Human Reproduction Flashcards
1
Q
What is reproduction?
A
Reproduction is the production of young ones by an organism.
2
Q
What type of reproduction do humans follow?
A
Humans are sexually reproducing and viviparous (give birth to live young).
3
Q
What are the four main components of the male reproductive system?
A
Paired testes, Accessory ducts, Accessory glands, and External genitalia (penis).
4
Q
What are the functions of the testes?
A
Produce sperm and secrete testosterone.
5
Q
Where are the testes formed, and when do they descend?
A
Formed in the abdomen, descend into the scrotum at birth or by the 8th month of pregnancy.
6
Q
Why is the scrotum important for sperm production?
A
It maintains a temperature 2-2.5°C lower than body temperature, which is essential for spermatogenesis.
7
Q
What are the dimensions of each testis?
A
Length: 4-5 cm, Width: 2-3 cm.
8
Q
How many lobules are in each testis?
A
About 250 lobules per testis.
9
Q
What is present inside each lobule?
A
1-3 coiled seminiferous tubules.
10
Q
What type of cells line the seminiferous tubules?
A
- Male germ cells (spermatogonia) – Develop into sperm.
- Sertoli cells – Provide nutrition to germ cells.
11
Q
What is found outside the seminiferous tubules?
A
Interstitial spaces containing Leydig cells, blood vessels, and immune cells.
12
Q
What is the function of Leydig cells?
A
Secrete androgens (testosterone).
13
Q
What are the accessory ducts in order of sperm transport?
A
Seminiferous tubules → Rete testis → Vasa efferentia → Epididymis → Vas deferens → Ejaculatory duct → Urethra → Urethral meatus.
14
Q
What is the function of the epididymis?
A
Stores sperm temporarily and helps in maturation.
15
Q
What does the urethra receive?
A
Ducts of the prostate and Cowper’s glands.
16
Q
What are the three accessory glands?
A
Prostate gland, Seminal vesicles (pair), and Cowper’s glands (pair).
17
Q
What is the collective secretion of these glands called?
A
Seminal plasma.
18
Q
What is the composition of seminal plasma?
A
Rich in fructose, calcium, and enzymes.
19
Q
What does seminal plasma + sperm form?
A
Semen.
20
Q
What are the functions of seminal plasma?
A
- Helps in sperm transport.
- Supplies nutrients to sperm.
- Provides alkalinity to neutralize the acidic environment of the uterus.
21
Q
What is the role of Cowper’s glands?
A
Lubricate the penis.
22
Q
What helps in sperm maturation and motility?
A
Secretions from the epididymis, vas deferens, seminal vesicles, and prostate.
23
Q
What is the function of the penis?
A
Copulatory organ that facilitates insemination.
24
Q
What type of tissue makes up the penis?
A
Erectile spongy tissue.
25
What causes an erection?
Filling of spongy tissue with blood.
26
What is the tip of the penis called?
Glans penis.
27
What covers the glans penis?
Prepuce (foreskin).
28
What is spermatogenesis, and where does it occur?
Spermatogenesis is the process of sperm formation that occurs in the seminiferous tubules of the testes.
29
What are spermatogonia?
Spermatogonia are diploid male germ cells present on the inner walls of the seminiferous tubules. They multiply by mitotic division.
30
What happens to primary spermatocytes during spermatogenesis?
Primary spermatocytes undergo meiosis. The first meiotic division produces two haploid secondary spermatocytes, each with 23 chromosomes.
31
What are spermatids, and how are they formed?
Spermatids are haploid cells formed after the second meiotic division of secondary spermatocytes. They undergo spermiogenesis to develop into spermatozoa.
32
What is spermiogenesis?
Spermiogenesis is the process where spermatids transform into mature spermatozoa (sperms).
33
What is the function of Sertoli cells in the seminiferous tubules?
Sertoli cells provide nutrition and support to developing spermatogenic cells.
34
Describe the structure of a sperm.
A sperm consists of the head, neck, middle piece, and tail. The head contains the nucleus and acrosome, the middle piece contains mitochondria, and the tail aids in movement.
35
What is the acrosome, and what is its role?
