Nervous System

Anatomical divisions

Central nervous system, peripheral nervous system

Central nervous system

compromised of brain and spinal cord

Peripheral nervous system

compromised of cranial and spinal nerves

Functional divisions

Motor (efferent) and Sensory (afferent)

Motor (efferent)

relays motor commands from CNS to effectors

Sensory (afferent)

relays sensory information to CNS

Sympathetic

flight or flight- heart rate, bp, breathing go out, digestion goes down

Parasympathetic

rest and digest

Somatic

motor commands going to skeletal muscle in craniosacral (voluntary)

Autonomic

controls unconscious body functions

Receptor

a cell that detects a change in environment (stimulus)

Transduction

turning one kind of stimulus into another

Types of receptors

thermoreceptors, mechanoreceptors, nociceptors, chemoreceptors, photoreceptors

Thermoreceptors

detect temperature

Mechanoreceptors

sense touch, vibration, stretch and pressure

Nociceptors

detect pain

Chemoreceptors

detect chemicals

Photoreceptors

detect photons (light)

Sclera

white part of eye, provides structural support and shape

Cornea

helps focus incoming light

Pupil

opening in the iris, regulates amount of light entering

Iris

colored part of eye, regulates diameter of pupil

Lens

clear structure, focuses things at different distances

Retina

covers inside of eye, holds photoreceptors

External ear

acts as a funnel to direct sound to middle ear

Tympanic membrane

converts sound waves into vibrations and transmits them to middle ear

Auditory tube

balances air pressure, drains fluid and protects ear from germs

Cochlea

turns sound vibrations into nerve signals your brain interprets as sound

Vestibular Apparatus

sensory system in ears that control balance

Neuron

most important cells of nervous system, responsible for processing and relaying electric signals

Dendrites

relays information to cell body

Cell body

processes information and houses all organelles

Axon

relays information away from cell body

Myelin sheath

prevents signals from going out of axon

Nodes of ranvier

keeps signals coming along

Synaptic knobs

stores or secretes neurotransmitters

Synapse

a space where a nerve cell passes a signal to another cell

Synapsis

when neurons communicate with other cells

Presynaptic membrane

releasing neurotransmitters and communicating

Synaptic cleft

space between presynaptic and postsynaptic

Postsynaptic

receiving information from the other cell

Nerves

a collection of axons surrounded by connective tissue

Nerve layer functions

helps physically and electrically separates layers

Epineurium

surrounds nerves

Perineurium

surrounds fascicles

Endoneurium

surrounds neurons

Brain protection

Skull, blood brain barrier, meninges, cerebrospinal fluid

Blood brain barrier

prevents pathogens and toxins from entering the brain

Meninges

3 layers of connective tissue surrounding the CNS

Layers of meninges

dura mater, arachnoid mater, pia mater

Dura mater

tough external later of meninges, attaches to skull

Arachnoid mater

middle, spider web like layer of meninges

Pia mater

thin innermost layer of meninges, directly adheres to CNS

Spaces between meninges

subdural, subarachnoid

Cerebrospinal fluid

modified blood plasma, removes waste, provides nutrients, protection and buoyancy- 500mL out 500 mL in a day

Cerebrum

responsible for everything we are consciously in charge of

Frontal lobe

skeletal muscle commands, speech production, behavior/personality

Parietal lobe

general sensory informtation

Temporal lobe

hearing, balance, understanding language

Occipital lobe

vision

Insula

taste and emotions

Thalamus

sensory filter

Hypothalamus

automatic functions and endocrine system

Mid brain

visual and auditory reflexes

Pons

respiratory integration

medulla oblongata

cardiovascular control center

Cerebellum

balance, coordination, muscle memory

Spinal cord

relays information, processes some information, compromised of white and gray matter

White matter

made of axons, relays information

Gray matter

made of cell bodies, processes information