Nervous System Flashcards
afferent/sensory neurons
information from skin/organs to brain and spinal cord
interneurons
connect spinal, motor, and sensory neurons
efferent/motor neurons
sends information away from nervous system to muscles/organs
dendrites
receive messages from other cells
axon
passes messages away from the cell body to other neurons, muscles, or glands
myelin sheath
covers the axon of some neurones and helps spread neural impulses
neural impulse
(action potentional) electrical signal traveling down the axon
terminal branches of axon
form junctions with other cells
cell body
the cell’s life support center
what are the steps to firing a neuron ?
- depolarization and action potential produced via neuron stimulation
- action potential travels further along neuron; sodium/potassium ion pump pushes ions out of cell
- action potential continues down the axon, first section has recharged and ready for stimulation again
what are the steps to neurons communicating ?
- electrical impulses travel down axon until reaching synapse (junction between neurons)
- neurotransmitter molecules released and go to the receiving neuron
- sending neuron reabsorbs excess neurotransmitter molecules, process called reuptake
acetylcholine (ach)
- connected to muscle movement
- curare
- plays a role in memory
- Alzheimer’s is associated with decline in ACh
dopamine
- pleasure chemical
- alertness
- happiness
- muscle control and coordination
- Parkinson’s = lack of dopamine
- Schizophrenia = excess dopamine
serotonin
- mood
- emotion
- used in SSRIs (Selective Serotonin Reuptake Inhibitors - anti-depressants)
- sleep
epinephrine
- adrenaline
- associated with energy
norepinephrine
- low levels connected to Depression
- alertness, blood pressure, and heart rate
gama-aminobutyric acid (GABA)
- inhibitory neurotransmitter
- slows and calms the nervous system
- sleepiness, less anxiety, less alertness and muscle tension
- too little is associated with anxiety disorders, seizures, tremors, and insomnia
glutamate
- excitatory neurotransmitter
- opposite of GABA
- involved in thinking, memory, and learning
- facilitates stronger neural connections
- too much can lead to migraines and seizures
endorphins
- body’s natural painkiller
- released during physical activities
agonist drugs do what ?
excite neurotransmitters
antagonist drugs do what ?
inhibit neurotransmitters
what are the two main parts of the overall nervous system ?
peripheral & central (brain and spinal cord)
what are the two parts of the peripheral nervous system ?
- autonomic (controls self-regulated action of internal organs and glands)
- somatic (controls voluntary movements of skeletal muscles)
what are the two parts of the autonomic nervous system ?
- sympathetic (arousing)
- parasympathetic (calming)
sympathetic nervous system
- excites
- fight or flight
- heart rate increases, pupils dilate, respiration increases, digestion slows
parasympathetic nervous system
calms
endocrine system
- works by passing hormones through the bloodstream
- slow to operate; longer lasting effects
- works as a team with the nervous system
pituitary gland
secretes many different horomes, some of which affect other glands
hypothalamus
brain region controlling the pituitary gland
thyroid gland
affects metabolism, among other things
parathyroids
help regulate the level of calcium in the blood
adrenal glands
triggers the “fight or flight” response
pancreas
regulates the level of sugar in the blood
testis
secretes male sex hormones
ovary
secrets female sex hormones
action potential
a neural impulse; a brief electrical charge that travels down an axon
synapse
the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron
neurotransmitters
chemical messengers that cross the synaptic gaps between neurons
peripheral nervous system
the sensory and motor neurons that connect the central nervous system to the rest of the body
nerves
bundled axons that form neural “cables” connecting the central nervous system with muscles, glands, and sense organs
somatic nervous system
the division of the peripheral nervous system that controls the body’s skeletal muscles
autonomic nervous system
controls the glands and muscles of the internal organs
reflex
simple, autonomic response to a sensory stimulus
hormones
chemical messengers that are produced by the endocrine glands, travel through the bloodstream, and affect other tissues
