Title: The Excretory System
Course: Question Banks

Q: What is osmoregulation?
- the maintenance of hormones and water balance across membranes within the body’s fluids. (Incorrect. Osmoregulation is maintenance of salt and water balance.)
- the maintenance of salt and hormone balance across membranes within the body’s fluid. (Incorrect. Osmoregulation is maintenance of salt and water balance.)
- the maintenance of salt and water balance across membranes within the body’s fluids (Correct.)
A: the maintenance of salt and water balance across membranes within the body’s fluids

Q: What is an electrolyte?
- a solute that doesn’t dissociate into ions during water dissolution (Incorrect. A non-electrolyte doesn’t dissociate into ions during water dissolution.)
- a messenger involved in osmoregulation. (Incorrect. A solute dissociates into ions when dissolved in water.)
- a solute that dissociates into ions when dissolved in water (Correct.)
A: a solute that dissociates into ions when dissolved in water

Q: What happens to a cell placed in a hypotonic solution?
- The cell membrane tends to shrivel up. (Incorrect. A cell placed in a solution with higher salt concentration, on the other hand, tends to make the membrane shrivel up due to loss of water into the hypertonic or “high salt” environment.)
- The cell maintains normal shape. (Incorrect. This happens when you have isotonic cells which have an equal concentration of solutes inside and outside the cell; this equalizes the osmotic pressure on either side of the cell membrane which is a semi-permeable membrane.)
- The cell tends to swell. (Correct. A cell placed in water tends to swell due to gain of water from the hypotonic or “low salt” environment.)
A: The cell tends to swell.

Q: What is the unit for measuring solutes?
- milliequivalents per liter (Incorrect. Electrolyte concentrations are usually expressed in terms of milliequivalents per liter (mEq/L).)
- milliliter (Incorrect. This is the unit of measure for liquids. Mole is the correct unit for measuring solutes.)
- mole (Correct.)
A: mole

Q: What is osmotic pressure influenced by ________.
- the size of the solute molecules (Incorrect. Osmotic pressure is influenced by the concentration of solutes in a solution.)
- cell membranes (Incorrect. Osmotic pressure is influenced by the concentration of solutes in a solution.)
- the concentration of solutes in a solution (Correct. It is directly proportional to the number of solute atoms or molecules and not dependent on the size of the solute molecules.)
A: the concentration of solutes in a solution

Q: Water can pass through membranes via ________.
- active transport (Incorrect. Water passes through the membrane by passive diffusion)
- facilitated diffusion (Incorrect. Water does not require protein-based channels for moving the solute, it passes through the membrane by passive diffusion.)
- passive diffusion (Correct.)
A: passive diffusion

Q: Seawater is ________ in comparison to human body fluids.
- isotonic (Incorrect. Most marine invertebrates may be isotonic with seawater. Seawater, however, is hypertonic in comparison to human body fluids.)
- hypotonic (Incorrect. Persons lost at sea without any fresh water to drink are at risk of severe dehydration because the human body cannot adapt to drinking seawater, which is hypertonic in comparison to body fluids.)
- hypertonic (Correct. Persons lost at sea without any fresh water to drink are at risk of severe dehydration because the human body cannot adapt to drinking seawater, which is hypertonic in comparison to body fluids.)
A: hypertonic

Q: What type of organism that can tolerate a relatively wide range of salinity?
- stenohaline (Incorrect. A stenohaline organism can only survive within a narrow range of salinities.)
- ureotelic (Incorrect. An organism that can tolerate a relatively wide range of salinity is euryhaline, a ureotelic organism secretes urea.)
- euryhaline (Correct. Organisms like the salmon and molly that can tolerate a relatively wide range of salinity are referred to as euryhaline organisms.)
A: euryhaline

Q: What is an osmoconformer?
- organisms that retain their body fluid concentrations despite the salt concentrations in their environment. (Incorrect. This is an osmoregulators which tightly regulates its body osmolarity. Osmoregulators actively control salt concentrations despite the salt concentrations in the environment. An example is freshwater fish.)
- organisms that can only survive within a narrow range of salinities. (Incorrect. This is a stenohaline, an osmoconformer changes their body fluid concentrations to conform to changes in seawater.)
- marine organisms that change their body fluid concentrations to conform to changes in seawater (Correct. Most marine invertebrates may be isotonic with seawater. Their body fluid concentrations conform to changes in seawater concentration.)
A: marine organisms that change their body fluid concentrations to conform to changes in seawater

