HESI Nervous System

Central Nervous System

Brain & spinal cord

Visceral sensory (autonomic afferent) neurons

convey impulses from viscera & glands to CNS

Somatic sensory neurons

convey impulses from bone, muscles & joints to CNS

Peripheral Nervous System

Cranial & spinal nerves and the autonomic nervous system

Function of PNS

Convey sensory impulses to CNS

Branches of PNS

Somatic & autonomic

Somatic nervous system

Controls voluntary movements of bone, muscle & joints

Autonomic nervous system

Involuntary movements (organs)

Ganglion

Collection of cell bodies in PNS

Frontal lobe

Muscle movements, concentration, planning, talking, problem solving, smell & regulating emotions

Parietal lobe

Sensation, perception & language comprehension

Temporal lobe

Hearing, smell, memory, abstract thought & judgment

Occipital lobe

Vision

Insula

Taste, pain, feelings, decision making & consciousness

Cerebellum

Coordination & balance

Cerebrum

Memory, behavior, learning, reasoning and interpretation of sensory input

Thalamus

Relays sensory information to the cerebral cortex

Hypothalamus

Regulates temp, water balance, thirst, hunger & pituitary gland

Brainstem

Midbrain, pons & medulla oblongata

Medulla oblongata

Regulates heart rate, blood pressure & breathing

Pons

Regulates respiration

Limbic system

Processes emotions, learning, memory & motivation

Cauda Equina

Horses tail or a bundle of nerve fibers below the spinal cord

How to remember cranial nerves

Oh, oh oh, to touch and feel very green vegetables AH!

How to remember if nerves are sensory, motor or mixed

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Cranial Nerve I: Olfactory

Smell

Cranial Nerve II: Optic

Vision

Cranial Nerve III: Oculomotor

Eye movement, pupil constriction

Cranial Nerve IV: Trochlear

Eye movement

Cranial Nerve V: Trigeminal

Face & chewing muscles (temporalis & masseter)

Cranial Nerve VI: Abducens

Eye movement

Cranial Nerve VII: Facial

Taste from the anterior 2/3 of the tongue & muscles of facial expression

Cranial Nerve VIII: Vestibulocochlear

Sensory, hearing & balance

Cranial Nerve IX: Glossopharyngeal

Taste from the posterior 1/3 of the tongue & swallowing muscles

Cranial Nerve X: Vagus

Organs, larynx/pharynx & ear

Cranial Nerve XI: Accessory

Shoulder movement & head rotation of sternocledomastoid and trapezius

Cranial Nerve XII: Hypoglossal

Tongue movement

Sympathetic Nervous System (ANS)

fight or flight; dilates pupils, increases heart rate & breathing, decreases digestion

Parasympathetic nervous system (ANS)

Rest & digest; constricts pupils, decreases heart rate & breathing, increases digestion

Neurons

Transmit & store information

What are neurons made of?

1 cell body, 1 axon & many dendrites

Dendrite

Part of neuron that receives impulses

Neuroglia

Support cells

Examples of neuroglia

astrocytes, oligodendrocytes, microglia & ependymal cells

Astrocytes

Star shaped, regulates electrolytes

Oligodendrocytes

Produce myelin

Ependymal cells

Produce CSF

Microglia

Clean up debris

Synapse

Connection between 2 neurons

Synaptic cleft

Space between neurons

Neurotransmitters

Chemical messengers that cross the synaptic cleft

Excitatory neurotransmitters

Stimulates the post-synaptic neuron

Examples of excitatory neurons

epinephrine, norepinephrine, acetylcholine, dopamine

Inhibitory neurotransmitters

Prevents the post-synaptic neuron from sending additional messages

Examples of inhibitory neurons

GABA, Serotonin & glycine

GABA

Anxiety, pain, sleep & calm. Decreases blood pressure

Epinephrine & norepinephrine

Adrenaline

Acetylcholine

Stimulates muscle contraction

Interneuron

Neuron found only in the CNS that bridges sensory & motor neurons

What charge do neurons hold?

Negative

What is a neurons cell membrane permeable to?

Sodium & mostly potassium

What does the sodium-potassium pump require?

ATP energy

Sodium gates

Activated by depolorization above threshold & inactivated when membrane acquires a positive membrane potential

Depolarization

The process during the action potential when sodium is rushing into the cell causing the interior to become more positive.

Action potential

The rapid change in potential from -55 to +30 mV in the axon hillock

Functions of the nervous system

Receive information from the environment, process & integrate the info & initiate a response