RespirationThe respiratory system brings air rich in oxygen into the body and gets rid of air rich in carbon dioxide.

2

12

nostril

mouth

larynx

lung

bronchus

nasal cavity

pharynx

trachea

bronchus

bronchiole

alveolidiaphragm

•Compare inhaled and exhaled air.•What is the trend?

GAS N2 O2 Ar CO2

INHALED

EXHALED

78%

78%

21%

16%

~1%

~1%

0.04%

5%

Breathing (Ventilation)• Inhalation

The diaphragm and intercostal muscles contract.

The chest cavity enlarges.

The pressure in the lungs decreases.

Air rushes into the lungs.

Breathing (Ventilation)

• Exhalation

The diaphragm and intercostal muscles relax.

The chest cavity decreases in size.

The pressure in the lungs increases.

Air rushes out of the lungs.

•What pathway does air follow as you inhale?

nasal cavity or mouth

pharynx (throat)

larynx and vocal cords

trachea

bronchi

bronchioles

alveoli

•What pathway does air follow as you exhale?

nasal cavity or mouth

pharynx (throat)

larynx and vocal cords

trachea

bronchi

bronchioles

alveoli

Air processingBlood vessels in your nasal cavity and respiratory passages warm the air.

Mucous in your nasal cavity and respiratory passages moistens the air

Nose hairs increase the surface area of this mucous

Cilia in your respiratory passages sweep mucous up out of lungs.

and also traps dust and germs.

Asthma

Gas Exchange• In the alveoli, oxygen diffuses into blood vessels

and carbon dioxide diffuses out of the blood vessels.

Circulation• The circulatory system

distributes nutrients and oxygen to all of the body’s cells,

removes waste from cells,

and regulates the body’s temperature.

BloodBlood is composed of cells and plasma.

Plasma is the liquid component of blood in which blood cells are suspended.

• Red blood cells carry oxygen from the lungs to the body’s cells,

and carbon dioxide from the body’s cells to the lungs.

• White blood cells fight infections.

• Platelets allow the blood to clot when blood vessels are broken.

Blood Vessels• Arteries carry blood away from the heart.

• Veins carry blood to the heart.

• Capillaries are the smallest blood vessels. Their walls are only one cell thick.

• Capillaries supply oxygen and nutrients to every cell in the body, and remove carbon dioxide and wastes.

The HeartThe heart has 4 chambers:

The right chambers receive deoxygenated blood from the body and pump it to the lungs.

The left chambers receive oxygenated blood from the lungs and pump it to the body.