Q: What is the effect of renin on osmoregulation?
- prevents water loss (Incorrect. Anti-diuretic hormone prevents water loss, renin increases blood pressure by acting on angiotensinogen.)
- prevents loss of sodium and water (Incorrect. Aldosterone prevents sodium and water loss, renin increases blood pressure by acting on angiotensinogen.)
- increases blood pressure by acting on angiotensinogen (Correct.)
A: increases blood pressure by acting on angiotensinogen

Q: How do epinephrine and norepinephrine impact osmoregulation?
- They decrease blood pressure by acting as a vasodilator and increasing glomerular filtration rate. (Incorrect. The atrial natriuretic peptide (ANP) lowers blood pressure by acting as a vasodilator. Epinephrine and norepinephrine temporarily halt kidney function.)
- They help the body conserve water when body fluid volume, especially that of blood, is low. (Incorrect.)
- They temporarily halt kidney function. (Correct. During stress, much of the body’s energy is used to combat imminent danger. Kidney function is halted temporarily by epinephrine and norepinephrine. These hormones function by acting directly on the smooth muscles of blood vessels to constrict them.)
A: They temporarily halt kidney function.

Q: Where is atrial natriuretic peptide (ANP) produced?
- the hypothalamus (Incorrect.)
- the adrenal cortex (Incorrect.)
- the heart (Correct.)
A: the heart

Q: What is the function of the kidney?
- to aid with digestion and regulate blood sugar (Incorrect. This is the pancreas.)
- to control the body’s calcium levels (Incorrect. The parathyroid controls the body’s calcium levels and the kidney in involved in filtering and purifying blood.)
- to filter blood and purify (Correct.)
A: to filter blood and purify

Q: What is the outermost layer of the kidney?
- renal capsule (Incorrect. The third and innermost layer is the renal capsule.)
- perirenal fat capsule (Incorrect. The second layer is called the perirenal fat capsule, which helps anchor the kidneys in place.)
- renal fascia (Correct. The outermost layer is a tough connective tissue layer called the renal fascia.)
A: renal fascia

Q: ________ is the functional unit of the kidney.
- The glomerulus (Incorrect. The nephron is the functional unit of the kidney, the glomerulus is a network of capillaries)
- Bowman’s capsule (Incorrect. This surround the glomerulus or network of capillaries. The nephron is the functional unit of the kidney.)
- The nephron (Correct.)
A: The nephron

Q: What is the second step in kidney filtration?
- Nephrons filter the blood that runs through the capillary network. (Incorrect. This is the first step.)
- Additional solutes and wastes are secreted into the kidney tubules during tubular secretion. (Incorrect. This is the third step.)
- The filtrate is collected in the renal tubules. (Correct.)
A: The filtrate is collected in the renal tubules.

Q: What is the juxtaglomerular complex?
- the concave part of the bean-shape where blood vessels and nerves enter and exit the kidney (Incorrect. The juxtaglomerular complex is an endocrine structure that secretes the enzyme renin and the hormone erythropoietin.)
- the initial blood-filtering component of the nephron (Incorrect. This is the renal corpuscle. The juxtaglomerular complex is an endocrine structure that secretes the enzyme renin and the hormone erythropoietin.)
- an endocrine structure that secretes the enzyme renin and the hormone erythropoietin (Correct.)
A: an endocrine structure that secretes the enzyme renin and the hormone erythropoietin

Q: All solutes in the glomerular capillaries, except ________, pass through by passive diffusion.
- lipid-derived hormones (Incorrect.)
- sodium (Incorrect.)
- for macromolecules like proteins (Correct.)
A: for macromolecules like proteins

Q: How does the amoeba and other unicellular organisms ingest food?
- exocytosis (Incorrect. Amoebas and other unicellular organisms use endocytosis to ingest food.)
- passive transport (Incorrect. Amoebas and other unicellular organisms use endocytosis to ingest food.)
- endocytosis (Correct. Some cells like bacteria, protozoa are able to engulf food by endocytosis—the formation of vesicles by involution of the cell membrane within the cells.)
A: endocytosis

Q: What organisms excrete waste by exocytosis?
- flatworms (Incorrect. Amoebas and other unicellular organisms use exocytosis to excrete cellular wastes and excess water.)
- earthworms (Incorrect. Amoebas and other unicellular organisms use exocytosis to excrete cellular wastes and excess water.)
- unicellular organisms (Correct. Amoebas and other unicellular organisms use exocytosis to excrete food.)
A: unicellular organisms

