The Reproductive System

production of new individuals of the same kind

(i) Seminal vesicles produce a secretion that serves as a medium for the transportation of the sperms.

(ii) It pours an alkaline secretion into the semen as it passes through the urethra. It neutralises acid in female's vagina.

(iii) The secretion of Cowper's gland serves as a lubricant.

(iv) Sperm duct (vas deferens) help in the transportation of the sperms from the testes upwards to the abdomen.

(i) False
Corrected Statement — One egg is released from one of the two ovaries every month.

(ii) True

(iii) True

(iv) True

(v) True

The three main regions of human sperm and their function are:

1. Head (Acrosome) — It secretes an enzyme (hyaluronidase) which facilitates entry of sperm into the egg by dissolving the wall of the ovum.
2. Middle Piece (Mitochondria) — It provides energy for the activity of the sperm to swim.
3. Tail (Axial filament) — Lashing movements of tail helps in propulsion.

(i) Three accessory glands of human male reproductive system are:

1. Seminal vesicles
2. Prostate gland
3. Bulbo-urethral gland (or Cowper's gland)

(ii) Two hormones secreted from placenta are:

1. Oestrogens
2. Progesterone

(iii) Two types of twins are:

1. Fraternal Twins
2. Identical Twins

(iv) Two layers of the wall of uterus are:

1. Endometrium
2. Myometrium

The foetus receives following substances from the mother through placenta:

1. Oxygen
2. Glucose
3. Amino acids
4. Lipids, fatty acids and glycerol
5. Vitamins
6. Mineral ions such as Na, K, Ca, Cl, etc.
7. Certain drugs
8. Alcohol, nicotine
9. Antibodies
10. Viruses

The placenta is formed of two sets of finger-like projections, the villi. One set is given out by uterine wall and the other set by allantois from the embryo. These two set of villi are interlocked. The impurities excreted by foetus are exchanged by their capillaries to the capillaries of uterine wall (mother).

(i) The gestation period refers to the full term of the embryo in the uterus.

(ii) In humans, the gestation period is 280 days.

(iii) During parturition, the baby is pushed out by powerful contraction, head first.

(iv) Placenta is the disc like structure attached to the uterine wall.

(v) After about 15 minutes of birth of baby, the placenta breaks from the uterus and is expelled out as "after-birth".

(vi) The umbilical cord is tied and cut after birth.

No

Reason — No, the foetus inside the mother's uterus does not breathe in the same way as a born baby or an adult. The exchange of gases between the mother's blood and the foetal blood takes place in the placenta, and the foetus obtains the necessary oxygen and eliminates carbon dioxide through this process. The actual breathing, as in inhaling and exhaling air into the lungs, only begins after birth when the baby takes its first breath.

(i) True

(ii) False
Corrected Statement — Amniotic fluid serves to provide protection to the foetus.

(iii) True

(iv) False
Corrected Statement — Mother's blood and the foetal blood do not directly mix in the placenta. Instead, the placenta acts as a barrier between the maternal and foetal circulations to allow for the exchange of oxygen, nutrients, and waste products without direct mixing of blood.

The human female gonads are ovaries. A maturing egg in the ovary is present in a sac of cells called follicle(1). As the egg grows larger, the follicle enlarges and gets filled with a fluid and is now called the Graafian (2) follicle. The process of releasing the egg from the ovary is called ovulation (3). The ovum is picked up by the oviductal funnel and fertilization takes place in the fallopian tube (4). In about a week the blastocyst gets fixed in the endometrium of the uterus and this process is called implantation (5).

Prostate gland

Reason — The secretion of prostate gland is alkaline in nature and it neutralises the acidity of the urethra and vagina.

Menarche

Reason — The term used for onset of menstruation in young female is called Menarche.

14 days

Reason — Ovulation occurs during mid-menstrual cycle.

Fallopian tube

Reason — Fertilization takes place in oviduct or Fallopian tube.

