The Respiratory System7SCIENCE

Why study the respiratory system?

• What do humans need to survive?• Humans need many things to survive, one is

food and the other is air• We are ALWAYS breathing• Breathing: – the process where fresh air

moves into your lungs and stale air moves out of your lungs

Connected to the digestive system

• The digestive system prepares and stores energy from digested food in your cells

• Respiration: the process of releasing this energy through using oxygen– Oxygen is required to release the energy from cells

• Carbon dioxide (what we breathe out) is a waste product from this respiration

Main organs of the respiratory system

• Nasal cavity• Pharynx• Larynx• Trachea • Bronchi (Bronchioles)• Lungs

Nasal Cavity, Pharynx, Larynx• Nasal cavity: Air enters

through your nose or mouth• Pharynx

– Tube that food and air pass through

– Epiglottis: a flap of muscle that prevents food from entering the larynx

• Larynx – Airway that attaches to vocal

cords • As air passes over vocal cords,

the muscles vibrate and tighten or loosen to make a sound (speaking!)

Trachea, Bronchi

• Trachea:– Below the larynx and is

made of cartilage rings

• Bronchi:– At the end of the trachea

are branches that carry air into the lungs

– Split into smaller branches called bronchioles

Lungs, Alveoli• Lungs:

– Take up most of the space in the chest

– Bronchi enter the lungs and split into bronchioles (smaller tubes)

– At the end of these tubes are clusters of tiny sacs, called alveoli

• Alveoli– Exchange of oxygen and

carbon dioxide– Happens easily because

alveoli have walls that are one cell thick