Nervous System 1 And 2

Front 1

acetylcholine

Back 1

neurotransmitter that is released from motor neurons and causes muscle contractions.

Front 2

acetylcholinesterase

Back 2

breaks down acetylcholine so later, the components can be reused

Front 3

action potential

Back 3

Electrical signal resulting from depolarization of the plasma membrane in a neuron.
Is generated if voltage across membrane declines to threshold level of -55mV, the voltage-activated ion channels open and Na+ flows into neuron

Front 4

afferent (sensory) neuron

Back 4

transmit info. from sensory organs to central nervous system

Front 5

association neuron (interneuron)

Back 5

link between sensory and motor neurons. Found in CNS

Front 6

autonomic nervous system

Back 6

-helps to maintain homeostasis in the internal environment
- works automatically without voluntary input
-effectors are smooth muscle, cardiac muscle, and glands
- divided into sympathetic and parasympathetic

Front 7

axon

Back 7

single, long cytoplasmic extension of the neuron projecting from the opposite end of the cell body as the dendrites;
- conducts nerve impulses away from cell body to another neuron or effector
-ends in a synaptic terminal

Front 8

carrier-mediated active transport

Back 8

transport across a membrane of a substance from a region of low concentration to a region of high concentration; requires both a transport protein with a binding site for a specific substance and an energy source (often ATP)

Front 9

cell body

Back 9

has nucleus, bulk of the cytoplasm, most of the organelles of a cell; integrates incoming signals

Front 10

cell processes

Back 10

Reception- stimulus detected by receptor
Transmission- message sent from neuron to neuron to CNS
Integration- signal is processed and interpreted
Response- messages are transmitted from CNS to effector organs and action takes place

Front 11

central nervous system

Back 11

brain and spinal cord; serves as central control

Front 12

cerebellum

Back 12

subdivision of brain concerned with muscle coordination of muscular movements, muscle tone, and balance

Front 13

cerebral cortex

Back 13

outer layer of cerebrum composed of gray matter and consisting mainly of nerve cell bodies

Front 14

chemical synapse

Back 14

pre- and post-synaptic neurons are further apart; since gap is big, action potential can't jump; electrical signal is converted into chemical via neurotransmitters

Front 15

chemically activated ion channels

Back 15

allow passage of specific ions; not gated
- potassium ions leak out passively, making ECF more positive; changes electrical gradient and influences ion flow

Front 16

cranial nerves

Back 16

the 10 to 12 pairs of nerves in vertebrates that emerge directly from the brain

Front 17

dendrite

Back 17

branch of neuron that receives and conducts nerve impulses toward the cell body

Front 18

depolarization

Back 18

decrease in the charge difference across a plasma membrane; may result in an action potential in a neuron

Front 19

effector

Back 19

muscle or gland that contracts or secretes in direct response to nerve impulses

Front 20

efferent (motor) neuron

Back 20

neurons that transmit action potentials from the brain or spinal cord to muscles or glands

Front 21

electrical synapse

Back 21

pre- and post-synaptic neurons are very close together and create gap junction; synapses are physically connected so transmission is very fast

Front 22

excitatory postsynaptic potential

Back 22

a change in membrane potential that brings a neuron closer to firing level

Front 23

facilitated diffusion

Back 23

passive transport of ions or molecules by a specific carrier protein in a membrane. As in simple diffusion, net transport is down a concentration gradient, and no additional energy has to be supplied

Front 24

forebrain

Back 24

thalamus, hypothalamus, cerebrum.
higher brain function, sensory and motor pathways; associative functions: memory, learning, emotion

Front 25

glial cells

Back 25

cells that support and transport nutrients to neurons; comprise 90% of nerve tissue; provide architecture of nerve system and help neurons end up in right place
-responsible for blood-brain barrier

Front 26

gray matter

Back 26

nervous tissue in the brain and spinal cord that contains cell bodies, dendrites, and unmyelinated axons

Front 27

hindbrain

Back 27

has medulla, pons, and cerebellum

Front 28

homeostasis

Back 28

the balanced internal environment of the body; the automatic tendency of an organism to maintain such a steady state

