The Nervous System Flashcards
what are the two types of cells in the nervous system
neurons and neuroglia
what is a neuron
nerve cell is an electrically excitable cell that communicates with other cell
how do neurons communicate with other cells
via specialized connections called synapses
what is the main component of nervous tissue in all animals
neurons
what is gilia
non-neuronal cells in the central nervous system and the peripheral nervous system that do not produce electrical impulses.
what is gilia also called
glial cells or neuroglia
what is the purpose of gilia
to maintain homeostasis for nervous tissues so that they can function normally
what are the two parts of the nervous system
central nervous system and the peripheral nervous system
what makes up the central nervous system
brain and spinal cord
what brings information to the CNS
afferent neurons
what sends information from the CNS
efferent neurons
what is the cell body of a neuron
main part of cell where organelles and nuclei reside
what is the dendrite of a neuron
many short extensions that carry impulses to a cell body
what is an axon
single long extension that carries impulses away from the cell body
what is a ganglion
a cluster of nerve cells
where are ganglions found
within the peripheral nervous system
what is a nucleus of a neuron
cluster of nerve cell bodies
where is a nucleus found
within the central nervous system
what is commonly referred to as a cluster of axons
nerve or nerve fiber
what is a myelin sheath
A lipid covering on long axons
what is the purpose of myelin sheath
to increase the speed of nerve impulse conduction, insulation, and regeneration
what type of cell are Schwann Cells
neuroglia
what are Schwann cells
the cells that make up myelin sheath in the PNS
what are oligodendrocytes
the cells that make up the myelin sheath in the CNS
what is the difference between oligodendrocytes and Schwann Cells
Oligodendrocytes are only in the CNS, and Schwann Cells are only in the PNS
what are nodes of ranvier
gaps between myelination on the axons
what is saltatory conduction
conduction of the nerve impulse from node to node
what is the rate of saltatory conduction
hundreds of meters per second
what are nerve impulses
electrical signals
how do ions move inside and outside the cell
by diffusion
when does resting potential occur
when the axon is not conducting a nerve impulse
what do Na ions do during resting potential
Na ions become more concentrated on the outside of the cell membrane
what do K ions do during resting potential
K ions become more concentrated on the inside of the cell
what do gated channels mean
that they open under the appropriate signals
what is the charge inside the axon during resting potential
-65 to -70mV
what is action potential
rapid change in the axon membrane ion balance that allows a nerve impulse to occur
what is the initial trigger of action potential
chemical signal or a voltage change
what way does action potential occur
in an all or nothing fashion
what needs to happen for action potential to occur
the chemical signal has to exceed threshold
what happens during action potential
sodium gates open letting Na open, potassium gates open letting K out
what occurs due to the Na+ gates opening
depolarization
how does the sodium gates affect the charge of the axon
the interior of the axon loses the negative charge, and goes up to about +40mV
what occurs due to potassium gates opening
repolarization
how does the potassium gates effect the charge of the axon
the interior of the axon regains the negative charge, going down to -65mV
how is resting potential created and maintained
by moving K inside and Na outside
what occurs after the potassium gates open
wave of depolarization/repolarization travel down the axon
what are the steps of action potential
cell membrane brought to threshold,
change in potential opens voltage gated Na ion channels,
Na moves into cell don it electrochemical gradient,
change in membrane potenital opens voltage gated K channels,
Na and K pump restores ion concentrations to normal
what is a synapse
a small gap between the sending neuron and the receiving neuron
what is the sending neuron also called
presynaptic membrane
what is the receiving membrane also called
postsynaptic membrane
where does transmission accomplished
across the synapse gap
how is transmission accomplished
through the synapse gap using a neurotransmitter as a signal
what are examples of chemical messengers
acetylcholine, adrenaline, dopamine, serotonin
where are neurotransmitters made
in neuronal cells
where are neurotransmitters stored
in synaptic vesicles in the axon terminals
how does transmission across the synapse occur
nerve impulse reaches the axon terminal,
calcium ions enter the axon terminal and stimulate the synaptic vesicles to fuse with presynaptic membrane,
neurotransmitters are released and diffuse across the synapse
what is integration
the summation of the inhibitory and excitatory signal received by a postsynaptic neuron
why does synaptic integration occur
because a neuron receives many signals - and this can be integrated over space and over time
what protects the central nervous system
bones, meninges, blood, and cerebrospinal fluid
what does the central nervous system consist of
brain and spinal cord
how does bone protect the CNS
skull and vertebral column
how does meninges protect the CNS
3 protective membranes wrap around the spinal cord
where is cerebrospinal fluid found
in the space between meninges
how does cerebrospinal fluid protect the CNS
the fluid fills space between meninges that cushions and protects the CNS
where is cerebrospinal fluid less commonly found
chambers in the brain called ventricles
how does blood protect the CNS
acts as a brain barrier
what is the brain barrier created by
endothelial cells
what is the function of endothelial cells
they act as gatekeepers to prevent biomolecules from reaching the brain in an unregulated fashion
what supports endothelial cells
astrocytes and astroglia
what makes it difficult for drugs to get to the brain
endothelial cells within the brain barrier of blood
what is the spinal cord
cord that extends from the base of the brain and along the length of vertebral canal formed by the vertebrae
what is the function of the spinal cord
to provide communication between the brain and most of the body
the spinal cord is the centre for…
reflex arcs
what is in the centre of the spinal cord
grey matter
what shape is the grey matter in the spinal cord
butterfly
what surrounds the grey matter
