unit 2 Flashcards
function of dendrite
receive incoming messages
function of cell body (soma)
contains nucleus
function of myelin sheath
fatty tissue that INSULATES axon speeding up transmission of messages
functions of node of ranvier
space between myelin sheath
function of schwann cells
non-neuronal cells in CNS that form myelin sheath
function of axon
longest part of neuron which the electrical message travels the length of neuron
function of axon terminal buds (buttons)
end point of a neuron that relates neurotransmitters into the synapse, hence sending the message onto next neurons
what is resting potential
neuron not firing, has negative charge with mostly potassium ions (K) inside & sodium (Na) outside which creates a polarized neuron
what ions are inside and outside during resting polarization, what is this also known as, and what is the neuron at
potassium inside + sodium outside; aka polarization; homeostasis
what is action potential
“nerve impulse”
causes the neuron to fire (electrical pulse travels length of axon)
all-or-nothing principle, maintains intensity
what is the all or nothing principle
when the nucleus decides to fire, it fires down axons completely or not at all
what is depolarization
when message begins, sodium (Na+) ions come in & depolarize (neutralize) section of axon (causing potassium ions to rush out)
what is the refractory period
potassium (+K) ions are pushed out and neurons “paused to reload”; during this time a neuron is unable to fire
how does the action potential work
- sodium channels open + sodium ions rush in
- potassium channels open + potassium ions rush
- sodium channels close, but channels further down open causing the process to go to the length of the axon
what sends to the neuron
terminal buds
what receives the messages
dendrites
what are neurotransmitters
chemical substance that crosses synapse to carry on message to next neuron
what is the synapse
open space between 2 neurons at which neurotransmitters cross
what do the receptor sites
specific points on dendrites of neurons that receive specific types of neurotransmitters
what is reuptake
the reabsorption by a neuron of transmission following the transmissions of a nerve impulse across a synapse
acetylcholine role + associated disorders
muscle contractions, memory and learning; Alzheimer’s disease
dopamine role + associated disorders
movement, thought process, rewarding sensation + pleasure; Parkinson’s (-), Schizophrenia (+), Drug Addiction (+)
serotonin role + associated disorders
emotional states, sleep + happiness; depression (-)
norepinephrine role + associated disorders
physical arousal, learning + memory; depression & stress (-)
GABA role + associated disorders
inhibition of brain activity, calming drug; anxiety disorders (-)
endorphins role + associated disorders
positive emotion, runners high, pain perception; opiate addiction
what are agonists and what is an example
imposter (mimics neurotransmitters)
fits into receptor site like a master key + notes
ex: morphine - opiate derivatives, mimics endorphins
what are antagonists and what is an example
blocker (blocks neurotransmitters)
fits in receptor site in fake key which prevents the neurotransmitter from working
ex: botox blocks acetylcholine
what does peripheral nervous system include
sensory motor neurons that connect CNS to rest of the body;
autonomic, somatic, sympathetic, parasympathetic
what does CNS include
spine + brain in the center of the body + interneurons
brain function
control center
spinal cord function
super highway of nerves;
body’s means of transmitting messages to or from brain
interneurons function
only neurons in CNS
“relay neuron”
messenger between sensory and motor
sensory [afferent] neurons function
carries incoming messages from sense receptors to CNS (feeling)
motor [efferent] neurons function
carries outgoing info from CNS to peripheral nervous system + muscles
autonomic nervous function
controls involuntary functions or things that happen autonomic
ex: breathing, heartbeat, digestion, etc.
somatic nervous function
controls voluntary movements + communication to and from sense organs; WE CONTROL
sympathetic nervous function
physically arouses the body and preps it to react in stressful situations expending energy
flight or fight
inhibits digestion
stimulates glucose release by liver
release of epinephrine + norephrine by adrenal gland
dilates pupils
parasympathetic nervous system
calms body, conserves energy + helps keep a constant internal state
rest + digest
stimulates digestion
contracts pupils
slows breathing + heart rate
what system does our endocrine system work with in normal circumstances
parasympathetic NS
what system does our endocrine system work with in crisis circumstances
sympathetic NS
endocrine system’s hormones are ____
released into and circulate thru the bloodstream; received ONLY at a specific site
pituitary gland function
master gland
directed by hypothalamus
thyroid gland function
produces hormone thyroxine which stimulates chemicals important to all body tissues