afferent

sensory neurons
bring sensory info to CNS from receptors in peripheral tissues

efferent

motor neurons
carries commands from CNS to effector tissues like muscles and glands

autonomic

nervous system (visceral motor system)

perikaryon

contains organelles in the neural cell body

nissl bodies

gray matter of the CNS
clustered areas of ribosomes and rough ER

ganglia

collections of neuron cell bodies in the PNS

myelinated axon

white matter is made of ________

anaxonic

neuron found in brain and some sense organs

bipolar

neuron found in special sensory organs

unipolar

neuron found in most sensory neurons of PNS

multipolar

neuron common in the CNS
includes all skeleal muscle motor neurons in PNS

visceral

sensory neuron that monitors the internal environment of the body

somatic

sensory neuron that monitors external environment and our position in it

interoceptors

sensory receptors that monitor internal organ systems and provide sensations including visceral pain, blood pH, and blood O2 levels

exteroceptors

sensory receptors that monitor the outside environment and provide sensastions including touch, temp, sight, smell, and hearing

proprioceptors

sensory receptors that monitor joint and muscle position

interneurons

located in the brain, spinal cord, and some ganglia
most common neuron type
responsible for distributing sensory info, coordinating motor info
active in higher functions (thought, memory, learning, planning)

neuroglia

cells that support and protect neurons
preserve physical and biochemical structure of neural tissue and are essential to survival and function of neurons

ependymal

neuroglial cells that line the ventricles and central canal and produce cerebrospinal fluid
also monitor and circulate the CSF

astrocyte

neuroglial cell that maintains the blood-brain barrier
cover surface of all capillaries
act as gatekeepers for substances entering the CSF/interstitial fluid
provide structural framework for the neurons of the CNS

oligodendrocyte

neuroglial cell that wrap around neuron axons
extensions contain myelin
axons myelinated at internodes; unmyelinated at nodes of Ranvier

microglia

neuroglial cells that are small and able to move through CNS
engulfs cellular debris, waste products, and infective organisms

satellite

neuroglial cells that surround the neuron cell bodies in ganglia
regulate the environment around neurons
similar to astrocytes in the CNS

schwann

neuroglial cells that myelinate sections of a single axon or surround sections of many unmyelinated axons

wallerian degeneration

axon distal to injury site degenerates and macrophages clean up debriss
in PNS, Scwann cells multiply and form a path for new axon growth
axon may or may not grow back to former destination (~2mm/day)

-70mV

resting potential of a neuron

graded potential

a local change in transmembrane potential
any stimulus that opens gated ion channels will produce this
causes depolarization or hyperpolarization

-60mV

threshold for axon (all-or-none principle)

refractory period

time during an AP when another AP cannot or is unlikely to occur

relative refractory period

Na+ channels are in normal resting state, but K+ channels are open or membrane is hyperpolalrized
AP possible, but requires larger stiulus

absolute refractory period

voltage-gated Na+ channels are either open or are inactivated

continuous propagation

AP propagation that occurs in unmyelinated axons (diffusion)

saltatory propagation

AP propagation that occurs in myelinated axons
occurs only at nodes--jumps from node-to-node
much faster, requires less energy

type A

AP
fibers that carry sensory info about position, balance, light, touch, pressure, and motor info

electrical

synapse where presynaptic and postsynaptic cell are linked at gap junctions
allows ions and AP to pass from cell-to-cell
rare in CNS and PNS
AP always occurs in the postsynaptic cell

chemical

synapse that involves the release of a neurotransmitter
release of the neurotransmitter may or may not cause an AP at the postsynaptic cell

excitatory

neurotransmitter that causes depolarization and promotes APs on postsynaptic cell

inhibitory

neurotransmitter that causes hyperpolarization and suppresses the generation of AP

Ach

neurotransmitter that is both excitatory and inhibitory

cholinergic

synapse that uses Ach as a neurotransmitter
all NMJ with skeletal muscles
many CNS synapses
many synapses in parasympathetic division of autonomic nervous system

synaptic delay

delay bw the arrival of the AP at the synaptic knob and the effect at the post-synaptic membrane
due to Ca2+ influx and neurotransmitter release
faster conduction occurs in routes with fewer synapses

norepinephrine

aka noradrenaline
found in brain and autonomic nervous system

dopamine

brain
too little=parkinson's

serotonin

brain
too little=depression

GABA

usually inhibitory

neuromodulators

chemicals that either alter the rate of neurotransmitter release at the presynaptic neuron or alter postsynaptic cell's response to neurotransmitters
ex: opioids

excitatory postsynaptic potential

EPSP

inhibitory postsynaptic potential

IPSP

EPSP

results from the opening of chemically gated membrane channels that lead to depolarization

