PNS

autonomic (visceral) and somatic

autonomic (visceral) and somatic

What are the two divisions of the motor division of the PNS?

sympathetic and parasympathetic

What are the two divisions of the autonomic/visceral nervous system?

olfactory

What is the first cranial nerve?

olfactory nerve

• is a sensory nerve

• sense of smell, no motor component

olfactory nerve

• hundreds of thin fibers, penetrates through cell wall

• has the cribiform plate

cribriform plate

thinnest barrier between the brain and the external environment

• bacteria and fungi can get in through here (infectious disease

• in between the olfactory bulb and the filaments

Olfactory nerve (cribriform plate)

Which nerve contains one of the most vulnerable areas in our anatomy?

Optic Nerve

• sensory nerve, no motor

• eye, comes from the retina, brings information about light

Optic Nerve

What is CN II?

optic tract

takes information back to processing areas of the optic nerve

medial

Optic nerve: Which half of the retina crosses info over to the opposite side of the brain?

Only medial because both eyes are used to see the same thing so it is not necessary.

Why doesn’t the lateral half cross to the opposite side of the brain?

decasation

crossing of information of one side of the brain over to the other; medial side corresponds with lateral side

occulomotor nerve

What is nerve III?

occulomotor nerve

• motor nerve

• controls eye movements, muscles of the eye

yes

Are all motor nerves part sensory?

Levator Palpebrae Muscle

occulomotor nerve: muscle that opens eyelid, part of the blink reflex

superior orbital fissure

What does the occulomotor nerve run through to get to the eye muscle?

Trochlear Nerve

• motor nerve

• supplies the superior oblique muscle of the eye

• goes through a fissure in the back of the eye

Trochlear Nerve

What is nerve IV?

Trigeminal Nerve

What is nerve V?

Trigeminal Nerve

• mainly sensory, partly motor (mandibular nerve branches)

• sensory function for the face (internal to the face)

semilunar ganglion

ganglion in the trigeminal nerve that divides the information coming from the nerve into three branches

V1 (Opthalmic) - goes to the eye

V2 (Maxillary) - goes to the upper jaw

V3 (Mandibular) - goes to lower jaw

What are the 3 branches that the semilunar ganglion splits information into?

mastication

moves the jaw up and down

the 3 branches of the trigeminal nerve

What explains why you feel a brain freeze on all different areas of your face?

muscles of the jaw

temporalis, medial pterygoid, masseter, lateral pterygoid, digastric muscle

Abducens Nerve

• motor nerve

• starts at posterior side of pons

• only goes to one muscle of the eye - the lateral rectus muscle

Abducens Nerve

What is nerve VI?

Facial Nerve

• mostly motor (to all the muscles of the face)

• facial expressions

• has sensory functions to all areas of the face

• parasympathetic efferents and sympathetic afferents

Facial Nerve

What is Nerve VII?

Vestibulocochlear Nerve

What is Nerve VIII?

Vestibulocochlear Nerve

• nerve that allows for hearing, position of the body (balance), auditory

• bottom of pons, comes in through the internal acoustic meatus

Glossopharyngeal Nerve

• nerve that goes to the tongue and pharynx

• innervation to the Parotid gland

• taste and sensory information coming from carotid areas (helps control blood pressure and CO2 concentrations in the blood)

• part of the swallowing reflex

Glossopharyngeal nerve

What nerve is part of the swallowing reflex?

Vagus Nerve

What is nerve X?

Vagus Nerve

• the longest cranial nerve in the body

• starts at the back part of the pons and ends in the abdomen

• main part of the swallowing reflex

Vagus Nerve

sends out some motor fibers that give us to the ability to speak

Vagus nerve

starts as a single nerve, branches out into many once in the thoracic region, comes single again when it leaves the thoracic region, branches again to all the organs in the abdomen

• major parasympathetic innervation to all of these organs

• picks up sensation from these organs

What does the vagus nerve do regarding organs?

Accessory Nerve

What is nerve XI?

Accessory Nerve

mainly a motor nerve going to the neck muscles (sternocleidomastoid and trapezius muscle); helps control the neck movements

the cervical spinal nerves

What does the accessory nerve have inputs from?

Hypoglossal nerve

What is nerve XII?

Hypoglossal Nerve

• nerve that serves the extrinsic and intrinsic muscles of the tongue (moving tongue around inside mouth and changing the shape of the tongue)

Hypoglossal nerve

nerve that arises from the medulla oblongata

31

How many pairs of spinal nerves are there?

8, 12, 5, 5

How many cervical, thoracic, lumbar, and sacral spinal nerves are there?

