Nerve Cells and Nerve Impulses Flashcards
(34 cards)
nervous tissue is found in
most species of multicellular animals
some single celled organisms have
electrical information transmission
For example, a jellyfish has
diffuse nerve nets and no central ner
what is a bilaterian
an animal with a bilateral symmetry
what is cephalisation
nervous tissue concentrated toward one end of an organism
What are the two components of NS
central nervous system and peripheral nervous system
central nervous sytem has
the brain and the spinal cord
peripheral nervous system has
NS other than brain / spinal cord eg nerves from sense organs to the central nervous system
nervous system microstructure consists of
nerve cells (neurone) and gilia cells
what is meant by “neurone are separable”
that there is a small gap between the tips of one neuron’s fibres and the next neuron –> the nervous system consists of individual neurons
what are the two main types of cells in the NS
neurons/ nerve cells and glial cells
Describe Glial cells
smaller than neurons and exceed neurons in numbers
most common glial
oligodendrocytes
Glia functions
are essentially support cells in NS and have many vital roles
1 . they provide structure ie surround neurons and hold them in place
2. Insulate nerve cells with myelin sheaths ( oligodendrocytes in the CNS)
Functions of astrocytes ( glia)
supply nutrients and oxygen to neuron
Further glia functions
- removal of dead neuronal tissue & immune defence of the CNS
- during development, glial cells provide scaffolds for neurons to migrate to their final destinations
- modulate neurotransmission in the synapses
What is Multiple Sclerosis (MS )
neurological condition common symptoms are vision problems, fatigue, difficulties with walking
what causes MS
demyelination of axons in the brain and spinal cord
what can demyelinated axon cause
can cause MS
define neurons
cells in the nervous system that specialise in performing information-processing tasks
what does each neuron consist of
1 body cell –> soma
2 fibres –> dendrites and an axon
Structure of Soma which is cell body
- contains nucleus and machinery
cell nucleus - contains the cells genetic material organised as DNA molecules
cell machinery : - mitochondria for metabolic activity
- ribosomes - protein production
- endoplasmic reticulum - transports protein to other locations
dendrites are
branching fibres receiving info from other neurons
where are synapses located on dendrites
on the surface
