L-16 Flashcards
What are the two divisions of the nervous system?
CNS + PNS
What is the CNS composed of?
The brain + spinal chord
What is the PNS composed of?
The peripheral nerves and ganglia
What are the two broad cell types of the nervous system?
Neurons and glia
What are the 4 main structural components of the Neuron?
- Dendrites
- Cell body
- Axon
- Axon Terminals
What do dendrites do?
Recieves information and sends to cell body
What is the function of the cell body?
Contains the nucleus + organelles and sums input information
What is the function of the axon?
Carries action potentials
What is the function of the Axon terminals?
Release the neurotransmitter in a synapse to communicate with other neurons
What are the 4 Morphological types of neurons?
- Unipolar
- Bipolar
- Multipolar
- Anaxonic
What makes a neuron unipolar?
Cell body lies to the side of main axon ( most PNS sensory neurons are unipolar)
What makes a neuron bipolar?
Two distinct processes branching off cell body ( one dendritic and one axonic)
What makes a neuron Multipolar?
Multiple dendrites branching off cell body with a singular axon (most common type found in CNS)
What makes a neuron anaxonic?
Poorly understood, located within brain and sensory organs, don’t have a clear axon
What is the input zone composed of and what does it do?
- dendrites +cell body
- receives chemical signals
What is the summation zone composed of and what is its function?
- Axon Hillock
- summation of inputs
What is the conduction zone composed of and what is its function?
- Axon
- Carrie’s electrical impulses
What is the output zone composed of and what is its purpose?
- Axon terminals
- release of neurotransmitter
How many basic types of Glial cells are there? Where are they found in the nervous system?
- 5
- 4 in CNS
- 1 in PNS
What are the 4 types of CNS Glia called?
- Astrocytes
- Microglia
- Ependymal cells
- Oligodendrocytes
What is the function of Astrocytes? (4)
- Supply nutrients to neurons
- ensheath blood capillaries
- injury response
- controls chemical environment around neurons
What is the functions of Microglia? (3)
- Act as immune cells of CNS
- engulf microorganisms and debris
- respond to injured neurons and protects them from pathogens
What are the functions of Ependymal cells? (2)
- Line fluid filled spaces of brain and spinal chord
- cilia aid in circulation of CSF
What is the function of Oligodendrocytes?
- Form myelin sheath around CNS neurons
What is the name of PNS Glia?
Schwann Cells
What is the function of Schwann Cells?
- form myelin sheath for PNS axons
What is a group of cell bodies in the CNS called?
Nucleus
What is a group of axons in the CNS called?
A Tract
What is a group of cell bodies in the cerebral cortex or spinal chord called?
Grey matter
What is a bundle of axons in the cerebral cortex or the spinal chord called?
White matter
What is a group of cell bodies in the PNS called?
A ganglion
What is a bundle of axons in the PNS called?
A nerve
What is a myelin sheath?
Lipid ( fat) wrapped around an axon that acts as an insulator and increases conduction velocity.
What are gaps in the myelin sheath / between Schwann cells called?
Nodes of Ranvier
What is a synapse?
The junction between neurons that allows for communication between them using neurotransmitters
How does communication occur at a synapse ( broadly)
An action potential stimulates a chemical release from the axon terminals of the pre-synaptic neuron that can then bind to receptors in the dendrites of the postsynaptic neuron.
Which direction is afferent information going?
Towards the brain
Which direction is efferent information going?
Away from the brain
