Respiratory System(part 2)

breathing● terrestrial- ventilate lungs by moving air into and out of respiratory tract

● ventilation is used to maintain a balance amount of oxygen and carbon dioxide between the air in the alveoli (lungs) and blood flowing in capillaries

● expiration- (exhalation) the act of moving air out of the lungs (inactive phase)

● inspiration- (inhalation) the act of moving air into lungs (active phase because muscles are required)

● Reptiles, birds and mammals- use negative pressure to move air into lungs and positive pressure to move air out of lungs

● amphibians- use positive pressure to force air into tract and then pushes air into lungs

Diaphragm● Diaphragm- horizontal muscle dividing the thoracic cavity and

the abdominal cavity

inspiration- lung volume increases and air flows in because of decreased air pressure in the thorax (active)

Expiration- pressure increases in the thorax so air is pushed out of the lungs, no muscle contraction (inactive)

4.B.2 Cooperative interactions within organisms promote efficiency in the use of energy and matter

internal/external intercostal muscles- antagonistic pairs

terrestrial vs. birds● terrestrial (Except birds) use “tidal ventilation mechanism” because air moves in

and out of the same routeo lungs are not completely emptiedo air is mixed with air from previous cycleo conserves water but decreases gas-exchange efficiency

● birds use “one-way ventilation mechanism”

o fresh air never mixes with air used by lungs

o much more efficient

2.D.2 Homeostatic mechanisms reflect both common ancestry and divergence due to adaptation in different environments

Modifications● Respiratory center- controls rhythm of ventilation

o located in the Medulla Oblongata in the brain

● Expiration- respiratory system stops sending neuronal signals to diaphragm and rib cage

● Inspiration- sends impulses by the phrenic nerve (spine) to the diaphragm and intercostal nerves to the muscles

● Also influenced by nervoUS AND CHEMICAL INPUT

○ after forced inspiration- stretch receptors in alveolar walls initiate inhibitory nerve impulses which stops respiratory center from sending impulses

4.A.4: Organisms exhibit complex properties due to interactions betweentheir constituent parts

pH● Respiratory center is sensitive to levels of hydrogen ions

o when carbon dioxide enters blood it releases hydrogen ions and helps regulate breathing rates

● chemoreceptors are sensitive to the changes in pH as well

o carotid bodies (carotid arteries) and aortic bodies (aorta) stimulate the respiratory center during intense exercise because of a reduction in pH or if arterial oxygen decreases by around 50%

● when carbon dioxide, and therefore, hydrogen ions rise and pH decreases then the respiratory center increases rate and depth of breathing

● PH OF BLOOD IS regulated TO STay BetweeN 7.35 TO 7.45 TO keeP ReSPIRaTORY RhyTHm STeady

Gas Exchange

● External Respiration- gas exchange between the air and the blood within the lungs

● Internal Respiration- gas exchange between the blood and tissue fluid

● diffusion governs the movement of gas○ Partial pressure- amount of pressure each gas exchanges ○ oxygen and carbon dioxide diffuse from higher to lower

pressure

● ventilation causes a higher oxygen pressure in the alveoli and a lower carbon dioxide pressure than the blood in the pulmonary capillaries which accounts for the exchange in the lungs

● cellular respiration causes tissue fluid to have a lower oxygen pressure and a higher carbon dioxide pressure than in the capillaries

● type II pneumocytes secrete a solution containing surfactant that creates a moist surface inside the alveoli to prevent the sides of the alveolus from adhering to each other by reducing surface tension

● electron

● type I pneumocytes are extremely thin alveolar cells that are adapted to carry out gas exchange

light microscope

External Respiration● when blood enters the lung, carbon dioxide is being carried by hemoglobin while

some is carrying hydrogen

● Reaction occurs in red blood cells, carbonic anhydrase speeds up the breakdown of carbonic acid

○ by breathing fast it pushes the equation to the far right and can cause you to stop breathing

○ by not breathing (temporary) and pushing the equation to the left breathing will resume because of the rise in hydrogen

● oxygen from lungs combines with hemoglobin in RBC’s to form oxyhemoglobin

● Each hemoglobin has 4 polypeptide chains and each chain is folded around an iron-containing group called heme