Coccygeal Nerve (Co)

What is the name of the nerve at the very end of the sacral nerves?

Cervical and Lumbar

What are the two enlargements?

cervical, brachial, lumbar, sacral

What are the different plexuses?

7 vertebrae, 8 spinal nerves

How many cervical vertebrae are there and how many cervical spinal nerves are there?

plexuses

superhighway of nerves

sympathetic chain ganglion

connect to the spinal nerve in thoracic and lumbar areas

Rami Communicantes

on the sympathetic chain ganglion; branches that take information to and from the ganglion

dorsal ramus

part of the spinal nerve that controls the back of the body

ventral ramus

part of the spinal nerve that control the front of the body

dorsal root ganglion

part of the spinal nerve that houses the body of sensory neurons

Phrenic nerve

nerve in the cervical plexus that goes down to the diaphragm

neck and diaphragm

What parts of the body is the cervical plexus responsible for?

The Phrenic nerve goes all the way down to the diaphragm but starts all the way up at C5 (breathing is essential to live)

Why is injury to C5 and above fatal?

brachial plexus

innervates most of the arm and some of the body wall

Lateral, Posterior, Medial

What are the names of the cords that come out of the brachial muscles?

Cords - lateral, posterior, medial

contain the branching patterns of the axons as they come down into the arm

Musculocutaneous (anterior)

nerve that goes to the upper arm (bicep region)

radial (posterior), median(anterior), ulnar(anterior)

What are the names of the nerves that supply most of the muscles in the arm? (descend down to the lower arm)

brachial plexus

Plexus that goes from C4-C8 and TI

lumbar plexus

• innervates the anterior leg

lumbar plexus

L1-L5

obturator and femoral

two parts of the lumbar plexus

Obturator

responsible for the anterior hip

Femoral

responsible for the anterior side of the leg

Sacral Plexus

S1-S5 and Co

Sacral plexus

innervates the posterior leg

pudendal and sciatic

What are the two parts of the sacral plexus?

pudendal

responsible for the hip and gluteal area

sciatic

responsible for most of the muscles on the back of the leg (branches feed)

dermatomes

areas of the skin that is innervated by the cutaneous branches of single sensory spinal nerves (shows the relationship between spinal nerves and skin)

C1

All spinal nerves except __ participate in dermatomes.

stimulus —> receptor —> sensory neuron —> integrating center —> association neuron —> motor neuron —> effector —> response

reflex arc

monosynaptic

What kind of reflex is the stretch reflex?

muscle stretch, muscle spindles

What is the initial stimulus in the stretch reflex? What is the receptor?

Afferent, spinal cord

Stretch reflex (1): _____________ impulses from stretch receptor to ________ ____.

Efferent, contraction

Stretch reflex (2): _____________ impulse to motor neurons cause _____________ of the stretched muscle that resists/reverse the stretch.

antagonist, reciprocal inhibition

Stretch reflex (3): Efferent impulses to _____________ muscles are damped which is called _______________ _____________.

hamstrings

What is the antagonist muscle in the patellar reflex?

Golgi Tendon Reflex

senses the amount of tension on the tendon, safety reflex

• pressure sensor

golgi tendon organs

Contracting the muscle activates the what?

golgi tendon reflex

opposite of the stretch reflex

Neurons inhibit the contracting muscle and the antagonistic muscle is activated.

• Result is the contracting muscle relaxes and the antagonist contracts.

When happens when afferent golgi tendon neurons are stimulated?

flexor reflex

initiated by a painful stimulus (actual or perceived) that causes automatic withdrawal of the threatened body part

1) The stimulated side is withdrawn.

2) The contralateral side (corresponding limb) is extended.

What are the two parts of the crossed extensor reflex?

Crossed Extensor Reflex

What reflex is this?

The right arm is hit with a ball. The right arm is stimulated so it flexes and moves in towards the body. The left arm extends and move outwards from the body.

Somatic

cell body in the CNS (brain or spinal cord) and sends out a branch to its target (normal looking neuron)

acetylcholine

What do both the sympathetic and parasympathetic pre-ganglionic neurons secrete?

ganglion

neurotransmission scenario: what is the connection point between the pre and post?

ganglion

neurons clustered together in PNS

Parasympathetic

ganglion is more towards the target tissue (farther away from the CNS)

Sympathetic

ganglion is part of the chain ganglion so is much closer to the CNS

The post-ganglionic neurons in the sympathetic system secrete norepinephrine.

What is the difference between the post-ganglionic neurons in the sympathetic system?