white matter
what is the function of the cerebral cortex
centre for primary motor and sensory areas of the cortex, contains association areas and processing centers
what is the cerebrum divided into
cerebral hemispheres and lobes
what connection does the cerebrum include
a connection between 2 hemispheres corpus callosum
what does the left hemisphere specialize in
language, math, logic operations, and the processing of serial sequences of information and visual and auditory details
what are the three functions of the left hemisphere
verbal, analytical, and specifics
what does the right hemisphere specialize in
pattern recognition, spatial relationships, nonverbal ideation, emotional processing and the parallel processing of information
what are the three main functions of the right hemisphere
visual, intuitive, and global
what is the cerebrum
the largest portion of the brain
what are the 4 lobes of the brain
frontal lobe, temporal lobe, parietal lobe, and occipital lobe
what is the function of the frontal lobe
primary motor area and conscious thought
what is the function of the temporal lobe
primary auditory, smell and speech area
what is the function of the parietal lobe
primary somatosensory and taste area
what is the function of the occipital lobe
primary visual area
what is the cerebral cortex
the thin, outer layer of grey matter
what does the primary motor area control
voluntary skeletal muscle
what does the primary somatosensory area control
sensory information from skeletal muscle and skin
what occurs in association areas
integration
what is an example of integration in association areas
face recognition
what does the processing centres focus on
performing higher level integration and it generates analytical function
what is the hypothalamus
part of the brain that helps maintain homeostasis and controls pituitary gland
what are examples of things that the hypothalamus regulates
hunger, sleep, thirst, body temperature, and water balance
what are the three other important brain centres
thalamus, epithalamus, and subthalamus
what is the cerebellum known as
the small brain
what does the cerebellum do
receives and integrates sensory input from the eyes, ears joints, and muscles about current position of the body
what is the function of the cerebellum
maintains posture, coordinates and refines voluntary movement, allows learning of new motor skills
what are the three parts of the brain stem
pons, medulla oblongata, reticular system
what is the pons
a bridge between cerebellum and the CNS
what is the function of the pons
regulates breathing rate, and acts as the reflex centre for head movement
what is the function of the medulla oblongata
acts as reflex centres for regulating breathing, heartbeat, and blood pressure
what is the functions of the reticular system
it activates higher brain centres and can filter out stimuli
what is an example of the function of the reticular system
“working” on your phone, checking Facebook during lectures
what is memory
the ability to hold a thought or to recall past events
what is short term memory
retention of information for only a few minutes
what is long term memory
retention of information for more than a few minutes
what are the two types of long term memory
episodic memory and semantic memory
what is episodic memory
retention of people and events
what is semantic memory
rentention of numbers, words, and language
what influences the transfer of information from short term to long term
emotional stress, and association with previously stored information
what enhances the transfer of information from short term to long term memory
repetition
what is skill memory
performing skilled motor acitivites
what are the five higher mental functions
memory, short term memory, long term memory, skill memory, and learning
how does learning occur
when we recall and use past memories
what are memories a result of
persistently reactivated circuits in the brain
what is long term potentiation
neuron activity can alter neuron protein function and synapse strength in stable ways, allowing past events to alter future function
what area of the brain is involved with short term memory
hippocampus
what area of the brain is involved with long term memory
cerebral cortex
what are the four hyper developed human traits
cognition, intelligence, language, and sociality
what are the two main divisions of the PNS
somatic division and autonomic division
what does the somatic division focus on
serves the skin, skeletal muscles, and tendons
what are automatic responses
reflexes
what is the function of the autonomic division
to regulate the activity of involuntary muscles and glands
what are thee two types of involuntary muscle that is regulated in the PNS
cardiac muscle and smooth muscle
what are the two divisions of the autonomic division
sympathetic and parasympathetic
what does the sympathetic division do
coordinates the body for the fight or flight response
how does the sympathetic division prepare us for fight or flight
by speeding up metabolism, heart rate, and breathing to improve skeletal muscle readiness while down regulating other functions
what is the function of the parasympathetic division
to counter the sympathetic system by brining up a relaxed state
what does the parasympathetic system bring up a relaxed state
by slowing down metabolism, heart rate, and breathing, and returning other functions to normal
what are the functions effected by both sympathetic and parasympathetic systems
DIgestive system and excretory system
What is the difference between mammalian in PNS to CNS
in PNS, it has some ability to repair and regenerate itself, while in the CNS is does not or is extremely limited
New nerve cells have been found in…
the hippocampus
how can treatment for damage to the CNS be advanced on
research on nerve cell development and neural stem cells
why must new cells have arisen from stem cells
mature human brain cells cannot undergo cell division
sensory neons collect information from what?
external and internal enviroments
how do sensory neurons relay informations
through interneurons, to other parts of the nervous system
what do motor neurones do
execute command or output from the nervous system to muscles and glands
what is the function of myelin sheath
they act as insulators during nerve impulse transmission down the axon
what type of cell make up white matter in the CNS
nerves with myelin sheaths
where does the CNS receive nutrients
from the cerebrospinal fluid
what is the largest part of the human brain
the cerebrum
