● `color{violet}("Pancreas")` is a composite `color{violet}("gland")` which acts as both `color{violet}("exocrine and endocrine gland.")`

● The `color{violet}("endocrine pancreas")` consists of `color{violet}("‘Islets of Langerhans’.")`

● There are about 1 to 2 million `color{violet}("Islets of Langerhans")` in a normal human pancreas representing only 1 to 2 per cent of the `color{violet}("pancreatic tissue.")`

● The two main types of cells in the `color{violet}("Islet of Langerhans")` are called `color{brown}("α cells")` and `color{brown}("β cells.")`

● The `color{brown}("α cells")` secrete a hormone called `color{brown}("glucagon,")` while the `color{violet}("β cells")` secrete `color{brown}("insulin.")`

● `color{violet}("Glucagon")` is a peptide `color{violet}("hormone")`, and plays an important role in maintaining the normal `color{violet}("blood glucose levels")`.

● `color{violet}("Glucagon")` acts mainly on the `color{violet}("liver cells")` (hepatocytes) and stimulates `color{violet}("glycogenolysis")` resulting in an increased `color{violet}("blood sugar")` ( `color{brown}("hyperglycemia")`).

● In addition, this `color{violet}("hormone")` stimulates the process of `color{violet}("gluconeogenesis")` which also contributes to `color{violet}("hyperglycemia.")`

● `color{violet}("Glucagon")` reduces the `color{violet}("cellular glucose")` uptake and utilisation.

● Thus, `color{violet}("glucagon")` is a `color{brown}("hyperglycemic hormone.")`

● Insulin is a peptide hormone, which plays a major role in the regulation of glucose homeostasis.

● `color{violet}("Insulin")` acts mainly on `color{violet}("hepatocytes")` and `color{violet}("adipocytes")` (cells of adipose tissue), and enhances `color{violet}("cellular glucose")` uptake and utilisation.

● As a result, there is a rapid movement of `color{violet}("glucose")` from `color{violet}("blood")` to `color{violet}("hepatocytes")` and `color{violet}("adipocytes")` resulting in decreased blood glucose levels ( `color{brown}("hypoglycemia")`).

● `color{violet}("Insulin")` also stimulates conversion of `color{violet}("glucose to glycogen")` ( `color{brown}("glycogenesis")`) in the target cells.

● The `color{violet}("glucose homeostasis"
)` in blood is thus maintained jointly by the two – `color{violet}("insulin and glucagons.")`

● `color{violet}("Prolonged hyperglycemia")` leads to a complex disorder called `color{brown}("diabetes mellitus")` which is associated with loss of glucose through `color{violet}("urine and formation")` of harmful compounds known as ketone bodies.

● `color{violet}("Diabetic patients")` are successfully treated with `color{violet}("insulin therapy.")`

● A pair of testis is present in the `color{violet}("scrotal sac")` (outside abdomen) of male individuals.

● Testis performs dual functions as a `color{violet}("primary sex organ")` as well as an endocrine gland.

● Testis is composed of `color{brown}("seminiferous tubules")` and `color{brown}("stromal or interstitial tissue.")`

● The `color{brown}("Leydig cells or interstitial cells")`, which are present in the intertubular spaces produce a group of hormones called `color{brown}("androgens")` mainly `color{brown}("testosterone.")`

● `color{violet}("Androgens")` regulate the development, maturation and functions of the `color{violet}("male accessory sex organs")` like epididymis, vas deferens, seminal vesicles, prostate gland, urethra etc.

● These `color{violet}("hormones stimulate muscular growth,")` growth of facial and `color{violet}("axillary hair, aggressiveness,")` low pitch of voice etc.

● `color{violet}("Androgens ")` play a major stimulatory role in the process of `color{violet}("spermatogenesis")` (formation of spermatozoa).

● `color{violet}("Androgens act")` on the `color{violet}("central neural system")` and `color{violet}("influence")` the `color{violet}("male sexual behaviour (libido).")`

● These `color{violet}("hormones")` produce `color{violet}("anabolic")` (synthetic) effects on protein and carbohydrate metabolism.

● Females have a pair of ovaries located in the `color{violet}("abdomen. ")`

● `color{violet}("Ovary")` is the `color{violet}("primary female sex organ")` which produces one `color{violet}("ovum")` during each `color{violet}("menstrual cycle.")`

● In addition, ovary also produces two groups of `color{violet}("steroid hormones")` called `color{brown}("estrogen")` and `color{brown}("progesterone.")`

● `color{violet}("Ovary")` is composed of `color{violet}("ovarian follicles")` and `color{violet}("stromal tissues.")`

● The `color{violet}("estrogen")` is `color{violet}("synthesised")` and secreted mainly by the growing ovarian follicles.

● After `color{violet}("ovulation")`, the `color{violet}("ruptured follicle")` is converted to a structure called `color{brown}("corpus luteum,")` which secretes mainly `color{brown}("progesterone.")`

● `color{violet}("Estrogens")` produce wide ranging actions such as stimulation of growth and activities of `color{violet}("female secondary sex organs")`, development of `color{violet}("growing ovarian follicles")`, appearance of `color{violet}("female secondary sex characters")` (e.g., high pitch of voice, etc.), `color{violet}("mammary gland")` development.

● `color{violet}("Estrogens")` also regulate female sexual behaviour.

● Progesterone supports `color{violet}("pregnancy.")`

● `color{violet}("Progesterone")` also acts on the `color{violet}("mammary glands")` and stimulates the formation of `color{violet}("alveoli (sac-like structures which store milk)")` and `color{violet}("milk secretion.")`