Front 29

hypothalamus

Back 29

regulates internal processes- homeostasis; provides input to centers in the medulla & spinal cord; regulates body temp, hunger, thirst

Front 30

inhibitory postsynaptic potential

Back 30

a change in membrane potential that takes a neuron farther from the firing level

Front 31

interneuron (association neuron)

Back 31

link between sensory and motor neurons

Front 32

medulla

Back 32

most posterior part of the brain; control center of almost all visceral functions: homeostasis, breathing, heartbeat, blood vessels, swallowing, vomiting, digestion

Front 33

midbrain

Back 33

receiving and integrating sensory info (visual & auditory)

Front 34

myelin sheath

Back 34

white, fatty material that forms a sheath around the axons of certain nerve cells, which are then called myelinated fibers

Front 35

neuron

Back 35

a nerve cell; a conducting cell of the nervous system that typically consists of a cell body, dendrites, and an axon

Front 36

neurotransmitter

Back 36

a chemical signal used by neurons to transmit impulses across a synapse

Front 37

nodes of Ranvier

Back 37

gaps in the myelin sheath

Front 38

norepinephrine

Back 38

a neurotransmitter that is also a hormone secreted by the adrenal medulla
- catecholamines
- can be excitatory or inhibitory

Front 39

parasympathetic system

Back 39

division of the autonomic nervous system concerned with control of the internal organs
- conserve and restore energy
-" rest or digest"
(relax heart rate and breathing)

Front 40

peripheral nervous system

Back 40

made up of sensory receptors and nerves; divided into autonomic and somatic nervous system

Front 41

polarized state

Back 41

Resting state
Has a membrane potential of -70 mV
-maintained by the activity of the sodium- potassium pump which pumps Na+ out of cell and K+ into cell

Front 42

postsynaptic neuron

Back 42

neuron that transmits an impulse away from a synapse

Front 43

presynaptic neuron

Back 43

neuron that transmits an impulse to a synapse

Front 44

reflex arc

Back 44

relatively fixed response pattern to a simple stimulus
* does not involve brain*

Front 45

refractory period

Back 45

brief period that elapses after the response of a neuron or muscle fiber, during which it cannot respond to another stimulus

Front 46

repolarization

Back 46

process of returning membrane potential to its resting level

Front 47

saltatory conduction

Back 47

transmission of a neural impulse along a myelinated neuron; ion activity at one node depolarizes the next node along the axon

Front 48

Schwann cell

Back 48

supporting cell found in nervous tissue outside the CNS; produce the myelin sheath around peripheral neurons

Front 49

sodium/potassium pump

Back 49

active transport system that transports sodium ions out of, and potassium ions into, cells

Front 50

somatic nervous system

Back 50

- part of peripheral nervous system
- mainly voluntary but sometimes involuntary
- react to changes in external environment
- includes sensory receptors on body surface and within muscles

Front 51

spinal nerves

Back 51

nerves that emerge from the spinal cord

Front 52

summation

Back 52

process of adding together excitatory postsynaptic potentials (EPSP)

Front 53

sympathetic system

Back 53

part of autonomic nervous system
-stimulates organs and mobilize energy
-"fight or flight"
- responds to stress ( heart rate increase, breathing faster, etc)

Front 54

synaptic cleft

Back 54

tiny space between two nerve cells across which acetylcholine diffuses

Front 55

synaptic knob or terminal

Back 55

a bulb at the end of an axon in which neurotransmitter molecules are stored and released

Front 56

synaptic vesicle

Back 56

store neurotransmitters released during calcium-regulated exocytosis at presynaptical terminal into synaptic cleft

Front 57

thalamus

Back 57

sorting and relay for motor and sensory messages before they are sent to cerebrum
- processes all sensory information except for smell

Front 58

tract

Back 58

a bundle of nerve fibers within the CNS

Front 59

ventricle

Back 59

one of the several cavities of the brain

Front 60

voltage activated ion channels

Back 60

ion channels in the plasma membrane of neurons that are regulated by changes in voltage

Front 61

white matter

Back 61

nervous tissue in the brain and spinal cord that contains myelinated axons