some cranial nerves (I, II,) contain only sensory fibers and are called sensory nerves. The rest are mixed nerves because they contain both sensory and motor fibers.
True
In terms of cranial nerve pathways, most motor fibers of these nerves begin in nuclei of the brainstem and lead to
glands and muscles
Cranial nerve sensory fibers begin in receptors located mainly in the head and neck and lead mainly to the _________
brainstem
Should you know all the cranial nerves, roman numerals, and functions?
Yes
What is the pneumonic to memorize these
O O O TO TOUCH AND FEEL VERY GOOD VELVET AH
Fibers transmit impulses associated with detecting odors – smell.
Olfactory nerve (CN I)
T or F: If I is damaged, the sense of smell is impaired; it can be tested by determining whether a patient can sense aromatic substances.
True
Fibers transmit impulses associated with vision.
Optic nerve (CN II)
If damaged, _______ occurs in part or all of the visual field; it can be tested by inspecting the retina and testing peripheral vision and visual acuity.
blindness
This nerve has motor impulses to muscles (that control mvmt of eyeball up, down, medially), focus lens (accommodation), and adjusting light entering eye (pupil diameter)
oculomotor nerve (CN III)
