nervous system, neurons, nerve impulse conduction, parts of a neuron, saltatory conduction, central nervous system, brain

function of the nervous system

maintain homeostasis & acts as a communication system

organization of the nervous system

Central Nervous System (CNS) and Peripheral Nervous System (PNS)

central nervous system

made up of the brain and spinal cord

peripheral nervous system

all nerves leading to an from the brain and spinal cord

subdivisons of PNS

somatic nervous system & autonomic nervous system

somatic nervous system

connect the CNS to the skeletal muscles, skin, and sense organs; controls voluntary body movements

autonomic nervous system

supplies the parts of the body that are not consciously controlled (glands, cardiac muscle, smooth muscle of the organs)

parasympathetic nervous system

rest and digest process, decelerates the body

sympathetic nervous system

fight or flight response, excites the nervous system

major components of the PNS

sensory receptors, peripheral nerve, and effectors

12 pairs of cranial nerves

supply the head and neck in the peripheral nerve

31 pairs of spinal nerves

found in the peripheral nerve, each contain both sensory and motor neurons

neurons

main structural and functional cell of the nervous system

motor neurons

carry motor information from the CNS to the effectors

sensory neurons

carry sensory information to the CNS

interneurons

connect motor and sensory neurons

glial cells

nerve impulse

electrochemical change that occurs across the neuron membrane

energy for impulse transmission

provided by ATP

resting membrane potential

the electrical charge of a neuron when it doesn't have an impulse traveling through it (-70mV)

why is the positive charge on the outside of the neuron membrane

- chlorine + large negative ions are found inside the neuron

- sodium potassium pump

action potential

ions around the neuron changes

what happens when a nerve impulse gets close?

chemistry around the neuron changes, which also changes the membrane potential

what happens when the membrane potential reaches -55mV?

- action potential occurs (nerve impulse now travels down the neuron)

- sodium channels open in the neuron membrane, sodium rushes into the axon

- negative on the outside and positive on the inside

peak membrane potential

peaks around +35mV, membrane repolarizes

what happens when peak membrane potential is reached?

- potassium ions open in the membrane, rushes out the neuron

- often overshoots the resting membrane potential to around -90mV, which then returns to -70mV with the help of the sodium potassium pump

repolarization

membrane resets itself

refractory period

a period of inactivity after a neuron has fired

dendrites

receive impulses and send them to the cell body

cell body

sends the impulse to the axon

axon

carries the impulse

nodes of ranvier

gaps between schwann cells where the axon is bare

terminal branches

extensions at the end of the axon, which have synaptic knobs

synaptic knobs

part of neuron that receives impulse and releases neurotransmitters

where do action potentials occur in myelinated axons?

at the nodes of ranvier

saltatory conduction

the jumping of action potentials from node to node

synapse

special location where an impulse is transmitted from 1 neuron to another

neuromuscular junction

synapse between a neuron and a muscle

synaptic gap/cleft

tiny gap between neurons

excitatory neurotransmitters

cause the impulse to be continued in adjacent neurons

examples of excitatory neurotransmitters

ACH, histamine, and norepinephrine

inhibitory neurotransmitters

stop the impulse from being continued

examples of inhibitory neurotransmitters

serotonin, epinephrine, and glycine

if an impulse's overall result is excitatory...

an impulse will be transmitted

if an impulse's overall result is inhibitory...

no impulse is transmitted

what makes up the tissues in the brain and spinal cord

grey & white matter

grey matter

made up of cell bodies, dendrites, and short unmyelinated axons

where is grey matter found?

outside regions of the brain, and in the core of the spinal cord

white matter

made up of myelinated axons

where is white matter found?

inner regions of the brain, outer regions of the spinal cord

functions of the spinal cord

- links the PNS and the brain

- reflex center

what surrounds the spinal cord?

series of bones (vertebrae) that make up the vertebral column

meninges

3 protective membranes that surround the brain and spinal cord

outermost layer of the meninges

dura mater

middle layer of the meninges

arachnoid mater

innermost layer of the meninges

pia mater

cerebrospinal fluid

fills the space between the pia and arachnoid mater & cushions the brain

blood brain barrier

a filtering mechanism of the capillaries that carry blood to the brain and spinal cord tissue, blocking the passage of certain substances.

3 regions of the brain

forebrain, midbrain, hindbrain

forebrain consists of...

cerebrum, thalamus, and hypothalamus

hindbrain consists of...

cerebellum, pons, and medulla oblongata

brainstem consists of...

pons, medulla, midbrain

folds on the outer layer of the cerebrum

convolutions

grooves on the outer layer of the cerebrum

sulci

bulging ridges on the outer layer of the cerebrum

gyri

2 identical parts of the cerebrum

right and left hemisphere

what divides the right and left hemisphere?

longitudinal fissure

corpus callosum

connection of the nerve fibers between the 2 hemispheres

cerebral cortex

outer layer of the cerebrum

cerebral cortex lobes

frontal, parietal, occipital, temporal

frontal lobe function

involuntary movements, memory, intelligence, personality

temporal lobe function

hearing and smell

parietal lobe function

receives sensory information from our skin

occipital lobe function

vision

broca's area

coordinates the muscles for speaking

wernicke's area

stores information for language comprehension