The Structure And Function Of The Nervous System Flashcards
Nervous system
Complex network of 10^11 cells
- specializes for reception, transmission, processing and generation of information
Two main divisions of nervous system
1) CNS - central nervous system
—> brain and spinal cord
2) PNS - peripheral nervous system
—> sensory & motor nerve fibres that extend from the CNS to other areas of the body
What is the nervous system made up of?
Neurons and supporting neuroglia/ glial cells
Neuron consists of:
- Cell body
- Dendrites
- Axon
- Synaptic terminals
Neuron cell bodies often aggregate in:
1) Grey matter of CNS
- Ganglia or Nuclei [compact groups]
- laminae [sheets]
2) PNS
- specialized ganglia
Nerve fibres consist of:
- Dendrites or axons [cytoplasmic processes extending from the cell body]
- Schwann cells [neurilemma and surrounding endoneurial sheath]
Where are nerve fibres found?
- white matter of CNS
- sling peripheral nerve tracts
Flow diagram of the passage of a nerve impulse from the taste bud to the areas of the brain in which taste is perceived:
- TASTE BUD
- MICROVILLI ON RECEPTOR CELLS
- AFFERENT SENSORY NERVE FIBRE
- MEDULLA
- THALAMUS
- PRIMARY GUSTATORY CORTEX
Structure of grey matter
- neuron cell bodies
- dendrites
- unmyelinated axons
- glia
- synapses and capillaries
Function of grey matter
- Connects CNS to other parts of the body
- Point at which axon receives impulses from other sensory neurons
- Motor neurons responsible for muscle contractions
- Glial cells provide support, nourishment and structure to nerve cells
Structure of white matter
- longe range myelinated axons
- dendrites
Function of white matter
- Connects grey matter areas and carries impulses between them
- Point at which axons receive impulses
Peripheral nerve structure
- afferent neurons
- efferent neurons
- cell bodies
- dendrites
- axons
- Schwann cells
- myelin sheath
- axon hillock
Peripheral nerve function
- Sensory nerves that bring impulses towards CNS
- Motor neurons carrying impulses away from CNS to muscles
- Point at which axons receive impulses from sensory neurons
- Schwann cells are specialized cells that make myelin sheath
- Myelin sheath is a layer that provides protection, insulation and a speeds transmission of signals
AFFERENT neuron
A neuron conducting impulses to the brain or spinal cord
- carries nerve impulses from receptors towards the CNS
Axon
Long, thread-like part of nerve cell along which impulses are conducted from the cell body to other cells
Axon (nerve) terminal
Enlarged, club-shaped endings in which axons make synaptic contact with other nerve cells or effector cells
Axon hillock
Specialized part of the cell body of a neuron that connects to the axon
- tapery region between a neuron’s cell body and it’s axon