The Breath of Life Video

Are the human lungs identical? (answer is at the bottom of the page)

A. Respiration - has two definitions

1) The release of energy from nutrients
2) The Gas Exchange of Oxygen and Carbon-Dioxide between the organism and the environment.

B. Requirements of a Respiratory Surface:

1) surface must be thin walled so that diffusion across it can occur rapidly
2) surface must be moist because the Oxygen and Carbon-Dioxide must be in a solution
3) surface must be in contact with a source of Oxygen that exists in the surroundings
4) surface must be in contact w/ the transport system that carries dissolved materials to & from the cells of the organism

II. Adaptions: processes of respiration are similar in most organisms, various adaptations for the exchange of respiratory gases are present in living things

A. Protista: (amoeba & paramecium)

1. don't need a special respiratory system
2. rely on direct diffusion w/ environment
3. also includes kingdoms: Monera & Fungi

B. Animals:

1. Hydra - same as protists
- don't need a special respiratory system
- rely on direct diffusion w/ environment

2. Aquatic Organisms (fish, clams, oysters, lobsters, sharks, etc.)
- must move large volumes of water over their respiratory surface because:
a) the concentration of Oxygen in water is low
b) the diffusion of Oxygen in water is slow
3) gills- thin filaments of skin richly supplied with blood vessels that provide a large surface area for gas exchange

3. Earthworm- belong to the phylum Annelid which means "segmented worm"
a) SKIN is respiratory surface which must be kept moist for oxygen to dissolve in & diffuse across the skin
b) skin secretes mucus which facilitates the diffusion of gases into & out of blood
c) hemoglobin- respiratory pigment proteins in blood that increases oxygen & carbon dioxide carrying capacity

4. Grasshopper- belong to the phylum Arthropod which means "jointed appendages"
a) air enters through openings called spiracles
b) spiracles lead to tracheal tubes (is the respiratory surface) which transport gases to all cells
c) no hemoglobin, so blood does NOT carry respiratory gases

5. Human Respiratory System
a) alveoli (respiratory surface) in the lungs are thin, moist, internal gas exchange surface
b) hemoglobin aids in the transport of oxygen
c) chart below describes flow of air during inhalation

Functional Organization of the Respiratory System	The respiratory system is composed of a network of passageways which permit air to flow from the external environment to the lungs
Nasal Cavity	The nasal cavity is exposed to the air through the nostrils which is lined with a ciliated mucous membrane which filters, warms, and moistens the air.
Pharynx	The pharynx is the area in which the oral cavity & nasal cavity meet. Food is prevented from entering the trachea by the epiglottis.
Trachea	The trachea is kept open by rings of cartilage. The ciliated mucous membrane which lines the trachea traps microscopic particles & sweeps them toward the bronchi. Deposits from cigarette smoke & other atmospheric pollutants may interfere with the action of cilia.
Bronchi	The 2 major subdivisions of the trachea are the bronchi. The bronchi are lined with mucous membrane & ringed with cartilage. Each bronchus extends into a lung where it subsidvides many times forming progressively smaller bronchioles.
Bronchioles	Bronchioles are lined with mucous membrane but lack cartilage rings and no cilia present. Tiny bronchioles terminate with the alveoli.
Alveoli	Alveoli are the functional units for gas exchange. They are thin, moist, & surrounded by capillaries. In humans, oxyhemoglobin is in highest concentration in the capillaries of alveoli.
Lung	Each bronchus with its bronchioles and alveoli is called a lung.

1. Breathing: bringing air into & out of lungs (2 PHASES)

Inhalation (inspiration)-	1. diaphragm pulled down
active phase	2. ribs pulled up & out
	3. (-) pressure causes air to fill lungs
Exhalation (expiration)-	1. diaphragm relaxes, comes up
passive phase	2. ribs relax, drop down & in
	3. (+) pressure forces air out of lungs

Breathing rate is affected by carbon dioxide level (NOT the AMOUNT of OXYGEN) in blood & its affect on the respiratory center of the brain. Also, the acidity of the blood (caused by lactic acid) stimulates the respiratory center.

2. External Respiration: exchange of gases between air & blood in the alveoli

3. Circulation: bringing respiratory gases to different parts of body

4. Internal Respiration: exchange of oxygen for carbon dioxide between blood & body cells

1. Asthma- severe allergic reaction that constricts bronchioles
2. Bronchitis- inflammation of bronchial tubes
3. Emphysema- lungs lose elasticity, shortness of breath
4. Pneumonia- fluid in alveoli
5. Lung Cancer- tumors form in lungs

Take a Body Quest Quiz on the Respiratory System lungs identical?

Science Trivia

1. Are the lungs identical? answer

2. Why does the human voice sound so strange after breathing helium? answer

return to Mr. Buono's syllabus