TEAS PNS

cranial nerves, spinal nerves, and autonomic nervous system

peripheral nervous system includes

PNS

divided into the somatic nervous system and the autonomic nervous system

somatic nervous system

which controls voluntary information such as with skeletal muscles

autonomic nervous system

• which control involuntary information such as with organs.

• also known as a visceral motor system.

• maintain homeostasis in the body even when it is in an unconscious state.

• 2 subdivisions

parasympathetic and sympathetic

what are the two subdivisions of the ANS?

cranial nerves

important in assessing the function of the nervous system

1. CN I

2. CN II

3. CN III

4. CN IV

5. CN V

6. CN VI

7. CN VII

8. CN VIII

9. CN IX

10. CN X

11. CN XI

12. CN XII

what are the 12 cranial nerves?

CN I

Olfactory nerve: Sense of smell.

CN II

Optic nerve: Vision.

CN III

Oculomotor nerve: Eye movement (pupil and eyelid).

CN IV

Trochlear nerve: Downward/inward eye movement.

CN V

Trigeminal nerve: Facial sensation and jaw movement (mastication).

CN VI

Abducens nerve: Lateral eye movement.

CN III, IV, VI

what cranial nerves work together to move eyes?

CN VII

Facial nerve: Facial expressions, taste (from anterior 2/3).

CN VIII

Vestibulocochlear nerve: Hearing, equilibrium and balance.

CN IX

Glossopharyngeal nerve: Throat sensation(swallowing) and taste (from posterior 1/3).

CN X

Vagus nerve: Parasympathetic control of heart, lungs, and digestion.

CN XI

Spinal Accessory nerve: Neck sternocleidomastoid and trapezius muscle movement.

CN XII

Hypoglossal nerve: Tongue movement.

I, II, VIII

what cranial nerves carry sensory information?

III, IV, VI, XI, XII

what cranial nerves carry motor information?

V, VII, IX, X

what cranial nerves carry sensory & motor information?

Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear, Glossopharyngeal, Vagus, Accessory, Hypoglossal

Oh Oh Oh To Touch And Feel Very Good Velvet AH

8 cervical, 12 thoracic, 5 lumbar, 5 sacral and 1 coccygeal

what are the 31 pair of spinal nerves?

spinal nerves

• formed by dorsal and ventral nerve roots.

• The nerves branch to the body with some nerves traveling to the autonomic nervous system.

• carry both sensory and motor information.

dermatomes

• The body can be divided into sections which represents a specific area of the body innervated by a spinal nerve.

• important in helping to localize peripheral nervous system injuries.

ANS

• can control respiratory, cardiovascular, urinary, digestive and reproductive functions.

• does this by sending motor impulses to viscera, cardiac and smooth muscle.

ANS

what works to maintain balance of fluids, electrolytes, blood pressure, nutrients, and blood gasses?

sympathetic

what is the fight or flight system?

sympathetic division

located in the thoracic and lumbar spines and sends fibers to the organs.

parasympathetic divison

located in the cervical and lower lumbar spines and sends fibers to the same organs as the sympathetic.

opposite

what effect does the sympathetic and parasympathetic divisions typically have on organs?

sympathetic increase heart rate; parasympathetic system decreases it. 

what is an example of the sympathetic and parasympathetic divisions having opposite effects?

sympathetic nervous system

works to

• dilate air passages,

• increase activity of sweat glands,

• increase glucose levels in the blood,

• dilate the pupils,

• increase heart rate,

• decrease digestive activity.

• increase the amount of blood moving to the cardiac and skeletal systems while decreasing blood flow to the skin.

• decreases urinary activity.

parasympathetic division

• originates in the brain and sacral region of the spinal cord.

• sometimes referred to as the craniosacral division of the ANS.

• sometimes called the rest and digest division

parasympathetic division

works to

• pupil constriction,

• decreasing the heart rate and breathing and

• increasing digestion.

mixed nerve

nerve that can carry both sensory and motor information

nerves

• bundles of fascicles(sections), which are further composed of individual nerve fibers (axons).

• contain numerous fibers

epineurium

• outer layer of a nerve

• consists of dense connective tissue that surrounds and protects the nerve

perineurium

Inside the nerve the fibers are bundled in fascicles with each fascicle surrounded by a sheath called?

neurons

what is within a fascicle?

endoneurium

what surrounds the neurons within a fascicle?

plexi

Spinal nerves can combine to form structures called

cervical plexus, phrenic plexus, lumbar plexus, sacral plexus

what are the 4 major plexi in the human body?

cervical plexus

• (C1-C4)

• innervates the posterior head and skin of the neck.

brachial plexus

• spinal nerves (C5-T1)

• form the axillary, radial, musculocutaneous, ulnar and median nerves.

lumbar plexus

• consists of spinal nerves L1-L4

sacral plexus

• consists of the ventral rami from spinal nerves L4-S4

lumbosacral plexus

• lumbar and sacral plexus referred to

• major nerves exiting the include the obturator, femoral, and sciatic.

