Lecture Outline - Chapter 8

 
8.1 Respiratory Tract (p. 164, Fig. 8.2, Table 8.1)
	1.	Air is inspired and expirated through a series of tubes, and at the same time, is warmed, moistened, and filtered.
	2.	The Nose Has Two Cavities (p. 165, Fig. 8.3)
		a.	The nose is partitioned into two cavities by a nasal septum.
		b.	Lacrimal (tear) glands drain into nasal cavities.
		c.	Nasal cavities communicate with air-filled, mucous membrane-lined sinuses of the skull.
		d.	Eustachian tubes lead from the nasopharynx to the middle ears.
	3.	The Pharynx Is a Crossroad (p. 165)
		The pharynx leads to the larynx and is a common passageway for air and food.
	4.	The Larynx Is the Voice Box (p. 166, Fig. 8.4)
		a.	The opening to the larynx, called the glottis, is protected during swallowing by the epiglottis.
		b.	The larynx houses the vocal cords, folds of mucous membrane supported by elastic ligaments.
		c.	The pitch of the voice is regulated by tension on the vocal cords, while volume is controlled by the force of air.
	5.	The Trachea Is a Windpipe (p. 166)
		a.	The trachea is supported by C-shaped cartilaginous rings and is lined with cilia that sweep mucus and debris toward the throat.
		b.	A tracheostomy is an incision made at the base of the throat. 
	6.	Bronchi Are Air Tubes (p. 166, Fig. 8.5)
		a.	Two large bronchi branch off the trachea, each one leading to a lung. From there, bronchioles lead to sections of the lungs.
		b.	During asthma attacks, bronchioles constrict, causing wheezing.
		c.	Bronchioles terminate in alveoli that comprise the lungs.
	7.	Lungs Have Many Alveoli (p. 167, Fig. 8.6)
		a.	The lungs are cone-shaped organs lying on either side of the heart. The right lung has three lobes; the left has two.
		b.	Alveoli Are 300 Million Air Sacs (p. 167)
			i.	Alveoli are made up of simple squamous epithelium surrounded by blood capillaries. Gas exchange occurs between air in the alveoli and blood in the capillaries.
			ii.	Alveoli are lined with a lipoprotein called surfactant that keeps alveoli open by lowering surface tension. 
			iii.	The 300 million alveoli represent a surface area 40 times that of the skin.
8.2 Mechanism of Breathing (p. 168)
	1.	Respiration refers to the four-step process of supplying oxygen to cells for aerobic cellular respiration and to the reverse process of removing waste products. 
		a.	During breathing, inspiration and expiration move air into and out of the lungs.
		b.	External respiration is the exchange of gases between air and the blood.
		c.	Internal respiration is the exchange of gases between the blood and tissue fluid.
		d.	Cellular respiration involves the use of oxygen to produce ATP in cells.
	2.	Getting Air to the Lungs (p. 168, Fig. 8.7)
		a.	The tidal volume is the normal volume of air moved in and out with each breath.
		b.	Vital capacity is the maximum amount a person can move in and out while inhaling deeply. 
		c.	Residual volume is the amount that remains in the lungs at all times and that is not used for gas exchange.
			ECOLOGY FOCUS: Photochemical Smog Can Kill (p. 169)
			i.	Photochemical smog is produced when certain pollutants react with each other in sunlight.
			ii.	Nitrogen oxides and hydrocarbons react to produce nitrogen dioxide, ozone, and PAN (peroxyacetyl nitrate).
			iii.	Breathing these substances affects the respiratory and nervous systems.
			iv.	Cities with sunny, warm climates are especially susceptible to photochemical smog buildup.
			v.	Preventive measures include using efficient automobiles, recycling, and reducing energy use.
	3.	Inspiration Precedes Expiration (p. 170)
		a.	The rib cage, diaphragm, and pleural membranes all interact to provide ventilation.
		b.	Inspiration Is Active (p. 170, Figs. 8.8, 8.9)
			i.	Breathing is regulated by the respiratory center in the medulla oblongata, which uses input on carbon dioxide and hydrogen ion content of the blood to modify breathing rate.
			ii.	Humans breathe by creating a vacuum that causes air to enter the lungs. The rib cage and diaphragm expand, pulling the pleural membranes with them and expanding the lungs. 
		c. Expiration Is Usually Passive (p. 171)
			Expiration occurs passively as the elastic recoil of inspiratory muscles decreases the volume of the chest cavity.
