Nervous Tissue Flashcards
(22 cards)
What is the CNS?
Central nervous system: Brain, spinal cord and optic nerve
What is the PNS?
Peripheral nervous system - all tissue outside of the CNS. Sends sensory info to the CNS
The nervous system helps to:
Maintain homeostasis, initiate voluntary movement, responsible for behaviour, perception and memory
What are the three activities of the NS, and what are their functions?
Sensory: (detection of external environment sent to CNS)
Integrative: (Analysis of information)
Motor: (stimulation of effectors e.g muscles and glands) through the PNS
What are neuroglia?
Small supportive cells to neurons, conscious and unconscious control
What are the features of neurons?
Short, have branched dendrites
What is the function of neurons?
Convey nerve impulses from a single axon
What are dendrites?
Receiving/input part of the neuron
Why do neurons die rapidly without CO2?
Because they have a high metabolic rate
What is the function of the axon?
Carries nerve impulses away from the neuron (output)
What is a multipolar neuron?
A neuron with 2 or more dendrites and a single axon
What is a bipolar neuron?
Neurons with one dendrite. Can branch at the tip but not at the cell body. They are rare and small. Has one axon leaving the neuron
What are bipolar neurons involved in?
Special senses (sight, smell etc)
What are unipolar neurons?
Neurons where the axons and dendrites are continuous (all in one place). Most sensory nerves are unipolar and they are very long
What are anaxonic neurons?
Neurons found in brain and special sense organs, very rare
How do neuroglia communicate?
By chemical means
How do neutrons receive their nutrient supply?
Neuroglia supply it
There are 2 classifications of neuroglia in the CNS, what are they?
Astrocytes and Oligodendrocytes
What shape are astrocytes?
Star-shaped
What is the function of astrocytes?
Support (due to microfilaments) and help repair (scars)
How do astrocytes communicate with neurons?
Via gilo transmitters e.g glutamate
What do astrocytes maintain?
Blood-brain barrier (wall of defence between CNS and outside world) e.g pericyte, if substances want to exit the capillary they must pass through astrocytes (permeability control)