The acrosome is a cap-like structure over the sperm's head. It contains enzymes that help in the penetration of the ovum during fertilization.
36
What is the significance of the middle piece of a sperm?
The middle piece contains mitochondria, which provide energy for the movement of the sperm.
37
How many sperms are released during ejaculation, and what percentage must show normal shape and vigorous motility?
About 200–300 million sperms are released, and at least 40% of them must show normal shape and vigorous motility.
38
What is oogenesis, and how does it differ from spermatogenesis?
Oogenesis is the formation of ova in the ovaries. Unlike spermatogenesis, it begins during embryonic development, pauses, and resumes at puberty.
39
What is the role of gonadotropin-releasing hormone (GnRH) in gametogenesis?
GnRH stimulates the anterior pituitary to release FSH and LH, which regulate spermatogenesis and oogenesis.
40
What is oogenesis?
Oogenesis is the process of formation of a mature female gamete (egg) that begins during the embryonic development stage.
41
What are oogonia, and what happens to them?
Oogonia are gamete mother cells which are cells formed during the fetal stage in the ovaries and undergo multiple mitotic divisions.
42
What happens to oogonia during embryonic development?
They multiply by mitosis and then begin meiosis, but get arrested at the prophase-I stage.
43
What is a primary oocyte, and where is it located?
A primary oocyte is an immature egg surrounded by granulosa cells, forming a primary follicle.
44
How many primary follicles are present at birth, and what happens to them?
About 60,000–80,000 primary follicles are present in each ovary at birth, but many degenerate during a female's lifetime.
45
What are secondary follicles?
Secondary follicles form when primary follicles mature and are surrounded by more layers of granulosa cells and a new outer layer called the theca.
46
What is a tertiary follicle?
A tertiary follicle forms from the secondary follicle, with a fluid-filled cavity called the antrum.
47
What significant change occurs in the tertiary follicle?
The primary oocyte completes its first meiotic division to form a secondary oocyte and a tiny polar body.
48
What is the zona pellucida?
The zona pellucida is a protective glycoprotein layer around the oocyte in the Graafian follicle.
49
What is the Graafian follicle?
The Graafian follicle is the mature stage of the tertiary follicle, containing a secondary oocyte ready for ovulation.
50
What is the chromosomal change during oogenesis?
Oogonia start with 46 chromosomes, which reduce to 23 in the secondary oocyte and ovum after meiosis.
51
What happens during ovulation?
The Graafian follicle releases the secondary oocyte from the ovary.
52
What are the components of the female reproductive system?
A pair of ovaries, a pair of oviducts (fallopian tubes), uterus, cervix, and vagina.
53
What is the primary female sex organ?
The ovaries.
54
What are the functions of the ovaries?
They produce female gametes (ova) and secrete hormones like estrogen and progesterone.
55
Describe the position and shape of the ovary.
Almond-shaped, 2–4 cm long, located in the lower abdomen.
56
What are the two zones of the ovary?
An outer cortex and an inner medulla.
57
What are the three regions of the oviduct (fallopian tube)?
Infundibulum, ampulla, and isthmus.
58
What is the infundibulum?
Funnel-shaped structure close to the ovary, with finger-like fimbriae that collect the ovum after ovulation.
59
What is the ampulla?
The widest and longest portion of the oviduct where fertilization usually occurs.
60
What is the isthmus?
Narrow part of the oviduct connecting it to the uterus.
61
What is the uterus?
A single, hollow, pear-shaped organ where the embryo implants and develops.
62
What are the three layers of the uterus wall?
Perimetrium (outer), myometrium (middle muscular), and endometrium (inner glandular).
63
What is the function of the myometrium?
It contracts during childbirth.
64
What happens to the endometrium during menstruation?
It undergoes cyclical changes and is shed if no fertilization occurs.
65
What is the cervix?
Lower narrow end of the uterus that opens into the vagina.
66
What forms the birth canal?
The cervix and the vagina.
67
What are mammary glands?
Glands present in female breasts responsible for milk production.
68
What are mammary lobes?
15–20 lobes in each mammary gland separated by fat and connective tissue.
