Question

1. Describe the dynamics of forced breathing (exercise)

2. Describe the effects of CO₂ and O₂ and pH on breathing.

3. What is ventilation-perfusion coupling?

4. Describe how CO₂ and O₂ are transported in blood. When describing carbon dioxide transport use the equations to describe the process at the lungs and at the tissues.

5. Describe using pressure gradients the diffusion of respiratory gases in internal respiration and external respiration.

6. Draw the hemoglobin-saturation curves (on the same graph) demonstrating non-exercise vs. exercise conditions.

Answer 1

1. During normal inspiration, the diaphragm and external intercostal muscles contract, causing the rib cage to expand and move outward, and expanding the thoracic cavity and lung volume . Forced or labored breathing involves the sternocleidomastoid and scalene muscles to lift the upper rib cage even more than in normal breathing. By lifting the upper portion of the rib cage the action of the intercostals is magnified.

during forced exhalation, the internal intercostals and abdominal muscles may be involved in forcing air out of the lungs.

2.Respiration of oxygen,particularly at increased barometric pressure increasesthe breathing and diminishes the pulse rate.These effect are presumably brought by slowing the bllod flow through the tissue,which protects them against the poisonous action of the high oxygen pressure.

As it combines with water, it forms carbonic acid, making the blood acidic. So CO2 in the bloodstream lowers the blood pH. ... Breathing rate and breathing volume increase, the blood pressure increases, the heart rate increases, and kidney bicarbonate production ( in order to buffer the effects of blood acidosis), occur.

Respiratory alkalosis occurs when you breathe too fast or too deep and carbon dioxide levels drop too low. This causes the pH of the blood to rise and become too alkaline. When the blood becomes too acidic, respiratory acidosis occurs

3)It is the coupled action of ventilation and perfusion processit is necessary for efficient gas exchange.

ventilation : the amount of air reaching the alveoli

perfusion :Blood flow in the capillaries

when the ventilation is decreased and perfusion is high ----increase in pco2 and decrease in the po2------pulmonary arterioles will constrict and reduce the perfusion.

when the ventilation is high and perfusion is low---po2 increase and pco2 decreases---- pulmonary arteoles will dilate and increase the perfusion

4) OXYGEN TRANSPORT

Oxygen is trnasported in the blood in 2 ways

1) BY RBC( 97 TO 98%)

bound to hemoglobin

2) DISSOLVED IN PLASMA (2 TO 3%)

CARBON DIOXIDE TRANSPORT

in 3 forms

1)dissolved form

2) As bicarbonate ion

3)carbamino compund (binding with the amino group of plasma protein anf hemoglobin)

most of the carbon dioxide from the tissue is transported in the form of bicarbonate ion

in systemic capillaries

the CO2 released from the tissue will bind with H2O in the RBC to form carbonic acid in the presence of carbonic anhydrase enzzyme. carbonic acid is splitted up to hydrogen ion and bicarbonate ion .this bicarbonate ion is exchanged with the intake of chloride ion .

H2O +CO2 -------------- H2CO3

H3CO3----------------- H+ +HCO3-

In alveolar capillaries

bicarbonate is entered to RBC in exchange of chloride ion, which will bind with the hydrogen ion to form carbonic acid ,this carbonic acid split into H2O and CO2 in the presence of carbonic anhydrase enzyme. CO2 is transpoted across the alveolar capillary membrane in exchange of oxygen.