Ch 3. Human Reproduction Flashcards
What is the scrotum?
Scrotum is a pouch like structure present outside the abdominal cavity and holds testes.
Scrotum in human males is situated outside the abdomen. What is the significance of this?
Significance: Lower temperature is necessary for spermatogenesis.
What are seminiferous tubules?
Seminiferous tubules are highly coiled structures present within the testes in which sperms are produced.
Name the functional units of testis where spermatogenesis occurs.
Seminiferous tubules.
Write the function of Leydig cells
Leydig cells synthesise and secrete testosterone
Name the cells of testis that synthesise and secrete androgens
Leydig cells
Mention the type of cells which provide nutrition to spermatogonia
Sertoli cells also called nurse cells.
Mention one function of sertoli cells
Sertoli cells provide nutrition to the germ cells.
Sertoli cells are very much essential during spermatogenesis. Why?
Sertoli cells provide nutrition to the germ cells.
Name an accessory duct of the male reproductive system in humans.
Rete testis. Vasa efferentia, Epididymis and Vas deferens.
Name an accessory gland of the male reproductive system in humans.
Seminal vesicle, Prostate and bulbourethral gland.
What is urethral meatus?
The urethra extends through the penis to its external opening called urethral meatus.
What is glans penis?
The enlarged end of penis is called glans penis.
What is foreskin?
Glans penis is covered by a loose fold of skin called foreskin
What is seminal plasma?
Seminal plasma includes the secretions of seminal vesicle, prostate, bulbourethral glands and is rich in fructose, calcium and certain enzymes.
Mention two functions of sertoli cells.
- Sertoli cells provide nutrition to the germ cells.
- Provides site for attachment of sperm head.
Name the honnones secreted by Leydig’s cells and corpus leuteum
Leydig’s cell - Androgen (Testosterone) Corpus luteum - progesterone
Name an accessory duct of the female reproductive system in humans.
Oviducts (fallopian tube), uterus and vagina
Name the funnel shaped part of the fallopian tube which lies close to the ovary
lnfundibulum
Name the finger-like projections present at the edges of the infundibulum of oviduct
Fimbriae
Name the middle part of the oviduct or fallopian tube
Ampulla
Name the last part of the oviduct or fallopian tube
Isthmus
What is birth canal?
Cervical canal along with vagina forms the birth canal.
Name the inner glandular layer of the uterus
Endometrium
Name the layer of uterus which undergoes cyclical changes during menstrual cycle
Endometrium
Name the layer of the uterus which exhibits strong contractions during parturition
Myometrium
What is the hymen?
The opening of the vagina is covered partially by a membrane called hymen.
Mention any four parts of the external genitalia in human females
Mons pubis, Labia majora, Labia minora, Clitoris.
Mention any two hormones secreted by ovary
Estrogen and progesterone
Mention the events that occur during the folloicular phase of menstrual cycle
- The increased levels of the pituitary hormones, LH and FSH induce the growth of primary follicles in the ovary.
- The growing follicles secrete estrogen which also helps in ovulation.
- The primary follicles in the ovary grow to become a fully mature Graafian follicle while the endometrium of the uterus regenerates through proliferation.
Define gametogenesis
Gametogenesis is a process in whic h the primary sex organs, testis in males and ovaries produce gametes, sperms and eggs respectively
Define spermatogenesis.
Spermatogenesis is a process in which immature male germ cells (spermatogonia) produce sperms.
What is the ploidy of primary spermatocytes?
2n-diploid
What is the ploidy of secondary spermiatocytes
n - haploid
What is the ploidy of spermatids
n - haploid
What would be the number of chromosome in the spermatids
Spermatids are haploid and they have 23 chromosomes each in human males.
Define spermiogenesis
Spermatids are transformed into spermatozoa (sperms) by the process called spermiogenesis.
Write the schematic representation of spermatogenesis
Briefly explain the role of three hormones during spermatogenesis
Spermatogenesis starts at the age of puberty due to increase in secretion of GnRH. It acts on anterior pituitary gland stimulates secretion of LH and FSH.
LH acts at the Leydig cells and stimulates secretion of androgens.
They inturn stimulate spematogenesis. FSH acts on sertoli cells and stimulate secretion of some factors which help in spermiogenesis.
