Reproductive

• Male reproductive system

  Located in the pelvis region
• Parts of the male reproductive system

  • Testes
  • Accessory ducts
  • Glands
  • External genitalia
• Sperm


  Microscopic structure composed of a head, neck, a middle piece and a tail
• Seminal plasma

  • Rich in fructose, calcium and certain enzymes
  • Secretions of bulbourethral glands help in the lubrication of the penis
• Female reproductive system

  Consists of a pair of ovaries, a pair of oviducts, uterus, cervix, vagina and the external genitalia located in pelvic region
• Oogenesis

  1. Primary oocytes undergo first meiotic division to form secondary oocytes and first polar body

  2. Secondary oocyte completes the second meiotic division after fertilization to form the ovum and second polar body
• Uterus

  • Single, pear-shaped organ supported by ligaments attached to the pelvic wall
  • Wall of the uterus has three layers: external thin membranous perimetrium, middle thick layer of smooth muscle (myometrium), and inner glandular layer (endometrium) that lines the uterine cavity
  • Endometrium undergoes cyclic changes during the menstrual cycle, while the myometrium exhibits strong contractions during delivery of the baby
• Regenesis


  The process of formation of a mature female gamete
• Primary oocyte

  • Grows in size and completes first meiotic division
  • Unequal division resulting in a large haploid secondary oocyte and a tiny first polar body
• Secondary oocyte

  Retains bulk of the nutrient rich cytoplasm of the primary oocyte
• Maturation of follicle

  Primary follicle further changes into the mature follicle or Graafian follicle
• Ovulation

  Release of the secondary oocyte (ovum) from the ovary
• Menstrual cycle


  The reproductive cycle in female primates
• Menstrual cycle

  1. Begins at puberty (menarche)

  2. Lasts about 28 days

  3. Includes menstrual phase with breakdown of endometrium and bleeding for 3-5 days
• Lack of menstruation


  May be indicative of pregnancy
• Follicular phase

  Gonadotropins (LH and FSH) increase and stimulate follicular development and estrogen secretion
• Ovulatory phase

  LH surge induces rupture of Graafian follicle and release of ovum (ovulation)
• Luteal phase


  Remaining parts of Graafian follicle form corpus luteum which secretes progesterone
• Corpus luteum is essential for maintenance of endometrium for implantation
• During pregnancy, menstrual cycle stops and there is no menstruation
• In the absence of fertilisation, corpus luteum degenerates leading to menstruation
• Menstrual cycles cease around 50 years of age, marking menopause
• Cyclic menstruation indicates normal reproductive phase between menarche and menopause
• Human female has XX chromosome pattern, male has XY
• Cleavage and blastocyst formation

  1. Zygote divides to form 2, 4, 8, 16 blastomeres

  2. Blastocyst forms with trophoblast and inner cell mass
• Implantation

  Blastocyst gets embedded in uterine endometrium
• Placenta formation

  1. Chorionic villi develop and interdigitate with uterine tissue

  2. Placenta facilitates exchange of oxygen, nutrients and waste between embryo and mother
• Parturition

  1. Signals from fully developed foetus and placenta induce uterine contractions

  2. Oxytocin release causes stronger contractions leading to birth
• Lactation

  Mammary glands undergo differentiation to produce milk for newborn
• Colostrum produced in initial days of lactation contains antibodies essential for infant
• Breastfeeding is recommended for healthy infant growth
• Chorion is the outer layer of placenta in humans
• Capacitation refers to changes in sperm before fertilisation
• Placenta and umbilical cord are rich sources of stem cells
• Oocytes adhere to follicle wall through a stalk-like structure called cumulus oophorus
• Hormonal regulation of menstrual cycle

  • GnRH from hypothalamus
  • FSH and LH from anterior pituitary
  • Estrogen and progesterone from ovary
• Testes are situated outside the abdominal cavity within a pouch called scrotum
• spermatic cord passes into the testicular through inguinal canal
• testis is made of three layers

  outermost- tunica vaginalis

  middle - tunica albuginea

  innermost - tunica vasculosa
• Each testicular has about 250 compartments called testicular lobules