neurons and neuroglia

what are the two types of cells in the nervous system?

neurons

• the cells that transmit and store information in the nervous system

• can connect and communicate with other neurons

neuroglia

support cells in the nervous system

star-shaped astrocytes, oligodendrocytes, ependymal cells, microglia

what are some examples of neuroglia?

star-shaped astrocytes

cells that help to regulate electrolytes

oligodendrocytes

cells that produce myelin

ependymal cells

cells that produce cerebrospinal fluid

microglia

cells that clean up debris

dendrites, cell body, axon hillock, axon, and axon terminal.

what are the parts of neurons?

synapse

what is the connection between neurons called?

synaptic cleft

the space between neurons

neurotransmitters

Neurons communicate with each other by sending chemical packets called …. across the synaptic cleft

presynaptic neuron

what is the neuron called that sends a neurotransmitter across the synaptic cleft?

post-synaptic neuron

what is the neuron called that receives the neurotransmitter?

excitatory message and inhibitory message

what are the essential messages that neurons send?

excitatory neurotransmitter

stimulates the post-synaptic neuron to send a message

inhibitory neurotransmitter

keeps the post-synaptic neuron from sending additional messages

interneuron

• a type of nerve cell (neuron) found only in the central nervous system

• acts as a link or bridge between other neurons (sensory neurons and motor neurons)

• allow the nervous system to process information, make decisions, and coordinate responses.

neurons

• do not exist at equilibrium with their surroundings

• net negative charge on the inside compared to the outside charge.

membrane permeability

This negative charge within neurons exists mostly because of differences in ………. to different electrolytes.

sodium and potassium

what elements are neurons slightly permeable to?

negatively charged ions

There are also a number of …… inside of the neuron’s cell membrane

phosphates, sulfates, ATP, RNA, and proteins

what are the negatively charged ions inside of the neuron’s cell membrane that can NOT leave?

sodium and potassium

what are the ONLY positively charged elements within a neuron?

ionic gradient

• difference in concentration and electrical charge of ions across a cell membrane, driving movement to store free energy.

• These gradients are maintained by active transport and are essential for nerve impulses, muscle contraction, and ATP production

ionic gradient

potassium diffuses out of the neuron at the same rate that it moves into the cell via a steady

sodium-potassium pump

work to maintain both sodium and potassium gradients by moving sodium out of the cell and potassium into the cell.

potassium

what element are neurons more permeable to?

energy in the form of ATP

what causes the sodium-potassium pump to function?

70%

how much energy used by the nervous system is used by the sodium-potassium pumps?

-70mV

what are neurons typical resting membrane potential?

resting membrane potential

is the stable, negative electrical charge difference (typically (-40) to (-90) mV) across a cell membrane, with the inside more negative than the outside, when a cell is at rest.

opening of sodium gates

what causes a post-synaptic neuron to receive neurotransmitters?

depolarization:

positively charged sodium enters into the post-synaptic neuron decreasing its potential (less negative)

what happens when sodium gates open to receive neurotransmitters?

depolarization

the rapid reduction of the membrane potential in excitable cells (neurons, muscle cells) where the internal charge becomes less negative or positive, triggered by the influx of +sodium ions.

threshold

if the stimulus is strong enough to cause enough of a change in potential to reach a certain level, the neuron will react by opening more sodium gates and depolarizing at a rapid rate.

-55mV to +30mV

what level would a stimulus have to get a neuron to in order to reach threshold?

+30mV to +40mV

what is the max depolarization?

action potential

The rapid change in resting membrane potential from -55 mV to +30mV is called?

all or none principle

once the threshold is reached, the neuron continues through the cycle of depolarization and repolarization to resting membrane potential.

axon hillock

where are action potentials genereated?

voltage-gated sodium channels

sodium gates that react/ open to changes in membrane potential

Voltage-gated potassium channels to open at the same time as the sodium channels

When a stimulus causes depolarization to the threshold, the voltage-gated sodium channels open, causing …

slower

potassium channels work …. than the sodium channels once at the threshold

Na closes, K stays open til resting membrane potential reached

After the maximum depolarization is reached at about +30mV to +40mV what happens to Na and K gates?

neurotransmitters

All of the activity in the brain is governed by

Excitatory neurotransmitters

• include epinephrine and norepinephrine (adrenaline and noradrenaline).

• Both are secreted by sympathetic neurons, so they cause the effects of the sympathetic nervous system on the body.

Epinephrine and norepinephrine

what hormones connect to adrenergic receptors on other neurons?

Dopamine

• plays a role in pleasure and motivation

• considered excitatory, but it can be inhibitory depending on the neurons

Acetylcholine

• excitatory neurotransmitter that is secreted by parasympathetic neurons and motor neurons attaching to muscles to stimulate muscle contraction. 

• considered cholinergic, so it will connect to cholinergic receptors on neurons