Neurons Flashcards
Parts of a neuron to remember
Soma (cell body): Contains everything you expect a cell to have. Produces the neurotransmitters.
Axon hillock: Serves as a tight junctions and can generate action potential. Full of voltage gated ion channels.
Schwann cells: made of cholesterol and protein and has a lot of myelin. Insulates the axon and makes sure the impulse doesn’t escape. Only in PNS
Glial cells of PNS and CNS
Cells that support neurons
Oligodendrocytes (CNS) and Schwann Cells (PNS)
These cells comprise the myelin sheath in the axons of nerves in the CNS and PNS
Ependymal Cells (CNS)
Line spinal cord and brain ventricles
Produce spinal fluid and absorbs excess
Have neuro-regeneration properties we’re just starting to understand
Astrocytes (CNS) and Satellite Cells (ganglia) (PNS)
Both provide nourishment, structure, help with message signaling, and maintain ion balance.
Astrocytes
- one of the most abundant in brain.
- regulate blood flow in brain
- fuel neurons with glucose
- help transport neurotransmitters
- regulate electrical impulses in brain
- support endothelial cells.
Satellite Cells
- Cushion and nourish and provide structure for soma of the ganglia: sensory and motor nerves
- moderate pain response
- house enzymes and can provide glutamine and lactate to neurons.
Microglia (CNS)
Macrophages
Remove damaged nerves, DNA fragments and plaque
Assist in immune defense
Resting membrane potential and Sodium-Potassium pump ATPase
Charge is steady at -70 mV=> resting potential
- Intracellular is slightly more negative.
Electrical gradient is stable due to sodium-potassium pump.
- pumps out 3 Na+ for every 2 K+ pumped in.
- using ATP
Electrochemical Gradient
3 things affect how ions move across membrane
- permeability of membrane
- relative concentrations
- relative charge difference between sides ( ion want to move to a lower concentration of opposite charge)
Nernst Equation
The point at which one ion reaches the point of equilibrium. Charge value and osmosis value cancel each other out.
Ion conc. Outside/ion conc. Inside
Goldman- Hodgkin-Katz equation
Way of describing overall resting cell potential
Action Potential
Charge reaches the axon hillocks and goes down the axon and triggers a cascade of activity in the neuronal system.
Speed of impulse
Influenced by:
- myelination: more means faster
- diameter: greater means faster
Ganglion
Nerve to nerve synapses=>ganglions
Axon terminal
Action potential reaches the axon terminal causes voltage gated calcium channels to open and calcium enters cell
Vesicles are sensitive to calcium and they will bind to membrane and release neurotransmitters.
Monoamines
Serotonin Dopamine Melatonin Epinephrine Noraepinephrine
