Topic 5 - Nervous system Flashcards
What is the nervous system?
- It’s for cell communication and control
- has 2 systems = peripheral and central systems
What are the things in each of the systems?
- Central = brain and spinal cord
- Peripheral = neurons leaving and entering organs (excludes brain)
What is the purpose of the CNS?
To integrate information and determine a response
What is the purpose of the PNS?
To pass information from the CNS to the rest of the body or vice versa
What are the 3 types of neurons in the PNS?
- Afferent neurons = transmit info to CNS (e.g sensory)
- Efferent neurons = transmit info from CNS (somatic/autonomic - sympathetic or parasympathetic)
- Enteric neurons = part of nervous system in GUT ONLY
What do neurons do?
transmit electrical signals & communicate excitability via release of neurotransmitters across synapse (small gap)
What are glial cells + examples?
Glial cells = support cells that provide appropriate environment for neuronal activity as neurons are weak and easily damaged
E.g = Schwan cells, astrocytes, Oligodendrocytes, Microglia & Ependymal cells
Where are all the types of Glial cells found (which of the 2 systems)?
CNS = Oligodendrocytes, Microglia, Astrocytes & Ependymal cells
PNS = Schwan cells (secrete neurotrophic factors also) & Satellite cells (support cell bodies)
What do Schwan cells & Oligodendrocytes do?
make myelin that wraps around axons of neurons & facilitate transmission of electrical activity
What do astrocytes do (4)?
- have many branches & help form blood-brain barrier (protect CNS)
- secrete neuotrophic factors -> support health & function of neurons
- Clean up neuronal microenvironment (neurons are very active & messy)
- Contact with neurons & blood vessels to transfer nutrients b/w them
What do Microglia do?
They’re immune cells acting as CNS scavengers - remove foreign invaders & damaged cells (considered resident macrophages of brain/spinal cord
What do Ependymal cells do?
type of epithelial cells; create selectively permeable barriers b/w compartments.
*also thought to be source of neuronal stem cells that replace dead/damaged neurons
What are some parts of a neuron?
- Dendrites = receive information - many to increase SA
- Axons = carry outgoing information& transmit electrical signals to axon terminal
- Have dramatically expanded RER’s & extensive microtubule network
*Axons hillock = point where action potential is initiated
Draw a neuron!!
*add photo
What does myelin do for a neuron?
It increases the conduction of nerve impulses
