Human Nervous System Flashcards
Stimulus
Changes in the external or internal environment
Receptor
Detect stimuli. Often part of sense organs. Contain receptor proteins in the cell membrane
Coordinator
The network of interneurones connecting sensory and motor neurones
Effector
Cause a response
Response
Movement aiding in survival
Exocrine
Secreting liquids to outside the body
Endocrine
Secreting hormones into the bloodstream
Neurone
Nerve cells, composed of a cell body, dendrons, dendrites, axons and synapses
Dendrons
Carry impulses towards cell body
Dendrites
Connect to other neurones
Axons
Carry impulses away from cell body
Synapse
Responsible for passing impulses between neurones
Nerve
Separate bundles of several thousand axons
Schwann Cells
Main component in the Myelin Sheath, wrapped in a spiral around axons
Myelin Sheath
Protective lipid layer, provides physical protection and electrical insulation
Sensory Neurones
Long dendrons, transmit impulses from sensory receptors all over the body
Effector Neurones
Also called motor neurones, long axons transmitting impulses from CNS to effectors all over the body
Inter Neurones
Also called connector/relay neurones, much smaller with many interconnections, make up the CNS and 99.9% of all neurones
Impulse
Simple on/off instructions
Membrane Potential
Always negative within cell, maintained by protein pump Na+K+ATPase moving sodium ions out/potassium ions into the cell, and sodium/potassium ion channels leaking ions down the concentration gradient