Write the schematic representation of oogenesis
Define spermiation
Sperms are finally released from the seminiferous tubules by the process called spermiation
What does GnRH stands for
Gonadotropin releasing hormone
Mention the role of LH during spermatogenesis
LH acts at the Leydig cells and stimulates synthesis and secretion of androgens.
In the absence of LH, spermatogenesis does not occur. Why?
In the absence of Luteinizing Hormone, the Leydig cells are not stimulated to produce Testosterone and the androgens required for spermatogenesis.
Mention the role of FSH in spermiogenesis
FSH acts on the sertoli cells which provide nutrition to the germ cells (spermatogonia) that undergo spermiogenesis.
In the absence of FSH, spermiation does not occur. Why?
Name the cap-like structure that covers the nucleus of the sperm anteriorly
Acrosome
Mention the role of acrosome
Acrosome is filled with enzymes that help sperm to penetrate the ovum.
What is semen?
The seminal plasma along with the sperms is semen.
Define oogenesis
The process of formation of a mature female gametes is called oogenesis.
Name the stage of meiosis in which the primary oocytes exist
Prophase - I
What are primary ovarian follicles
Each primary oocyte gets surrounded by a layer of granulosa cells called primary ovarian follicle.
What are secondary ovarian follicles?
The primary follicle get surrounded by more layers of granulosa cells and a new theca called secondary ovarion follicle.
What are tertiary ovarian follicles?(
The tertiary follicles is characterised by a fluid filled cavity called antrum. The theca layer is organized into an inner theca intema and an outer theca externa.
Name the cavity of tertiary follicles and Graafian follicles.
Antrum
Define ovulation
Ovulation is a process of release of secondary oocyte from ovary.
Differentiate spermiogenesis from spermiation
Spermiogenesis: The process of transformation of spermatids into spermatozoa (sperms).
Spermiation: Release of sperms from seminiferous tubules is called spermiation.
What is the role of FSH in spermiation
FSH acts on sertoli cells and stimulates secretion of some factors which helps in the process of spermiation .
Define menstrual cycle
The cycle of events starting from one menstruation till the next one in human females is called menstrual cycle.
What is menarche?(
The first menstruation begins at puberty and is called menarche.
What is menopause?The permanent stoppage of menstrual cycle is termed as menopa use.
The permanent stoppage of menstrual cycle at the end of the reproductive phase is termed as menopause.
During which phase of the menstrnal cycle the endometrial lining of uterus and its blood vessels breakdown resulting in bleeding?
Menstrual phase
Mention a gonadotropin which promotes follicular development during menstrual cycle
LH - Luteinizing Hormone
FSH - Follicle Stimulating Hormone
Name the ho rmone which induces the rupturing of Graafian follicle
LH
Name a hormone which induces ovulation
LH
Ovulation takes place on the 14th day of menstrual cycle. Why?
LH surge induces rupture of Graafian follicle and thereby ovulation, takes place on 14th day of menstrual cycle.
During which phase of the menstrual cycle the mature Graafian follicle ruptures to release the ovum?
Ovulatory phase
During which phase of the menstrual cycle corpus luteum is formed?
Luteal phase
Name the hormone secreted by corpus luteum.
Progesterone
Mention the function of progesterone
It maintains the thickness of endometrium which is necessary for implantation and maintenance of pregnancy.
What is menstrual cycle?
Name the hormones which regulate menstrual cycle
Cycle of events starting from one menstruation till the next one is called menstrual cycle.
Hormones that regulate menstrual cycle are FSH, estrogen, LH and Progesterone.
Name the gonadotropins whose concentration gradually increases during the follicular phase of menstrual cycle.(
LH and FSH
Mention two events that occur during the follicular phase of menstrual cycle
- LH and FSH stimulates the follicular development
- Growing follicle secretes estrogen.
Define ovulation. Mention the hormone that induces ovulation
Release of ovum/ secondary oocyte from ovary is called ovulation.
LH induces ovulation
Mention two events that occur during the luteal phase of menstrual cycle.
- Graafian follicle transforms as the corpus luteum and secretes progesterone.
- Progesterone thickness the endometrium and prepares for implantation.
Differentiate menarche and menopause
Menarche: The first menstruation begins at puberty is called menarche.
Menopause: Premanent stoppage of menstrual cycle around 50 years of age is called menopause
What is coitus?
