Cells of the Nervous System Flashcards
What are the basic parts of a neuron cell?
Soma (cell body): nucleus and metabolic processes occur here
Dendrites: receive information from other neurons
Axon: carries information from soma to terminal buttons by an electrical current (action potential)
Myelin sheath: surrounds axons in order to increase the conduction velocity of the electrical current (message)
Nodes of Ranvier: gaps in between myelin
Terminal buttons: release neurotransmitters (chemical messengers) to other axons
What type of neuron is primarily found in the vision and auditory sensory systems?
Bipolar neuron
What are the supporting cells in the nervous system and what are their functions?
Glia Cells: support the structure of the Central Nervous system
Astrocytes: contact between neurons and blood vessels, they can absorb glucose that is trying to enter the brain
Oligodendrocytes: helps in the process of laying down myelin sheath around axons in the CNS
Schwann Cells: helps in the process of laying down myelin sheath around axons in the PNS
What is the Blood Brain Barrier and what is its function?
Capillaries in the brain that screen chemicals from entering into the brain. The capillaries are so small and dense that it makes it harder for certain chemicals and cells from entering the brain.
What is the difference between depolarization and hyperpolarization?
Depolarization is the occurrence of a DECREASE in membrane potential where the potential is moving closer to zero polarity
Hyperpolarization is the occurrence of an INCREASE in membrane potential (larger difference, moving farther away from zero)
What is an action potential?
a rapid reversal of membrane polarity
What factors maintain resting potential (-70mV)?
Diffusion: ions move from a high concentration to a low concentration, a passive force
Electrostatic pressure: opposite charges attract and like charges repel one another
Differential membrane permeability: K+ and Cl- pass through membrane more readily than Na+ or negatively charged proteins
Sodium-Potassium pumps: proteins that force Na+ out of neuron and K+ into the neuron – will go against diffusion and electrostatic pressure
What happens when the membrane potential reaches the threshold of excitation (-65mV to -55mV)?
Action potential is activated.
Action potential will open voltage-dependent ion channels like the sodium-potassium pump. Action potential conduction follows the all-or-none law where the external stimulus will determine if the action potential will help reach the resting potential.
What is a synapse and what is its function?