IPSP

results from the opening of chemically gated membrane channels that lead to hyperpolarization

temporal

summation that includes subsequent stimuli from one synapse

spatial

summation that includes subsequent stimuli from 2 or more synapses

presynaptic inhibition

inhibitory neuron releases neurotransmitter on presynaptic neuron axon and prevents Ca2+ channels from opening

presynaptic facilitation

facilitory neuron releases neurotransmitter on presynaptic neuron axon and keeps Ca2+ channels open longer

cerebrum

largest part of the brain
divided into left and right cerebral hemispheres

gyri

raised areas of the cerebrum
increase the surface area

sulci

depressions of the cerebrum

fissure

very deep depression in the cerebrum
separates lobes

longitudinal fissure

separates cerebral hemisphere

lobes

divisions of hemispheres in the cerebrum

meninges

sheets of connective and epithelial tissues that surrounds the brain and spinal cord

cerebrospinal fluid

fluid that brain and spinal cord floats in
separates it from blood contents

dura mater

superficial meninges
2 layers
between layers are venous sinuses

pia mater

deep meninges
anchored by astrocytes

arachnoid mater

intermediate meninges

epidural space

space between the 2 dura mater layers
venous sinuses here

subdural space

between dural mater and arachnoid mater

subarachnoid space

contains the CSF
contains arachnoid granulations

arachnoid granulations

absorbs CSF into venous circulation

falx cerebri

dural fold that projects bw the cerebral hemispheres into longtiudinal fissure

tentorium cerebelli

dural fold that separates cerebellum and cerebrum

falx cerebelli

dural fold that divides ceerebellar hemispheres below the tenorium cerebelli

lateral

ventricles (2) one in each cerebral hemisphere

third

ventricle of the diencephalon

fourth

ventricle that extends into medulla oblongata

choroid plexus

ependymal cells and permeable capillaries that produce CSF

hydrocephalus

results is impaired reabsorption of CSF
Water on the brain

internal jugular veins

receive blood from dural venous sinuses
drains blood from the bain

cranial nerves

nerves that originate from the brain or brain stem

brain stem

processes/relays info between spinal cord and cerebrum or cerebellum
-midbrain, pons, medulla oblongata

medulla oblongata

connects the brain to the spinal cord
-regulates autonomic functions (HR, BP, respiration with pons)

pons

links cerebellum to the midbrain (mesencephalon), diencephalon, cerebrum, and spinal cord
-respiration
-relays info to and from cerebellum

cerebellum

coordinates body movements/balance
-monitors proprioceptive inputs from PNS

ataxia

inability to coordinate movements
-damage to cerebellum

midbrain

processes sight and sound associated reflexes
-maintains consciousness through reticular activating system
-affects fluid movement and muscle tone

diencephalon

links cerebrum with brain stem
-epithalamus, thalamus, hypothalamus

epithalamus

region of the diencephalon
-contains the pineal gland that secretes melatonin and is stimulated by the hypothalamus

thalamus

region of the diencephalon
-relay center
-receives sensory input from cerebellum, body, basal nuclei, eyes, ears
-includes part of the limbic system (emotions)

hypothalamus

region of the diencephalon
-regulates hormone production, emotion, autonomic function, circadian rhythms, and pituitary gland

infundibulum

how the pituitary gland is connected to the hypothalamus

central sulcus

divides frontal lobe from parietal lobe
-separates precentral gyrus from postcentral gyrus

lateral sulcus

divides frontal lobe from temporal lobe

precentral gyrus

located in frontal lobe
-primary motor cortex

postcentral gyrus

located in frontal lobe
-primary sensory cortex

sensory

association areas that interpret arriving info based on past experiences

somatic motor

association area that coordinates motor responses (learned movements)
-located in premotor cortex

association

fibers that form connections within one hemisphere

commissural

fibers that connect L and R hemispheres
-corpus callosum

projection

fibers that connect cerebrum with diencephalon and brainstem--vertically

basal nuclei

masses of gray matter that direct subconscious activities