Nervous System, Senses and Skeleton Flashcards
Central nervous system
Consists of the brain and spinal chord
Peripheral nervous system
Consists of a vast network of nerves that carry messages between the CNS and the rest of the body
Neuron
A nerve cell
Sensory neuron
Brings messages from a sense organ to the CNS
Motor neuron
Takes a message from the CNS to a muscle of gland
Receptor
A cell or group of cells which detect a stimulus
Nerve endings
Connect sensory neutrons to receptor cells or sense organs
Dendrites
Fibres that carry impulses towards the cell body
Axons
Fibres that carry impulses away from the cell body
Schwann cells
Produce myelin sheath
Myelin sheath
A fat rich layer that insulated impulses
Cell body
Contains a nucleus and cell organelles
Axon terminals
Branches formed from the splitting of an axon which carry an impulse to a swelling called a neurotransmitter swelling
Neurotransmitter swellings
Release chemicals that carry the impulse from one nerve cell to another. Chemicals are called neurotransmitters
Inter neuron
Carries information between sensory and motor neurons
Threshold
The minimum stimulus necessary to cause an impulse to be carried in a neuron
Refractory period
A short time span after a neuron has carried an impulse during which a stimulus fails to cause a response
Synapse
A region where two neuronscome into close contact
Synaptic cleft
The tiny gap between the two neurons at a synapse
Reflex action
An automatic involuntary unthinking response to a stimulus
Reflex arc
The pathway taken by a nerve in a reflex action
Axial skeleton
Consists of the ribs, skull, spine and sternum
Pelvic girdle
Composed of two halves of the hip joined to the sacrum
Appendicular skeleton
Composed of the pectoral girdle the pelvic girdle and the limbs
