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Mixed Test (Biology)

Description: This test will help the students to apply the concepts of the topics while answering the questions and thus to revise the topic thoroughly.
Number of Questions: 15
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Tags: Sexual Reproduction Mechanism of Fertilization and Implantation Fertilisation and Implantation Structure of Reproductive System Female Reproductive System Male Reproductive System Spermatogenesis Menstrual Cycle
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At what stage of the cell cycle can one see the primordial germ cells in a prepubertal male under the microscope?

  1. Interphase

  2. Prophase

  3. Anaphase

  4. Telophase

  5. Metaphase


Correct Option: A
Explanation:

Interphase occurs just prior to cell division. Prepubertal male primordial germ cells are reactivated from interphase at puberty and enter rounds of mitosis followed by meiosis 1 and 2 to produce unique haploid sperm.

Which of the following statements is CORRECT regarding normal gestation in humans?

  1. Sex-determining region Y (SRY) protein, is a RNA-binding protein in males.

  2. SRY is located on the X chromosome.

  3. In the absence of SRY, a female phenotype will develop.

  4. Only one X chromosome is necessary for normal ovarian development.

  5. In the presence of SRY, a female phenotype will develop.


Correct Option: C
Explanation:

In the absence of a Y chromosome, the fetus develops ovaries and female phenotypes. Hence, SRY switches on the male sex determination.

What part of the embryo is the origin of the primordial germ cells?

  1. Extraembryonic ectoderm

  2. Coelomic epithelium

  3. Extraembryonic mesoderm

  4. Gonadal ridge

  5. Endoderm of the yolk sac


Correct Option: E
Explanation:

In gonadal development, undifferentiated primordial germ cells arise from the endoderm lining the yolk sac.

The mesenchyme developing just below the germinal epithelium is the origin of which analogous cell types?

  1. Leydig and thecal cells

  2. Spermatogonia and oogonia

  3. Sertoli and granulosa cells

  4. Sex cords

  5. Ovarian tissue


Correct Option: A
Explanation:

Mesenchyme arising beneath the germinal epithelium in the testes is the precursor to testicular interstitial cells or Leydig cells. In the ovaries it is the precursor to ovarian stroma or thecal cells.

Which of the following structures originate from the Mullerian ducts?

  1. Urogenital sinus

  2. Urinary bladder

  3. Ovaries

  4. Uterus

  5. Upper two-thirds of the vagina


Correct Option: D
Explanation:

Once the Mullerian ducts have reached the urogenital sinus and the vaginal plate has formed, the ducts will begin to fuse centrally. This forms the body of the uterus.

MIS stands for Mullerian inhibiting substance. It is secreted by ____________.

  1. cells of the prostate gland

  2. leydig cells

  3. sertoli cell

  4. cells of the seminal vesicles

  5. cells of Cowper’s Glands


Correct Option: C
Explanation:

A Sertoli cell is a 'nurse' cell of the testes. The MIS glycoprotein is produced by Sertoli cells of the testes during fetal and neo-natal life in males.

The right testicular vein get emptied into which vascular structure?

  1. Inferior vena cava

  2. Left renal vein

  3. Pampiniform plexus

  4. Right renal artery

  5. Superior vena cava


Correct Option: A
Explanation:

The right testicular vein drains into the inferior vena cava at an acute angle.

Which of the following provides blood supply to the penis?

  1. Greater palatine artery

  2. Femoral artery

  3. Pampiniform plexus

  4. Internal pudendal arteries

  5. Genitofemoral artery


Correct Option: D
Explanation:

The internal pudendal arteries serve as the penile blood supply by entering the penis dorsally and running deep into the tissues of the corpora cavernosa. The internal pudendal artery becomes the penile artery.

A 35-year-old man is noted to have azoospermia on semen analysis but his history is significant for vasectomy. For which of the following functions of spermatogenesis, is the vas deferens important?

  1. Sperm transit

  2. Testosterone production

  3. Maintaining the blood–testis barrier

  4. Sperm storage

  5. Sperm nourishment


Correct Option: A
Explanation:

Both the epididymis and the vas deferens are made up of ducts, which have muscular components. These muscular parts aid in peristalsis, which helps move spermatozoa along the ducts.

Which of the following nerves innervates penis in males?

  1. Iliohypogastric nerve

  2. Ilioinguinal nerve

  3. Labialscrotal nerve

  4. Genitofemoral nerve

  5. Sacral nerves 2, 3 and 4


Correct Option: E
Explanation:

Innervation of the penis comes from the pudendal nerve which is made up of the 2nd, 3rd and 4th sacral nerves. The penile nerve (also known as the dorsal nerve of the penis) is the deepest branch of the pudendal nerve.

Which of the following can be EXCLUDED from the function of Sertoli cells?

  1. Metabolic support of developing spermatozoa.

  2. Synthesis of inhibin and antimullerian hormone.

  3. Maintaining the position of primordial germ cells against the basement membrane.

  4. Maintenance of the blood–testis barrier.

  5. Aromatisation of androgen precursors to estrogen.


Correct Option: C
Explanation:

Primordial germ cells are maintained against the basement membrane of the seminiferous tubules; Sertoli cells do not appear to have a role in this process.

A young woman undergoing laparoscopy is noted to have a cyst on her ovary. The cyst is described as a “blister” on the surface of the ovary. Which of the following options shows the correct answer?

  1. Corpus luteum

  2. Cancer

  3. An ectopic pregnancy

  4. Impending ovulation

  5. Corpus allatum


Correct Option: D
Explanation:

During initial follicular growth, the oocyte grows larger, granulosa cells increase in number and a zona pellucida or protein matrix, forms around the oocyte. The fluid filling the follicler continues to accumulate and the cellular surface of the follicle thins in preparation for ovulation. This process can be seen grossly and has been described as a blister on the ovarian surface.

Which of the following is unlikely to be a consequence of testicular growth in males?

  1. Leydig cell stimulation

  2. Decreased Mullerian inhibiting substance

  3. Initiation of spermatogenesis  

  4. Increased mass of seminiferous tubules

  5. Spermatogenesis occurs in many structures of the male reproductive system


Correct Option: B
Explanation:

Mullerian inhibiting substance (MIS) is responsible for causing the müllerian ducts to degenerate, accounting for the sole development of male internal genitalia in a fetus with a functional testis. If it is absent during fetal development, female internal genitalia would develop by default.

 During the follicular phase, the dominant follicle arises as a result of secretion of _____________.

  1. matrix-degrading proteases

  2. hCG

  3. androgen

  4. LH

  5. FSH


Correct Option: E
Explanation:

Follicle-stimulating hormone (FSH) causes maturation of a cohort of early-stage ovarian follicles; one of these will ultimately become the dominant or Graafian follicle.

The myometrium is the middle layer of the uterine wall in females. Which of the following statements does not characterise the myometrium?

  1. Gap junctions allow rapid communication between myocytes.

  2. Initial weeks of pregnancy are maintained by corpus luteum.

  3. It can enlarge via hypertrophy and recruitment of new myocytes.

  4. It induces uterine contractions.

  5. After delivery the myometrium expands further to expel the placenta.


Correct Option: E
Explanation:

After delivery the myometrium contracts to expel the placenta and to minimise blood loss from  the body.

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