BIO 105 EXAM 3 PRACTICE QUESTIONS WITH
DETAILED EXPLANATIONS 2026
◉ What is the primary function of the urinary system regarding
metabolic waste?
Answer: Excretion: the removal of metabolic waste products like
urea, uric acid, and creatinine from the body.
◉ How do the kidneys maintain blood pH?
Answer: By excreting excess hydrogen ions (H+) when blood is too
acidic and reabsorbing bicarbonate ions (HCO3-) when blood is too
alkaline.
◉ What is the effect of high salt (NaCl) levels in the blood on blood
volume and pressure?
Answer: It increases blood volume and blood pressure.
◉ Which hormone secreted by the kidneys stimulates red blood cell
production?
Answer: Erythropoietin.
◉ What is the role of Renin in the urinary system?
,Answer: It initiates a series of events leading to the production of
angiotensin II, which regulates blood pressure and electrolyte
balance.
◉ What is the two-step process for Vitamin D activation?
Answer: First, conversion in the liver, followed by renal conversion
in the kidneys.
◉ What causes gout?
Answer: The accumulation of uric acid crystals in the joints, leading
to inflammatory arthritis.
◉ What is the micturition reflex?
Answer: The reflex initiated by stretch receptors in the bladder wall
when it fills, signaling the brain that urination is needed.
◉ What are the three prominent regions of the kidney?
Answer: Renal cortex (outer), renal medulla (inner), and renal pelvis
(central cavity).
◉ What is a nephron?
Answer: The microscopic functional unit of the kidney responsible
for producing urine.
, ◉ Where does the filtration of blood occur within the nephron?
Answer: In the glomerular capsule (Bowman's capsule).
◉ What is the difference between tubular reabsorption and tubular
secretion?
Answer: Reabsorption returns essential molecules from the filtrate
to the blood, while secretion removes waste products from the blood
into the tubules.
◉ Name the three sections of the renal tubule.
Answer: Proximal convoluted tubule (PCT), loop of the nephron
(Loop of Henle), and distal convoluted tubule (DCT).
◉ What is the function of Aldosterone in urine regulation?
Answer: It increases the reabsorption of sodium and water, thereby
increasing blood volume and pressure.
◉ What is the function of Antidiuretic hormone (ADH)?
Answer: It increases the absorption of water, conserving water and
increasing blood volume.
◉ What is the function of Atrial natriuretic peptide (ANP)?
Answer: It decreases the reabsorption of sodium and water, leading
to decreased blood volume and pressure.
DETAILED EXPLANATIONS 2026
◉ What is the primary function of the urinary system regarding
metabolic waste?
Answer: Excretion: the removal of metabolic waste products like
urea, uric acid, and creatinine from the body.
◉ How do the kidneys maintain blood pH?
Answer: By excreting excess hydrogen ions (H+) when blood is too
acidic and reabsorbing bicarbonate ions (HCO3-) when blood is too
alkaline.
◉ What is the effect of high salt (NaCl) levels in the blood on blood
volume and pressure?
Answer: It increases blood volume and blood pressure.
◉ Which hormone secreted by the kidneys stimulates red blood cell
production?
Answer: Erythropoietin.
◉ What is the role of Renin in the urinary system?
,Answer: It initiates a series of events leading to the production of
angiotensin II, which regulates blood pressure and electrolyte
balance.
◉ What is the two-step process for Vitamin D activation?
Answer: First, conversion in the liver, followed by renal conversion
in the kidneys.
◉ What causes gout?
Answer: The accumulation of uric acid crystals in the joints, leading
to inflammatory arthritis.
◉ What is the micturition reflex?
Answer: The reflex initiated by stretch receptors in the bladder wall
when it fills, signaling the brain that urination is needed.
◉ What are the three prominent regions of the kidney?
Answer: Renal cortex (outer), renal medulla (inner), and renal pelvis
(central cavity).
◉ What is a nephron?
Answer: The microscopic functional unit of the kidney responsible
for producing urine.
, ◉ Where does the filtration of blood occur within the nephron?
Answer: In the glomerular capsule (Bowman's capsule).
◉ What is the difference between tubular reabsorption and tubular
secretion?
Answer: Reabsorption returns essential molecules from the filtrate
to the blood, while secretion removes waste products from the blood
into the tubules.
◉ Name the three sections of the renal tubule.
Answer: Proximal convoluted tubule (PCT), loop of the nephron
(Loop of Henle), and distal convoluted tubule (DCT).
◉ What is the function of Aldosterone in urine regulation?
Answer: It increases the reabsorption of sodium and water, thereby
increasing blood volume and pressure.
◉ What is the function of Antidiuretic hormone (ADH)?
Answer: It increases the absorption of water, conserving water and
increasing blood volume.
◉ What is the function of Atrial natriuretic peptide (ANP)?
Answer: It decreases the reabsorption of sodium and water, leading
to decreased blood volume and pressure.
