BIOS 256 FINAL EXAM QUESTIONS AND ANSWERS 2025
what are male gametes? - (ANSWER)Sperm
What are female gametes? - (ANSWER)Secondary oocytes
Embryonic period? - (ANSWER)From fertilization through the eighth week of development
Fetal period? - (ANSWER)Begins at week 9 and continues on until birth
Describe the first trimester? - (ANSWER)The first trimester is from conception to 13 weeks. This period is
very critical to babies health due to the extensive oran-system development, and baby is most
vulnerable to teratogens.
Describe the second trimester? - (ANSWER)14 weeks to 27 weeks. Baby begins to develop human like
features
Describe the third trimester? - (ANSWER)28 weeks to 40 weeks. Rapid fetal growth, fetus doubles in
weight.
Cleavage of zygote - (ANSWER)Mitotic division after fertilization
Day 1: two-cell stage
Day 2: four-cell stage
Day 3: eight-cell stage
Day 4: morula
Day 5: blastocyst
Day 6: Implantation in uterine wall
FIGURE 29.5
What factors stimulate the thirst center in the hypothalamus? - (ANSWER)Increased blood
osmolarity(more solutes)
, BIOS 256 FINAL EXAM QUESTIONS AND ANSWERS 2025
Decreased blood volume
Decreased blood pressure
Dry mouth
What does a decreased blood pressure stimulate in the kidneys? - (ANSWER)Stimulates the release of
renin, which increases angiotensin II formation, leading to increased thirst, increased water intake, and
increased blood volume, and increased blood pressure
What are the two main solutes in extracellular fluid and in urine? - (ANSWER)Na+ and Cl-
ADH function - (ANSWER)ADH responds to increased osmolarity, by inserting aquaporins in late DCT and
collecting ducts, which increases the permeability to water and allows for more water to be reabsorbed,
decreasing blood osmolarity, increasing blood volume, increasing blood pressure
What are the two most important hormones in renal reabsorption and urine regulation? -
(ANSWER)Aldosterone and ANP
When is RAAS activated? - (ANSWER)Decreased blood pressure or Na+ deficiency in plasma, this causes
an increase in renin release which activates the RAAS system. This increases Na+ reabsorption and water
reabsorption in the late DCT and collecting ducts
Functions of ANP - (ANSWER)ANP responds to increased blood volume and increased stretch of atria of
the heart, promoting natriuresis (elevated excretion of Na+ into urine). Where sodium goes, water
follows, therefore there is also a loss of water, and a decrease in blood volume.
What are the most abundant cation and anion of ECF? - (ANSWER)Na+ and Cl-
What are the most abundant cation and anion of the ICF? - (ANSWER)K+, proteins, and phosphates
3 buffer systems in the body - (ANSWER)(1) the carbonic acid-sodium bicarbonate buffer system, (2) the
phosphate buffer system, and (3) the protein buffer system.
what are male gametes? - (ANSWER)Sperm
What are female gametes? - (ANSWER)Secondary oocytes
Embryonic period? - (ANSWER)From fertilization through the eighth week of development
Fetal period? - (ANSWER)Begins at week 9 and continues on until birth
Describe the first trimester? - (ANSWER)The first trimester is from conception to 13 weeks. This period is
very critical to babies health due to the extensive oran-system development, and baby is most
vulnerable to teratogens.
Describe the second trimester? - (ANSWER)14 weeks to 27 weeks. Baby begins to develop human like
features
Describe the third trimester? - (ANSWER)28 weeks to 40 weeks. Rapid fetal growth, fetus doubles in
weight.
Cleavage of zygote - (ANSWER)Mitotic division after fertilization
Day 1: two-cell stage
Day 2: four-cell stage
Day 3: eight-cell stage
Day 4: morula
Day 5: blastocyst
Day 6: Implantation in uterine wall
FIGURE 29.5
What factors stimulate the thirst center in the hypothalamus? - (ANSWER)Increased blood
osmolarity(more solutes)
, BIOS 256 FINAL EXAM QUESTIONS AND ANSWERS 2025
Decreased blood volume
Decreased blood pressure
Dry mouth
What does a decreased blood pressure stimulate in the kidneys? - (ANSWER)Stimulates the release of
renin, which increases angiotensin II formation, leading to increased thirst, increased water intake, and
increased blood volume, and increased blood pressure
What are the two main solutes in extracellular fluid and in urine? - (ANSWER)Na+ and Cl-
ADH function - (ANSWER)ADH responds to increased osmolarity, by inserting aquaporins in late DCT and
collecting ducts, which increases the permeability to water and allows for more water to be reabsorbed,
decreasing blood osmolarity, increasing blood volume, increasing blood pressure
What are the two most important hormones in renal reabsorption and urine regulation? -
(ANSWER)Aldosterone and ANP
When is RAAS activated? - (ANSWER)Decreased blood pressure or Na+ deficiency in plasma, this causes
an increase in renin release which activates the RAAS system. This increases Na+ reabsorption and water
reabsorption in the late DCT and collecting ducts
Functions of ANP - (ANSWER)ANP responds to increased blood volume and increased stretch of atria of
the heart, promoting natriuresis (elevated excretion of Na+ into urine). Where sodium goes, water
follows, therefore there is also a loss of water, and a decrease in blood volume.
What are the most abundant cation and anion of ECF? - (ANSWER)Na+ and Cl-
What are the most abundant cation and anion of the ICF? - (ANSWER)K+, proteins, and phosphates
3 buffer systems in the body - (ANSWER)(1) the carbonic acid-sodium bicarbonate buffer system, (2) the
phosphate buffer system, and (3) the protein buffer system.
