Organ systems in Humans

Chapter 3.3

This year we will look at 3 of the 11 organ systems found in humans;

1. Digestive system2. Respiratory

system3. Circulatory

system

Structures

BLM 3-12

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.

http://www.youtube.com/watch?v=q3986Yfl5cU&feature=related

BLM 3-13

Respiratory system• Air enters through mouth/nose

• Goes through esophagus

• Continues with larynx, trachea, bronchus, bronchioles, and alveoli (alveolus)

http://www.youtube.com/watch?v=HiT621PrrO0&feature=related

BLM 3-14

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: Videohttp://www.youtube.com/watch?v=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 O2 for cells and removes waste CO2. ( 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)

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 O2 into body and removes CO2 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 O2 and CO2 must diffuse through them.

• We breathe in air. It travels to the alveoli. The capillaries wrap themselves around the alveoli and collect the diffused O2 and bring it to the rest of body.

• The reverse happens when we breathe out.

Page 84 Figure 3.19

Digestive and CirculatoryFood 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.