The Respiratory SystemThe Respiratory System

Grade 7; GLE 10http://www.science-class.net/Biology/Anatomy.htm

Purpose of the respiratory system

• To provide a constant supply of oxygen to keep your body cells functioning

• To remove carbon dioxide from the body cells

Organs of the respiratory system• Nose / mouth• Nasal cavity• Pharynx • Epiglottis • Larynx • Trachea

• Trachea• Bronchus (bronchi)• Bronchioles• Alveoli • Pleura • Diaphragm

Lungs

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Mouth & Nose

• Brings air into the body

• Nasal hairs in nostrils trap dust

Nasal cavity

• Warms & moistens air

• Glands that produce sticky mucus line the nasal cavity – traps dust, pollen, and other materials that

were not trapped by nasal hairs – cilia sweep mucus and trapped material to

the back of the throat where it can be swallowed

Pharynx

• Tube-like passageway used by food, liquid, and air

• At the lower end of the pharynx is a flap of tissue called the epiglottis – covers the trachea during swallowing so

that food does not enter the lungs

Larynx

• “Voice box”

• The airway to which two pairs of horizontal folds of tissue, called vocal cords, are attached

Trachea

• Air-conducting tube

• Connects the larynx with the bronchi

• Lined with mucous membranes and cilia

• Contains strong cartilage rings

Bronchi

• Two short tubes that branch off the lower end of the trachea

• Carry air into the lungs.

• Singular - bronchus

Bronchioles

• Tiny branches of air tubes in the lungs

• Connect bronchi to alveoli

Alveoli

• Tiny, thin-walled, grapelike clusters at the end of each bronchiole

• Surrounded by capillaries

• Where carbon dioxide and oxygen exchange take place

• Singular - alveolus

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Pleura

• Membrane lining the lungs and chest cavity

Diaphragm

• Muscle wall between the chest and the abdomen that the body uses for breathing

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Relationship to digestive system

• Cellular respiration requires glucose and oxygen to release energy to the body

• C6H12O6  +  6O2    6CO2  +  6 H2O  +  Energy

• Oxygen is provided by the respiratory system

• Glucose is provided by the digestive system

• (glucose is made during photosynthesis)