Friday, December 25, 2020

Human Reproduction | Plus 2 Zoology| Exam Capsule Notes (Web and PDF)

HUMAN REPRODUCTION: 
CHAPTER AT A GLANCE







Sequence of milk conduction in mammary glands: 

    Mammary alveoli → mammary tubules → mammary duct → mammary ampulla → lactiferous duct.

Spermatogenesis



Structure of sperm

  • Acrosome: Releases lytic enzymes to penetrate the layers of ovum.
  • Mitochondria: Provides energy for tail movement. 
Oogenesis


Structure of ovum (egg) 


3 membranes: 
  • Plasma membrane 
  • Zona pellucida 
  • Corona radiata 
Sectional view of a seminiferous tubule 


Structure of ovary

  • Primary sex organ. 
  • Produce ovum and oestrogen & progesterone. 
MENSTRUAL CYCLE (REPRODUCTIVE CYCLE) 

Phases

Days

Main events

1.  Menstrual phase

1-5th day

Menstrual flow (bleeding).

2.  Follicular (Proliferative) phase

5-13th day

o Primary follicles Graafian follicles.

o Proliferation of ruptured uterine endometrium.

3.  Ovulatory phase

14th day

LH surge → rupture of Graafian follicle → ovulation.

4.  Secretory (Luteal) phase

15-28th day

Corpus luteum forms → progesterone → endometrium maximum vascular, thick and soft


  • Menarche: The first menstruation during puberty. 
  • Menopause: Permanent stopping of menstrual cycle at the age of 50. 

FERTILIZATION AND IMPLANTATION 


Zygote → cleavage → morula (8-16 blastomeres) → blastocyst → embryo 


Blastocyst 
  • A. Inner cell mass: Becomes embryo. 
  • B. Trophoblast: Gives nourishment to inner cell mass. Also, it is attached to endometrium. 
After attachment, blastocyst is embedded in endometrium. It is called implantation. 

PREGNANCY AND EMBRYONIC DEVELOPMENT 

Placenta: A structural & functional unit b/w foetus & uterine wall formed by interdigitation of chorionic villi & uterine tissue. 

Functions of placenta: 
  • Supply O2, nutrients etc. from mother to foetus. 
  • Remove CO2 and excretory wastes from foetus. 
  • Acts as an endocrine gland. It secretes Human chorionic gonadotropin (hCG), human placental lactogen (hPL), oestrogens, progesterone & relaxin. 


Changes in embryo during pregnancy:
  • After one month: Heart is formed.
  • End of second month: Limbs and digits are developed.
  • End of 12 weeks (first trimester): Major organs (limbs, external genital organs etc.)
  • 5th month: Hair on the head. First movement of foetus.
  • End of 24 weeks (2nd trimester): Fine body hair, eyelids separate and eye lashes are formed.
  • End of 9 months: Ready for delivery.
PARTURITION AND LACTATION 
  • Signals from foetus & placenta → mild uterine contractions (fetal ejection reflex)oxytocin from pituitary → stronger uterine muscle contractions → further secretion of oxytocin → Parturition (giving birth). 
  • Lactation: Production of milk from mammary glands. 
  • Colostrum: Yellowish milk produced during the initial few days of lactation. It is rich in antibodies essential to develop resistance for the new born babies.

πŸ‘‰ Download PDF


Other Chapters πŸ‘‡

πŸ‘‰ Class 11
πŸ‘‰ Class 12


2 comments:

  1. Its saves my time and help me a lot...you are doing great workπŸ™ŒπŸ˜‡

    ReplyDelete
  2. Good note.. Its very helpful 😍

    ReplyDelete