BIOS 256 Final Exam QUESTIONS
AND VERIFIED ANSWERS
2026/2027 UPDATE
What are male gametes?
Sperm
What are female gametes?
Secondary oocytes
Embryonic period?
From fertilization through the eighth week of development
Fetal period?
Begins at week 9 and continues on until birth
Describe the first trimester?
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?
14 weeks to 27 weeks. Baby begins to develop human like features
Describe the third trimester?
28 weeks to 40 weeks. Rapid fetal growth, fetus doubles in weight.
Cleavage of zygote
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?
Increased blood osmolarity(more solutes)
decreased blood volume
, decreased blood pressure
dry mouth
What does a decreased blood pressure stimulate in the kidneys?
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?
Na+ and cl-
Adh function
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?
Aldosterone and anp
When is raas activated?
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
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?
Na+ and cl-
What are the most abundant cation and anion of the icf?
K+, proteins, and phosphates
3 buffer systems in the body
(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
AND VERIFIED ANSWERS
2026/2027 UPDATE
What are male gametes?
Sperm
What are female gametes?
Secondary oocytes
Embryonic period?
From fertilization through the eighth week of development
Fetal period?
Begins at week 9 and continues on until birth
Describe the first trimester?
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?
14 weeks to 27 weeks. Baby begins to develop human like features
Describe the third trimester?
28 weeks to 40 weeks. Rapid fetal growth, fetus doubles in weight.
Cleavage of zygote
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?
Increased blood osmolarity(more solutes)
decreased blood volume
, decreased blood pressure
dry mouth
What does a decreased blood pressure stimulate in the kidneys?
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?
Na+ and cl-
Adh function
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?
Aldosterone and anp
When is raas activated?
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
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?
Na+ and cl-
What are the most abundant cation and anion of the icf?
K+, proteins, and phosphates
3 buffer systems in the body
(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
