/
Human Embryology and Reproductive Development
Save to my account
Sign up
Human Embryology and Reproductive Development
Human Embryology and Reproductive Development
Study
1
Question
How does the cell cycle of the early embryo differ from the standard somatic cell cycle?
Page 1
Answer
The early embryonic cell cycle completely bypasses the \(G_1\) and \(G_2\) phases, moving directly between the S phase and M phase.
2
Question
What occurs to the size and volume of daughter cells during the first week of embryonic cleavage?
Page 1
Answer
Each daughter cell is half the size and half the volume of the parent cell because no growth occurs between divisions.
3
Question
Describe the status of male germ cells before the onset of puberty.
Page 1
Answer
In the testes, only primordial germ cells exist within the seminiferous tubules, supported and protected by Sertoli cells.
4
Question
What is the difference between spermatogenesis and spermiogenesis?
Page 1
Answer
Spermatogenesis is the entire process of producing gametes through meiosis. Spermiogenesis is the specific transformation of round spermatids into mobile spermatozoa without further division.
5
Question
Define the chromosomal and DNA status of a primary spermatocyte.
Page 1
Answer
A primary spermatocyte is diploid, containing 46 chromosomes and 4N DNA (doubled DNA).
6
Question
At what stage of development are oocytes arrested in a newborn girl?
Page 2
Answer
All germ cells are primary oocytes arrested at the prophase of Meiosis I.
7
Question
What condition must be met for a secondary oocyte to complete Meiosis II?
Page 2
Answer
Fertilization by a sperm must occur; otherwise, the secondary oocyte degenerates.
8
Question
What is the function of Leydig cells in male reproduction?
Page 2
Answer
Leydig cells possess LH receptors and secrete testosterone, which is mandatory for sperm production.
9
Question
Describe the formation and purpose of the acrosome in spermiogenesis.
Page 3
Answer
Enzymes from the RER are packaged by the Golgi into an acrosome vesicle that caps the nucleus; it contains lytic enzymes to penetrate the oocyte.
10
Question
What are the three accessory glands of the male reproductive system and their collective product?
Page 3
Answer
The seminal vesicles, prostate gland, and bulbourethral glands; their secretions combined with spermatozoa form semen.
11
Question
Define a follicle in the context of oogenesis.
Page 4
Answer
A follicle consists of an oocyte surrounded by supportive follicular (granulosa) cells.
12
Question
Distinguish between a primordial follicle and a primary follicle.
Page 4
Answer
A primordial follicle has a primary oocyte with flat (squamous) follicular cells. In a primary follicle, these cells become cuboidal and may proliferate into multiple layers.
13
Question
What is the defining feature of a Tertiary (Graafian) follicle?
Page 4
Answer
The merger of fluid spaces into one large central cavity called the antrum.
14
Question
What is the corpus luteum and what are its potential fates?
Page 4
Answer
It is an endocrine structure formed from leftover granulosa cells. It persists if fertilization occurs; if not, it degenerates into a corpus albicans scar.
15
Question
How does basal body temperature (BBT) change during the menstrual cycle relative to ovulation?
Page 5
Answer
BBT is lower (36.5–37.0°C) in the first two weeks, drops slightly just before ovulation, then rises sharply to 37.0°C or higher for the final two weeks.
16
Question
Identify the four regions of the uterine (Fallopian) tubes.
Page 5
Answer
1. Fimbriae 2. Ampulla 3. Isthmus 4. Intramural (Interstitial) part.
17
Question
Name and describe the two types of epithelial cells in the uterine tubes.
Page 6
Answer
Ciliated columnar cells (move the oocyte/zygote toward the uterus) and Peg cells (secretory cells providing nutrients).
18
Question
Differentiate between the functional layer and basal layer of the endometrium.
Page 6
Answer
The functional layer (compact + spongy) thickens and sheds during menstruation; the basal layer never sheds and regenerates the functional layer.
19
Question
What is the typical viability duration for a human oocyte and a sperm cell?
Page 6
Answer
Oocytes are viable for 12–24 hours; sperm are viable for 24–48 hours (but can last up to 6 days).
20
Question
Define 'capacitation' and its significance in sperm maturation.
Page 6
Answer
It occurs in the female tract; it removes the glycoprotein coat and seminal proteins from the sperm head to prepare it for fertilization.
21
Question
What enzymes are released during the acrosome reaction and what are their specific targets?
Page 6
Answer
Hyaluronidase (breaks corona radiata); Acrosin, esterases, and neuraminidase (break zona pellucida).
22
Question
Explain the 'block to polyspermy' mechanism after sperm entry.
Page 6
Answer
Cortical granules release enzymes that harden the zona pellucida and destroy ZP3 receptors to prevent further sperm entry.
23
Question
Define the terms Oligozoospermia, Teratozoospermia, and Asthenozoospermia.
Page 7
Answer
Oligozoospermia: low count (<1.5 mL volume); Teratozoospermia: >30% abnormal forms; Asthenozoospermia: <70% progressive motility.
24
Question
Outline the timeline of embryonic development from Day 0 to Day 6.
Page 7
Answer
Day 0: Fertilization; Days 1–2: 2-cell stage; Day 3: Morula (12–16 cells); Day 4: Early blastocyst; Day 5: Hatching; Day 6: Implantation begins.
25
Question
Describe the two main cell populations in a blastocyst and their future fates.
Page 7
Answer
The Embryoblast (inner cell mass) becomes the embryo; the Trophoblast (outer layer) becomes the placenta.
26
Question
What is Early Pregnancy Factor (EPF) and why is it clinically significant?
Page 7
Answer
An immunosuppressant protein appearing 24–48 hours after fertilization; it is the basis of very early pregnancy detection.
27
Question
Describe the differentiation of the trophoblast during the 2nd week of development.
Page 8
Answer
The trophoblast forms two layers: an inner mitotically active Cytotrophoblast and an outer invasive, multinucleated Syncytiotrophoblast that produces hCG.
28
Question
What is the 'decidual reaction' in the endometrium?
Page 8
Answer
The transformation of stromal cells into glycogen and lipid-rich decidual cells to support the implanted embryo.
29
Question
Define the two layers of the bilaminar embryonic disc.
Page 8
Answer
The Epiblast (columnar cells, forms embryo proper/amniotic cavity) and the Hypoblast (cuboidal cells, lines blastocyst cavity/yolk sac).
30
Question
What is the chorionic sac (chorion) composed of?
Page 8
Answer
Trophoblast and extraembryonic somatic mesoderm.