69
What are alveoli in mammary glands?
Grape-like clusters of milk-secreting cells within lobes.
70
What is the function of alveoli?
They secrete milk, which is stored in the lumen of alveoli.
71
What is the pathway of milk secretion?
Alveoli → Mammary ducts → Ampulla → Lactiferous duct → Nipple.
72
What is the ampulla in the mammary gland?
An enlarged part of the duct where milk is stored before release.
73
What are the components of the female external genitalia?
Mons pubis, labia majora, labia minora, hymen, and clitoris.
74
What is the mons pubis?
A cushion of fatty tissue covered by skin and pubic hair.
75
What are the labia majora?
Fleshy folds of tissue that extend down from the mons pubis and surround the vaginal opening.
76
What are the labia minora?
Paired folds of tissue located beneath the labia majora.
77
What is the hymen?
A membrane that partially covers the opening of the vagina.
78
What is the clitoris?
A tiny, finger-like structure located at the upper junction of the two labia minora, above the urethral opening.
79
What is the reproductive cycle in female primates called?
Menstrual cycle.
80
What is menarche?
The first menstruation, which begins at puberty.
81
What marks the end of the menstrual cycle in females?
Menopause, around the age of 50.
82
How many days does the menstrual cycle usually last?
Approximately 28/29 days.
83
Which phase of the menstrual cycle involves menstrual flow?
The menstrual phase.
84
What leads to the breakdown of the endometrial lining?
Lack of fertilization of the released ovum.
85
What hormone peaks during ovulation?
Luteinizing Hormone (LH).
86
What happens during the follicular phase?
The development of primary follicles into Graafian follicles, and endometrium regeneration through proliferation.
87
What marks the beginning of the secretory phase?
Ovulation.
88
What does the corpus luteum secrete?
Progesterone, which is essential for endometrium maintenance.
89
What happens to the corpus luteum in the absence of fertilization?
It degenerates, leading to menstruation.
90
What is the role of estrogen in the menstrual cycle?
It helps in the proliferation of the endometrium during the follicular phase.
91
On which days does ovulation typically occur in a menstrual cycle?
Around the 14th day.
92
In the menstrual cycle diagram, what represents the peak levels of LH?
The sharp spike in the LH curve during the mid-cycle.
93
During which phase do progesterone levels remain high?
The luteal phase.
94
What is fertilization, and where does it occur?
Fertilization is the fusion of sperm and ovum, occurring in the ampullary region of the fallopian tube.
95
What layer of the ovum prevents entry of additional sperms during fertilization?
The zona pellucida.
96
What is a zygote?
A diploid cell formed by the fusion of haploid sperm and ovum nuclei.
97
In the fertilization diagram, which part of the ovum is surrounded by corona radiata?
The zona pellucida.
98
What is cleavage in embryonic development?
Mitotic division of the zygote resulting in daughter cells called blastomeres.
99
What is implantation?
The embedding of the blastocyst into the uterine endometrium.
100
In the transport of ovum diagram, what does the blastocyst stage correspond to?
The stage where the embryo embeds into the uterine wall.
101
What is the function of chorionic villi in pregnancy?
They facilitate nutrient and waste exchange between the embryo and the mother.
102
What is parturition, and what triggers it?
Parturition is childbirth, triggered by the fetal ejection reflex and release of oxytocin.
103
In the diagram of the human fetus, what connects the fetus to the placenta?
The umbilical cord.
104
What are the three germ layers formed during embryogenesis?
Ectoderm, mesoderm, and endoderm.
105
What is lactation?
Lactation is the process where mammary glands produce and secrete milk during and after pregnancy to feed the newborn.
106
What is the first milk produced by the mammary glands called?
Colostrum.
107
Why is colostrum important for the newborn?
Colostrum is rich in antibodies and nutrients, providing immunity and aiding in the newborn's growth and development.
108
What hormone stimulates milk ejection from the mammary glands?
Oxytocin.
109
How does breastfeeding benefit the mother and the baby?
Breastfeeding provides the baby with nutrients and immunity. For the mother, it helps the uterus return to its normal size and reduces the risk of certain diseases.