Leydig cells

Reason — The packing tissues between the coils of the seminiferous tubules are called as interstitial cells or Leydig cells.

Haemoglobin

Reason — There is exchange of substances between the capillaries of foetus and mother but their blood never mixes. Therefore, there is no exchange of Haemoglobin.

Scrotal sac

Reason — Testis descends into scrotal sac.

Chorion

Reason — The outermost layer of uterine wall around the foetus is chorion.

Gestation

Reason — The duration between fertilization and birth of baby is called gestation period. It is 280 days in case of humans.

Inguinal canal

Reason — The canal through which each testis descends into the scrotum just before the birth of a male baby is inguinal canal.

(ii) and (iv)

Reason — The bulbo-urethral glands secrete a lubricating fluid. The seminal vesicles secrete a fluid that forms a major part of semen and helps in the transport of sperms.

R and S

Reason — Fraternal twins are dizygotic twins formed from two separate ova, each fertilised by a different sperm cell.

Both A and R are True.

Explanation
The placenta begins developing from the blastocyst shortly after implantation. The placenta connects to the fetus via the umbilical cord.

A is False and R is True.

Explanation
Leydig cells, also known as interstitial cells, primarily produce testosterone, not oestrogen and progesterone. Oestrogen and progesterone are mainly produced by the ovaries in females.

A is True and R is False.

Explanation
Prostate gland is a bilobed gland located below the bladder and surrounds the urethra.

A is False and R is True.

Explanation
Fertilization of the ovum and sperm occurs in the fallopian tube of the female reproductive system.

(a) 3 male accessory glands in humans are:

1. Seminal vesicle
2. Prostate gland
3. Cowper's gland

(b) 2 hormones secreted from the corpus luteum are:

1. Oestrogen
2. Progesterone

(c) 4 phases of the menstrual cycle are:

1. Menstrual phase
2. Follicular phase
3. Ovulatory phase
4. Luteal phase

(d) 2 types of twins are:

1. Fraternal Twins
2. Identical Twins

(e) 3 membranous, protective layers around the foetus are:

1. Chorion
2. Amnion
3. Allantois

(a) Ovulation → fertilization → implantation → gestation → child birth

(b) Sperm → sperm duct → urethra → coitus → vagina

(c) Testes → Sperms → Sperm duct → Semen → Penis

(d) Reproductive age → Puberty → Menarche → Menstruals → Menopause

(e) Ovum → Graafian follicle → Ostium → Fallopian tube → Uterus.

(a) Menarche

(b) Ovulation

(c) Menstruation

(d) Fertilization

(e) Implantation

(a) Sperm : Spermatogenesis : Ovum : Oogenesis

(b) Female gonad : Ovaries :: Male gonad : testes

(c) Follicle cells : Ova :: Seminiferous tubules : Sperms

(d) Leydig cells : Testosterone :: Corpus Luteum : Oestrogen

(e) Follicular phase : 5-12 days :: Luteal phase : 15-28 days.

(a) Odd term: Uterine tube
Category: Male reproductive system organs

(b) Odd term: Seminiferous tubule
Category: Male accessory glands

(c) Odd term: Ureter
Category: Female reproductive system organs

(d) Odd term: Choroid
Category: Protective membranes around foetus.

(e) Odd term: Zona pellucida
Category: Parts of sperm

(a)

1. False
2. False
3. False

(b)

1. Corrected Sentence — Fertilization occurs in the fallopian tube.
2. Corrected Sentence — Vagina is also known as the birth canal.
3. Corrected Sentence — Nutrition and oxygen diffuse from the mother's blood into the foetus's blood through placenta.

(a) Foetus —

• It is contained in the uterus.
• In foetus, limbs have appeared and resembles the humans unlike the embryo which is a growing or dividing zygote.

(b) Hyaluronidase —

• Enzyme
• It is an enzyme secreted by the sperm that allows the sperm to penetrate the egg.

