Unit 2.1: Function & Components of the Nervous System Flashcards
What are the functions of the nervous system?
- Receives information (using sensory neurons to receive from external environment)
- Integrates information (organizes the information and brings it together with already stored information)
- Transduces information (sends appropriate signals to the appropriate target)
What are the 2 main parts of the nervous system?
- Central nervous system (brain and spinal cord)
2. Peripheral nervous system (everything else) - consists of efferent (motor) and afferent (sensory) neurons
What are the cells found in the nervous system?
Neurons and glial cells
What do neurons do?
They generate and transmit electrical impulses over long distances
What are the 4 main parts of a neuron?
- Soma (cell body)
- Dendrites
- Axon
- Axon terminals
What is a cluster of neurons in the CNS?
Nuclei
What is a cluster of neurons in the PNS?
Ganglia
What are dendrites?
Slender processes that receive information and transmit electrical signals towards the soma
What are axons?
Cytoplasmic extension that sends out information, transmit electrical signals away from the soma
What are bundles of axons in the CNS?
Tracts
What are bundles of axons in the PNS?
Nerves
What are axon terminals?
End of axon, connection between neuron and other cells
What are the different structures of neurons?
Pseudounipolar Bipolar Anaxonic Multipolar - CNS Multipolar - Efferent (motor)
What are the different functions that classify neurons?
Afferent (sensory), Interneurons, Efferent (motor)
What are afferent neurons?
Receive info from receptor cell, send to CNS via interneurons
cell bodies are found outside the CNS
What are interneurons?
Located within the CNS
Make up 96% of the CNS
Integrate info received from afferent and send to efferent
What are efferent neurons?
Receive info from interneurons
Cell bodies are found in the CNS
Transmit info to effectors
What are glial cells?
Outnumber neurons 50:1
Don’t carry electrical signals over long distances
How to glial cells contribute to the function of neurons in 2 main ways?
- Aid in nerve impulse conduction
2. Maintain the microenvironment around neurons
What are the PNS glial cells?
Schwann cells & Satellite Cells
What are Schwann cells?
Special glial cells that are wrapped around axons
Forms myelin
Gap junctions found between layers of myelin sheath
What is the importance of myelin?
Acts as an electrical insulator
What are satellite cells?
Non-myelinating Schwann cells, support nerve cell bodies (soma)
What are the CNS glial cells?
Oligodendia, astroglia, microglia, & ependymal cells
How are Schwann cells and oligodendria similar and different?
They both wrap around axons to form myelin sheathes, but Shwann cells can only myelinate one area of the axon whereas oligodendria can myelinate more than one region of the axon and more than one axon
What are astroglia?
small star shaped cells
What is the function of astroglia?
Maintain neuron’s microenvironment
What are microglia?
very small cells
What is the function of microglia?
They are specialised immune cells, they remove damaged cells and foreign invaders
What are ependymal cells?
They produce cerebral spinal fluid (CSF)
What is the function of ependymal cells?
Create selectively permeable barrier between compartments of the brain
