A&P PNS

bundles of axons in the PNS are referred to as…

nerves

the outer surface of a nerve is a surrounding layer of fibrous connective tissue called the…

epineurium

within the nerve, axons are further bundled into…

fasicles

each fascicle is surrounded by its own layer of fibrous connective tissue called…

perineurium

individual axons are surrounded by loose connective tissue called the…

endoneurium

what is the main difference between sensory axons and motor axons

sensory axons enter the brain to synapse in a nucleus

motor axons connect to skeletal muscles of the head or neck

list which cervical nerves are sensory, motor, and both

three are sensory

five are motor

four are both

mnemonic to remember cervical nerves

Oh - Olfactory

Oh - Optic

Oh - Oculomotor

To - Trochlear

Touch - Trigeminal

And - Abducens

Feel - Facial

Veiny - Vestibulocochlear

Gorillas’ - Glossopharyngeal

Veins - Vagus

And - Accessory

Hair - Hypoglossal

this cranial nerve is responsible for the sense of smell

olfactory nerve

this cranial nerve is responsible for the sense of vision

optic nerve

this cranial nerve is responsible for eye movements by controlling four of the extraocular muscles; also responsible for lifting the upper eyelid when the eyes point up, and for pupillary constriction

oculomotor nerve

these cervical nerves are both responsible for eye movement, but do so by controlling different extraocular muscles

trochlear and abducens nerves

this cranial nerve is responsible for cutaneous sensations of the face and controlling the muscles of mastication

trigeminal nerve

this cranial nerve is responsible for the muscles involved in facial expressions, as well as part of the sense of taste and the production of saliva

facial nerve

this cranial nerve is responsible for the sense of hearing and balance

vestibulocochlear nerve

this cranial nerve is responsible for controlling muscles in the oral cavity and upper throat, as well as part of the sense of taste and the production of saliva

glossopharyngeal nerve

this cranial nerve is responsible for contributing to homeostatic control of the organs of the thoracic and upper abdominal cavities

vagus nerve

cranial nerve responsible for controlling the muscles of the neck, along with cervical spinal nerves

spinal accessory nerve

cranial nerve responsible for controlling the muscles of the lower throat and tongue

hypoglossal nerve

what is the mnemonic to remember the basic function of each cranial nerve (Motor, sensory, or both)

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are the spinal nerves sensory, motor, or both?

both sensory and motor

the sensory axons enter the spinal cord as…

dorsal nerve root

the motor fibers, both somatic and autonomic, emerge as…

ventral nerve root

the dorsal root ganglion for each spinal nerve is…

an enlargement of the spinal nerve

how many spinal nerves are there

31

how are the spinal nerves named

for the level of the spinal cord at which each one emerges

how many cervical spinal nerves are there

8 pairs designated C1 to C8

how many thoracic spinal nerves are there

12 designated T1 to T12

How many lumbar spinal nerves are there

5 pairs designated L1 to L5

how many sacral spinal nerves are there

5 pairs designated S1 to S5

How many coccygeal spinal nerves are there

1 pair

Each spinal nerve emerges from…

the vertebral column through the intervertebral foramen

the first spinal nerve, C1, emerges between…

the first cervical vertebra and the occipital bone

the second spinal nerve, C2, emerges between…

the first and second cervical vertebrae

Spinal nerve C8 emerges between…

the seventh cervical vertebra and the first thoracic vertebra

the sacral spinal nerves emerge from…

the sacral foramina along the length of that unique vertebra

for the thoracic and lumbar spinal nerves, each one emerges between…

the vertebra that has the same designation and the next vertebra in the column

spinal nerves extend _________ from the vertebral column to innervate the periphery

outward

axons from different spinal nerves will come together into a…

systemic nerve

networks of nerve fibers with no associated cell bodies; four main ones in the spine

nerve plexus

how many nerve plexuses are found at the cervical level

2

how many nerve plexuses are found at the lumbar level

1

hoe many nerve plexuses are found at the sacral level

1

this nerve plexus is composed of axons from spinal nerves C1 through C5 and branches into nerves in the posterior neck and head, as well as the phrenic nerve

cervical plexus

this nerve connects to the diaphragm at the base of the thoracic cavity

phrenic nerve

the other plexus from the cervical level is the ___________; spinal nerves C4 through T1 reorganize through this plexus to give rise to the nerves of the arms

brachial plexus

a large nerve from the brachial plexus is the ______ from which the axillary nerve branches to go to the armpit region

radial nerve

the radial nerve continues through the arm and is paralleled by the _____ and the __________

ulnar and median nerve

this nerve plexus arises from all the lumbar spinal nerves and gives rise to nerves enervating the pelvic region and the anterior leg

lumbar plexus

this nerve is one of the major nerves from the lumbar plexus, which gives rise to the saphenous nerve as a branch that extends through the anterior lower leg

