the role of the nervous system Flashcards
what are the three basic functions of the nervous system?
- sensory changes with sensory receptors
- interpreting and remembering those changes
- reaction to those changes with effectors
what does the central nervous system control
brain and spinal cord
what does the peripheral nervous system control
- spinal nerves
- cranial nerves
3 main parts of the neuron
- cell body
- dendrites
- axon
what do neurons conduct and at what speed
- conduct electrical impulses
- speed from 0.5 to 130 m/s
what do neurons connect
they connect receptors to the CNS and also connect one part of the nervous system to another i.e. brain and spinal cord
where can neurons carry impulses from
from nervous system to effector organs such as muscles and glands
3 basic neuron types
- bipolar
- unipolar
- multipolar
what are neuroglia
- 10-15x more numerous than neurons
- supportive tissue
- half volume of CNS
- capable of rapid division
- non-excitable
- holds CNS together
primary function of neuroglia
- support the neurosn
- term means ‘nerve glue’
4 cell types of neuroglia in CNS
- astrocytes
- oligodendrocytes
- microglia
- ependymal
(glial cells)
2 cell types in PNS
- schwann
- satellite cells
function of glial cells (microglia)
- small cells found near blood vessels
- clean up debris
- transport nutrients to neurons
- promote synaptic connections
functions of glial cells (oligodendrocytes)
- most common cell type
- close to neuron
- forms myelin sheath in CNS (similar to shwann cells)
functions of glial cells (ependymal)
- produce cerebrospinal fluid (CSF)
what is myelin
fatty white substance that forms a sheath around axon of nerve cells
function of myelin
- essential for functioning of nervous system
- forms electrical insulating layer
- main function to INCREASE SPEED
what does myelination produce
myelin sheath
when does myelination occur
during foetal development
- only minimal production occurs
what cells myelinate axons in CNS
oligodendrocytes
myelination in the CNS
- no neurolemma formed
- broad flat processes wrap around CNS axons
- cells bodies do not surround axons
- little regrowth after injury
what is demyelination
- a medical condition that involves the loss of myelin sheath surrounding the nerves
- ## associated with motor-neurone disease
what can demyelination affect and what are the symptoms
- affect speech, vision and cognitive awareness
- fatigue, difficulty to control bowel movements
white matter
myelinated processes