It is process of introducing penis into vagina to facilitate the transfer of gametes.
What is insemination?
During coitus semen is released by the penis into the vagina is called insemination
Define fertilization
The process of fusion of a spenn with an ovum is called fertilization
In which part of the fallopian tube of the female reproductive system fertilization occurs?
Ampullaryisthmic junction of fallopian tube
Why all copulations do not lead to fertilization and pregnancy in healthy couple?
Fertilization can only occur if the ovum and sperms are transported simultaneously to the ampullaryisthmic junction.
When does the secondary oocyte complete second meiotic division
Soon after penetration of sperm into ovum.
Define cleavage
Cleavage is the mitotic division which starts as the zygote moves through the isthmus of the oviduct.
What is trophoblast
Trophoblast is cells the outer layer of a blastocyst, which provide nutrients to the embryo and later develops into a major part of the placenta.
Why the cells of the inner cell mass ofblastocyst are called stern cells
What are stem cells?(
The cells which have the potency to give rise to all the tissue and organs are called stem cells.
Define implantation
Embedding of blastocyst in the endometrium of uterus is called implantation.
Define fertilization.
In which part of the fallopian tube of the female reproductive system does fertilization occur
The process of fusion of a sperm with an ovum is called fenilisation.
It takes place in the ampullary isthmic junction of fallopian tube.
Name the finger like projections that appear on the trophoblast after the implantation.
Chorionic villi
Define placenta?
The structural and functional unit between develop ing embryo (foetus) and maternal body called place nta.
Expand hCG.
Human chorionic gonadotropin
Expand hPL
Human placental lactogen
Mention any one hormone secreted by the placenta
hCG
Mention one function of placenta.
Placenta acts as foetal endocrine gland.
Mention the hormone produced only during pregnancy by the ovary in human females
Relaxin
Which part of the female reproductivesystem produces relaxin?
Ovary
In which month of pregnancy, embryo’s heart is fonned?
After one month of pregnancy.
In which month of human pregnancy, fetus develops limbs and digits?
By the end of the second month of pregnancy.
At which month of pregnancy first foetal movement and appearance of hair on head can be noticed?
During fifth month
Mention the functions of placenta
- It facilitates the supply of oxygen and nutrients to the embryo and also removal of CO2 and excretory waste produced by embryo.
- It acts as an endocrine gland and secrete hormones like hcG, hpL, estrogen, progestogens and relaxin.
What is placenta?
Mention any two hormones secreted by placenta
- Placenta is the structural and functional unit between developing embryo (foetus) and maternal body
- hCG and hPL
Name any four hormones which increase several folds in maternal blood during pregnancy.
Estrogen, Progestogen, Cortisol, prolactin, thyroxin
What is gestation period?
The average duration of human pregnancy is about 9 months which is called the gestation period.
Define parturition
The process of delivery of the foetus (child birth) is called parturition .
What is foetal ejection reflex?
The signals for parturition originate from the fully developed foetus and the placenta which induce mild uterine contractions called foetal ejection reflex.
Name a hormone which induces parturition
oxytocin
Why is oxytocin is necessary for parturition?
Oxytocin acts on the uterine muscle and causes stronger uterine contractions.
Define lactation
The mammary glands of the female undergo differentiation during pregnancy and starts producing milk towards the end of pregnancy by the process called lactation.
What is colostrum?
The milk produced during the initial few days of lactation is called colostrum.
“Colostrum is considered as essential for newborn baby”. Why?
Colostrum contains several antibodies absolutely essential to develop resistance for the new - born babies.
Define parturition
Name the hormone released by the pituitary which induces parturition
The process of delivery of the foetus (child birth) is called parturition.
Oxytocin is the hormone released by the pituitary to induce parturition.
Men tion the function of progesterone and oxytocin
Progesterone: It triggers the endometrium lining to thicken to accept a fertilized egg and helps to maintain the pregnancy after fertilization.
Oxytocin: It acts on the uterine muscle to cause strong uterine contractions needed for the expulsion of the baby out of the uterus.
Explain the neuroendocrine mechanism which induces parturition
Parturition is induced by a complex neuroendocrine mechanism. The signals for parturition originate from the fully developed foetus and the placenta which induce mild uterine contractions called foetal ejection reflex. This triggers release of oxytocin from the maternal pituitary.
