ENDOCRINE & REPRODUCTIVE NOTES.pdf M56BOOKSTORE - JOIN US TELEGRAM----SD

1. Endocrinology & Reproductive physiology
(Salient figures & flowcharts to remember ) M56BOOKSTORE

2. Feedback regulation of growth hormone
secretion
Rate of GH secretion throughout life
24-hour fluctuations in plasma GH level
Note that secretion is maximum during pubertal life
Note, about two-thirds of secretion occurs in the midnight.

3. Restoration of blood volume by ADH in volume depletion state
(NTS: Nucleus tractus solitarious).

4. Milk-ejection reflex
Afferent limb is the ascending spinothalamic tract that gives
collateral to supraoptic and paraventricular nuclei (SON and
PVN) of hypothalamus.
The efferent limb is mainly humoral, in which oxytocin from
posterior pituitary released into circulation causes contraction
of myoepithelial cells of alveoli to eject milk into the milk duct

5. Mechanism of action of thyroxine
Mechanism of thyroxine action is similar to steroid hormones. (TR:
Thyroid hormone receptor; TRE: Thyroid-hormone response
element; MC: Mitochondria).

6. Mechanisms of increased cardiac output by thyroid hormones.

7. Physiological actions of Thyroid
hormone

8. Summary of metabolic actions of cortisol

9. Pheochromocytoma
Pheochromocytoma is a tumor of adrenal medulla that occurs due to hyperplasia of chromaffin cells. Also,
proliferation of chromaffin cells of paraganglia
Concentration of epinephrine and norepinephrine is very high
Clinical features: Sustained hypertension, increased metabolic rate, profuse sweating, extreme anxiety,
palpitations, extreme tachycardia and high, BP, hyperglycemia, and loss of appetite and body weight.
Diagnosis is established by detecting increased concentration of catecholamines
Urinary excretion of metanephrine and VMA also increases.

10. Summary of insulin actions
(GP: Glycerophosphate; HSL: Hormone sensitive lipase; LL: Lipoprotein lipase).

11. Summary of effects of PTH

12. Summary of effects of calcitonin

13. Summary of physiological effects of vitamin D

14. Steps of
spermatogenesis
• Till the stage of primary
spermatocyte, each cell contains
46 chromosomes
• From secondary spermatocyte to
spermatozoa, each cell contains 23
chromosomes

15. Mechanisms of testosterone
action
• Note that testosterone (T) is converted to
dihydrotestosterone (DHT) in the cell.
• There are separate receptors (R) for both
testosterone and DHT in the nucleus.
• Therefore, two separate mechanisms exist in
different cells for testosterone actions.

16. Stages of development of ovarian follicle. (A) Primordial follicular stage (Stage 1); (B) Primary follicular stage
(Stage 2) (C) Secondary follicular stage (Stage 3) (D) Tertiary follicular stage (Stage 4, or Matured follicle)

17. Stages of oogenesis
Note, first meiotic division of
oocyte begins during fetal life and
completes prior to ovulation,
whereas second meiotic division
completes at the time of
fertilization.

18. Indicators of Ovulation
Rise in of basal
body
temperature
Fleeting lower
abdominal pain
(mittelschmerz)
Vaginal
discharge
(spotting)
Spinnbarkeit
Fern test
Laparoscopic
observation:
Demonstrating
ovum in the
abdominal
cavity
Demonstration of
LH peak

19. Changes in secretion of hormones in menstrual cycle
(A) Changes in LH and FSH level (B) Changes in estrogen and progesterone level

20. Level of various hormones in maternal plasma in pregnancy