Central Nervous System (CNS)

Flashcards about the Central Nervous System

CENTRAL NERVOUS SYSTEM

The Central Nervous System (CNS), which acts as the integrating center

Somatic motor:

Efferent neurons that project to the skeletal muscle of the body wall and limbs and control posture and movement

Autonomic:

Efferent neurons that innervate the smooth muscle of all the organs of the body (gut, glands, lungs, kidney, blood vessels etc) and cardiac muscle of the heart

Afferent

Sensory neurons that carry information to the CNS from sensory receptors in the peripheral organs

Synapse

Region of contact between two neurons or a neuron and muscle

Presynaptic neuron

Delivers a signal to the synapse

Postsynaptic neuron

Receives the signal

Voltage-gated channels

Open and close in response to membrane potential changes. Selective for particular ions.

Ligand-gated channels

Open and close in response to binding of ligands such as neurotransmitters to the extracellular side of the channel proteins.

Mechanically-gated channels

Open and close in response to physical forces such as vibration, stretch etc.

EQUILIBRIUM POTENTIAL

The potential, for any ion, at which there is no net flux of that ion across the membrane because the chemical and electrical forces that tend to move the ion exactly balance

RESTING MEMBRANE POTENTIAL

Membrane potential of excitable cells (e.g. neurons) at rest. An equilibrium state in which there is no net flux of any ions across the cell membrane. Resting membrane potential is similar (but not identical) to the K+ equilibrium potential because at rest cells are much more permeable to K+ than to other ions.

SALTATORY CONDUCTION

Saltatory conduction occurs along myelinated axons

White matter

Areas of CNS that contain a high number of myelinated axons

Grey matter

Areas of CNS that contain a high number of cell bodies, dendrites and unmyelinated axons

Meninges

Protective membranes between the bone and nervous tissue

Blood-brain barrier

Functional barrier between blood and brain interstitial fluid