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Flashcards in Signal Integration, CNS & PNS Deck (24):

Define Convergence of Input.

One cell is influence by many others.


Define Divergence of Output.

One cell influences many others.


What is Synaptic Integration?

Integrates multiple inputs to single neuron, can either be spatially or temporally.


What is Spatial Summation?

When two or more excitatory post-synaptic potentials or IPSPs are generated at one time along different regions of the dendrites and cell body; their effects sum together.


What is Temporal Summation?

When two or more EPSPs arrive at the same location in quick succession.


Neurons have the same basic electrophysiology but diversity of post-synaptic regulation is possible through:

Multiple synaptic inputs per effector, a wide variety of neurotransmitters, different receptor proteins, and several intracellular signally pathways.


What is the Nervous System Pattern like in Cnidarians?

Example: sea anemone. Radially symmetrical, sponges (assymetrical) have no neurons but still have basic cell physiology (communication) through changing membrane potential. The nerve net is the most primitive form of nervous system because there is no controlling brain and when a stimulus occurs, it spreads throughout the whole body.


What is the Nervous System Pattern like in Planarians?

Example: flatworm. Bilateral symmetry, contains ganglia; collections of neuronal cell bodies, which are the sites of integration.


What is the Nervous System Pattern like in Arthropods?

Example: grasshopper. Bilateral symmetry, dorsal ganglia and integration centres located throughout the body.


What is the Nervous System Pattern like in Mollusks?

Example: octopus. Bilateral symmetry, lobed brain with specialized parts.


What is the Nervous System Pattern like in Echinoderms?

Example: Sea Star, radially symmetrical. Nerve ring regulates the activity of the arms - bit more sophisticated than cnidarians, but no brain.


What is the Nervous System Pattern like in Chordates?

Example: salamander. Bilateral symmetry, has a brain.


What is Cephalization?

In all bilaterally symmetrical animals, the mani nervous system (brain) is located in the head near the sensory organs so that signal doesn't have to travel far.


What are the overall trends in the evolution of the CNS?

1. Membrane potentials regulate cell physiology
2. There are specialized signally cells (neurons)
3. Ganglia increase integration
4. Cephalization


What is the relationship between brain mass and body mass?

A linear relationship except for dolphins and humans. Complexity is due to more neurons and synaptic connections.


Why are there folds in the brain?

Folding increases surface area, increasing the number of neuron and synapses.


What are the regions of the brain in a 4-week old embryo?

Forebrain, midbrain, hindbrain.


What are the regions of the forebrain in an adult?

Telencephalon [cerebrum, higher functions such as thought, action, and communication - largest neuron network], Thalamus [receives sensory input and relays it to the cerebral cortex], Hypothalamus [centre for homeostatic control].


What are the regions of the midbrain in an adult?

Mesencephalon, Midbrain, cooridinated involuntary reactions and relays signals to telencephalon.


What are the regions of the hindbrain in an adult?

Cerebullum Pons [integrates signals for muscle movement, centre for information flow between cerebellum and telencephalon], and Medulla Oblongata [controls many involuntary tasks].


What is the Somatic System?

Part of the efferent system that regulates skeletal muscles, controls movements that are mostly voluntary; includes shivering and reflexes. Fight or flight. Stimulates.


What is the Autonomic System?

Part of the efferent system that regulates involuntary activities, divided into the parasympathetic and sympathetic divisions. Rest and digest. Slows down.


What is the Sympathetic Division?

The accelerator.


What is the Parasympathetic Division?

The brakes.