(c) Morula —

• It is the stage in the development of human embryo which consists of a spherical mass of cells.
• Blastocyst

(d) Amniotic fluid —

• Between amnion and embryo
• The functions of Amniotic fluid are:
  1. It protects the embryo from physical damage by jerks or mechanical shocks.
  2. Keeps an even pressure all around the embryo.
  3. Allows the foetus some restricted movement.
  4. Prevents sticking of the foetus to the amnion.

(e) Placenta —

• Placenta is formed by two sets of minute finger like processes called the villi. One set of villi is from the uterine wall and the other set is from the allantois.
• Carbon dioxide and Urea pass from foetus to mother through placenta.
• Two hormones produced by Placenta are Progesterone and Oestrogens.

(f) Implantation —

• Blastocyst
• It occurs in about 5-7 days after fertilisation.

(a) Inguinal canal allows the descent of testes into scrotal sac.

(b) Testis produce and store sperms and also secrete testosterone hormone.

(c) Ovaries produce the egg cells, called the ova. The corpus luteum in the ovary secretes two hormones — Oestrogen and Progesterone.

(d) Oviducts (Fallopian tubes) carry the released ovum from the ovary to the uterus. Fertilisation also occurs in the Oviduct.

(e) The uterus is responsible for nurturing and housing a developing fetus during pregnancy.

(a) Seminal vesicles are located between the posterior surface of the urinary bladder and the rectum in males.

(b) Uterus is situated in the pelvic cavity between the urinary bladder and the rectum in females.

(c) Placenta is attached to the uterine wall.

(d) Head of sperm.

(e) Vagina starts from lower end of uterus to outside.

(a) Reproduction — Reproduction is the process of formation of new individuals by sexual or asexual means, which can repeat the process in their own turn.

(b) Hernia — Hernia is an abnormal condition which is caused when the intestine due to the pressure in abdomen bulges into the scrotum through the inguinal canal.

(c) Ovulation — Ovulation is the rupture of the follicle releasing the egg .

(d) Puberty — Puberty is the period during which immature reproductive system in boys and girls matures and becomes capable of reproduction.

(e) Fertilization — The fusion of the male gamete (sperm) and the female gamete (ovum) to form a zygote is called fertilisation.

(f) Hymen — Hymen is a thin membrane which partially covers the opening of the vagina in young females.

(a) Difference between spermatogenesis and oogenesis —

(b) Difference between implantation and gestation —

(c) Difference between pregnancy and parturition —

(d) Difference between placenta and umbilical cord —

(e) Difference between identical and fraternal twins —

(f) Difference between Menarche and Menopause —

Testes are responsible for the production of male gametes i.e. sperms. The normal body temperature does not allow the maturation of the sperms. Being suspended outside the body cavity, the temperature in the scrotal sac is 2 to 3°C lower than that of the body which is the suitable temperature for the maturation of the sperms.
When it is too hot, the skin of the scrotum loosens so that the testes hang down away from the body. When it is too cold, the skin contracts in a folded manner and draws the testes closer to the body for warmth.
In an abnormal condition, in the embryonic stage, the testes do not descend into the scrotum. It can lead to sterility or incapability to produce sperms.

Secondary sexual characteristics in males:

1. Deeper voice
2. Hair growth on the face in the form of beard and moustache
3. Stronger muscular built

Secondary sexual characteristics in females:

1. High pitched voice
2. Broad hips
3. Development of breasts

The accessory reproductive organs include all those structures, ducts and glands which help in the transfer and meeting of two kinds of sex cells leading to fertilization and in the growth and development of the egg up to the birth of the baby.

For example: Uterus in females, Penis in males.

The different stages in the development of human embryo are described below:

Testosterone is the male reproductive hormone produced by the interstitial cells or the Leydig cells. These cells are located in the testes. They serve as a packing tissue between the coils of the seminiferous tubules. Therefore, it can be said that the testes produce the male hormone testosterone.

(a) Excretory system and Female Reproductive system.

