Lab 8: Peripheral & Autonomic Nervous System

neuron

a nerve cell; the basic building block of the nervous system

soma

the cell body of a neuron, which contains the nucleus

dendrites

branchlike parts of a neuron that are specialized to receive information.

axon

the neuron extension that passes messages through its branches to other neurons or to muscles or glands

axon hillock

cone shaped region of an axon where it joins the cell body

axon collaterals

side branches of the axon

neurofibril nodes

gaps between myelin sheath

myeline sheath

layer of fatty tissue segmentally encasing the fibers of many neurons; enables vastly greater transmission speed of neural impulses as the impulse hops from one node to the next

telodendria

fine extensions of distal axon

synaptic knobs

rounded areas on the end of telodendria that contain synaptic vesicles

endoneurium

innermost layer of connective tissue that surrounds individual axons within a nerve

perineurium

middle layer; separates nerve into fascicles (axon bundles)

epineurium

outermost layer of dense irregular connective tissue surrounding a peripheral nerve

cranial nerves

12 pairs of nerves that carry messages to and from the brain

I. olfactory nerve

olfaction (sensory)

II. optic nerve

vision (sensory)

III. oculomotor nerve

eye movement and focus (motor)

IV. trochlear nerve

eye movement down and out (motor)

V. trigeminal nerve

mastication and face sensitivity (both)

VI. abducens nerve

lateral eye movement (motor)

VII. facial nerve

facial expression and anterior 2/3 taste of tongue (both)

VIII. vestibulocochlear nerve

hearing and balance (sensory)

IX. glossopharyngeal nerve

1/3 posterior tongue, pharynx, salivation (both)

X. vagus nerve

sensitivity/movement of the ventral cavity, organs, and larynx (both)

XI. accessory nerve

movement of neck muscles, including sternocleidomastoid, trapezius (motor)

XII. hypoglossal nerve

tongue movement beneath tongue (motor)

spinal nerves

31 pairs of nerves arising from the spinal cord

cervicle nerves

8 pairs

thoracic nerves

12 pairs

lumbar nerves

5 pairs

sacral nerves

5 pairs

coccygeal nerves

1 pair

nerve plexus

network of interweaving anterior rami of spinal nerves

cervical plexus

c1-c4

cutaneous branches of cervical plexus

C1-C3

phrenic nerve

innervates the diaphragm, allowing you to breathe (C3,4,5)

brachial plexus

innervates the pectoral girdle and upper limbs (C5-T1)

lateral cord of brachial plexus

musculocutaneous and median nerves

musculocutaneous nerve

innervates anterior upper arm

median nerve

sensory-motor nerve that is smaller than the ulnar and radial nerves and that, with its branches, supplies the arm and hand

posterior cord of brachial plexus

axillary nerve and radial nerve

axillary nerve

innervates deltoid and teres minor

radial nerve

sensory-motor nerve that, with its branches, supplies the thumb side of the arm and back of the hand

medial cord of brachial plexus

ulnar and median nerve

ulnar nerve

sensory-motor nerve that, with its branches, affects the little-finger side of the arm and palm of the hand

lumbar plexus

innervates anterior and medial thigh (L1-L4)

femoral nerve

innervates the muscles that extend leg and flex the thigh, rectus femoris, vastis medialis

obturator nerve

passes through obturator foramen to innervate adductor muscles

sacral plexus

innervates the posterior thigh and most of the leg and foot (L4-S4)

sciatic nerve

nerve extending from the base of the spine down the thigh, lower leg, and foot; largest nerve in the body

tibial nerve

division of the sciatic nerve that passes behind the knee; subdivides and supplies impulses to the knee, the muscles of the calf, the skin of the leg, and the sole, heel, and underside of the toes

common fibular nerve

controls muscles on the anterior and lateral leg (primarily dorsiflexors) and foot

superficial fibular nerve

innervates lateral compartment of leg (fibularis longus, fibularis brevis)

deep fibular nerve

innervates of tibialis anterior

superior gluteal nerve

innervates gluteus medius, gluteus minimus, tensor fasciae latae

inferior gluteal nerve

innervates gluteus maximus

pudendal nerve

innervates muscles of the perineum

parasympathetic nervous system

the division of the autonomic nervous system that calms the body, conserving its energy

sympathetic nervous system

the division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations

effect of sympathetic stimulation on blood vessels

vasoconstriction, increases blood pressure

effect of sympathetic stimulation on eyes

dilates pupils

effect of parasympathetic stimulation on eyes

pupils constrict

effect of sympathetic stimulation on lungs

dilates bronchioles

effect of sympathetic stimulation on digestive system

decreases digestion

effect of sympathetic stimulation on heart

increases heart rate

effect of parasympathetic stimulation on blood vessels

decreases blood pressure and dilates vessels

effect of parasympathetic stimulation on heart

decreases heart rate

effect of parasympathetic stimulation on lungs

constricts bronchioles and stimulates mucus secretion

effect of parasympathetic stimulation on digestive system

increases digestion