Lecture 16: Cells and Organisation of the Nervous System Flashcards
Give an example of integration in terms of food.
- Am I hungry?
- Do I want that kind of food?
- Do I want that much food?
Give an example of coordination in terms of food.
Preparation for eating, cravings for different foods, etc.
Give an example of response in terms of food.
Ordering food, action.
What is the CNS?
Central Nervous System
What is the PNS?
Peripheral Nervous System
What does the CNS consist of?
The CNS consists of the brain and spinal cord.
What does the PNS consist of?
All peripheral nerves.
What are the two main types of cells in the nervous system?
Glia and neurons.
What 4 types of glia are in the CNS and what are their purposes?
Astrocytes: supply nutrients to neurons, ensheath blood capillaries, transmit information.
Microglia: Immune cells of CNS, engulf micro-organisms and debris.
Ependdymal Cells: Line the fluid filled spaces of brain and spinal cord, have cilia to circulate CSF.
Oligodendrocytes: Support nerve fibres and ensheath them inn myelin.
What is a Schwann cell?
The glia of the PNS, supports peripheral nerve fibres, ensheathes them in myelin (like oligodendrocytes). “Swiss roll”
What produces the myelin sheath?
Oligodendrocytes in the CNS and Schwann cells ion the PNS.
What is the purpose of the myelin sheath?
To increase the conduction velocity.
What are the 4 parts of a neuron, and what are their purposes?
Dendrites: Receive input
Cell Body: Contains nucleus and organelles, sums input.
Axon: Carries electrical impulses, may or may not be myelinated.
Axon terminal: End of axon, releases neurotransmitters.
What are the Nodes of Ranvier?
Gaps between the myelin on a myelinated axon, which allow potential to be regenerated, allowing for increase in speed.
What is an example of the results of demylination?
Multiple Sclerosis.
What is the structure and function of the summation zone on a nueron?
Axon hillock, decision to further transmit signal or not. If many inputs, more likely.
What is the structure and function of the input zone on a nueron?
Dendrites and cell body, receives CHEMICAL signals from other neurons’ axons.
What is the structure and function of the conduction zone on a nueron?
Axon, often very long, carries ELECTIRAL signals between brain areas, to and from spinal cord or to and from PNS sensory receptors.
What is the structure and function of the output zone on a nueron?
Axon terminals, in contact with the input zone of other neurons, releases CHEMICAL neurotransmitter, passing info on.
What are the 3 morphological types of neurons?
Multipolar: multiple processes; multiple dendrites and single axon.
Bipolar: 2 processes; a dendrite and an axon.
[Pseudo]unipolar: Only 1 process emanates from cell body, which branches into dendrite and axon.
What happens at a synapse?
Electrical impulse is converted to a chemical neurotransmitter release which is sensed and converted to another electrical impulse.
What do synaptic vesicles contain?
Neurotransmitter.
What is the synaptic cleft?
The gap between axon and dendrite at the synapse.
What are the 3 types of synapses?
Axodendritic, Axosynaptic, Axoaxonic.
What is the most common type of synapse in the CNS?
Axodendritic.
What is information going into the brain called?
Afferent, ascending.
What is information going out of the brain called?
Efferent, descending.
What is the 4 step flow of information in the nervous system?
Afferent info from sensory neuron (PNS) ➡ Integration (CNS) ➡ Coordination (CNS) ➡ Efferent info to muscles and glands, response (PNS).
What is a tract?
A bundle of axons. CNS
What is grey matter?
Group of cell bodies in the cerebral cortex. CNS
What is white matter?
Bundle of axons in cerebral cortex. CNS
What is nuclei in the CNS?
A group of cell bodies
What are ganglion?
A group of cell bodies in the PNS
What is a bundle of axons called in the PNS?
Nerve
The myelin sheath in the CNS is made of what?
Oligodendrocytes.
The part of neurotransmission that is carried out through a chemical signal is called what?
Synapse
The part of a neuron that makes the decision about whether to propogate an action potential in response to inputs is called what?
Axon hillock.
