Nervous system Flashcards
What 2 structures are a part of the CNS?
Brain and spinal cord
What makes up the PNS?
peripheral nerves and ganglia
What 2 cell classes make up the nervous system (CNS & PNS)?
Neurons and glia
What is the function of neurons?
transmission of information
What is the function of glia?
Provide support for neurons
How many types of glia is there? How many in each division of the nervous system?
5 basic types (4 in CNS, 1 in PNS)
Name 2 functions of dendrites
- Receive input from other cells
- Collect info and send to cell body
Name 2 functions of the cell body
- Contains nucleus and organelles
- Sums input from dendrites
Name 2 functions/features of the axon
- Carries electrical impulses (action potential)
- May or may not have myelin sheath
Name 2 functions of the axon terminal
- End of the axon
- Releases neurotransmitters
In the CNS, what is a group of cell bodies generally called?
A nucleus
In the CNS, what is a bundle of axons generally called?
A track
In the CNS, what is a group of cell bodies called on exception? What is this exception?
Grey matter
- in cerebral cortex and spinal cord
In the CNS, what is a bundle of axons called on exception? What is this exception?
White matter
- in cerebral cortex and spinal cord
In the PNS, what is a group of cell bodies called?
Ganglion
In the PNS, what is a bundle of axons called?
A nerve
What event occurs at the axon hillock?
Summation of inputs and initiation of AP
Name the 4 morphological types/shapes of neurons
Multipolar, bipolar, unipolar, anaxonic
Name the 4 types of glia in the CNS
Astrocytes, microglia, ependymal cells, oligodendrocytes
Name the type glial cell found in the PNS
Schwann cells
What are 3 functions of astrocytes?
- Supply nutrients to neurons
- Ensheath blood capillaries to control what nutrients go in/out of neuron
- Injury response
What are 2 functions of microglia?
- Start immune response if needed (these are the immune cells of the CNS)
- Engulf microorganisms/debris
Name 2 functions of ependymal cells
- Line fluid filled spaces of brain/spinal cord
* Have cilia that beat rhythmically in a particular direction to circulate cerebral spinal fluid
Name 2 functions of oligodendrocytes
- Support nerve fibres (axons)
* Make myelin sheath
Where are Schwann cells found
Ensheathing most neurons in the PNS, lined up along axon
What is the function of Schwann cells? (brief)
To ensheath PNS neuron axons with myelin by wrapping in many layers of plasma membrane (lipid = fat)
What 2 types of cells provide myelin sheath?
Oligodendrocytes (CNS) and Schwann cells (PNS)
What is the myelin sheath?
Layers of lipid wrapped around axon
What are the gaps between schwann cells called?
Nodes of Ranvier
What is the function of the Nodes of Ranvier?
To increase conductivity velocity
What is a synapse?
The space between output zone of one cell and input zone of another
Why aren’t neurons electrically coupled?
Because chemical transmission
= allows flexibility
= can transmit more and different signals via the different neurotransmitters and receptors
Which direction does afferent info flow in?
Ascending: information into the brain (e.g. sensory info in)
What direction does efferent info flow in?
Descending: response that comes out of brain (e.g. motor response)
