E3 Ch. 14 Flashcards
the PNS is functionally divided into what 2 divisions
sensory and motor divisions
what are the sensory inputs and motor outputs subdivided into
somatic and visceral, general and special
what is the general visceral motor part of the PNS
autonomic nervous system (ANS)
what are the divisions of the ANS
parasympathetic and sympathetic
describe nerves in the PNS
bundles of peripheral axons
describe ganglia in the PNS
clusters of peripheral neuronal cll bodies
what are motor endings and their function
axon terminals of motor neurons, innervate effectors (muscle fibers and glands)
what are peripheral sensory receptors and their function
structures that pick up sensory stimuli, initiate signals in sensory axons
what are the 2 main categories of sensory receptors
free nerve endings of sensory neurons, and complete receptor cells
function of free nerve endings of sensory neurons
monitor general sensory info
function of complete receptor cells
specialized epithelial cells or small neurons, monitor most types of special sensory info.
sensory receptors are also classified according to what
location, type of stimulus detected, and structure
describe exteroceptors in terms of location, where they receive stimuli, and types received
sensitive to stimuli arising outside the body, located at/near body surface, include receptors for touch, pressure, pain, and tempt.
describe interoceptors in terms of location, where they receive stimuli, and types received
receive stimuli from internal viscera, located in digestive tube, bladder, and lungs, monitor changes in chemical concentration, taste, stretching of tissues, and tempt.
describe proprioceptors in terms of location, where they receive stimuli, and types received
located in skeletal muscles, tendons, joints, and ligaments, monitor degree of stretch, send inputs on body movement to CNS
what type os stimuli do mechanoreceptors respond to
mechanical forces, touch, pressure, stretch, vibration, and itch
baroreceptors
monitor BP
what type of stimuli do thermoreceptors respond to
tempt. changes
what type of stimuli do chemoreceptors respond to
chemical in solution
what types of stimuli do photoreceptors respond to
light, located in eye
what type of stimuli do nociceptors respond to
harmful stimuli that result in pain
general sensory receptors are widely distributed and nerve endings of sensory neurons monitor what types of stimuli
touch, pressure, vibration, stretch, pain, tempt, and proprioception
what 2 groups are general sensory receptors divided into
free nerve endings, and encapsulated nerve endings
where are free nerve endings most abundant
in epithelia and underlying connective tissue
what type of stimuli do free nerve endings respond to and monitor
respond to pain and temp. monitor affective senses
name the 2 specialized types of free nerve endings
epithelial tactile complexes (merkel discs), and hair follicle receptors
describe epithelial tactile complexes (merkel discs)
consist of tactile epithelial cell innervated by sensory nerve endings, slowly adapting receptors for light touch
describe hair follicle receptors
wrap around hair follicles, rapidly adapting receptors
describe the physical aspects of encapsulated nerve endings
consist of one or more end fibers of sensory neurons, enclosed in connective tissue, and are mechanoreceptors
what are the 4 main types of encapsulated nerve endings
tactile (meissner’s) corpuscles, lamellar (pacinian) corpuscles, bulbous corpuscles (ruffini endings), and proprioceptors
describe tactile (meissner’s) corpuscles, where they occur, type of stimuli received, and where they occur
spiraling nerve ending surrounded by Schwann cells, occur in dermal papillae, rapidly adapting receptor for discriminative touch, occur in sensitive, hairless ares of skin
describe Lemellar corpuscles, where they occur, and type of stimuli received
singel nerve ending surrounded by layers of flattened schwann cells, occur in hypodermis, sensitive to deep pressure-rapidly adapting receptors
function and location of bulbous corpuscles (ruffini endings)
dermis and respond to pressure, monitor continuous pressure on skin-adapt slowly
function of proprioceptors
monitor stretch in locomotory organs
name the 3 types of proprioceptors
muscle spindles, tendon organs, and joint kinesthetic receptors
function and location of muscle spindle proprioceptors
measure changing length of muscle, embedded in perimysium b/t muscle fascicles
intrafusal muscle fibers
modified skeletal muscle fibers located w/ in muscle spindles
anulospiral endings
located around middle of intrafusal fibers, stimulated by rate and degree of stretch
function and location of tendon organ proprioceptors
located near muscle-tendon junction, monitor tension w/in tendons
what are joint kinesthetic receptor proprioceptors
sensory nerve endings w/in joint cpasules
name the 4 types of joint kinesthetic receptor proprioceptors
lamellar corpuscles, bulbous corpuscles, free nerve endings, and receptors resembling tendon organs
where do the various cranial nerves attach to
nerves I-II attach to forebrain, all others attach to brain stem
which is the only cranial nerve that extends into the abdomen
CN X- vagus nerve
describe olfactory nerves, where are receptor cells are located, and what structures does it pass though
special visceral sensory- sense of smell, receptor cells located in olfactory epithelium of nasal cavity, pass though cribriform foramina of ethmoid bone
describe optic nerves, where they originate, and structures it passes through
special somatic sensory-vision, originate on retina of eye, pass though optic canals of sphenoid bone
describe oculomotor nerves, function, and structures it passes through
somatic motor funcntion-innervates 4 extrinsic eye muscles, visceral motor function: constricts pupil, controls shape of lens, pass through superior orbital fissure
list the 4 extrinsic eye muscles that the oculomotor nerves innervate
superior rectus, medial rectus, inferior rectus, and inferior oblique
describe trochlear nerves, and structures it passes though