femoral nerve

this nerve plexus comes from the lower lumbar nerves L4 and L5 and the sacral nerves S1 to S4

sacral plexus

The most significant systemic nerve to come from this plexus is the _____, which is a combination of the tibial and fibular nerve

sciatic nerve

the sciatic nerve extends across the hip joint and is most commonly associated with the condition _______, which is the result of compression or irritation of the nerve or any of the spinal nerves giving rise to it

sciatica

spinal nerves of the thoracic region, T2 through T11, are not part of the plexuses but rather emerge and give rise to the _______ found between the ribs, which articulate with the vertebrae surrounding the spinal nerve

intercostal nerves

the somatic nervous system causes…

contraction of skeletal muscles

the autonomic nervous system controls…

cardiac and smooth muscles, as well as glandular tissue

the somatic nervous system is associated with __ responses

voluntary

the autonomic nervous system is associated with ______ responses

involuntary

the two divisions of the autonomic nervous system

sympathetic and parasympathetic

the _____ division of the ANS is associated with the fight-or-flight response

sympathetic

the ____ division of the ANS can be referred to by the epithet of rest and digest

parasympathetic

homeostasis is the balance between sympathetic and parasympathetic systems. At each target effector, _______ determines activity

dual innervation

the sympathetic division is also referred to as the _________ because it emerges from the thoracic and upper lumbar spinal cord

thoracolumbar system

an axon from the central neuron that projects to a sympathetic ganglion, and represents the output from the CNS to the ganglion; relatively short and myelinated

preganglionic fiber/neuron

the axon from a ganglionic neuron that projects to the target effector; represents the output of a ganglion that directly influences the organ; long and unmyelinated

postganglionic fiber/neuron

this type of receptor responds to touch, pressure, vibration, and stretch

mechanoreceptors

this receptor responds to temperature changes

thermoreceptors

this receptor responds to light

photoreceptors

this receptor responds to chemicals in solution (blood, saliva, etc.)

chemoreceptors

this receptor responds to damaging stimuli that cause pain

nociceptors

this type of pain originates from skin, bones, skeletal muscles; stimuli includes friction, pressure, stretch, etc.

somatic pain

this type of pain originates from abdominal and thoracic organs; e.g., heart, lungs, intestines, kidneys; may feel like aching, burning, or pressure; stimuli include stretching, low blood flow, chemicals, smooth muscle spasms

visceral pain

this type of pain happens when stimuli in one location causes the brain to think it’s coming from somewhere else; e.g., heart attack pain in the arm; due to shared ascending pathways

referred pain

what are reflex arcs

protection without needing to think; very fast; processed through gray matter of spinal cord or brain

this reflex arc involves receptors near body surface, muscles, bones; somatic nervous system activates skeletal muscle effectors via the spinal cord gray matter

somatic reflex arc

this reflex arc involves receptors and effectors in soft tissue organs; run by autonomic nervous system via spinal cord or brain

visceral reflex arc

these receptors detect stimuli outside of the body; e.g., touch, pressure, pain, temperature via skin; e.g., vision, hearing, smell, taste via special sense organs

exteroceptors

these receptors detect visceral sensations; e.g., stretch, temp, chemicals; allow one to feel pain, discomfort, hunger, thirst

interoceptors

these receptors detect stretch in skeletal muscles, tendons, joints, ligaments; monitor for stability of joints and posture; help us know our position in space

proprioceptors

three layers of tissue that make up the eyeball

tunics: fibrous layer, vascular layer (uvea), inner layer (retina)

dense avascular connective tissue layer of the eyeball: sclera and cornea

fibrous layer

the white of the eye

sclera

the clear anterior portion of the eyeball; innervated but avascular

cornea

colored part of the eye; contains smooth muscles that open and close around a central hole, the pupil

iris

the vascular layer or uvea of the eye contains which structures

choroid, ciliary body, and iris

the posterior 5/6 of the vascular layer of the eye; rich in blood vessels

choroid

the anterior ring of tissue encircling the lens of the eye

ciliary body

this layer of the eye contains millions of photoreceptors, neurons, glial cells; contains a pigmented layer and neural layer

inner layer aka retina

inner neural layer of eyeball consists of…

photoreceptors, bipolar cells, and ganglion cells; ganglion cells leave the eye as the optic nerve; blind spot created where nerve exits

two types of photoreceptors in the eye

rods and cones

these eyeball photoreceptors are dim light and peripheral vision receptors

rods

these eyeball photoreceptors are bright-light and color vision receptors

cones

this structure allows air into nose

nostrils

these are nose hairs that filter the air

cilia

this traps particles in the nose

mucus

these chemicals can only be detected when they dissolve into the fluid covering the olfactory epithelium

odorants

sense of taste

gustation

the sense organ for taste

taste buds

what is another word for eardrum

tympanic membrane

ear bones

ossicles