Nervous System Physiology and Glial Cells

These flashcards cover key concepts related to the phases of action potentials in neurons as well as the types and functions of glial cells in the peripheral and central nervous systems.

Resting state

Condition where Na and K channels are open, allowing ions to pass continuously, resulting in a negative current.

Depolarization phase

The phase where the neuron is stimulated, Na voltage gated channels open, Na rushes into the cell, leading to a positive membrane potential.

Repolarization phase

Phase characterized by the closing of Na voltage gated channels and opening of K voltage gated channels, resulting in K leaving the cell and making it more negative.

Hyperpolarization phase

Phase where K voltage gated channels close slowly, allowing extra K to leave the cell, causing the membrane potential to dip below resting potential.

Satellite Cells

Glial cells found in the PNS that form a protective layer around neuronal cell bodies.

Schwann Cells

PNS glial cells that form myelin sheaths around axons, increasing the velocity of action potentials.

Oligodendrocytes

CNS glial cells that form myelin sheaths, providing electrical insulation to axons.

Astrocytes

Most abundant CNS glial cells that form the blood-brain barrier and regulate molecule entry into the CNS.

Microglia

Resident immune cells in the CNS that act as phagocytes to protect the brain from infection.

Ependymal cells

CNS cells that line brain and spinal cord cavities, some of which secrete and circulate cerebrospinal fluid.