Nervous and Digestive System

Topics: Nervous system, Digestion, Stomach Pages: 5 (1285 words) Published: March 7, 2013
Cerebellum – coordination of movement and aspects of motor learning Cerebrum – conscious activity including perception, emotion, thought, and planning Thalamus – Brain’s switchboard – filters and then relays information to various brain regions Medulla – vital reflexes as heart beat and respiration

Brainstem – medulla, pons, and midbrain (involuntary responses) and relays information from spine to upper brain Hypothalamus– involved in regulating activities internal organs, monitoring information from the autonomic nervous system

Basic functional cell of nervous system
Transmits impulses (up to 250 mph)

Parts of a Neuron
Dendrite – receive stimulus and carries it impulses toward the cell body Cell Body with nucleus – nucleus & most of cytoplasm
Axon – fiber which carries impulses away from cell body
Schwann Cells- cells which produce myelin or fat layer in the Peripheral Nervous System Myelin sheath – dense lipid layer which insulates the axon – makes the axon look gray Node of Ranvier – gaps or nodes in the myelin sheath

Impulses travel from dendrite to cell body to axon
Neurotransmitters – Chemicals in the junction which allow impulses to be started in the second neuron

A stimulus is a change in the environment with sufficient strength to initiate a response. Excitability is the ability of a neuron to respond to the stimulus and convert it into a nerve impulse All of Nothing Rule – The stimulus is either strong enough to start and impulse or nothing happens Impulses are always the same strength along a given neuron and they are self-propagation – once it starts it continues to the end of the neuron in only one direction- from dendrite to cell body to axon The nerve impulse causes a movement of ions across the cell membrane of the nerve cell. Epilepsy - common and diverse set of chronic neurological disorders characterized by seizures. Seizures - the physical findings or changes in behavior that occur after an episode of abnormal electrical activity in the brain and are caused by abnormal electrical discharges in the brain Alzheimer’s Disease - a degenerative disease of the brain that causes dementia, which is a gradual loss of memory, judgment, and ability to function. - the most common form of dementia- affects an estimated 1 in 10 people over age 65 Multiple Sclerosis - an autoimmune disease that affects the brain and spinal cord (central nervous system) - body's immune system eats away at the protective myelin sheath that covers the axons of the neurons and interferes with the communication - MS can affect vision, sensation, coordination, movement, and bladder and bowel control. Parkinson’s Disease - disorder of the brain that leads to shaking (tremors) and difficulty with walking, movement, and coordination. People with Parkinson's disease have low brain dopamine concentrations. Shingles (herpes zoster) - painful, blistering skin rash due to the varicella-zoster virus, the virus that causes chickenpox – the virus remains inactive (becomes dormant) in certain nerves in the body. Shingles occurs after the virus becomes active again Cerebral Palsy - group of disorders that can involve brain and nervous system functions such as movement, learning, hearing, seeing, and thinking resulting from damage to certain parts of the developing brain Glaucoma - a group of eye conditions that lead to damage to the optic nerve due to increased pressure in the eye - the eye’s drainage system becomes clogged so the intraocular fluid cannot drain and as the fluid builds up, it causes pressure to build within the eye. High pressure damages the sensitive optic nerve. Pink eye (Conjunctivitis) – infection of the conjunctiva of the eye

Effects of Drugs on the Nervous System
Alcohol - central nervous system depressant – cell membranes are highly permeable to alcohol so once in the bloodstream it can diffuse into almost all body tissues. It is absorbed in the stomach so it gets into the blood stream quickly...
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