nervous system Flashcards
3 general functions of nervous system
- motor (efferent) functioning
- sensory (afferent) functioning
- integrative (associative) functioning
motor functioning
- aka
- two functions
- efferent functioning
- controls muscle contractions and gland secretions
sensory functioning
- aka
- function
- afferent functioning
- detection of body’s internal/external environment
integrative functioning
- aka
- five functions
- associative functioning
- memory, emotion, interpretation of senses, logic, creativity
central nervous system consists of what 2 things
- brain
- spinal cord
peripheral nervous system consists of what 3 things
- nerves
- sensory receptors
- sensory organs
peripheral nervous system: motor
2 divisions
- somatic nervous system
- autonomic nervous system
somatic nervous system
- what wired to what
- controls what
- nerves wired to skeletal muscles (motor units)
- controls voluntary skeletal muscle contractions
autonomic nervous system
- what wired to what 3 things
- controls what 3 things
- nerves wired to smooth muscle, cardiac muscle and glands
- controls involuntary smooth muscle and cardiac contractions, controls gland secretions
peripheral nervous system: sensory
- what wired to what 2 things
- relay what to what
- nerves wired to sensory receptors and sensory organs
- relay sensory impulses to central nervous system
2 main nervous system cell types
- glial cells
- neurons
glial cells
- aka
- what are they
- neuroglia
- supporting cells that surround and maintain the environment around neurons
6 types of glial cells
- astrocytes
- microglia
- ependymal cells
- oligodendrocytes
- satellite cells
- schwann cells
astrocytes
- most what
- location
- shape
- function one
- function two
- most abundant type of nervous system cell
- found in brain and spinal cord
- star shaped
- hold neurons in place
- have extensions that wrap around capillaries of brain and spinal cord to help regulate which chemicals can cross from blood to brain and spinal cord
microglia
immune cells in the brain and spinal cord
ependymal cells
- location
- function
- line the walls of the brain’s ventricles
- continuously filter blood and produce new cerebrospinal fluid
oligodendrocytes
- location
- function
- found in brain and spinal cord
- wrap around the axons of neurons forming a myelin sheath
myelin sheath function
insulate and speed up conduction of electricity down the length of an axon
satellite cells
- just like what other cells
- location
- like astrocytes
- found in peripheral nervous system
schwann cells
- just like what other cells
- location
- added function
- like oligodendrocytes
- found in peripheral nervous system
- involved in repairing axons
neurons are what
cells that generate and conduct electricity
9 structures of a neuron
- nucleus
- cell body
- dendrites
- axon hillock
- axon
- axon terminal
- synapse
- post synoptic cell
- nodes of ranvier
dendrites function
receive signals that either activate or inhibit neuron
axon function
conducts electricity down its length
axon terminal function
stores and when electricity enters it, releases neurotransmitters in vesicles
synapse
fluid outside the axon terminal where neurotransmitters are released
post synoptic cell could be 1 of the 3 things
- muscle cell
- gland cell
- another neuron
nodes of ranvier
spaces between the myelin sheaths along the axon
2 ways neurons are classified
- structural classification
- functional classification
3 structural classifications of neurons
- multipolar neurons
- bipolar neurons
- unipolar neurons
multipolar neurons
- most what
- what is it
- most common type
- multiple dendrites attached directly to the cell body
bipolar neurons are what
one dendrite attached directly to the cell body
unipolar neurons are what
cell body w/ only an axon attached
functional classification of motor neurons
- wired to what 2 things
- type of structure
- controls what 2 things
- wired to skeletal muscles and glands
- multipolar
- controls muscle contractions and gland secretions
functional classification of sensory neurons
- type of structure
- do what
- any of 3 structural types
- relay impulses from sensory receptors to brain and or spinal cord
functional classification of integrative neurons
- type of structure
- found in what 2 places
- multipolar
- found in brain and spinal cord
2 types of nervous tissue and what they are made of what do they both have in common
- white matter: myelinated axons
- gray matter: dendrites, cell bodies, unmyelinated axons
both types have neuroglia
electricity is what
movement of charged particles (sodium ions in humans) through an object
ion channels
