(c) McGraw Hill Ryerson 2007 2.3 The Circulatory and Respiratory Systems The circulatory system...

(c) McGraw Hill Ryerson 2007

2.3 The Circulatory and Respiratory Systems

• The circulatory system consists of the heart, arteries, capillaries, and veins.

• Your heart is a pump that pushes approximately 4 L of blood through your body every minute.

• The main purpose of the respiratory system is to exchange gases.

• The main organ of the respiratory system is the lungs.

See pages 82 - 83

Amazing Heart Facts

Put your hand on your heart. Where is it?

•Hold out your hand and make a fist. size of heart: child = 1 fist; adult = 2 fists!

•Your heart beats about 100,000 times in one day and about 35 million times in a year.

•During an average lifetime, the human heart will beat more than 2.5 billion times.

•Even at rest, the muscles of the heart work twice as hard as the leg muscles of a person sprinting

• In one day, the blood travels a total of 19,000 km. That's 4 times the distance across CANADA from coast to coast.

•When you are resting, it takes 35-40 seconds for the blood to move through your body. What about when you are exercising?

• approximately 10 seconds

•How much does your heart weigh?

only 2/3 of a pound!

• Give a tennis ball a good, hard squeeze. You're using about the same amount of force your heart uses to pump blood out to the body

(c) McGraw Hill Ryerson 2007

Taking a Closer Look at the Heart

• The heart pumps blood throughout the body.• The heart has four chambers:

Left atrium Blood arrives from your lungs

Right atrium Blood arrives from your body

Left ventricle Pumps blood to your body

Right ventricle Pumps blood to your lungs

• Between each of these chambers is a valve.See page 84

The human heart has The human heart has 44 well developed well developed chamberschambers

Right Atrium

Left Atrium

Right Ventricle

Left Ventricle

Taking a Closer Look at the Heart

(c) McGraw Hill Ryerson 2007

(c) McGraw Hill Ryerson 2007

The Circulatory System

• Starting with the right atrium, try placing the following structures in the correct order that blood flows through the body. Left ventricle Body Right atrium Left atrium Lungs Right ventricle

(c) McGraw Hill Ryerson 2007

The Circulatory System

• The circulatory system moves blood throughout the body.

See pages 85 - 86

The Circulatory System

• There are three types of blood vessels: Arteries

Carry oxygenated blood away from your heart Capillaries are tiny blood vessels

Responsible for transfer of oxygen and nutrients into the body cells and collecting wastefrom the cells.

Veins Blood containing waste

products returning to the heart.(c) McGraw Hill Ryerson 2007

The Circulatory System

(c) McGraw Hill Ryerson 2007

The Major Blood The Major Blood Vessels of the BodyVessels of the Body

• Capillaries, on the other hand, are so small that it takes ten of them to equal the thickness of a human hair.

•If you stretched your veins out, and hooked If you stretched your veins out, and hooked them all together, they would go around the them all together, they would go around the world 2 times!!world 2 times!!

• One pound of excess fat adds approximately 200 miles of extra capillaries. This increases BP!

• The aorta in a blue whale is so big, you could swim down it!!!

• The aorta, the largest artery in the body, is almost the diameter of a garden hose.

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The Components of Blood

See pages 88 -89

• About 55% of blood is a liquid called plasma. Contains proteins, minerals, and other

substances.

• Red blood cells carry oxygen from the lungs to the cells.

• White blood cells fight infection.• Platelets are important for clotting

blood.

(c) McGraw Hill Ryerson 2007

(c) McGraw Hill Ryerson 2007

The Respiratory System

See page 90

• The respiratory system moves oxygen into your body and carbon dioxide out of your body.

The right lung is slightly larger than the left.

Hairs in the nose help to clean the air we breathe, as well as warming it.

The highest recorded "sneeze speed" is 165 km per hour.

The surface area of the lungs is roughly the same size as a tennis court.

The capillaries in the lungs would extend 1,600 kilometres if placed end to end.

We lose half a litre of water a day through breathing. This is the water vapour we see when we breathe onto glass.

A person at rest usually breathes between 12 and 15 times a minute.

The breathing rate is faster in children and women than in men.

The Respiratory System

• When you inhale, air is filtered by tiny hairs called cilia.

• Air passes through your larynx and continues down your trachea towards your lungs.

• At the base of the trachea are two tubes called bronchi.

• Bronchi branch into smaller air tubes called bronchioles.

(c) McGraw Hill Ryerson 2007

This is the common passageway for air and food

This is a flap of tissue that covers the top of the trachea when swallowing to ensure that food enters the esophagus and not the lungs.

When the epiglottis is opened, the air is able to pass through the larynx (voice box) and into the trachea.

The larynx contains the vocal cords (two tendons that adjust the pitch of sounds according to how taut they are).

When a guy goes through puberty, his vocal chords and voice box (larynx) grow larger, and begins to stick out at the front of the throat. This lump is called the Adam's Apple.

This is the windpipe.

This passageway is held open by the presence of C-shaped rings of cartilage. This is a protective adaptation.

The trachea conducts air into the bronchi.

•Cilia and mucus filter the air as it moves through the trachea.

•The mucous traps the dirt and other particles, and the cilia push it to the back of the throat so we swallow it into our digestive system

The trachea splits into two bronchi and takes the air into each lung.

These branches also have cartilage around them, for the same reason.

The bronchi conducts air into smaller branching passageways called bronchioles.

The bronchioles are branching passageways that carry air to its ultimate destination, the alveoli.

(c) McGraw Hill Ryerson 2007

Gas Exchange in the Alveoli

See page 91

• There are millions of alveoli at the ends of the bronchioles, and this is where gas exchange takes place.

• Oxygen and carbon dioxide move back and forth between the alveoli and the surrounding blood vessels.

Why are they so special?

1. Each adult lung contains millions of alveoli. This provides lots of surface area for the gases to be exchanged.

2. The walls of alveoli are only one cell thick.

3. They have stretch receptors that signal when the alveoli are full enough (stretched). They send a message to the brain to start breathing out.

4. They are very moist and this helps gas exchange.

5. They are covered with a LOT of blood capillaries so oxygen and carbon dioxide can be exchanged efficiently.

This is a sheet of muscle that separates the chest cavity from the abdominal cavity.

When you inhale it moves down.

When you exhale it moves up.

These are the bones that are connected to the vertebral column and sternum.

These are muscles between the ribs, which help to move the ribs…

1. Up and out when we inhale.2. Down and in when we exhale.

See a Working Respiratory System: http://www.smm.org/heart/lungs/breathing.htm

(c) McGraw Hill Ryerson 2007

Smoking

• Smoking may cause both respiratory disease and heart disease.• Respiratory diseases could include emphysema and lung cancer.

Emphysema causes the alveoli walls to lose their elasticity. This may make breathing very difficult.

• Smoking also destroys the cilia lining your respiratory system.

See page 92

SMOKING POSTER CHILDhttp://www.tobaccofacts.org/poster/index.html

ANIMATION: WHAT SMOKING DOES TO YOUR BODYhttp://www.mydr.com.au/default.asp?article=4215

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