Control and Coordination: Concept 1-The Nervous System-Vocab section

Bio 2 by Anthony Hernandez

soma (cell body)

the main life support that contains the nucleus and most of the organelles (especially tons of mitochondria)

Dendrites

the main receptor of signals and the input region

axon

generates and also transmits nerve impulses. It is the conducting region, but it is also known as the nerve fiber

ganglion

a collection of nerve cell bodies that are located all over the body.

nerve

a bundle of axons that extend from the brain and the spinal cord to the rest of the body.

axon terminal

located at the end of the axon and releases neurotransmitters towards a synapse when a nerve impulse is received. it is known as the secretory region

myelin sheath

covers long axons (nerve fibers) to protect and electrically insulate the fibers to increase the speed of nerve impulse transmission

Nodes of Ranvier

unmyelinated gaps in the myelin sheath that aid in increasing the velocity of nerve signal conduction.

sensory neurons

transmit information from sensory neurons to central nervous system

motor neurons

transport info from cns to the rest of the body

interneurons

housed in the CNS and transports information between sensory and motor neurons

resting membrane

the voltage across the cell membrane

graded potential

a short lived and a localized change in the membrane potential that varies in strength

threshold

minimum level of stimulus needed for muscle fiber to contract.

action potential

a huge change in membrane potential that spreads rapidly across a cell with the movement of ions

nerve impulse

a cell signal that is transmitted along a nerve fiber

depolarization

a change within a cell resulting in less negative charges inside a cell

repolarization

change in membrane potential. cell RETURNS to being more negative on the inside

hyperpolarization

cell gets even more negative in charge before returning to its resting state

synapse

between two neurons and mediates the transfer of a signal from the presynaptic neuron to the postsynaptic neuron.

meninges

layers of tissue that protects the brain and skull

ventricles

hollow fluid filled cavities within the brain that contain choroid plexus which make up cerebrospinal fluid

cerebrum

largest part of the brain. made of left sad right hemispheres, divided into four lobes. functions in learning, speech, emotion, reasoning, vision hearing and fine movements.

cerebellum

under the cerebrum. maintains posture and balance. coordinates timing and patterns for smooth and agile subconscious movements

brain stem

base of the cerebrum and anterior to the cerebellum

neurotransmitter

chemicals released from neurons to cross synapses

hormone

chemicals released from glands and into the bloodstream

mechanoreceptor

mechanical force, like vibration, pressure stretch and touch

thermoreceptor

change in temperature

chemoreceptors

chemicals

nociceptors

pain

reflex

an automatic reaction to stimuli