Flashcards in Lecture 16: Cells & Organisation of the Nervous System Deck (27)
Why is integration and coordination important? Give examples
- They match our sensory environment with our body's needs
- Thirsty / Drink Water
- Cold / Get Warmer
- Hear loud or scary noise / fight or flight
- See food / Am I hungry? / Order some!
The central nervous system is composed of the:
- Brain / nervous + glia (non-neurons)
- Spinal Cord / neurons + glia (non-neurons)
The peripheral nervous system is composed of:
- Peripheral Nerves / neurons + glia
What are 3 general features of Glia Cells?
1. Support for neurons
2. Five basic types - 4 in CNS, 1 in PNS
3. Each type has a specific function
What are 3 general features of Neurons?
1. Cells are specialised for transmission
The 4 cells of the Central Nervous System are:
What are 3 features of Astrocytes?
- Supply nutrients to neurons
- Ensheath blood capillaries
- Transmit information
What are 2 features of Microglia?
- Immune cells of the CNS
What are 2 features of the Ependymal Cells?
- Line fluid-filled spaces of brain + spinal cord
- Circulate cerebrospinal fluid
- Have cilia
What are 2 features of Oligodendrocytes?
- Support nerve fibres
- Ensheath them with myelin
What cell is only found in the PNS?
- Schwann Cell
What are some features of the Schwann Cell?
- They support peripheral nerve fibres
- Wrap their membrane around the axon
What is the myelin sheath?
- Lipid wrapped around axon
Where does myelin come from in the CNS vs PNS?
- CNS : Oligodendrocytes
- PNS : Schwann Cell
What does the myelin sheath do?
- Increases conduction ( ___ n ____ n ____ n )
What is the structure of the Neuron?
- Cell Body
- Axon Terminal
What are the nodes of ranvier?
- The gaps between the myelin sheath
What happens when axons become demyelinated?
- Impaired nerve conduction (weakness, uncoordination, visual, speech impairment)
- Multiple Sclerosis
Describe what happens in the input zone of an axon
- Information is received via chemical signals by dendrites
Describe what happens in the summation zone of an axon
- The axon hillock decides whether to transmit signal further
- Receiving a text, send it on or no?
Describe what happens in the conduction zone of an axon
- Electrical signals between brain + spine
Describe what happens in the output zone of an axon
- Chemical signals are sent to the next axon
What are the three basic types of the nervous system?
- Multipolar ( -------OE_-_-_-_-) V
- Bipolar ( ------O------- ) I
- Unipolar (one process to the side) ( ------------- )
Where does communication happen between neurons?
- In the synapse / synaptic cleft via neurotransmitters
What are the 3 synapse types?
- Axosomatic (synapse connects to soma)
- Axoaxonic (synapse connects to axon)
Information that goes into the brain is:
- Afferent (Ascending)