nervous tissue unit 1

nervous tissue

-the central nervous sytstem consists of the brain and the spinal cords

- its made up of billions of myilated nerve cells and longer myelated axons

- nervouse tissue is made up of nerve cells called neurones

neurones are cells that recieve  nerve impulses or action potentials across there membrane and pass them onto the next neurone

action potentail

Action potentials are an all or nothing response because once the threshold is reached each action potential always depolarises the axon to the same voltage by voltage-gated sodium channels.

-When the neurone receives an impulse from sensory receptors, sodium channels on the dendrites open, leading to the movement of Na+ ions into the cell causing depolarisation.

-If this depolarisation reaches the threshold potential it activates voltage-gated sodium channels causing an action…