322 ^|

A Handbook of Biology



A pair of ovaries is located in the abdomen. Ovary is formed of ovarian

follicles and stromal tissues. Ovarian follicles produce estrogen (a

steroid hormone).



After ovulation, ruptured follicle forms a structure called corpus luteum.

It secretes progesterone (a steroid hormone).

(NEET 2017)

FUNCTIONS OF ESTROGEN

Growth and activities

of female secondary

sex organs

Development of

ovarian follicles &

mammary glands

Female secondary

sex characters (e. g.

high pitch voice) and

sexual behavior

1

2

3

FÜÑÇTÏØÑS ØF PRØGËSTËRØÑË:



It supports pregnancy.



It acts on mammary glands to stimulate formation of alveoli (sacs to

store milk) and milk secretion.

HØRMØÑËS ØF HËÅRT, KÏDÑËÝ & GÅSTRØÏÑTËSTÏÑÅL TRÅÇT

1. ÅTRÏÅL WÅLL ØF HËÅRT



Produce a peptide hormone called Atrial natriuretic factor (ANF). When

BP increases, ANF causes the dilation of blood vessels and thereby

reduces the BP.

2. JGÅ ØF KÏDÑËÝ:



Produces erythropoietin (peptide hormone). Stimulates erythropoiesis

3. GÅSTRØ - ÏÑTËSTÏÑÅL GLÅÑDS

Produce peptide hormones

Gastrin: Stimulates

secretion of HCI and

pepsinogen from

gastric glands.

Secretin: Stimulates

secretion of water

and bicarbonate

ions from exocrine

pancreas.

Cholecystokinin

(CCK): Stimulates

secretion of bile from

gall bladder and

pancreatic enzymes

from pancreas.

Gastric inhibitory

peptide (GIP):

Inhibits gastric

secretion.