Question

1. The lungs and the circulatory system cooperate to supply the body with oxygen and to remove carbon dioxide. In the table below, indicate the relative oxygen and carbon dioxide levels found in the listed structures by writing high, low, or being exchanged.  

Structure	Oxygen Levels	Carbon dioxide levels
Left atrium / left ventricle
Aorta /systemic arteries
Systemic capillaries
Systemic veins/ vena cavae
Right atrium / right ventricle
Capillaries surrounding alveoli
Pulmonary artery
Pulmonary vein

2. Heavy smokers often develop abnormally high blood pressure. The nicotine in tobacco is a potent vasoconstrictor. Explain the connection between these two facts. (Make sure you include what kind of blood vessel is likely affected.
3. When you sneeze, abdominal muscles abruptly contract, pushing your diaphragm upward. Given what you know about respiration, why does this cause air to be expelled from your nose?

Answer 1

1.

Structure	Oxygen Levels	Carbon dioxide Levels
Left atrium/ left ventricle	High	Low
Aorta/ Systemic arteries	High	Low
Systemic capillaries	Exchanged	Exchanged
Systemic veins/ vena cavae	Low	High
Right atrium/ right ventricle	Low	High
Capillaries surrounding alveoli	Exchanged	Exchanged
Pulmonary artery	Low	High
Pulmonary vein	High	Low

- Left atrium recieves oxygenated blood from pulmonary circulation and hence the oxygen levels are high and carbondioxide level is low.

-Left ventricle pumps oxygenated blood into systemic circulation and hence the oxygen level in left ventricle is high and carbondioxide level is low.

-Aorta carries oxygenated blood from left venticle into systemic capillaries so oxygen level is high and carbondioxide levels are low.

- Systemic capillaries are junction points between arteries and veins. They allow nutrients and oxygen into the muscle cells and organ cells from outside and removal of wastes and carbondioxide out of the cell. Hence, here the exchange of oxygen into the cell and carbondioxide out of the cell is taking place.

- Systemic veins carry oxygen poor blood from body to right atrium. So, there is low oxygen level and more high carbondioxide levels.

- Right atrium recieves deoxygenated blood from systemic circulation and right ventricle pumps deoxygenated blood to the pulmmonary circulation . Hence, they have low oxygen level and high carbondioxide level.

-Gaseous exchange takes place in the alveoli in lungs and the capillaries that envelope them. Inhaled oxygen moves from alveoli to blood in capillaries, and carbondioxide moves from blood in capillaries to air in alveoli, Hence, exchange of gases takes place,

- Pulmonary artery carries dexygenated blood from right atrium into the lungs for oxygenation. Hence, pulmonary artery has high levels of carbondioxide and low levels of oxygen.

- Pulmonary vein carry oxygenated blood from lungs to left atrium. So, they have high oxygen and low carbon dioxide levels.

2.Nicotine causes blood vessels to constrict and the flow of blood to the organs through blood vessels is decreased which increases blood pressure.

Some of the blood vessels that are affected are as follows

:Coronary artery, aorta, etc.

Blood pressure is influenced adversely with high rate due to smoking.

Transiently sympathetic responses are observed when a smoker is actively smoking which raises the blood pressure acutely.

However, Epidemiological survey has demonstrated that individuals who smoke has low blood pressure than the non-smokers. This could be primarily attributed to Chronic smoking which could be associated with loss in body weight which is resulting in low blood pressure.

Active smoking is inversely proportional to Systolic Blood Pressure (120/80 mm Hg is normal BP, the top number 120 indicates Systolic blood pressure which is the amount pressure during contraction of heart in the arteries.). So, if there is active smoking there is reduction in Systolic blood pressure. When compared to non smokers there is a Systolic Blood pressure reduction of 4.6 mm Hg in 3.7% of heavy smokers.

No evidence of diastolic blood pressure abnormalities are identified yet.

3.Diaphragm is a thin skeletal muscle which separates abdomen from chest. It sits at the base of the chest.When you breathe in the diaphragm contracts and moves downwards to make space results in chest enlargement and reducing the pressure in the lungs, to balance this the air enters the lungs. In contrast when we breathe out the diaphragm relaxes and moves upwards the lung and chest wall elasticity pushes the air out.

So, we sneeze when a foreign particle enters the nose and causes irritation. This leads the diaphragm to contract suddenly and diaphragm moves upward and to release the irritation in the nose the air is expelled through the nose when the diaphragm contracts and moves upward which generally contracts and moves downwards during inhalation.