(b) The parts numbered 1-10 are:

• 1 → Kidney
• 2 → Ureter
• 3 → Fallopian Tube
• 4 → Oviducal Funnel
• 5 → Ovary
• 6 → Uterus
• 7 → Urinary Bladder
• 8 → Cervix
• 9 → Vagina
• 10 → Vulva

(c) Functions of the parts are:

• Fallopian Tube (part 3) — The fallopian tubes carry the ovum released from the ovary to the uterus.
• Oviducal Funnel (part 4) — It is the funnel shaped distal end of the ovary which picks up the released ovum and pushes it further on its passage into the fallopian tube.
• Ovary (part 5) — Ovary produces female gametes i.e. ova.
• Uterus (part 6) — Uterus allows the growth and development of the embryo.

(d) If fallopian tube (part 3) on both sides gets blocked, the ovum released by the ovary will not be pushed into the oviduct and hence, there will be no possibility of fertilisation.

(a) Male Reproductive Organ System

(b)

• 1 → Testes
• 2 → Scrotal sac
• 3 → Epididymis
• 4 → Sperm duct
• 5 → Seminal vesicle
• 6 → Bulbo-Urethral Gland
• 7 → Urethra

(c) Part 3 (Epididymis) — It stores the sperms for some days during which they mature and become motile.
Part 6 (Bulbo-Urethral Gland) — Their secretion serves as a lubricant.

(d) Leydig cells

(e) The normal body temperature does not allow the maturation of the sperms. Being suspended outside the body cavity, the temperature in the scrotal sac is 2 to 3°C lower than that of the body which is the suitable temperature for the maturation of the sperms.

(a) Testis.
They are located in scrotal sac.

(b)

• 1 → Epididymis
• 2 → Efferent ducts
• 3 → Seminiferous tubules
• 4 → Sperm duct

(c) Efferent ducts (Part 2) conduct sperm to epididymis.
Sperm duct (Part 4) transmit sperms from testes to urethra.

(d) Sperms and testosterone.

(e) Labelled diagram of the cellular structure of the sperm is given below:

• 1 → Urinary bladder
• 2 → Ureter
• 3 → Bulbo-urethral glands
• 4 → Sperm duct/Vas deferens
• 5 → Urethra
• 6 → Testis
• 7 → Scrotum
• 8 → Epididymis

Fallopian tubes (oviducts) in females are analogous to sperm ducts in males. Sperm ducts carry sperms to the urethra, while fallopian tubes carry ova to the uterus.

(a) The parts 1 to 5 are:

• 1 → Umbilical cord
• 2 → Placenta
• 3 → Amnion
• 4 → Mouth of uterus
• 5 → Muscular wall of uterus

(b) Gestation

(c) 280 days

(d) Placenta provides the foetus with oxygen and nutrients. In addition, the placenta also removes carbon dioxide and waste products of the foetus.

(e) Progesterone

(a) The labelled guidelines are:

• 1 → Vagina
• 2 → Ovary
• 3 → Funnel of Oviduct
• 4 → Fallopian tube
• 5 → Uterus
• 6 → Uterus lining

(b) 280 days

(c) Vagina

(d) Ovary releases egg and produces hormones (oestrogen, progesterone)

(e) Implantation

(a) The reproductive cells A and B are:

• A → Ovum
• B → Sperm

(b) Parts of the reproductive system where the above cells are produced are:

• Sperms are produced in the testis.
• The ovum is produced in the ovary.

(c) The reproductive cells unite in the fallopian tubes of the female reproductive system.

(d) The main hormone secreted are:

• Ovary → Oestrogen and progesterone
• Testis →Testosterone

(e) Accessory glands found in the male reproductive system along with their functions are mentioned below:

• Seminal vesicle — They produce a secretion which serves as a medium for the transportation of the sperms.
• Prostate gland — It produces an alkaline secretion which mixes with the semen and helps neutralise acid in female's vagina.
• Bulbo-urethral gland — They produce a secretion which serves as a lubricant.