30.1 Respiratory and Circulatory Functions

The respiratory and circulatory systems bring oxygen and nutrients to the cells.

30.1 Respiratory and Circulatory Functions

The respiratory system is where gas exchange occurs.

– picks up oxygen from inhaled air – expels carbon dioxide and water

nose

sinus

mouth

epiglottistrachea

lungs

30.1 Respiratory and Circulatory Functions

Breathing in driven by the diaphragm and muscles of the rib cage.

• Air flows from areas of high pressure to low pressure.

Air inhaled.

Muscles contract andrib cage expands.

Diaphragm flattensand moves downward.

Air exhaled.

Muscles andrib cage relax.

Diaphragm relaxesand rises.

30.1 Respiratory and Circulatory Functions

Path of Air

(Hair filters dust)

(Drives breathing)

(Suspended in chest cavity

bounded by ribs)Alveoli(Tiny air sacs surrounded

by capillaries)

(small tubes)(long, straight tube

in chest cavity)

(Muscular tube)

(voice box with epiglottis (flap))

30.1 Respiratory and Circulatory Functions

30.1 Respiratory and Circulatory Functions

Oxygen and carbon dioxide are carried by the blood to and from the alveoli.

– oxygen diffuses from alveoli into capillary – oxygen binds to hemoglobin in red blood cells – carbon dioxide diffuses from capillary into alveoli

ALVEOLI GAS EXCHANGES

capillaries

alveolus

capillary

co2

o2

Co2 diffusesinto alveolus.

O2 diffusesinto blood.

30.1 Respiratory and Circulatory Functions

Lung diseases reduce airflow and oxygen absorption.

– Asthma constricts airways. – Emphysema destroys alveoli.– Cystic fibrosis produces sticky mucus.