Chapter 3.3

This year we will look at 3 of the 11 organ systems found in humans; 1. Digestive system 2. Respiratory system 3. Circulatory system

Structures

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Digestive system Begins with mouth Salivary glands start breaking down starches. Food travels through esophagus, stomach, small intestine, large intestine, rectum, anus Others that assist: liver, pancreas and gallbladder. =q3986Yfl5cU&feature=related

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Respiratory system Air enters through mouth/nose Goes through esophagus Continues with larynx, trachea, bronchus, bronchioles, and alveoli (alveolus) =HiT621PrrO0&feature=related

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Circulatory system Two parts A system of tubes that carry blood through body A “pump”  Heart Made of blood vessels: Arteries Veins Capillaries

The circulatory system: Video H04d3rJCLCE&feature=related

Blood Vessels

Page 81 Figure 3.17

Arteries Carries blood away from the heart to the rest of body Walls are thick and muscular to avoid collapsing under pressure of pumping blood. Usually depicted as red (full of oxygen)

Veins Carries blood back to the heart from the rest of body. Blood moves slow now because of traveling through body Walls are thin. Have valves to stop blood from flowing backwards. Usually depicted as blue (lacking oxygen)

Capillaries Connect arteries and veins Hair thin vessels, walls only one cell thick

Blood

Functions

1. Digestive system Breaks down food into small parts.

2. Respiratory system Moves air in and out of the body. The in and out movement of air supplies O 2 for cells and removes waste CO 2. ( gas exchange)

3. Circulatory system Circulates blood around body Delivers food, dissolved gasses, and other materials Carries away waste.

Connections between systems.

Page 82 Figure 3.18 (A&B)

Respiratory and Circulatory These systems are the 2 main ways in which the needs of each cell are met. The Resp. Sys. Brings O 2 into body and removes CO 2 and the Circ. Sys is the road it travels. The alveoli and the capillaries are where the 2 sys. meet.

Respiratory and Circulatory The bronchioles of the lungs end in a grape-like cluster of the alveoli. The purpose of the alveoli is to give a very large surface area for gas exchange to occur.

Respiratory and Circulatory The alveoli and the capillaries are both very thin walled because O 2 and CO 2 must diffuse through them. We breathe in air. It travels to the alveoli. The capillaries wrap themselves around the alveoli and collect the diffused O 2 and bring it to the rest of body. The reverse happens when we breathe out.

Page 84 Figure 3.19

Digestive and Circulatory Food transfers from Digest. Sys to Circ Sys. in the small intestine. It is lined with hair like things called villi. Each villus has a network of capillaries. Dissolved food particles pass from the intestine into the capillaries by a process called absorption.

Mechanics of breathing.