Nervous System and The Brain
The Nervous System Subdivided into two categories: Central Nervous System Contains brain and spinal cord Peripheral Nervous System Nerves and ganglia outside of CNS Reflexes A hot stove
The Nervous System The nervous system has a coordinating role where it receives, processes, stores, and transmits information that comes from the body and the outside world The neuron is the basic unit (cell) of the nervous system Impulses (signals) are carried throught the body by nerves
Neurons Dendrite receives impulses Axon propagates the impulses Longest neuron in the body? Sciatic nerve which connects toes to spinal cord
Neurons The neurons are the only cells that react to a stimulus A stimulus is a change in the environment that results in nerve excitation Ex. sun shining in your eyes or hearing a sound Nerves are structures that help transmit information between the central nervous system and the various regions of the body https://www.youtube.com/watch?v=Ibzfwtdtong
Transmitting Signals Neurons must pick up stimuli, transform them into nerve impulses and then transmit these impulses on to the next neuron A nerve impulse is therefore any electric signal transmitted by a neuron As signals move from one neuron to another, they must cross the synapse. This is the transition zone between two neurons (a very small gap)
Basic Tasks of the Nervous System Sensory Input: Monitor both external and internal environments. Integration: Process the information and often integrate it with stored information. Motor output: If necessary, signal effector organs to make an appropriate response.
Nervous System Composed of CNS and PNS The central nervous system is made of the brain and the spinal cord
The Brain Some brain myths… http://www.popsci.com/10-brain-myths-busted?image=0 https://www.exploratorium.edu/hockey/saves2.html
The Brain The brain controls everything in the body The brain contains more than 100 billion neurons (nerve cells) and is the biggest part of the central nervous system
Size isn’t everything… Neanderthal brains had more capacity devoted to vision and body control, with less left over for social interactions and complex cognition Morton – racist brain size study http://www.smithsonianmag.com/science- nature/science-shows-why-youre-smarter-than-a- neanderthal-1885827/
Parts of the Brain The Brain has three main parts… Cerebrum Cerebellum Medulla oblongata (brain stem)
Concussions https://www.youtube.com/watch?v=tgChTeALF7g Fencing response
The Cerebrum The largest part of the brain It controls your: Thinking Memory Speaking Movement Identifies info gathered by your sensory organs