The Breath of Life

Respiration Most organisms on Earth are aerobic. Meaning, they require oxygen to survive. The basic function of the respiratory system is to take in oxygen and release carbon dioxide

Two Conditions There must be a surface to carry out the gas exchange: Skin, Gills or Lungs Gas exchange must occur in a moist environment.

Respiration – Subdivided into 4 categories Breathing – the physical act of taking in a releasing air. External respiration – the exchange of oxygen and carbon dioxide between the air and blood. Internal respiration – exchange of gases between blood and cells. Cellular respiration – chemical reactions taking place within the cells.

Gas Exchange Gases diffuse due to a concentration gradient. Oxygen present in air and water move from an area of high concentration to an area of low concentration. Question 1 - what is the gradient? Question 2 - what causes the gradient?

How gas exchange works? Gills, skin and lungs have many things in common. all must be moist have a large thin surface area a special blood supply. Why are these requirements of a respiratory system? Answers???? ……

Surface area!!! All gas exchangers increase their effectiveness by increasing their surface area. This often involves folds, wrinkles or sacs - anything that will increase area (but stay thin).

Examples

Anatomy of the Respiratory System nose (nostrils) nasal passages Pharnyx Glottis and epiglottis larnyx trachea (windpipe) bronchi bronchiole tubes bronchioles alveoli diaphragm

End of show Review the names for each part of the respiratory system. Read pages 332 – 337 Do #1,2,3 & 5

Mechanics of Breathing

Four Physical Stages of Gas Exchange breathing - the movement of air in and out of the lungs external respiration - the exchange of O2 and CO2 between air and the blood in the lungs internal respiration - exchange of O2 and CO2 between blood in capillaries Cellular respiration - cellular process.

Breathing inhale and exhale lungs are elastic - no muscles - they don’t move on their own lungs expand and contract as a result of pressure changes from movements of the diaphragm, ribs and rib muscles

Bulk Flow: Air into Lungs • Diaphragm allows inspiration • Intercostal muscles allow forceful expiration

Inhale External intercostal muscles contract pulling the ribs up diaphragm contracts and pulls down this increases the chest cavity size causing the pressure in the lungs to decrease. outside air then rushes inside as lungs expand

Inspiration

Exhale A passive activity due to the elastic, spongy nature of lung tissue Diaphragm relaxes moving upward Intercostals relax causing ribs to drop chest cavity size decreases causing lung pressure increases causing air to be forced out of the lungs

Expiration

Gas Exchange External Respiration

External Respiration the exchange of O2 and CO2 in air and lungs O2 dissolves in moist lining of alveoli CO2 diffuses out of alveoli ! Gases diffuse down a concentration gradient !

Gas Exchange Internal Respiration

Internal Respiration Cells are constantly using oxygen The concentration of oxygen in the cell is less than that in the blood. Therefore oxygen will leave the blood and diffuse into the cell - Remember substances diffuse from areas of high concentration to areas of low concentration.

Internal Respiration ( Continued) Cells produce carbon dioxide as a waste product The cellular concentration of carbon dioxide is higher than the blood concentration. Therefore, carbon dioxide will diffuse out of the cell into the blood where it is taken to the lungs to be expelled

Gas Exchange

Blood Flow Blood flow to an organ of respiration can greatly increase the amount of gases exchanged. Transporting away oxygen and bringing carbon dioxide to the gas exchanger.

Respiration Review Air bulk flow caused by lungs From air in lungs to red blood cells Blood bulk flow caused by heart From red blood cells to body cells

Transport of Gases in Blood Oxygen is bound to hemoglobin in RBC’s. Some carbon dioxide is transported bound to hemoglobin and some dissolves in plasma - Most carbon dioxide is transported in the form of bicarbonate ions - once in the lungs the bicarbonate is converted back to carbon dioxide

Bulk Flow: Blood carries O2 to Body Cells

End of Show

Respiratory Health

Carbon Monoxide Poisoning Binds to hemoglobin very strongly and doesn’t let go easily. This prevents oxygen from binding This decreases the amount of oxygen reaching cells If severe you get tired, feel like sleeping, lie down and DIE!!!!

Diseases of the Respiratory System Pneumonia  a disease of the lungs where the alveoli become inflamed and fill with liquids. This prevents oxygen adsorption so the body becomes starved for oxygen. Still one of the leading causes of death amongst the elderly. 2 types: Lobar and Bronchial

Bronchitis  bacterial or viral infections that cause increased mucus production in lungs Asthma  allergic reaction, swelling of the bronchioles

Emphysema  lungs loose their elasticity and there is increased resistance to airflow through the bronchioles Lung Cancer – an uncontrollable growth of cells within the lung. Causes most problem when the cells break free and move throughout the body.

Lung Cancer