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MC Bio 204 ch 14
the peripheral nervous system
Question | Answer |
---|---|
endoneurium | individual axons, whether myelinated or unmyelinated, are wrapped in ----- |
perineurium | groups of axons are arranged in bundles called fascicles, each of which is wrapped in ----- |
epineurium | the superficial covering over the entire nerve |
olfactory receptors | L/olfactory epithelium (superior part of nasal cavity) |
olfactory nerve | (I) (S) F/smell |
optic nerve | (II) (S) F/vision |
oculomotor nerve | (III) (M) somatic motor F/movement of upper eyelid and eyeball || autonomic motor F/alters lens shape and pupil size |
trochlear nerve | (IV) (M) somatic motor F/movement of the eyeball |
optic chiasm | X-shaped area where the optic nerves cross || L/anterior to the primary visual area (occipital lobe of cerebral cortex) |
trigeminal nerve | (V) (B) S/three branches: ophthalmic, maxillary, mandibular || sensory F/touch, pain, temperature, proprioception || somatic motor F/chewing |
abducens nerve | (VI) (M) F/movement of the eyeball |
facial nerve | (VII) (B) sensory F/taste and proprioception || somatic motor F/facial expression || autonomic motor F/secretion of tears and saliva |
vestibulocochlear nerve | (VIII) (S) S/two branches: vestibular and cochlear || vestibular branch F/conveys impulses related to equilibrium || cochlear branch F/hearing |
glossopharyngeal nerve | (IX) (B) sensory F/taste and other sensations from tongue; proprioception in swallowing muscles; monitoring blood pressure and blood gases || somatic motor F/swallowing and speech || autonomic motor F/stimulates secretion of saliva |
vagus nerve | (X) (B) sensory F/taste and sensations from epiglottis and pharynx; from visceral organs in thorax and abdomen || somatic motor F/swallowing and speech || autonomic motor F/muscle contractions in organs of the resp. and GI tract; secretion of digestive fl |
accessory nerve | (XI) (M) somatic motor F/swallowing and head movement |
hypoglossal nerve | (XII) (M) F/movement of tongue during speech and swallowing |
31 pairs of spinal nerves | 8 cervical (C1-C8) || 12 thoracic (T1-T12) || 5 lumbar (L1-L5) || 5 sacral (S1-S5) || 1 coccygeal (Co1) |
posterior root ganglion | F/contains bodies of sensory neurons |
rami | after passing through its intervertebral foramen, a spinal nerve divides into several branches known as ----- |
typical branches of a spinal nerve | posterior ramus, anterior ramus, meningeal branch, rami communicantes |
plexus | a "braid" or network of rami from multiple spinal nerves (T2-T12 do not participate) |
cervical plexus | formed by C1-C4, with contributions from C5 |
brachial plexus | formed by C5-C8 and T1 |
lumbar plexus | formed by L1-L4 |
sacral plexus | formed by L4-L5 and S1-S4 |
lesser occipital nerve | O/C2 || F/S/skin of scalp posterior and superior to ear |
greater auricular nerve | O/C2-C3 || F/S/skin over ear and over parotid glands |
transverse cervical nerve | O/C2-C3 || F/S/skin over the anterior neck |
supraclavicular nerve | O/C3-C4 || F/S/skin over superior chest and shoulder |
ansa cervicalis nerve | O/C1-C3 || F/M/infrahyiod and geniohyoid muscles of the neck |
phrenic nerve | O/C3-C5 || F/M/diaphragm |
long thoracic nerve | O/C5-C7 || F/M/serratus anterior muscle |
pectoral nerve | O/C5-T1 || F/M/pectoralis major and pectoralis minor muscles |
axillary nerve | O/C5-C6 || F/M/deltoid and teres minor muscles || F/S/skin over deltoid and superior posterior arm |
median nerve | O/C5-T1 || F/M/flexors of forearm, except flexor carpi ulnaris || F/S/lateral two thirds of palm of hand and fingers |
radial nerve | O/C5-T1 || F/M/triceps brachii and other extensor muscles of arm and forearm || F/S/posterior arm and forearm, lateral two-thirds of dorsum of hand |
ulnar nerve | O/C8-T1 || F/M/flexor carpi ulnaris, flexor digitorum profundus, and most muscles of the hand || F/S/skin over medial hand |
iliohypogastric nerve | O/L1 || F/M/abdominal muscles || F/S/skin over inferior abdomen and buttocks |
iliolinguinal nerve | O/L1 || F/M/abdominal muscles || F/S/skin of superior medial thigh, genitals |
obturator nerve | O/L2-L4 || F/M/adductor muscles of thigh || F/S/skin over medial thigh |
femoral nerve | O/L2-L4 || F/M/flexor muscles of thigh and extensor muscles of leg || F/S/skin over anterior and medial thigh and medial side of leg and foot |
sciatic nerve | O/L4-S3 || S/two branches: tibial and common fibular || F/M/hamstring and adductor magnus muscles || F/S/tibial branch/skin over posterior leg and plantar surface of foot || F/S/common f branch/skin over anterior leg and dorsum of foot |