8.3 External and Internal Respiration (p. 172, Fig. 8.10)
	1.	The principles of diffusion govern the exchange of gases between the different components involved in respiration.
	2.	External Respiration Cleanses Blood (p. 172)
		a.	External respiration is the exchange of gases between the atmosphere and the blood within the alveoli.
		b.	When the partial pressure of CO2 is greater in the blood than in the alveoli, CO2 diffuses out of the blood. This reaction is sped up by carbonic anhydrase, present in red blood cells. Hemoglobin gives up its hydrogen ions, becoming deoxyhemoglobin.
		c.	When the partial pressure of oxygen is greater in alveoli than in blood, oxygen diffuses into the blood; hemoglobin becomes oxyhemoglobin.
	3.	Internal Respiration Cleanses Tissue Fluid (p. 172)
		a.	Bright red oxyhemoglobin gives up its oxygen when it encounters tissues with a lower partial pressure of oxygen.  
		b.	Carbon dioxide leaves tissues when its partial pressure is greater in tissue than in blood, giving rise to carbaminohemoglobin.
	4.	External and Internal Respiration Revisited (p. 174, Fig. 8.11)
		Whether hemoglobin takes up or gives off oxygen depends on differences in partial pressure, temperature, and pH between the lungs and the tissues. 
8.4 Respiration and Health (p. 175, Fig. 8.12)
	1.	Strep Throat: Risk of Rheumatic Fever (p. 175)
		Strep throat is caused by the bacterium Streptococcus pyogenes and is a serious condition that can lead to rheumatic fever.
	2.	Bronchitis: Acute and Chronic (p. 175)
		a.	Acute bronchitis is usually due to a secondary bacterial infection.
		b.	Chronic bronchitis can be due to constant irritation of the bronchial linings, such as occurs from cigarette smoking.
	3.	Pneumonia: Lobules Fill and Breathing Ceases (p. 175)
		a.	Bacterial or viral infections of the lungs can cause pneumonia. 
		b.	Lobules of the lungs become nonfunctional as they fill with fluid as a result of the infection.
			HEALTH FOCUS: The Most Often Asked Questions About Smoking, Tobacco, and Health, and... The Answers (p. 176, Fig. 8B)
			i.	There is no safe way to smoke, and smoking causes cancer and other lung diseases. The survival rate for lung cancer is very low (13%).
			ii.	Cigarette smoking also affects the heart and is dangerous to unborn fetuses whose mothers smoke.
			iii.	Smoking worsens allergies and breathing difficulties.
			iv.	Passive smoking is also dangerous, as is the use of snuff and chewing tobacco.
	4.	Pulmonary Tuberculosis: Past and Recent Threat (p. 178)
		a.	Tuberculosis is caused by a bacterium that triggers the body to produce tubercles surrounding these bacteria in the lungs. 
		b.	Antibiotic therapy kept tuberculosis at bay early in the twentieth century, but its incidence is on the increase among AIDS patients, the homeless, and the rural poor. Also, new resistant strains are evolving.
	5.	Emphysema: Bronchioles Collapse and Alveoli Burst (p. 178)
		Emphysema is caused by lung tissue that is destroyed as bronchioles collapse and alveoli balloon and burst. 
	6.	Pulmonary Fibrosis: Inhaling Particles (p. 178)
		Inhaling particles (coal dust, fiberglass, asbestos) can lead to pulmonary fibrosis, the buildup of fibrous connective tissue in the lungs. Breathing becomes difficult, and cancer often develops.
	7.	Lung Cancer: Women Catch Up (p. 178)
		a.	More women smoke today than in the past, which has resulted in their rates of lung cancer catching up to those of men.
		b.	Passive, or involuntary, smoking can also lead to lung cancer. 
		c.	If people stop both voluntary and involuntary smoking before lung cancer arises, the lung tissues heal and return to normal with time.
8.5 Working Together (p. 178)
	The Working Together box (p. 179) illustrates how the respiratory system works with the other systems of the body to maintain homeostasis.