Test 1: Cells Flashcards
Purpose of cells associated with the NS
- Transduce environmental energy into electric signals (receptor neurons)
- Conduct Info into NS and process it
- Info is conducted back to effectors
Types of Neurons that conduct info into the NS and process it
- Sensory/Afferent n (PNS-> CNS)
- Motor/Efferent n (CNS-> PNS)
- Internerons (CNS->CNS)
Info from the CS is conducted back to effectors in what two ways?
Muscles and glands (exocrine and endocrine)
What are the structural units of the NS?
Cytology
How do those cells conduct and process info?
Physiology
How are these cells organized into systems?
Anatomy
Soma
Cell body; contains cell nucleus and much of the chemical machinery common to most cells
Dendrites
Receive info
Axon
Long, thin fiber that transmits signals away from the soma to other neurons or to muscles or glands
Myelin sheath
Insulating material that encases some axons to speed transmission of signals
Nodes of Ranvier
Gaps in myelin sheath that facilitate conduction of electrical impulses
Terminal arborizations
End of axon that is usually near other neurons or muscles
Terminal Buttons
Small knobs that secrete chemicals called NTs
Synapse
A junction where info is transmitted from one neuron to another
Ways neurons can be classified
- Number of axon processes
- Function
- NT used by neuron
- Effects of NT (excitatory vs inhibitory)
Membrane
- Defines boundary of cell
- Phospholipid bilayer
- Specialized proteins: receptor proteins, signal p, channel p, transport p
Steps of Protein Synthesis
Transcription and translation
Endoplasmic reticulum
system of tubes for transport of materials within cytoplasm
Golgi apparatus
packages peptides and proteins
Microtubles
System of transport for materials within a neuron
What are the support cells in the NS? How many are there?
Glia. 100 billion neurons; 10-50 times as many glial cells
Types of glia
- Astrocyte
- Oligodendrocyte
- Schwann Cell
- Microglia
- Ependymal Cells
Astrocyte
- Provides physical support
- Provides nutrients and other substances
- Regulates chemical composition of extracellular fluid
- Phagocytosis
Oligodendrocyte
Forms myelin sheath in CNS
Schwann Cell
- Forms myelin sheath i PNS
- Neuronal regeneration of PNS
- Provides nutrition for PNS neurons
Microglia
- Phagocytosis
- Immune Function
Ependymal Cell
Line the ventricle of the brain and central canal of the spinal cord
Blood-Brain Barrier
Semi-permeable barrier produced by cells in the walls of the capillaries in the brain