Q: What is the function of contractile vacuoles?
- to store food and water (Incorrect. Vacuoles store food and water, contractile vacuoles are involved in excretion.)
- to provide structure and support to the cell (Incorrect. Central vacuoles provide structure and support to plant cells, contractile vacuoles are involved in excretion.)
- to merge with the cell membranes and expel waste (Correct.)
A: to merge with the cell membranes and expel waste

Q: What type of excretion system do flatworms have?
- exocytosis (Incorrect. Unicellular organisms use exocytosis for excretion, flatworms have two tubules connected to a highly branched duct system.)
- excretory structures called nephridia (Incorrect. This is the excretion system of earthworms, flatworms have two tubules connected to a highly branched duct system.)
- two tubules connected to a highly branched duct system (Correct.)
A: two tubules connected to a highly branched duct system

Q: What type of cells does the excretory system of flatworms have?
- nephridia (Incorrect. Earthworms (annelids) have slightly more evolved excretory structures called nephridia. Flatworms have flame cells.)
- microvilli (Incorrect. Malpighian tubules are convoluted, which increases their surface area, and they are lined with microvilli for reabsorption and maintenance of osmotic balance. Flatworms have flame cells.)
- flame cells (Correct. Their excretory system of flatworms consist of two tubules connected to a highly branched duct system. The cells in the tubules are called flame cells.)
A: flame cells

Q: In what organism does excretion occur through a pore called the nephridiopore?
- flatworm (Incorrect. Excretion in earthworm occurs through the nephridiopore.)
- unicellular organisms (Incorrect. Excretion in earthworm occurs through the nephridiopore.)
- earthworm (Correct. Earthworms (annelids) have slightly more evolved excretory structures than flatworms called nephridia. Excretion occurs through a pore called the nephridiopore.)
A: earthworm

Q: What are Malpighian tubules?
- part of the nephridia, an excretory organ (Incorrect. This is the nephridiopore which is found in organisms like flatworms.)
- tubules of the flatworm excretory system (Incorrect. Malpighian tubules are found in some insects.)
- a type of excretory and osmoregulatory system found in some insects (Correct.)
A: a type of excretory and osmoregulatory system found in some insects

Q: What are Malpighian tubules lined with ________.
- flame cells (Incorrect. The excretory system of flatworms consist of two tubules connected to a highly branched duct system. The cells in the tubules are called flame cells.)
- nephridia (Incorrect. The nephridia is an excretory organ found in organisms such as flatworms.)
- microvilli (Correct. Malpighian tubules are convoluted, which increases their surface area, and they are lined with microvilli for reabsorption and maintenance of osmotic balance.)
A: microvilli

Q: What are actively transported into the lumen of the Malpighian tubules?
- H^+ ions (Incorrect. There are exchange pumps lining the tubules, which actively transport H^+ ions into the cell and K^+ or Na^+ ions out; water passively follows to form urine.)
- Na^+ and/or Cl^− ions (Incorrect. There are exchange pumps lining the tubules, which actively transport H^+ ions into the cell and K+ or Na^+ ions out; water passively follows to form urine.)
- Na^+ and/or K^+ ions (Correct. There are exchange pumps lining the tubules, which actively transport H^+ ions into the cell and K^+ or Na^+ ions out; water passively follows to form urine.)
A: Na^+ and/or K^+ ions

Q: Animals that live in aquatic environments tend to release ________ into the water.
- urea (Incorrect. Animals that live in aquatic environments tend to release ammonia into the water.)
- uric acid (Incorrect. Animals that live in aquatic environments tend to release ammonia into the water.)
- ammonia (Correct.)
A: ammonia

Q: What are ureotelic animals?
- animals that secrete ammonia as the primary nitrogenous waste (Incorrect. These animals are ammonotelic, ureotelic animals secrete urea.)
- animals that secrete uric acid as the primary nitrogenous waste (Incorrect. These animals are uricotelic, ureotelic animals secrete urea.)
- animals that secrete urea as the primary nitrogenous waste (Correct.)
A: animals that secrete urea as the primary nitrogenous waste

Q: Urea is made in the ________ and excreted in urine.
- kidneys (Incorrect. The urea cycle is the primary mechanism by which mammals convert ammonia to urea. Urea is made in the liver and excreted in urine.)
- pancreas (Incorrect. The urea cycle is the primary mechanism by which mammals convert ammonia to urea. Urea is made in the liver and excreted in urine.)
- liver (Correct. The urea cycle is the primary mechanism by which mammals convert ammonia to urea. Urea is made in the liver and excreted in urine.)
A: liver