Digestive System and Nervous System

nervous system

the body's speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems

central nervous system

consists of the brain and spinal cord

peripheral nervous system

A division of the nervous system consisting of all nerves that are not part of the brain or spinal cord.

somatic nervous system

A subdivision of the peripheral nervous system. Enables voluntary actions to be undertaken due to its control of skeletal muscles

autonomic nervous system

A subdivision of the peripheral nervous system. Controls involuntary activity of visceral muscles and internal organs and glands.

brain

The mass of nerve tissue that is the main control center of the nervous system

Cerebellum

Balance and coordination

Cerebrum

Largest part of the brain; responsible for voluntary muscular activity, vision, speech, taste, hearing, thought, and memory.

brain stem function

1. control heartbeat

2. breathing

3. blood pressure

spinal cord

Nerves that run up and down the length of the back and transmit most messages between the body and brain

Neurons

a nerve cell; the basic building block of the nervous system

Soma

cell body of a neuron

Dendrites

Branchlike parts of a neuron that are specialized to receive information.

Axon

A threadlike extension of a neuron that carries nerve impulses away from the cell body.

myelin sheath

covers the axon of some neurons and helps speed neural impulses

Synapse

Gap between neurons

sensory neurons

carry impulses from the sense organs to the spinal cord and brain

motor neurons

neurons that carry signals from the spinal cord to the muscles to produce movement

reflex

a simple, automatic response to a sensory stimulus, such as the knee-jerk response

multiple sclerosis

A chronic disease of the central nervous system marked by damage to the myelin sheath. Plaques occur in the brain and spinal cord causing tremor, weakness, incoordination, paresthesia, and disturbances in vision and speech

Alzheimer's disease

a progressive and irreversible brain disorder characterized by gradual deterioration of memory, reasoning, language, and, finally, physical functioning

Epilepsy

chronic brain disorder characterized by recurrent seizure activity

Parkinson's disease

A disorder of the central nervous system that affects movement, often including tremors.

digestive system

Breaks down food into absorbable units that enter the blood for distribution to body cells.

mouth

where digestion begins

mechanical digestion

Physical breakdown of large pieces of food into smaller pieces

chemical digestion

Process by which enzymes break down food into small molecules that the body can use

saliva

digestive juice produced by salivary glands

Esophagus

A muscular tube that connects the mouth to the stomach.

stomach

A muscular and elastic sac that serves mainly to store food, break it up mechanically, and begin chemical digestion of proteins and fat.

small intestine

Digestive organ where most chemical digestion and absorption of food takes place

large intestine

The last section of the digestive system, where water is absorbed from food and the remaining material is eliminated from the body

Rectum

A short tube at the end of the large intestine where waste material is compressed into a solid form before being eliminated

liver

produces bile

Gallbladder

A muscular sac attached to the liver that secretes bile and stores it until needed for digestion

Pancreas

produces digestive enzymes and bicarbonate, which are delivered to the small intestine via the pancreatic duct.

celiac disease

disease caused by sensitivity to gluten

Villi

Tiny finger-shaped structures that cover the inner surface of the small intestine and provide a large surface area through which digested food is absorbed