Bios 256 Exam 3
Bios 256 Exam 3
Bios 256 Exam 3
Accurate Exam Coverage Area
1. Acid-Base Balance: Normal blood pH range; respiratory versus metabolic
acidosis and alkalosis; compensation mechanisms; bicarbonate, phosphate,
and protein buffer systems.
2. Fluid and Electrolyte Balance: Body fluid compartments; interstitial versus
intravascular fluid; sodium, potassium, and calcium regulation; role of kidneys
and hormones in fluid homeostasis.
3. Male Reproductive System: Spermatogenesis in seminiferous tubules; roles of
Sertoli and Leydig cells; inhibin and FSH/LH regulation; accessory glands and
semen composition; fructose function.
4. Female Reproductive System: Oogenesis and ovarian follicle development;
hormonal regulation of the menstrual cycle; estrogen and progesterone roles;
corpus luteum function; site of fertilization in the fallopian tube.
5. Pregnancy and Development: Fertilization and zygote formation; morula and
blastocyst stages; gastrulation and germ layer formation; placental structure
and hormone production; fetal circulation.
, 6. Genetics and Chromosomal Disorders: Turner syndrome (XO), Klinefelter
syndrome (XXY), Jacobs syndrome (XYY), Poly-X syndrome; nondisjunction;
inheritance patterns.
7. Reproductive Hormonal Feedback Loops: Hypothalamic-pituitary-gonadal axis;
GnRH, FSH, and LH secretion patterns; negative and positive feedback in
reproduction; inhibin's suppressive effects.
8. Acid-Base Clinical Correlations: Conditions causing metabolic acidosis
(diarrhea, diabetes, renal failure); respiratory compensation; interpretation of
arterial blood gas values.
9. Buffer System Integration: How bicarbonate, phosphate, and protein buffers
work together; respiratory and renal regulation of hydrogen ion concentration;
role of hemoglobin as a buffer.
10. Embryological Development and Twinning: Monozygotic versus dizygotic
twins; implantation; early embryonic development; placental exchange between
chorionic villi and maternal sinus.
Bios 256 Exam 3
Bios 256 Exam 3
250 Multiple-Choice Questions with Answers and Rationales
1. Which of the following statements accurately describes the normal pH range
of human arterial blood and the condition that results when the pH falls below
this range?
,A) 7.15–7.25; the condition is called alkalosis
B) 7.35–7.45; the condition is called acidosis
C) 7.45–7.55; the condition is called acidosis
D) 7.25–7.35; the condition is called alkalosis
Answer: B
Rationale: Normal arterial blood pH is tightly regulated between 7.35 and 7.45.
When pH drops below 7.35, the condition is acidosis, reflecting an excess of
hydrogen ions or a loss of bicarbonate buffer . 9
2. Which of the following sets correctly identifies the three major buffer systems
that work together to maintain acid-base balance in the human body?
A) Bicarbonate buffer system, chloride buffer system, and sodium buffer system
B) Bicarbonate buffer system, phosphate buffer system, and protein buffer system
C) Protein buffer system, calcium buffer system, and potassium buffer system
D) Phosphate buffer system, magnesium buffer system, and bicarbonate buffer
system
Answer: B
Rationale: The three primary buffer systems are the bicarbonate buffer system
(HCO₃⁻), the phosphate buffer system, and the protein buffer system, which
includes hemoglobin acting as an intracellular buffer . 9
3. A patient with severe diarrhea is admitted with a blood pH of 7.30 and a
decreased bicarbonate level; which of the following best describes the acid-
base disturbance and its most likely cause?
A) Respiratory alkalosis caused by hyperventilation
B) Metabolic acidosis caused by bicarbonate loss through the gastrointestinal
, tract
C) Respiratory acidosis caused by hypoventilation
D) Metabolic alkalosis caused by excessive vomiting
Answer: B
Rationale: Severe diarrhea causes loss of bicarbonate-rich intestinal fluid, leading
to metabolic acidosis. The low pH and low bicarbonate confirm a metabolic origin
rather than a respiratory one . 1
4. In the male reproductive system, spermatogenesis occurs within which
specific anatomical structure, and which cell type provides essential support
and nutrition to developing sperm?
A) Epididymis; Leydig cells
B) Seminiferous tubules; Sertoli cells
C) Vas deferens; interstitial cells
D) Prostate gland; germ cells
Answer: B
Rationale: Spermatogenesis takes place in the seminiferous tubules of the testes.
Sertoli cells (nurse cells) extend from the basement membrane to the lumen and
provide structural support and nutrients to developing sperm cells . 1 8
5. Which hormone is secreted by Sertoli cells in males and by granulosa cells in
females, and what is its primary suppressive effect on the anterior pituitary?
A) Inhibin; it suppresses follicle-stimulating hormone (FSH) secretion
B) Testosterone; it suppresses luteinizing hormone (LH) secretion
C) Estrogen; it suppresses gonadotropin-releasing hormone (GnRH) secretion
D) Progesterone; it suppresses both FSH and LH secretion