BIOS 256 Final Exam 2

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BIOS 256 Final Exam 2

• 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 –Answer two-cell stage 1 / 3

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Day 2 –Answer four-cell stage Day 3 –Answer eight-cell stage Day 4 –Answer morula Day 5 –Answer blastocyst Day 6 –Answer Implantation in uterine wall FIGURE 29.5

• What factors stimulate the thirst center in the hypothalamus?

–Answer Increased blood osmolarity(more solutes) Decreased blood volume Decreased blood pressure Dry mouth

• What does a decreased blood pressure stimulate in the kidneys?

–Answer Stim- ulates 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? 2 / 3

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–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 systm.

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.

• Exhalation of CO2 as a buffer system

–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

• Kidneys as a buffer system

–Answer Renal tubules secrete H+ in urine, and reabsorb HCO3- so it is not lost in urine

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