Human movement and sensation - L16 Flashcards
What does our nervous system do>
Senses our environment (through sensory systmem) and provides an appropriate response to the stimulus
Maintaining homeostasis
Integration –> Co-ordination –> response
*Is the environment safe/dangerous
*Are there any challenges
What does the CNS consist of?
The brain and the spinal cord
What are the cells classes of the CNS?
Neurons and neuroglia
What does the PNS consists of?
Peripheral nerves and ganglia
What are the cells classes of the PNS?
Neurons and neuroglia
General features of neurons?
*Cells specialised in transmission of info
*4 morphological types
General features of neuroglia?
*Supports neurons and not involved in the transmission of info
*5 types - 4 in CNS, 1 in the PNS
*Each type has a specific function
What are the structural components of neurons
*Dendrites
*Cell bodies
*Axons
*Axon terminals
Dendrites
*Receives info from other neurons and passes it down to the cell body
Cell body
*Receives info, holds and integrates it
*Control centre of the cell
Axon
*Transmits info in the form of an AP - electrical impulse over a long distance
*May or may not be myelinated
Axon terminals
*End of axon
*Neurotransmitter release to another cell
How are neurons usually arranged?
In a row
In the CNS, groups of cell bodies are called?
Nucleus pl. Nuclei
*Neurons with the same function
In the CNS, bundles of axons are called?
Tracts
In the CNS, groups of cell bodies in cerebral cortex and spinal cord is called?
Grey matter
In the CNS, bundles of axons in cerebral cortex and spinal cord is called?
White matter
Groups of cell bodies in the PNS
Ganglia
bundles of axons in the PNS
Nerve
What is the input zone?
Cell body and dendrites
*Receives chem signals from other neurons
Summation zone
Axon hillock
*Where all the info gets collected and a “decision” is made
Conduction zone
Axon that can be quite long
*Carries electrical signals
Output zone
Axons terminals
*Releases neurotrans
*Contacts other neurons or effectors
Why are there different shapes for neurons?
They are specialised for different tasks
4 basic types of neurons
*Multipolar
*Bipolar
*Unipolar
*Anaxonic
Multipolar
Multiple processes (axon or dendrites) from the cell body
Bipolar
Two processes from cell body
Unipolar
One single process that then branch to form input and output zones
Anaxonic
All processes look alike and dont have a specific process (axon)
Glial cells of the CNS
*Astrocytes
*Oligodendrocytes
*Microglia
*Ependymal cells
Astrocytes
*Star shaped cells
*Supply nutrients to neurons
*Go to site of injury and help neurons to survive the injury
Ensheath blood capillaries
Microglia
*Immune cells
*Patrol and engulf microorganisms and debris
Ependymal cells
*Line fluid filled spaces of brain
*cillia move the CSF
Oligodendrocytes
*Support nerve fibres
*Manufacture myelin sheath
Glial cells in the PNS
Shwann cell
Shnwann cell
*ensheaths axon with myelin
*Plasma mem wrapped around axon
*Multiple cells around axon
*Support PNS nerves
What is myelin?
Phospholip sheath (plasma mem) around the axon
What does myelin do?
Increases conduction velocity
Gap between shwann cells
Nodes of Ranvier
What is a synapse?
Output of one neuron and an input zone of another neuron
*release of neurotrans)
Neuron before synapse
presynaptic neuron output zone
*Has synaptic vesicles that carry neurotrans
Neuron after synapse
Postsynaptic neuron (input zone)
*Receives neurotans
How does info changes as its passed?
Elecrical –> chemical –> electrical
Space between synapse?
Synaptic cleft
Info that goes into brain
Afferent (Away from body)
*Ascending
Info that goes out of brain
Efferent
*Descending
