neuro exam.docx

What is brain? The brain is a tissue, organ, and basically just that wrinkly thing in your head, however, you can't do certain behaviours without a spinal cord. The nervous system is made up of the central nervous system and the peripheral nervous system. The CNS is made up of the brain, spinal c...

What is brain? The brain is a tissue, organ, and basically just that wrinkly thing in your head, however, you can't do certain behaviours without a spinal cord. The nervous system is made up of the central nervous system and the peripheral nervous system. The CNS is made up of the brain, spinal column, cerebellum. And communication is neural. The PNS is made up of nerves that make you move basically. And communication is neural. The autonomic nervous system has a different type of communication than PNS, CNS. It communicates chemically. The hormones are secreted into bloodstream by ductless glands. Pituitary gland is the master gland What is behaviour? - The manner of conducting oneself - Anything that an organism does involving action and response to stimulation. - The response of an individual, group, or species to its environment. Cranial nervous system controls input and output from the stuff in the head. The brainstem gets inputs from the senses and outputs to the rest of the body. You can divide it into hindbrain, midbrain, diencephalon. Hind brain: fine movements, balance, cerebellum, reticular formation. Mid brain: - Tectum: the region of the midbrain posterior to the cerebral aqueduct of Sylvius. - Superior colliculus does vision - Inferior colliculus does audition - Below the tectum is the tegmentum, also important in movement. Diencephalon: hypothalamus The synapse is a gap between the axon and the dendrite about 20-40 nm. Neurotransmitters are released across this gap. Sometimes, if all the transmitter isn't absorbed it is taken back up, this is known as reuptake. Three pools of neurotransmitters - Ready releasable - Recycling - Reserve Fusion pore - SNARE - Full collapse fusion - Kiss and run Kiss and run enables more efficient vesicle recycling and can limit how much neurotransmitter is released due to a smaller fusion pore and a shorter time during which neurotransmitters can actually be released. Types of synapses: 1. Dendrodendritic: dendrites send messages to other dendrites 2. Axodendritic: axon terminal of one neuron synapses on dendritic spine of another. 3. Axoextracellular: terminal with no specific target. Secretes transmitter into extracellular fluid. 4. Axosomatic: axon terminal end on cell body. 5. Axosynaptic: axon terminal ends on another terminal. 6. Axoaxonic: axon terminal ends on another axon. 7. Axosecretory: axon terminal ends on tiny blood vessel and secretes transmitter directly into blood. 1. Synthesis 2. Storage 3. Release 4. Receptor interaction 5. Inactivation 6. Reuptake 7. Degradation 5 conditions that must be met before calling something a neurotransmitter: 1. Present in terminal 2. Released on firing 3. Placing substance on organ or another neuron emulates firing 4. Uptake for inactivation 5. Inactivation blocks stimulation Receptors: transmitters bind to receptors sort of like a lock and a key. Theyre the binding site. Usually, one neuron has only one type of receptor. Electrical synapses: only 2.5 nm apart. Allows flow of ions from one neuron to another bi directionally. Used when you need very fast reaction. No receptor or binding site, but a connexon. Habituation: decrease in the strength of a response after repeated presentation of a discreet stimulus. LTP (long term potentiation): a neuromodulator basically allows LTP to happen. LTP is a phenomenon in which chemical synaptic transmission is enhanced in a lasting fashion through co-incident pre- and post-synaptic activity. It has several properties that make it an attractive candidate memory mechanism. The axon hillock: where the axon starts. Has a lot of voltage sensitive channels. Needs -50 mV for depolarization. Patch clamp: it is an electrophysiological method that allows the recording of whole cell or single channel currents flowing across biological membranes through ion channels.