Respiratory System – Chapter 8The function of the respiratory system

•We breathe so that the cells in our body receive oxygen to perform cellular respiration to keep us alive. •The respiratory system also functions to remove the waste products of cellular respiration from our bodies (carbon dioxide.)•The respiratory system is divided into two parts – the upper respiratory tract and the lower respiratory tract. •The membrane surrounding the chest cavity and lungs is called the pleura.

Components of the Upper Respiratory Tract

Mouth and Nose• Brings air into the body• Receptors for smell• Nasal hairs filter incoming air for things such as dust and

pollen• Moistens and warms incoming air

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, which covers the trachea during swallowing so that food does not enter the lungs.

Components of the Lower Respiratory Tract

• Larynx: Maintains an open airway, routes food and air appropriately, assists in sound production.

• Trachea: Transports air to and from lungs; connects the larynx with the bronchi; lined with a mucus membrane and cilia.

• Bronchi: Two short tubes that branch off of the trachea into the lungs; singular - bronchus.

• Bronchioles: Tiny branches of air tubes in the lungs that connect the bronchi to the 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.

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

Lower Respiratory Tract

Gas Exchange Between the Blood and Alveoli

Respiratory Cycle

Figure 10.9

• Reduced air flow: asthma, emphysema, bronchitis.• Infections: pneumonia, tuberculosis, botulism.• Lung cancer• Congestive heart failure• Cystic fibrosis

Disorders of Respiratory System

• Inspiration/Expiration: air in/air out• Cycle:

• Relaxed state: Diaphragm and intercostal muscles relaxed.• Inspiration: Diaphragm contracts, pulling muscle down,

intercostal muscles contract elevating chest wall and expanding volume of chest, lowering pressure in lungs, pulling in air.

• Expiration: Muscles relax, diaphragm resumes dome shape, intercostal muscles allow chest to lower resulting in increase of pressure in chest and expulsion of air.

Process of Breathing: Pressure Gradient

• Gases diffuse according to their partial pressures

• External Respiration: Gases exchanged between air and blood

• Internal Respiration: Gases exchanged with tissue fluids

• Oxygen Transport: Bound to hemoglobin in red blood cells or dissolved in blood plasma

• Carbon Dioxide Transport: Dissolved in blood plasma, bound to hemoglobin, or in the form of plasma bicarbonate

Gas Exchange & Transport: A Passive Process

• Respiratory center in the medulla oblongata: establishes basic breathing pattern

• Chemical receptors: monitor carbon dioxide, hydrogen ions, and oxygen levels

• Medulla: sensitive to hydrogen ions in cerebrospinal fluid resulting from carbon dioxide in blood

Regulation of Breathing: Nervous System Involvement

• Breathing: air in to and out of lungs• External Respiration: gas exchange between air and blood• Internal Respiration: gas exchange between blood and

tissues• Cellular Respiration: oxygen use to produce ATP, carbon

dioxide as waste

Four Respiration Processes

Extra Resources

http://hrsbstaff.ednet.ns.ca/holmesdl/Adv%20Bio%2011/Bild2Lec14.pdf

http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter25/animation__gas_exchange_during_respiration.html

http://www.youtube.com/watch?v=SPGRkexI_cs

http://www.youtube.com/watch?v=qGiPZf7njqY