Human Reproduction: Key Concepts and Biological Processes
English with a size of 1.95 MBHuman Reproduction
1. Key Concepts in Reproduction
- (a) Ovulation is induced by: Luteinizing hormone (LH)
- (b) Acrosome of sperm is formed from: Golgi apparatus
- (c) Cessation of menstrual cycle in female is called: Menopause
- (d) Progesterone is secreted by: Corpus luteum
- (e) Connection between foetus and uterus: Placenta
- (f) Acrosome of sperm is formed from: Golgi body
- (g) Release of ovum from a mature follicle: Ovulation
- (h) Cells that nourish sperm: Sertoli cells
- (i) Genes located in Y chromosome: Holandric genes
- (j) Anterior part of sperm: Head
- (k) Germinal epithelium of gonads: Germ epithelium
- (l) Function of interstitial cells: Secretion of testosterone
- (m) Ovulation is induced by: Luteinizing hormone (LH)
- (n) Acrosomal vesicle contains: Hyaluronidase (acrosin also present)
2. Definitions and Processes
What is menopause? Permanent cessation of the menstrual cycle in females.
What is ovulation? Release of a mature ovum from the ovary.
3. Follicular Phase Changes
- Follicles in the ovary grow under FSH stimulation.
- Estrogen secretion increases.
- Endometrium regenerates and thickens.
- One Graafian follicle becomes mature.
4. Reproductive Health and Biology
Why has amniocentesis been banned? It is banned to prevent sex determination and female foeticide, as it was misused to identify the sex of the fetus.
5. Comparative Biology
Spermatogenesis vs. Oogenesis
- Spermatogenesis: Occurs in testes, starts at puberty, produces sperm, equal division of cytoplasm.
- Oogenesis: Occurs in ovaries, begins before birth, produces ovum, unequal division.
Follicular vs. Luteal Phase
- Follicular Phase: Before ovulation, estrogen dominant, follicle develops, endometrium regenerates.
- Luteal Phase: After ovulation, progesterone dominant, corpus luteum forms, endometrium maintained.
6. Embryonic Development
How is the placenta formed? It forms from the chorionic villi of the embryo and the uterine endometrium of the mother. These tissues interlock to allow the exchange of nutrients, gases, and wastes.
How does implantation occur? After reaching the uterus, the blastocyst attaches to and embeds in the endometrium. Trophoblast cells invade the uterine lining and implantation is completed.
7. Diagrams and Anatomy
Cross section of seminiferous tubule: 
Diagram of sperm: 
Leydig cells: Interstitial cells in the testes that secrete testosterone, responsible for male secondary sexual characters and spermatogenesis.
Sex determination: Y chromosome is present only in males. Sex is determined by sperm: X sperm → Female (XX); Y sperm → Male (XY).
Seminal plasma: Formed from secretions of seminal vesicles, prostate gland, and bulbourethral glands. It provides nutrients and a medium for sperm movement.
Molecular structure of human foetus in uterus: 
Why do sperm contain mitochondria? Mitochondria provide energy (ATP) for the movement of the sperm tail (flagellum).
Formation of placenta: Formed by the fusion of foetal chorion and maternal uterine tissue. It aids in nutrition, respiration, excretion, and hormone secretion.
Phases of spermatogenesis: 
8. Differences
- Parturition vs. Lactation: Parturition is the process of childbirth; Lactation is the production of milk by mammary glands.
- Morula vs. Blastula: Morula is a solid ball of cells; Blastula is a hollow ball of cells with a blastocoel cavity.
9. Menstrual Cycle
The menstrual cycle is a monthly cyclic change in the ovaries and uterus of human females that prepares the body for pregnancy. It is controlled by FSH, LH, estrogen, and progesterone.
T.S. of ovary: 
T.S. of testis: 
Male reproductive part: 
Phases of menstrual cycle: The cycle is a roughly 28-day process characterized by four main phases: Menstruation (shedding lining), Follicular Phase (follicle/lining growth), Ovulation (egg release), and Luteal Phase (progesterone surge). 