Respiratory System Notes
Textbook Online

Class Notes

Function: Gas exchange between living organisms and the environment.

      Deliver air to the lungs:

O2 from lungs to blood

CO2 from blood to lungs


Nose: Nasal Cavity- main use for breathing in and out. Nasal cavity is cleaned, moistened and warmed to prevent injury to membranes in the lungs.

*Mouth breathing brings cold and unfiltered air to lungs and creates a dry lining of the mouth and throat.

Pharynx: throat- incoming air. adenoids & tonsils (lymphatic tissue)

where nasal cavity and mouth meet.

Larynx: voice box- guards entrance for the trachea. 

*contains vocal cords. (boys grow longer to 1 1/4inches for deeper  voice)(girls is 3/4) adam’s apple (lump of cartilage) also grows.

* adam’s apple in frontof trachea, also grows for men.

*glottis- opening to windpipe, slit in larynx.

*epiglottis- flap to cover glottis, stops food from entering into the trachea.

Trachea: windpipe- flexible tube with u-shaped rings of cartilage.

Back tube is the esophagus- leading to the stomach: which is why the trachea is flexible, it collapses for food to pass by.

Bronchi: two tubes branch from the trachea to the lungs

singular- bronchus

Lungs: cone shaped soft bags. has blood vessels, lymphatic vessels and nerves.

*pleura- thin membrane covering lungs.

*pneumonia- infection caused by infection or bacteria in the lungs.

Bronchioles:  smaller branches of bronchi within the lungs.

*bronchitis- inflamation of bronchial tubes.

*asthma- bronchial spasms, decr5ease air movement & air trapped in alveoli.

Alveoli: tiny air sacs exchange gases between air and blood.

300 million in lungs. fill up like balloons when breath in.

capillaries- blood vessels 

Diaphragm: Flat sheet of muscle that seperates the chest and abdominal cavities.

*contracts and increases size in chest cavity and air gets vacuumed in; hi - lo pressure.

* hiccup- sudden contraction of diaphragm and vocal cords snap shut.


Breathing: contraction and relaxation of muscles.

pressure and volume of air moves from high concentration to low.

inspiration- diaphragm contracts

expiration- diaphragm relaxes

*Oxygen attatches to hemoglobin and then spreads out throughout the body.

*rate of breathing is controlled by the medulla oblongata. decided by CO2 in the blood ( increase of CO2 levels increases breathing)


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