A&PII PNS Review

im so cooked omfg

What is the PNS composed of?

Spinal nerves, cranial nerves

What are the 2 subdivisions of the PNS?

Somatic and autonomic

What are the two subdivisions of the ANS?

Parasympathetic and sympathetic

Endoneurium

Loose CT around an individual neuron

Perineurium

Loose CT around groups of neurons (fasicles)

Epineurium

Dense CT around a nerve (several fasicles)

3 functions a nerve can have:

sensory, motor, or mixed

2 Origins of a nerve

Cranial, spinal

Cranial nerve 1 (I)

Olfactory nerve (smell)

Cranial nerve 2 (II)

Optic nerve (vision)

Cranial nerve 3 (III)

Oculomotor nerve

Oculomotor nerve

Motor, does all eye movements except lateral abduction and down and out

What muscles does the oculomotor nerve go to?

Superior rectus, interior rectus, and medial rectus

Cranial nerve 4 (IV)

Trochlear nerve

Trochlear nerve

Motor nerve (smallest pair), controls trochlea, performs down and out movement

Cranial nerve 5 (V)

Trigeminal nerve

What are the three branches of the trigeminal nerve?

Ophthalmic (v1), Maxillary (V2), Mandibular (V3)

Ophthalmic branch of trigeminal

Sensory of upper portion of face

Maxillary branch of trigeminal

medial muscles of face and skin

Mandibular branch of trigeminal

lower muscles of the face

Muscles of mastication (chewing):

Masseter, temporalis, and tongue muscles

Cranial nerve 6 (VI)

Abducens nerve

Abducens nerve

Motor to lateral rectus (lateral abduction)

Eye nerves:

Optic nerve, oculomotor nerve, trochlear nerve, and abducens nerve

Cranial nerve 7 (VII)

Facial nerve

Facial nerve

Mixed nerve; sensory is taste, motor for facial expressions, tear glands, and salivary glands

Cranial nerve 8 (VIII)

Vestibulocochlear (hearing and balance) sensory

Cranial nerve 9 (IX)

Glossopharyngeal nerve

Glossopharyngeal nerve

Mixed nerve; sensory to throat and taste to posterior 1/3 of tongue, motor for swallowing and uvula

Cranial nerve 10 (X)

Vagas nerve

Vagas nerve

Mixed nerve, controls 75% of ANS. Motor to heart and viscera in the thorax and abdomen, speech; sensory to the pharynx, larynx, esophagus, and other viscera (parasympathetic)

Cranial nerve 11 (XI)

Accessory nerve

Accessory nerve two branches:

Cranial and spinal

Cranial nerve 12 (XII)

Hypoglossal (motor to tongue)

What are the four PNS plexuses?

Brachial, lumbar + sacral (lumbosacral), and cervical

Spinal nerves are composed of:

anterior motor root, posterior sensory root, and a DRG

What are the four branches of spinal nerves outside of the spinal cord?

Meningeal, posterior branch, anterior branch, visceral branch (thoracic and lumbar)

Cervical plexus

Contains phrenic nerves, goes to diaphragm

Brachial plexus four branches:

Musculocutaneus, ulnar and median, radial, and axillary

Brachial plexus musculocutaneous branch

Muscles of anterior arms and skin of forearms

Brachial plexus ulnar and median branch

Muscles of forearms and hands, skin of hands

Brachial plexus radial branch

Muscles of posterior arms, skin of forearms and hands

Brachial plexus axillary branch

Skin of anterior, lateral, and posterior arms

Lumbosacral plexus 3 branches:

Obturator, femoral, and sciatic nerve

Lumbosacral plexus obturator branch

Motor, adductors of thighs

Lumbosacral plexus femoral branch

Mixed, motor and sensory to thighs

Lumbosacral sciatic nerve branch

Motor to all muscles S3 and belove (calves and feet)

ANS motor pathways contain a chain of two neurons:

Preganglionic and postganglionic

Where are the cell bodies of preganglionic neurons?

CNS, lateral horn of the grey matter

Where are the cells bodies of postganglionic neurons?

Paravertebral ganglia

Sympathetic trunks

chains of sympathetic ganglia that are parallel to either side of the spinal cord; the trunk interacts closely with the associated spinal nerves (sympathetic chain ganglia + sympathetic neurons (fibers))

Postganglionic fibers in the sympathetic division release what?

Epinephrine (adrenaline) and norepinephrine

Preganglionic fibers in the parasympathetic divisions goes from what to what?

Brainstem or s2-s4 --> terminal ganglia or in visceral organs

What cranial nerves are apart of the preganglionic fibers of the parasympathetic division?

III (oculomotor), VIII (facial), IX (glossopharyngeal), X (vagas)

ANS two neurotransmitters

Cholinergic neurons and adrenergic neurons

All sympathetic preganglionic neurons are. . .

Cholinergic

Most sympathetic postganglionic neurons are. . .

Adrenergic

What are the two types of cholinergic receptors:

Muscarinic and nicotinuc

Muscarinic receptors

Excitatory, slow, can also be activated by a fungal toxin (muscarine)

nicotinic receptors

Excitatory, rapid, can also be activated by a tobacco toxin (nicotine)

Two types of adrenergic receptors

Alpha and beta

Acetylcholinesterase (AChE)

decomposes acetylcholine from stimulated postsynaptic cell

Monoamine oxidase (MAO)

inactivates norepinephrine from synapse

Hypothalamus

Body temperature, hunger, thirst, electrolyte balance

Medulla oblongata

ANS relfex center for cardiac, vasomotor, and respiratory

Limbic system

controls emotional response

What are the main CNS centers for the ANS?

Hypothalamus, medulla oblongata, limbic system

What is found at all preganglionic-postganglion synapses

Acetylcholine

What ANS neuron releases ACh?

Cholinergic

Most nerves are . . .

Mixed

How many spinal nerves are there?

31

How many cervical spinal nerves are there?

8

How many thoracic nerves are there?

12

How many lumbar spinal nerves are there?

5

How many sacral spinal nerves are there?

5

How many coccygeal spinal nerves are there?

1

What does taste for the anterior 2/3 of the tongue?

Facial nerve

What is the nerve responsible for sensory control of the pharynx and salivary glands?

Glossopharyngeal

What nerve is responsible for motor control to the neck muscles?

Accessory nerve

If a lesion occurs to the hypoglossal nerve, the tongue will . . .

deviate toward the side of the lesion.

What nerve does taste for the poster 1/3 of the tongue?

Glossopharyngeal

The cervical and lumbosacral enlargement control sensory and motor for. . .

lower and upper extremities

Filum terminale

anchors the spinal cord to coccyx

Denticulate ligament

Extensions of pia mater and holds spinal cord in place

What does the pia mater contain?

Blood vessels

What is innervation?

nerve supply

Dorsal/posterior is almost always. . .

sensory/afferent

Ventral/anterior is almost always

motor/efferent

Where are nerve plexuses not found in the spinal cord?

Levels t1-t12

What cervical nerves form the phrenic nerve?

c3, c4, c5

What levels does the cervical plexus run?

c1-c4

Brachial plexus runs from. . .

C5-T1

Sensory to lateral brachium

c5

Sensory to antebrachium, thumb, and index finger

c6

sensory to third digit of hand and center of hand

c7

sensory to the 4th, and 5th digits of hand, and medial antebrachium to elbow

c8

sensory to medial brachium

t1

sensory to axilla

t2

What function do paravertebral ganglion perform?

sympathetic (fight or flight)