LECTURE TWENTY-ONE

THE PITUITARY GLAND IS CALLED THE
MASTER GLAND BECAUSE IT PRODUCES A LARGE
NUMBER OF HORMONES, MANY OF WHICH ARE
-TROPIN TYPE HORMONES




THE ANTERIOR AND INTERMEDIATE LOBES OF
THE PITUITARY GLAND ARE MADE OF ECTODERM,
THE POSTERIOR LOBE IS MADE OF NERVOUS TISSUE

THE PITUITARY GLAND IS CONNECTED TO THE
HYPOTHALAMUS BY THE INFUNDIBULUM




THE ANTERIOR LOBE OF THE PITUITARY GLAND
PRODUCES SIX HORMONES:
THYROTROPIN
ADRENOCORTICOTROPIC HORMONE     ACTH
FOLLICLE STIMULATING HORMONE    FSH
LUTEINIZING HORMONE             LH
PROLACTIN
GROWTH HORMONE

FSH AND LH ARE GONADOTROPINS



THE HYPOTHALAMUS PRODUCES SIX RELEASING
FACTORS THAT CAUSE THE RELEASE OF THE
ANTERIOR PITUITARY HORMONES

THE HYPOTHALAMUS IS CALLED THE MASTER
OF THE MASTER GLAND




THYROTROPIN CAUSES THE THYROID GLAND TO
PRODUCE AND RELEASE THE HORMONE THYROXINE

THYROXINE IS A PROTEIN HORMONE THAT
CONTAINS IODINE




THE TARGET ORGANS FOR THYROXINE ARE MANY
CELLS IN THE BODY BUT NOT THE BRAIN

THYROXINE CAUSES AN INCREASE IN THE
METABOLIC RATE OF THE CELLS




AN ENLARGED THYROID GLAND IS CALLED A
GOITER, WHICH MAY BE CAUSED BY A TUMOR,
OR BY A DEFICIENCY OF IODINE IN THE DIET




HYPOFUNCTIONING OF THE THYROID GLAND
LEADS TO CRETINISM IN CHILDREN
HYPOFUNCTIONING OF THE THYROID GLAND
IN ADULTS CAUSES MYXEDEMA




HYPERFUNCTIONING OF THE THYROID GLAND
CAUSES EXOPTHALMIC GOITER (= GRAVE'S DISEASE)




THE THYROID GLAND ALSO PRODUCES THE HORMONE CALCITONIN, WHICH CONTROLS CALCIUM AND
PHOSPHORUS METABOLISM




THE STIMULUS FOR RELEASE OF ACTH IS A
PHYSICAL STRESS

THE TARGET ORGAN FOR ACTH IS THE CORTEX
OF THE ADRENAL GLAND



THE ADRENAL CORTEX PRODUCES 3 TYPES OF
HORMONES, ALL OF THEM ARE STEROIDS
 

GLUCOCORTICOIDS         CORTISOL AND CORTISONE

MINERALOCORTICOIDS      ALDOSTERONE AND DEOXYCORTICOSTERONE

ANDROGENS               TESTOSTERONE



HYPERPRODUCTION OF ANDROGENS LEADS TO
VIRILISM IN WOMEN



THE GLUCOCORTICOIDS ARE UNDER DIRECT
CONTROL BY ACTH AND THEY INDUCE THE
GENERAL ADAPTATION SYNDROME OR
ANTI-INFLAMMATORY RESPONSE



HYPOFUNCTIONING OF THE ADRENAL CORTEX LEADS
TO ADDISON'S DISEASE



IN MALES, FSH STIMULATES SPERMATOGENESIS
IN THE SEMINIFEROUS TUBULES
LH STIMULATES ANDROGEN AND TESTOSTERONE
PRODUCTION IN THE TESTES
TESTOSTERONE THEN FURTHER STIMULATES SPERM
PRODUCTION AND CAUSES GROWTH OF THE
ACCESSORY REPRODUCTIVE STRUCTURES,
SECONDARY SEXUAL CHARACTERISTICS AND
REPRODUCTIVE BEHAVIOR



IN WOMEN, FSH AND LH ARE THE MAJOR
DETERMINANTS OF THE MENSTRUAL CYCLE

FSH AND LH HAVE THE OVARIES AS THEIR
TARGET ORGANS
THE OVARIES PRODUCE ESTROGEN, ESTRADIOL,
AND PROGESTERONE IN RESPONSE TO FSH AND LH
ESTROGEN, ESTRADIOL AND PROGESTERONE HAVE
THE ENDOMETRIUM OF THE UTERUS AS THEIR
TARGET ORGAN