Bio 235 Assignment 3 | Anatomy and Physiology |
Graded A+ | New 2025-2026 Update
, lOMoAR cPSD| 6861666
Bio 235 Assignment 3 | Anatomy and Physiology |
Graded A+ | New 2025-2026 Update
Answer the following short-answer questions.
1. Some patients who suffer from hypertension (high blood pressure) are prescribed
medications that are in the category of angiotensin-converting enzyme (ACE)
inhibitors. Explain why these drugs are used to combat hypertension.
The enzyme Angiotensin Converting Enzyme (ACE) converts Angiotensin I to Angiotensin II.
Angiotensin II stimulates the suprarenal cortex to release aldosterone, which raises blood
volume and pressure. Aldosterone stimulates Na+ reabsorption in the kidneys, which leads to
osmotic reabsorption of water. As a result, the amount of water lost in the urine is reduced.
In addition, aldosterone encourages the kidneys to secrete more K+ and H+ into the urine.
Blood volume rises as a result of increased water reabsorption by the kidneys. Blood pressure
returns to normal when blood volume increases. Angiotensin II also promotes smooth muscle
contraction in arteriole walls. The resultant vasoconstriction of the arterioles raises blood
pressure, which aids in bringing it back to normal.
Any medication that inhibits ACE will have the opposite effect.
Reference* The Principles of anatomy and physiology (15th Edition).
Gerard J. Tortora, Bryan H Derrickson
2. Describe the fate of an RBC traveling from the heart to the left elbow and back to the
heart.
The blood leaving the left side of the heart will be oxygenated and pumped into systemic
circulation from the left atrium through the left atrioventricular valve to the left ventricle
through the aortic valve to the ascending aorta, aortic arch into the left subclavian artery
through the left axillary artery to the left brachial artery. At the elbow, the blood will flow into
the arterioles and capillaries and then enter the venous system.
In the venous system, the blood in the capillaries will drain into the venules and the left
brachial vein, left median cubital vein, and left cephalic vein. From here it will travel into the
left axillary into the left sub clavian vein into the superior vena cava and into the right atrium.
, lOMoAR cPSD| 6861666
3. Explain the steps that result in antibody production and describe the process that
results in an activated B-cell.
The steps that lead to the production of antibodies include:
• The activation of B-Cells as a result of exposure to a foreign antigen.
• The B-Cell goes through clonal selection, which means it develops a clone of
plasmocytes and memory cells that release antigen-specific antibodies.
• The antibodies go to the invasion site.
• The B-Cell is activated.
• The B-Cell receptor (BCR) binds to an antigen.
• The antigen is taken in by the B-cell, which then breaks it down into peptide
fragments and fuses it with MHC II self-antigens before moving it into its plasma membrane.
• Helper T-Cells identify the antigen-MHC II complex and release interleukin 2 and
other cytokines, causing B-Cells to become activated, proliferate, and differentiate.
• When B-Cells are activated, they generate a clone of B-Cells that includes
plasmocytes and memory B-Cells. Antibodies specific to the antigen that prompted its
activation are secreted by plasma cells.
4. State Boyle’s Law and explain how it relates to the process of pulmonary ventilation.
The pressure of gas in a closed container is inversely proportional to the volume of gas in the
container, according to Boyle's law. Intrapleural pressure is roughly 4 mmHg lower than
atmospheric pressure just before inhalation, or around 756 mmHg at an ambient pressure of
760 mmHg. The capacity of the pleural cavity grows when the diaphragm and external
intercostals contract and the total size of the thoracic cavity increases, lowering intrapleural
pressure to around 754 mmHg. The parietal pleura that lines the thoracic cavity is dragged
outward in all directions as the cavity grows, and the visceral pleura and lungs are drawn along
with it. The pressure of air within the alveoli of the lungs, known as the alveolar
(intrapulmonic) pressure, reduces from 760 to 758 mmHg when the capacity of the lungs
grows in this fashion. As a result, a pressure differential between the atmosphere and the
alveoli is established. Inhalation occurs when air travels from a location of greater pressure to
a region of lower pressure.
5. Describe the Bohr Effect. Explain how PO2 in the lungs and tissue cells determines
whether oxygen binding or dissociation occurs with hemoglobin.
