Excitable Cells Flashcards
Excitable cells
Nerve or muscle cells that are electrically charged
Astrocytes
Specialised glial cells
Regulate the chemical content of the extracellular space by soaking up chemicals produced by the neurons
Schwann cells
Oligodendrologlial cells (provide support and function)
Specialised glial cells -> produce myelin
Provide myelination of axons -> facilitates propagation of information down neurons
Central Nervous system
Brain and spinal cord
Peripheral nervous system
Long axons radiate from CNS
Inner ages the rest of the body
Afferent axons
Sensory neurons
Take information from the periphery (skin) to the CNS
Efferent axons
Motor neurones
Convey information from the CNS to muscles
Generate muscle contraction and movement
Dorsal roots
Contain afferent axons
Come from skin to spinal cord
Ventral roots
Contain efferent axons
Spinal nerves
Contain a mixture of efferent and afferent axons - if there is damage to spinal nerves sensation and!! Movement is lost
Excitable cells are electrically charged and use electrical currents to
Sense stimuli (e.g. chemicals, pressure,touch)
Transmit information (to each other over long distances)
Do something (contract a muscle fibre, release messenger molecules like hormones or neurotransmitters)
Leak potassium channels
Are open at rest
Set the resting potential and are regulated by pH, oxygen tension and stretch
Resting membrane potential
Used to counteract the movement of potassium ions via diffusion
-> no movement by electrical current so overall n o net movement of K+
Electrophysiology
How resting potential is measured
A pulled glass electrode placed in or on a cell and measures resting potential compared with the ground reference electrode
Action potentials
Brief electrical pulses generated by excitable cells using bio electricity
