30.2 Respiration and Gas Exchange

The respiratory system exchanges oxygen and carbon dioxide.

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

30.2 Respiration and Gas Exchange

• Nose & mouth – air enters here. Nose is lined with hair and mucus membranes to help trap particles.

• Epiglottis - flap of skin that covers the trachea when swallowing

• Larynx – “voice box” where vocal cord are (2 ligaments)

Path of air

nose

mouth

epiglottistrachea

larynx

30.2 Respiration and Gas Exchange

• Trachea – cartilaginous “windpipe”

• Bronchi – tubes that lead to each lung

• Bronchioles – branches off the bronchi

• Alveoli – air sacs at the end of the bronchi where gas exchange with the blood occurs

Path of air

lungs

bronchitrachea

bronchioles

lungs

bronchi

30.2 Respiration and Gas Exchange

Breathing involves 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.

30.2 Respiration and Gas Exchange

The respiratory system moves gases into and out of the blood.• The lungs contain the bronchi, bronchioles, and alveoli. • Millions of alveoli give the lungs a huge surface area.• The alveoli absorb oxygen from the air you inhale.

30.2 Respiration and Gas Exchange

Gas exchange occurs in the alveoli of the lungs.

• 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.

30.2 Respiration and Gas Exchange

Gas exchange occurs in the alveoli of the lungs.

• Breathing is regulated by the brain stem.

midbrainpons

medulla oblongata

spinal chord

30.2 Respiration and Gas Exchange

• Smoking is the leading cause of lung diseases.

30.2 Respiration and Gas Exchange

Smoking

• Destroys alveoli. • Paralyzes the cilia that line your trachea and bronchi.• Causes genetic mutations leading to cancer.• Particles build up in your lungs and form tar.

30.2 Respiration and Gas Exchange

Emphysema destroys alveoli.

Person has trouble exhaling enough air and looks “barrel-chested”

Lung diseases reduce airflow and oxygen absorption.

30.2 Respiration and Gas Exchange

– Asthma causes bronchioles to constrict due to muscle spasms

– Attacks can be triggered by allergies, stress, exposure to smoke & chemicals, or exercise

30.2 Respiration and Gas Exchange

– Cystic fibrosis genetic disease that produces sticky mucus

- Clogs airways- Allows

microorganisms to thrive in lungs

Respiratory diseases interfere with gas exchange.