somatic motor function- innervate superior oblique muscle, pass ventrally/laterally around midbrain, superior orbital fissure
what are the 3 divisions of the trigeminal nerves
ophthalamic division (V1), maxillary division (V2), and mandibular division (V3)
where are the cell bodies of snesory neurons of the trigeminal nerves located
trigeminal ganglion
what are the pathways of the tribeminal nerve divisions
ophthalamic division (V1)- superior orbital fissure, maxillary division (V2)-foramen rotundum, mandibular division (V3)-foramen ovale; mandibular foramen
describe the abducens nerves and structure it passes though
somatic motor function, innervates lateral rectus muscle abducts eye, pass through superior orbital fissure
list the 3 different functions of facial nerves
sensory function, somatic motor function, and visceral motor function
describe the sensory function of the facial nerves
special visceral sensory from taste buds on anterior 2/3 of tongue
describe the somatic motor function of facial nerves
5 branches-innervae facial muscles
describe visceral motor function of the facial nerves
innervation of lacrimal glands, submandibular and sublingual salivary glands
what is the pathway of facial nerves
enter temporal bone though internal acoustic meatus
function of vestibulocochlear nerves and its pathway
sensory nerve of hearing and equilibrium, vestibular branch-speical somatic sensory: equilibrium, cochlear branch-speical somatic sensory: hearing, pathway from inner ear cavity, fibers pass through internal acoustic meatus
describe glossopharyngeal nerves
special visceral snesory from taste buds on posterior 1/3 of tongue, general visceral sensory
describe the somatic and visceral motor functions of glossopharyngeal nerves, and its pathway
somatic motor function-elevate pharynx during swallowing
visceral motor function- innervate parotid salivary gland
pathway- fibers pass through jugular foramen
describe the sensory, somatic motor, visceral motor functions, and pathway of the vagus nerves
sensory functions-general visceral sensory from thoracic and abdominal viscera, special visceral sensory-taste buds on epiglottis
somatic motor functions- skeletal muscles of pharynx and larynx
visceral motor functions-parasympathetic innervation to heart, lungs, abdominal viscera
pathway- fibers exit through jugular foramen
function of accessory nerves
somatic motor function- innervates trapezius and sternocleidomastoid
what are the accessory nerves formed from, structure they pass, and where they exit
formed from ventral rootlets of C1-C5, doesn’t arise from brain stem, spinal rootlets merge to form this nerve, pas into skull though foramen magnum, exit skull through jugular foramen
function of hypoglossal nerves and where do they exit
somatic motor function, innervates tongue muscles, exit skull through hypoglossal canal
how many pairs of spinal nerves are found in the body
31
how many pairs of cervical nerves
8 (C1-C8)
how many pairs of thoracic nerves
12 (T1-T12)
how many pairs of lumbar nerves
5 (L1-L5)
how many pairs of sacral nerves
5 (S1-S5)
how many pairs of coccygeal nerves
1 (Co1)
what structure connects the spinal nerves to spinal cord
by dorsal root and ventral root
spinal nerves branch into what
dorsal ramus and ventral ramus, which contain sensory and motor fibers
function of rami communicantes
connect to base of ventral ramus, lead to sympathetic chain ganglia
what does the dorsal rami innervate
neat, segmented pattern innervate back muscles
what do intercostal nerves supply
intercostal muscles, skin, and abdominal wall
define nerve plexus
a network of nerves
where is the cervical plexus located
deep to sternocleidomastoid muscle
what forms the cervical plexus
formed by ventral rami of 1-4pcervical nerves (C1-C4)
name the most important nerve of the cervical plexus
phrenic nerve
what is the phrenic nerve made up of, and what does it innervate
formed from fibers C3-C5, innervates diaphragm
where is the brachial plexus located, formed by, and give rise to
lies in the neck and axilla, formed by ventral rami of C5-C8, cords give rise to main nerves of upper limb
musculocutaneous
main branch of lateral cord, innervates biceps brachii and brachialis
median
originates from both later and medial cords, innervates anterior forearm muscles and lateral palm
ulnar
branches from medial cord, innervates intrinsic hand muscles and skin of medial hand
list the nerves of form the posterior cord
radial and axillary
radial
continuation of posterior cord, largest branch of brachial plexus, innervates muscles of posterior upper limb
axillary
innervates deltoid and teres minor
describe te lumbar plexus
arise from L1-L4, smaller branches innervate posterior abdominal wall and psoas muscle, main branches innervate anterior thigh
femoral nerve
innervates anterior thigh muscles
obturator nerve
innervates adductor muscles
describe the sacral plexus
arises from spinal nerves L4-S4, caudal to lumbar plexus
sciatic nerve
largest nerve of the sacral plexus
name the 2 nerves found in one sheath that make up the sciatic nerve
tibial and common fibular (peroneal) nerve
tibial nerve
innervates most of the posterior lower limb
common fibular (peroneal) nerve
innervates muscles of anterolateral leg
superior and inferior gluteal nerves
innervate gluteal muscles
pudendal nerve
innervates muscles of perineum
dermatome
an area of skin, innervated by cutaneous branches of a single spinal nerve
describe shingles (herpes zoster)
viral infection, stem from chicken pox, often brought on by stress, experienced by people over 50b
migraine headache
relates to sensory innervation of cerebral arteries, which dilate and compress and irritate sensory nerve endings
what is peripheral neuropathy
pathological condition of peripheral nerves
symptoms of peripheral neuropathy
symptoms of sensory nerve: paresthesia, pain, burning, loss of sensation
symptoms of motor nerve: muscle weakness and paralysis
cases of peripheral neuropathy
trauma, repetitive use, systemic disorders (HIV, diabetes, vitamin B deficiency)
describe the PNS during weeks 4 and 5
spinal nerves form late in week 4, 31 pairs present, during week 5 nerves reach organs they innervate
