BIOS 256 FINAL EXAM QUESTIONS AND
ANSWERS 2026 LATEST UPDATE
what are male gametes? - correct answer -Sperm
What are female gametes? - correct answer -Secondary oocytes
Embryonic period? - correct answer -From fertilization through the eighth week
of development
Fetal period? - correct answer -Begins at week 9 and continues on until birth
Describe the first trimester? - correct 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? - correct answer -14 weeks to 27 weeks. Baby
begins to develop human like features
Describe the third trimester? - correct answer -28 weeks to 40 weeks. Rapid fetal
growth, fetus doubles in weight.
Cleavage of zygote - correct 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? - correct answer -
Increased blood osmolarity(more solutes)
Decreased blood volume
Decreased blood pressure
Dry mouth
, What does a decreased blood pressure stimulate in the kidneys? - correct
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? - correct answer
-Na+ and Cl-
ADH function - correct 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? -
correct answer -Aldosterone and ANP
When is RAAS activated? - correct 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 - correct 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? - correct answer -Na+
and Cl-
What are the most abundant cation and anion of the ICF? - correct answer -K+,
proteins, and phosphates
3 buffer systems in the body - correct answer -(1) the carbonic acid-sodium
bicarbonate buffer system, (2) the phosphate buffer system, and (3) the protein buffer
system.
Exhalation of CO2 as a buffer system - correct answer -Increased exhalation of
CO2 increases exhalation of H+ and increases the pH, decreased exhalation of CO2
decreases exhalation of H+ and decreases the pH
ANSWERS 2026 LATEST UPDATE
what are male gametes? - correct answer -Sperm
What are female gametes? - correct answer -Secondary oocytes
Embryonic period? - correct answer -From fertilization through the eighth week
of development
Fetal period? - correct answer -Begins at week 9 and continues on until birth
Describe the first trimester? - correct 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? - correct answer -14 weeks to 27 weeks. Baby
begins to develop human like features
Describe the third trimester? - correct answer -28 weeks to 40 weeks. Rapid fetal
growth, fetus doubles in weight.
Cleavage of zygote - correct 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? - correct answer -
Increased blood osmolarity(more solutes)
Decreased blood volume
Decreased blood pressure
Dry mouth
, What does a decreased blood pressure stimulate in the kidneys? - correct
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? - correct answer
-Na+ and Cl-
ADH function - correct 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? -
correct answer -Aldosterone and ANP
When is RAAS activated? - correct 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 - correct 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? - correct answer -Na+
and Cl-
What are the most abundant cation and anion of the ICF? - correct answer -K+,
proteins, and phosphates
3 buffer systems in the body - correct answer -(1) the carbonic acid-sodium
bicarbonate buffer system, (2) the phosphate buffer system, and (3) the protein buffer
system.
Exhalation of CO2 as a buffer system - correct answer -Increased exhalation of
CO2 increases exhalation of H+ and increases the pH, decreased exhalation of CO2
decreases exhalation of H+ and decreases the pH
