The Nervous System - C6 Flashcards
What do these types of receptors respond to?
Chemoreceptors, Mechanoreceptors, Thermoreceptors, Photoreceptors, Baroreceptors, Osmoreceptors, Proprioceptors, Nocirecptors.
Chemical, mechanical, temperature, light, pressure, osmolarity of fluid, sense of position, noxious stimuli
What functions do neurons (nerve cells) carry out?
Moving muscles (motor neurons), forming memories and regulating behavior
What do dendrites do?
Receive input from other neurons
What is the function of the cell body?
Performs cellular functions ( protein production, metabolism)
What is the function of the axon?
Carries electrical signals to terminals
What is the function of the axon terminal?
Release neurotransmitters into the synapse
What is the function of a myelin sheath
Made of Schwann cells wrapped around axon to insulate the electrochemical so it can travel faster (Multiple Sclerosis damages myelin sheath)
What are the three types of neurons?
Motor (controlling muscles or glands)
Interneurons (processing and transmitting information coming into central nervous system or initiating actions), sensory neurons (transmit information to enable the senses)
What do dendrites do?
Receive input from other neurons
What is the function of the axon?
Carries electrical signals to axon terminals
What is the function of axon terminals?
To release neurotransmitters
What is the myelin sheath?
Made of Schwann cells wrapped around the axon to insulate the electrochemical so it can travel faster
What are the three types of neurons?
Sensory (Afferent), Motor (Efferent) and Interneurons
What are afferent neurons?
Detectors of change in the internal and external environment
What are efferent neurons?
Detectors involved in controlling muscles or glands
What are interneurons?
For processing and transmitting information coming into the central nervous system or initiating actions
Outline the process of a nerve impulse being created
- Potassium is inside the cell, and sodium is outside (inside = -, outside = +)
- If the channel protein for sodium becomes triggered, it will open and sodium floods into the cell and the charge becomes more positive
(note: if trigger is strong enough, nearby sodium channels open within cell, creating a chain reaction) - Then potassium pumps push the potassium ions back into the cell a little too much, making the cell overcompensate, going to around -100 (resting potential is -70)
- Ion pumps fine tune this process and add back in the right amount of sodium to bring the charge back to resting -70
What is the resting potential of a nerve cell?
-70mV
Define action potential
How information travels in nervous systems - it is the rapid, brief reversal of membrane potential charges in and outside the cell. It is an all or nothing event.
Where does action potential initiate?
At the axon hillcock
What does the axon hillcock contain?
A high concentration of voltage gate sodium ion channels
What is the action potential threshold?
When voltage gated sodium channels open. A stimulus from a sensory neuron causes target neuron to depolarize. If the threshold of excitation is reached, all of the sodium channels open and the membrane depolarizes. The influx of sodium into the cell through these channels is the beginning of action potential
Is potassium or sodium inside a nerve cell in a high concentration before action potential
Potassium
Can action potential travel faster in myelinated or unmyelinated neurons? Why?
Myelinated, because the signal can jump between the nodes of Ranvier via saltatory conduction - does not need to be reinitiated constantly, like a non-myelinated sheath does
What is a synapse?
Where one nerve cell meets another (the axon terminal of ones meets the dendrites of another)
How does an electrical signal travel across a synapse?
The electrical signal is converted into a chemical signal using neurotransmitters, and the chemical signal jumps the gap and is picked up by the neighboring neurons’ dendrites
