L16 Cells and organisation of the nervous system

Flashcards covering the cells and organization of the nervous system, including neurons, glia, and synapses.

Integrating and coordinating roles of the nervous system

Senses the environment and produces an appropriate response.

Basic anatomical organisation of the nervous system

Brain, spinal cord, peripheral nerves & ganglia

Two general cell classes of the nervous system

Neurons and Glia

Neurons

Cells specialised for transmission of information.

Glia

Support for neurons; Five basic types (4 in CNS, 1 in PNS); Each type has a specific function

Cell body (of a neuron)

Contains nucleus & organelles; Sums input

Axon

Carries electrical impulses; May or may not be myelinated

Axon terminal(s)

End (terminus) of the axon; Neurotransmitter release

Dendrites

Receive input; Send info to cell body

Ganglion

Group of cell bodies in the PNS

Nerve

Bundle of axons in the PNS

Grey matter

Group of cell bodies in cerebral cortex or spinal cord

White matter

Bundle of axons in cerebral cortex or spinal cord

Input zone of a neuron

Dendrites and cell body; Receives chemical signals from other neurons

Summation zone of a neuron

Axon hillock; Summation of inputs

Conduction zone of a neuron

Axon; Carry electrical signals between brain areas, to and from spinal cord, or from peripheral sensory receptors and to effector cells

Output zone of a neuron

Axon terminals; Contact with input zone of other neurons or effectors; Release of neurotransmitter = chemical signal

Multipolar neuron

Multiple processes emanate from the cell body.

Bipolar neuron

Two processes emanate from the cell body.

Unipolar neuron

One process emanates from the cell body, then branches into dendrite and axon.

Anaxonic neuron

No distinct axon; All processes look alike.

Astrocytes

Supply nutrients to neurons; Cover blood capillaries; Injury response

Ependymal cells

Line fluid-filled spaces of brain and spinal cord; Have cilia to circulate CSF

Oligodendrocytes

Support nerve fibres; Ensheath them with myelin

Microglia

Immune cells of the CNS; Engulf microorganisms and debris

Schwann cells

Support peripheral nerve fibres; Ensheath them with myelin

Myelin sheath

Lipid (fat) wrapped around axon; Increases conduction velocity

Nodes of Ranvier

Gaps between myelin; Increase conduction velocity

Synapse

Communication between neurons occurs through a junction.

Pre-synaptic neuron

Releases neurotransmitter (chemical signal) from axon terminal; Contains synaptic vesicles

Post-synaptic neuron

Contains receptors for neurotransmitter

Afferent

Information that goes INTO the brain

Efferent

Response that comes OUT OF the brain