Respiratory System: Gas Exchange & Regulation

Question 1

Oxygen

Answer 1

• Constantly being used by cells in the tissues
• Always a LOW partial pressure of O2 in the cells, so it is able to move INTO the cells
• Required for cellular respiration

Question 2

Carbon Dioxide:

Answer 2

• Constantly being produced by cells in the tissues
• Always a HIGH partial pressure of CO2 in the cells, so it is able to move OUT OF the cells
• Product of cellular respiration

Question 3

Hemoglobin

Answer 3

oxygen-carrying molecule, consisting of iron and protein that forms a weak bond with dissolved O2 molecule. There are MILLIONS of hemoglobin on EVERY red blood cell, which can carry 4 oxygen molecules each.

Question 4

CO2 Transport

Answer 4

20X more soluble than oxygen and can move through the body by:
- Dissolved in the plasma (~9%)
- Attached to hemoglobin (~27%) → carbaminohemoglobin
- As carbonic acid with water (~64%) → bicarbonate ions in the blood for pH buffering
CO2 + H2O → H2CO3

Question 5

Chemoreceptors

Answer 5

Specialized nerve receptors that are sensitive to specific chemicals.

Question 6

Carbon Dioxide Chemoreceptors:

Answer 6

• MAIN regulators of breathing
• Located in the medulla oblongata of the brain
• Detects increased amount of CO2 in the form of an acid in blood
  -Nerves cells in medulla oblongata send nerve impulses to diaphragm and intercostal muscles to increase breathing rate
  Increases exchange of CO2 and O2
  When CO2 levels decrease, the chemoreceptors inactivate

Question 7

Oxygen Chemoreceptors:

Answer 7

BACKUP regulators of breathing
Located in the carotid and aortic arteries
Detects decreased levels of O2 [but normal CO2]
Eg. high altitudes, carbon monoxide poisoning
Sends nerve impulses to the medulla oblongata, which send nerve impulses to diaphragm and intercostal muscles to increase breathing rate

Question 8

Factors That INCREASE Breathing rate

Answer 8

CO2 Increase:
O2 Decrease:
[H+] Increase = more acid = more carbonic acid = CO2 + water = carbonic acid:

Question 9

Bronchitis

Answer 9

Inflation of bronchioles
Caused by bacterial or viral infections
Narrowing of air passages
Increased mucus secretions
Difficulty with air movement

Question 10

Asthma

Answer 10

Reversible narrowing of the bronchial passage
Tissues that line the walls of the bronchioles swell and may spasm
Increase in mucus secretions causing difficulty with breathing
May hear wheezing as flow is restricted

Question 11

Emphysema

Answer 11

-Over-inflation of the lungs cause the walls of the alveoli to stretch and rupture
-Loss of alveoli = less surface area for gas exchange = lower O2 level
-Usually accompanied by chronic bronchitis in a condition called Chronic Obstructive Pulmonary Disease (COPD)

Question 12

Lung Cancer:

Answer 12

Uncontrolled growth of cells = tumor
Causes decrease in surface area for gas diffusion
Tumors may even block the bronchioles, reducing the airflow to the lungs (potentially causing lung collapse)

Question 13

Pneumothorax

Answer 13

Collapsed lung

Question 13

Laryngitis

Answer 13

Inflammation of the larynx

Question 14

Respiratory Distress Syndrome

Answer 14

When the lipoprotein on the alveoli is missing in some newborns (especially premature babies) the force to overcome the surface tension is so great that the alveoli are collapsed. May result in death.

Question 15

Oxygen

Answer 15

Highest in atmosphere and Trachea
Lowest in the tissues/cells
Diffuses from atmosphere into alveoli and into blood

Question 16

Hemogoblin ;

Answer 16

bonds to O2 to form oxyhemogoblin
O2 diffuses into tissues

Question 17

CO2

Answer 17

combines with water from plasma forming Carbonic Acid; decreases CO2 in blood
- diffuses from blood into alveoli and eliminated thru exhalation