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CHAPTER 15
REPRODUCTIVE SYSTEM
- Anatomy of male and female reproductive system
- Physiology of menstruation
- Spermatogenesis and Oogenesis
- Pregnancy and Parturition Prepared by- Titas Debnath, Assistant Professor 1
HUMAN REPRODUCTIVE SYSTEM
The human reproductive system includes a set of male and female reproductive organs which functions together to produce offspring. The male reproductive system contains three main parts: 1. The testes , which produces sperm, 2. Spermatic ducts , which transport sperm, and 3. The Penis , which inserted the sperm into the vagina. The female reproductive system which functions to produce egg cells, and to protect and nourish the fetus until birth. The female reproductive system contains three main parts: 1. The vulva , which is the external genital. 2. The internal genitalia , which produce the female's ova and holds the developing fetus.
- The brests, which act as a accessory reproductive organs. 2
1. Scrotum- The scrotum is a pouch of pigmented skin, fibrous and connective tissue and smooth muscle. It is a thin external sac that is located under the penis and divided into two compartments by the scrotal septum. 2. Testis- The testes are the male reproductive glands and are about 4. 5 cm long, 2. 5 cm wide and 3 cm thick. They remain suspended in the scrotum by the spermatic cords. Each Testis is surrounded by three layers of tissues- Tunica vaginalis, Tunica albuginea and Tunica vusculosa. 3. Epididymis- It is a single, narrow, tightly coiled tube in adult humans ( coiled- 2. 4 to 2. 8 inch and uncoiled- 20 feet) After production in testis sperms are stored and slowly moved in the epididymis and getting mature. 4
4. Vas deferens- Also called Ductus Deferens or Deferent Duct. It is a muscular tube which carries the sperm in the upward direction from epididymis to reach and joined by the duct from the seminal vesicle to form the ejaculatory duct. 5. Seminal vesicles- These are paired exocrine glands present behind the urinary bladder and in front of the rectum. The alkaline liquid produced by them form the semisolid liquid (semen) with sperm and contains proteins and mucus, and allows the sperm to survive in the acidic vaginal environment. 6. Ejaculatory duct- The ejaculatory ducts are two tubes each about 2 cm long and formed by the union of the duct from a seminal vesicle and a vas deference. They pass through the prostate gland and join the prostatic urethra, carrying seminal fluid and sperm to the urethra during ejaculation. 5
FEMALE REPRODUCTIVE SYSTEM
The female reproductive system includes a group of
organs in a woman's lower belly and pelvis.
The female reproductive system consists of internal and
external body parts that help to reproduce, menstruate
and have sex. Additionally, the female breast is
considered an accessory organ of reproduction.
So, various parts of female reproductive systems are-
A. External genitalia.
B. Internal genitalia.
C. Breast.
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The components of
the External genetalia
or vulva are-
1. The mons pubis
2. Labia majora
3. Labia minora
4. Clitoris
5. Vestibular bulbs
6. Bartholin's glands
7. Urethra
8. Vaginal opening.
A. External Genitalia or Vulva
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4. Clitoris- It is small finger like structure, present at the
upper junction of the two labia minora above the urethral
opening. It corresponds to the penis in the male and
important in female sexual pleasure.
5. Vestibular bulbs- The vestibular bulbs are bilateral
structures that sit on both sides of the vaginal orifice. They
are approximately 3 cm long and consist of erectile tissue.
The vestibular bulbs cause "vaginal" orgasmic contractions,
through the rhythmic contraction.
6. Bartholin's glands- The vestibular (Bartholin’s) glands are
situated one on each side near the vaginal opening. These
small glands secretes mucus that keeps the vulva moist. This
substance is also believed to act as an antimicrobial.
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7. Urethra- The female urethra is embedded within the
vaginal wall, and its opening is situated between the
labia. It begins at the bladder neck and opens to the
outside just after passing through the urethral sphincter.
8. Vaginal opening- The vaginal opening is right below
urethral opening. It is the hole where a penis, finger,
menstrual cup can be inserted. menstrual blood leaves
body and babies are born through the vaginal opening.
Hymen- A thin membrane called a hymen usually
surrounds or partially covers vaginal opening.
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1. Vagina- Vagina is an elastic, muscular tube which
joins the uterine cervix with the vulva opening outside
the body. It is about 3 inch long and less than an inch
in diameter.
It has the ability to several inches longer and wider
during sexual intercourse and childbirth.
The epithelial tissue produces watery secretions for
vagina lubrication and protecting the friction to the
vaginal layers.
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2. Uterus- The uterus is a hollow, muscular, pear-shaped
organ lying in the pelvic cavity between the urinary
bladder and the recturm. It is about 7. 5 cm long and 5
cm wide, and its walls are about 2. 5 cm thick. Weighing
30 - 40 g. It connects the vagina with the uterine tubes
The walls of the uterus are composed of three layers of
tissues- Peritoneum/Perimetrium, Myometrium and
Endometrium.
It recives the fertilised ovum, reatains the foetus during
pregnancy, and provides nourishment. After maturity it
expels the foetus by contracting its muscular walls.
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C. Breasts
The breasts or mammary glands are accessory glands of the female reproductive system. The mammary glands are paired structures of glandular, fibrous and fatty tissues. Structures- Fibrous connective tissues anchor the breast to the chest wall. The breast contains about 20 lobes, each of which contains a number of glandular structures called lobules. 16
Physiology of Menstruation
Menstrual Cycle or Menstruation is a series of
events, occurring regularly in females every 26 to
30 days between the age of first menstrual period
(Menarche) and stop menstruation permanently
(menopause).
Various phases of menstruation are-
Phases Days Menstrual Phase 1 st
- 5 th Follicular Phase ( Proliferative Phase) 5 th
- 13 th Ovulation 14 th Luteal Phase ( Secretory Phase) 15 th
- 28 th 17
Phases of Menstruation
1. Menstrual Phase- 1
st
to 5
th
day of Cycle.
This phase is characterised by vaginal bleeding, known
as menstruation ( also called menstrual bleeding or
menses or periods).
Menstrual flow consists of the secretion of endometrial
glands, endometrial cells, blood from the
degenerating capillaries and the unfertilised ovum.
Plasmin (enzyme present in endometrium) inhibits blood
clotting , resulting in blood loss. Due to this reason
dietary consumption of iron is required in females.
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2. Proliferative Phase- 5
th
to 13
th
day of cycle.
One or more overian follicles stimulated by FSH, grow
towards maturity and produce increasing amounts
of oestrogen.
This stimulates proliferation of the functional layer of
the endometrium in preparation of receiving a
fertilised ovum.
During this phase the uterus lining becomes thick due
to the increasing amount of oestogen.
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