proteins in plasma membrane of cell that allow a specific ion to pass in or out of the cell
3 classes of ion channels in neurons
- ligand-gated
- mechanically-gated
3 voltage-gated
ligand-gated ion channels open when what is a ligand
open in response to binding of a specific ligand
ligand is a chemical that binds to a protein (a neurotransmitter, a hormone or a drug)
mechanically-gated ion channels open when
open in response to pressure or stretch
voltage-gated ions open when
open in response to a specific voltage surrounding the channel
neuron’s resting membrane potential
the electrical charge in neurons when they aren’t conducting electricity = -70 millivolts
when a neuron is at rest
- what ion is more abundant outside of it
- what ion is more abundant inside of it
- more sodium outside
- more potassium inside
main cation inside and outside of neurons
inside= potassium
outside= sodium
5 stages of action potential
- resting membrane potential of neuron/cell of -70mv
- threshold for action potential to occur is -55mv
- depolarization caused by sodium entering cell spikes charge to +30mv
- repolarization caused by potassium leaving cell drops charge down to below -70mv
- hyperpolarization when the cell’s charge is below -70mv but quickly corrected back to -70mv by moving sodium out of cell and potassium back in
depolarization
when a neuron/cell becomes less negative and then eventually positive because ion channels open and sodium enters the neuron/cell
repolarization
when a neuron/cell beomes more negative because ion channels open and potassium exits the neuron/cell
hyperpolarization
when a neuron/cell after repolarization actually gets more negative than resting membrane potential, but this is corrected quickly
after neurotransmitter molecules are released into the synapse they can diffuse across what then bind to and activate what
diffuse across synapse then bind to and activate neurotransmitter receptors on the post synaptic cells
when the post synaptic cell a neurotransmitter activates is a muscle cell what is triggered
muscle cell contraction or relaxation
when the post synaptic cell a neurotransmitter activates is a gland what is triggered
secretion or inhibition of secretion
when the post synaptic cell a neurotransmitter binds to is a neuron the neurotransmitter receptor would be a what kind of gated channel and trigger what 2 possible outcomes
the neurotransmitter receptor would be a ligand-gated ion channel and trigger either depolarization (activation) or hyperpolarization (inhibition)
after neurotransmitter molecules are released into the synapse they can diffuse out of what and then be taken up by what
diffuse out of synapse then taken up by neuroglia
after neurotransmitter molecules are released into the synapse some synapses have what that break them down and remove them to prevent what
some synapses have enzymes that break down the neurotransmitter molecules and remove them from the synapse to prevent the post synaptic cell from being overstimulated
after neurotransmitter molecules are released into the synapse some what have channels or pumps that move them back into where for what 2 reasons
some axon terminals have channels or pumps that move the neurotransmitter molecules back into the axon terminal to be reused and prevent the post synaptic cell from being overstimulated
some drugs can act on the nervous system/neurons by mimicking what by binding to and activating what give example
mimic a neurotransmitter by binding to and activating neurotransmitter receptors EX: opioids mimic endorphin
some drugs can act on the nervous system/neurons by binding to and blocking what give example
bind to and block neurotransmitter receptors from being activated EX: narcan blocks endorphin receptors
some drugs can act on the nervous system/neurons by blocking what from breaking down what
block synapse enzymes from breaking down the neurotransmitters molecules
some drugs can act on the nervous system/neurons by blocking what from moving neurotransmitter molecules where these are know as what give example
block axon terminal channels/pumps from moving neurotransmitter molecules back into the axon terminal known as reuptake inhibitors EX: prozac blocks the reuptake of serotonin
neurogenesis is what
formation of new neurons that only occurs during development in adults it only occurs in olfactory neurons
neuroregeneration is what
repair of damaged axons of the peripheral nervous system
2 steps of how neuroregeneration works
- immune cells break down the axon downstream of the damage site
- schwann cells/myelin sheath remain intact and guide the regrowth of the axon