structure and functions of cells of the nervous system Flashcards
reading 2
contrast the locations of the central and peripheral nervous systems:
- Central nervous system= the brain and spinal cord.
- Peripheral nervous system= nerves and the rest of the body.
- Relies on the use of sensory neurons (detects changes in environment and sends info to the CNS) and motor neurons (contractions of muscles/ secretion of glands) and interneurons (located entirely within the CNS)
what Is the cell body of a neuron?
(soma)= contains the nucleus of the neuron cell and can vary in shape.
what are dendrites?
receive neural messages that are transmitted across the synapse from the terminal button to the cell membrane.
describe the function of the axon:
the outer surface carries information from the cell body to the terminal buttons. Carries the action potential which requires a chemical and electrical impulse.
○ Action potential= a brief electrical and chemical event that that starts at the end of the axon (near the cell body) and travels towards the terminal buttons. (outside of an axon)
what is axoplasmic transport and what are the different types?
Axoplasmic transport= propels substances that run along “tracks” inside of the axon.
- Anterograde axoplasmic transport= movement from cell body to terminal buttons.
- Retrograde axoplasmic transport= movement from terminal buttons to cell body.
what is the function of the myelin sheath?
fatty substance that provides insulation for the electrical substance.
what is the function of the terminal buttons?
the bud at the end of an axon branch which forms synapses with another neuron- sends information to that neuron.
explain neural communication in withdrawal reflexes:
If an individual picks up a hot object that causes pain in their hands, the motor neuron will send an impulse through its axon from the terminal buttons. However, the individual is able to override the pain in order to place the hot object on a table. This is because ethe brain sends an impulse called the inhibitory neuron. This is when an axon from the brain reaches the spinal cord where its terminal buttons form synapses with an inhibitory interneuron, which releases and inhibitory neurotransmitter to decrease the motor neuron activity and prevent the individual rom dropping the hot object.
what is the resting potential of a neuron?
when the neuron is at rest and not involved in communicating with other neurons, remains at approx. -70mV.
what is hyperpolarisation?
when the inside of the axon is more negative in comparison to the outside.Makes it harder for the cell to send a message to the postsynaptic cell.
what is depolarisation of a neuron?
when the inside of the axon is more positive in comparison to the outside. Makes it much more likely that the neuron will send its message to the postsynaptic cell.
what is the action potential in a neuron?
a burst of rapid depolarisation followed by hyperpolarisation which begins to spread along the cell membrane starting at the point the cell body (soma) meets the axon and moves towards the terminal buttons, triggering them to release the neurotransmitter into the synapse.
what is diffusion?
movement of molecules from a place of high concentration to low concertation.
what is electrostatic force?
forces exerted by the attraction or repulsion of molecules.
what is intracellular fluid?
(internal) organic anions, potassium, sodium and chloride ions.