The Body Systems and Homeostasis

How you work and stay alive

Regulation

Regulation: Maintenance over time.

This is mainly done by the Nervous and Endocrine systems

The Nervous System

• Controlled by the brain• Made of nerves which are bundles of

neurons

Neuron

The Brain

1. Cerebrum: Conscious thought, feelings, language, “humanness.”

2. Cerebellum: Coordination, balance3. Medulla Oblongata: Involuntary actions.

The Brain

Synapses

The Endocrine system

• Controlled by the brain: pituitary, hypothalamus

• Made of glands that secrete hormones• Examples: adrenals, pancreas, testes, uterus

Endocrine vs. Nervous• The Endocrine systems sends complex

messages (“go through puberty”) that lasts a long time.

• The nervous systems sends short, simple messages (“MOVE”, “JUMP”).

• Endocrine messages are sent using hormones in the circulatory system

• Nervous messages are sent using electrochemical signals using the nervous system

The Digestive System• Breaks down food into nutrients, absorbs

nutrients, eliminates undigested waste.• Mouth>Esophagus>stomach>Small

Intestine>Large Intestine>Exit• PERISTALSIS• Mechanical Digestion: Breaks food into

smaller pieces (teeth, bile)• Chemical Digestion: Breaks bonds between

atoms in the food (enzymes, gastric juices).

The Digestive System (pic)

The Excretory System

• The various organs used to get rid of waste products

• Lungs, Skin, Urinary System (kidneys and bladder)

Circulation• Moves blood throughout the body.• Brings nutrients to cells (oxygen), removes

waste from cells.• Blood vessels: Heart > Arteries >

Arterioles> Capillaries > veinules > Veins > Heart

• The Heart pumps the blood through the blood vessels.

The Heart

The Respiratory System• Supplies the body with oxygen, which is

needed for cellular respiration:

C6H12O6 + 6o2 -> 6CO2 + 6 H20

Oxygen and CO2 are exchanged between the body and the atmosphere at the lungs.

The Immune System• Provides defense from harmful foreign

invaders (bacteria, viruses) and substances.• The “Non-specific” Immune System is the

physical barriers your body has (mucus, skin, gastric juice, etc) and the inflammatory response to wounds.

• The “specific” immune system: White Blood Cells produce antibodies for a particular disease organism (“antigen”). The antibodies “tag” the disease organism for destruction by other white blood cells.

Homeostasis

Homeostasis: the internal balance needed to remain alive.

Examples: reflexes, glucose regulation, valves, respiratory cilia, water balance,

Disease

• Any disruption of homeostasis

Examples: Emphysema, HIV, Heart Attack, Stroke, Diabetes, Hemophilia, Cancer, ulcers.