○ there are about 250 million hemoglobin molecules in each RBC, so each is capable of carrying 1 billion oxygen molecules

Internal Respiration● RBC’s are red because they contain oxyhemoglobin

o because temperature in tissues is higher and the ph is lower than lungs--therefore oxyhemoglobin has a tendency to give up oxygen

● oxygen diffuses out because oxygen pressure in tissue is lower than blood because of the constant respiration in cells--oxyhemoglobin gives up oxygen, oxygen leaves blood and enters tissue fluid, where it is taken up by cells

● carbon dioxide is produced and taken in by protein portion of the hemoglobin which makes carbaminohemoglobin but most is transported in the form of bicarbonate ion

○ hemoglobin’s oxygen binding affinity is inversely related to the ph and concentration of carbon dioxide (BOHR SHIFT)

Exercise● percentage of saturation of hemoglobin with oxygen determines the content of

oxygen in blood so after around 7000 feet above sea level the saturation of oxyhemoglobin decreases

● Athletes use this to help their performance because it increases the hemoglobin content therefore giving them an advantage when they return to lower ground

AIM 8:Some sports, such as high altitude mountain climbing or scuba diving, may

push the limits of the human body beyond endurance and cause damage. Should they be controlled or banned?

● “Death zones” above 26,000 feet- where no human body can adapt too

Controlled ventilation● ventilation can be monitored by observation or data logging with the use of a

spirometer or chest belt and pressure metero rate and volume are

measured

● ventilation can be measured at rest and also after mild or vigorous exercise with either method

Extras● Fetal hemoglobin is different than adult hemoglobin which allows the

transfer of oxygen in the placenta o because it has a greater affinity to oxygen in has an easier supply to

his/her mother’s oxygen

● Myoglobin is found in the muscle cells and has a greater affinity to oxygen than hemoglobin which is located in red blood cells because more oxygen is needed when muscles are active

INfectionsBronchitus-Airways become inflamed due to infection (acute) or an irritant (chronic)

Pneumonia-bronchi & alveoli fill with fluid

● deep coughs● mucus in throat

● high fever● chest pain● chills● headaches

InfectionsPneumocytis pneumonia- rare form of pneumonia, AIDS patients most susceptible

● used as an identifier if a person may be HIV positive● almost never seen in people with healthy immune systems

Pulmonary Tuberculosis-tubercle bacilli invade lung tissue

● protective capsule formed around bacteria called a tubercle

● elasticity of the lungs is reduced● symptoms include: cough, weight loss, no appetite

Diseases

Pulmonary fibrosis-fibrous connective tissue build up in lungs

● do not inflate properly● caused inhaling sand, coal dust, & asbestos

emphysema- alveoli walls damaged, reducing surface area for gas exchange

● oxygen reaching heart & lungs reduced○ overworking of heart○ depressed, irritable, and sluggish

treatments: pulmonary rehab, nutrition therapy, lung transplant

DisordersAsthma-disease of bronchi & bronchioles. Airways are unusually sensitive to irritants. When exposed, the bronchioles spasm

● pollen● dander● dust ● cigarette smoke

overuse of antibiotics-chances of resistance increase when antibiotics are not used long enough or are taken for the wrong reasons, allowing bacteria to survive and adapt

1.A.2: Natural selection acts on phenotypic variations in populations

Lung Cancer● surpassed breast cancer as a leading cause of death in women

● 150,000 deaths per year, 85% linked to smoking

Stages1. thickening of airway lining

2. loss of cilia- impossible to prevent dust and dirt from accumulating in lungs

3. cells w/ atypical nuclei appear in the lining

4. disordered cells consisting of the atypical nuclei from a tumor

5. cells break loose & spread to other tissueAim 8: social consequences of lung cancer and emphysema?

New Research (published april 20, 2015)

● Lung cancer is the leading cancer killer in the world- 240,000 will be diagnosed this year, while 160,000 will die from it

● A new drug (Keytruda) launches the body’s own immune system to fight tumors, including lung cancer

● most patients saw the cancer stop growing for an average of a year● some still haven’t had the cancer return● After a year, 74% of patients who took keytruda every two weeks

remained alive with the cancer.