The Structure And Function Of The Nervous System Flashcards
(45 cards)
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
Cell body
The soma, the part of a neuron containing the nucleus but not incorporating the axon and dendrites
Central canal (spinal cord)
The cerebrospinal fluid filled space that runs longitudinally through the lengthy of the entire spinal cord
Dendrites
Short, branches extension of a nerve cell along which impulses received from other cells at synapses are transmitted to the cell body
Dorsal
On or relating to the upper side of back of animal, plant or organ
Dorsal (posterior) horn
A longitudinal subdivision of grey matter in the dorsal part of each lateral half of the spinal cord that received several types of sensory info from the body
Dorsal fissure
A kind narrow opening
- any cleft or grove, especially a deep fold in the cerebral cortex involving its entire thickness