pudendal nerve | O/S2-S4 || F/M/muscles of perineum || F/S/genitals |
cranial reflexes vs. spinal reflexes | cranial: integration occurs in the gray matter of the brain stem || spinal: integration occurs in gray matter of the spinal cord |
somatic reflexes vs. autonomic reflexes | somatic involve contraction of skeletal muscles || autonomic involve responses of smooth muscle, cardiac muscle, and glands (often not perceived) |
five functional components of a reflex arc | sensory receptor, sensory neuron, integrating center, motor neuron, effector |
pupillary light reflex | a rare example of an autonomic reflex that can easily be tested clinically |
monosynaptic vs. polysynaptic reflex arcs | monosynaptic arcs have only one synapse in the integrating center || polysynaptic arcs (more common) involve more than two types of neurons and more than one integrating center synapse |
reciprocal innervation | a neural circuit in which the integrating center inhibits muscles antagonistic to the primary muscle involved in the reflex || ----- prevents conflict between opposing muscles and is vital in coordinating body movements |
patellar reflex | the "knee jerk" in medical checkups || a type of monosynaptic, ipsilateral stretch reflex |
the flexor reflex | aka withdrawal reflex || a polysynaptic, ipsilateral reflex that activates several muscles in response to a painful stimulus |
special senses vs. somatic senses | 5 special senses: vision, hearing, taste, smell, equilibrium || 4 somatic senses: pain, thermal, tactile, and proprioceptive sensations |
interoceptors | sensory receptors that monitor the internal environment of the body; their sensations are not usually consciously perceived |
dual innervation | most organs receive impulses from both the sympathatic and parasympathetic autonomic motor systems || exceptions: kidney, spleen, hair follicles/arrector pili |
preganglionic vs. postganglionic neurons | in autonomic motor pathways, preganglionic neurons transmit impulses from the CNS to an autonomic ganglion; postganglionic neurons transmit from the autonomic ganglion to an effector |
two types of sympathetic ganglia | sympathetic trunk ganglia and prevertebral ganglia |
sympathetic trunk ganglia | L/in a vertical row on either side of the vertebral column |
prevertebral ganglia | L/in the abdomen, anterior to the vertebral column |
terminal ganglia | in parasympathetic motor pathways, ----- are located close to or within their target organ (thus, in the parasympathetic division postganglionic neurons are short) |
pelvic splanchic nerves | parasympathetic preganglionic neurons leaving sacral segments of the spinal cord extend through the anterior roots of spinal nerves, then branch off to form ----- that continue to terminal ganglia near or within the walls of visceral effectors |
autonomic plexuses | in the thorax, abdomen, and pelvis, axons of both symp and parasymp neurons form tangled networks called -----, many of which lie along major arteries |
cardiac plexus | an autonomic plexus that supplies the heart |
pulmonary plexus | an autonomic plexus that supplies the bronchial tree |
cholinergic vs. adrenergic neurons: neurotransmitters | cholinergic release the neurotransmitter acetylcholine (ACh) || adrenergic release norepinephrine |
cholinergic vs. adrenergic neurons: location | cholinergic = all symp + parasymp pregang neurons; symp postgang neurons that innervate sweat glands; all parasym postgang neurons || adrenergic = most symp postgang neurons |
two major types of cholinergic receptor | nicotinic (main effect: muscle contraction) || muscarinic (main effect: sweating) |
two major types of adrenergic receptor | alpha (1 and 2) and beta (1, 2, and 3) |
autonomic tone | the balance between symp and parasymp activity or ----- is regulated by the hypothalamus |
the fight-or-flight response | the classic symp response || elements: dilation of pupils; increase in heart rate and blood pressure; constriction of blood vessels that serve GI tract; dilation of vessels that supply skeletal muscles, heart, liver; liver breaks down glycogen to glucose |
five major parasympathetic responses | SLUDD || salivation, lacrimation, urination, digestion, defecation |
L/the integrating centers for most autonomic reflexes | the hypothalamus and brain stem |
musculocutaneous nerve | O/C5-C7 || F/M/flexors of arm, including biceps brachii || F/S/skin over lateral forearm |