Movement and Sensation Flashcards
What are the three stages to maintain homeostasis?
Integration, coordination and response
(Am I hungry? -> cravings for type of food -> order some)
What does the CNS consist of?
Brain
Spinal Cord
(Both composed of neurons and glia)
What does the PNS consist of?
Peripheral nerves
Ganglia
(Both composed of neurons and glia)
What are the 2 general features of neurons?
- Cell specialised for transmission of information
- Four morphological types
What are the 3 general features of glia?
- Support for neurons
- Five basic types
- Each type has a specific function
What are dendrites?
Part of the neuron that receives input and sends information to cell body
What are cell bodies?
Parts of neurons that contain nucleus and organelles
Sums input - holds information received from dendrites
Group of cell bodies is a nucleus
What are axons?
Part of neurons that carry electrical impulses (action potentials)
May or may not be myelinated
Bundle of axons is a tract
What are axon terminals?
Part of the neuron at ends of the axon which release neurotransmitters (passes information to where it needs to go)
What is grey matter?
Group of cell bodies in cerebral cortex or spinal cord
What is white matter?
Bundle of axons in cerebral cortex or spinal cord
What is the input zone of a neuron?
Dendrites and cell bodies receive chemical signals from other neurons
What is the summation zone of a neuron?
Axon hillock sums inputs before action potential
What is the conduction zone in neurons?
Axons carry electrical signals between brain areas to and from spinal cord, or from peripheral sensory receptors and to effector cells
What is the output zone in neurons?
Axon terminals that contact with input zone of other neurons or effectors and release neurotransmitters
What is a multipolar neuron?
A neuron which has multiple dendrites and axons
Multiple processes emanate from the cell body
What is a bipolar neuron?
Two processes emanate from the cell body
What is a unipolar neuron?
One process emanates from the cell body, then branches into dendrite and axon
What is an anaxonic neuron?
A neuron that has no distinct axon and where all processes look alike
What are astrocytes?
They supply nutrients to neurons, ensheath blood capillaries and respond to injury
What are microglia?
Immune cells of the CNS that engulf/remove microorganisms and debris
Very tiny cells
What are ependymal cells?
Cells that line fluid filled spaces of brain and spinal cord that have cilia to circulate CSF
What are oligodendeocytes?
Cells that support nerve fibres and ensheath them with myelin
What are Schwann cells?
Cells that support peripheral nerve fibres and ensheath them with myelin (similar to oligodendrocytes)
What is a myelin sheath?
Lipid wrapped around an axon that increases conduction velocity
In CNS comes from oligodendrocytes
In PNS comes from Schwann cells
What are nodes of Ranvier?
Gaps between myelin that increase conduction velocity
How does a synapse occur ?
Axon terminal releases neurotransmitter that contains synaptic vesicles —> synaptic cleft and are synapsed —> axon hillock where they are stored for next neurotransmitter release
What does afferent mean?
Information that goes into the brain (ascending)
e.g. sensing something in the environment
What does efferent mean?
Response that comes out of the brain (descending)
e.g. Respond to something with appropriate action