Graded A+ | New 2025-2026 Update
, lOMoAR cPSD| 6861666
Bio 235 Assignment 3 | Anatomy and Physiology |
Graded A+ | New 2025-2026 Update
Answer the following short-answer questions.
1. Some patients who suffer from hypertension (high blood pressure) are prescribed
medications that are in the category of angiotensin-converting enzyme (ACE)
inhibitors. Explain why these drugs are used to combat hypertension.
The enzyme Angiotensin Converting Enzyme (ACE) converts Angiotensin I to Angiotensin II.
Angiotensin II stimulates the suprarenal cortex to release aldosterone, which raises blood
volume and pressure. Aldosterone stimulates Na+ reabsorption in the kidneys, which leads to
osmotic reabsorption of water. As a result, the amount of water lost in the urine is reduced.
In addition, aldosterone encourages the kidneys to secrete more K+ and H+ into the urine.
Blood volume rises as a result of increased water reabsorption by the kidneys. Blood pressure
returns to normal when blood volume increases. Angiotensin II also promotes smooth muscle
contraction in arteriole walls. The resultant vasoconstriction of the arterioles raises blood
pressure, which aids in bringing it back to normal.
Any medication that inhibits ACE will have the opposite effect.
Reference* The Principles of anatomy and physiology (15th Edition).
Gerard J. Tortora, Bryan H Derrickson
2. Describe the fate of an RBC traveling from the heart to the left elbow and back to the
heart.
The blood leaving the left side of the heart will be oxygenated and pumped into systemic
circulation from the left atrium through the left atrioventricular valve to the left ventricle
through the aortic valve to the ascending aorta, aortic arch into the left subclavian artery
through the left axillary artery to the left brachial artery. At the elbow, the blood will flow into
the arterioles and capillaries and then enter the venous system.
In the venous system, the blood in the capillaries will drain into the venules and the left
brachial vein, left median cubital vein, and left cephalic vein. From here it will travel into the
left axillary into the left sub clavian vein into the superior vena cava and into the right atrium.
, lOMoAR cPSD| 6861666
3. Explain the steps that result in antibody production and describe the process that
results in an activated B-cell.
The steps that lead to the production of antibodies include:
• The activation of B-Cells as a result of exposure to a foreign antigen.
• The B-Cell goes through clonal selection, which means it develops a clone of
plasmocytes and memory cells that release antigen-specific antibodies.
• The antibodies go to the invasion site.
• The B-Cell is activated.
• The B-Cell receptor (BCR) binds to an antigen.
• The antigen is taken in by the B-cell, which then breaks it down into peptide
fragments and fuses it with MHC II self-antigens before moving it into its plasma membrane.
• Helper T-Cells identify the antigen-MHC II complex and release interleukin 2 and
other cytokines, causing B-Cells to become activated, proliferate, and differentiate.
• When B-Cells are activated, they generate a clone of B-Cells that includes
plasmocytes and memory B-Cells. Antibodies specific to the antigen that prompted its
activation are secreted by plasma cells.
4. State Boyle’s Law and explain how it relates to the process of pulmonary ventilation.
The pressure of gas in a closed container is inversely proportional to the volume of gas in the
container, according to Boyle's law. Intrapleural pressure is roughly 4 mmHg lower than
atmospheric pressure just before inhalation, or around 756 mmHg at an ambient pressure of
760 mmHg. The capacity of the pleural cavity grows when the diaphragm and external
intercostals contract and the total size of the thoracic cavity increases, lowering intrapleural
pressure to around 754 mmHg. The parietal pleura that lines the thoracic cavity is dragged
outward in all directions as the cavity grows, and the visceral pleura and lungs are drawn along
with it. The pressure of air within the alveoli of the lungs, known as the alveolar
(intrapulmonic) pressure, reduces from 760 to 758 mmHg when the capacity of the lungs
grows in this fashion. As a result, a pressure differential between the atmosphere and the
alveoli is established. Inhalation occurs when air travels from a location of greater pressure to
a region of lower pressure.
5. Describe the Bohr Effect. Explain how PO2 in the lungs and tissue cells determines
whether oxygen binding or dissociation occurs with hemoglobin.
