ANATOMY, PHYSIOLOGY, IMPORTANCE OF THE ENDOCRINE SYSTEM (AN OVERVIEW)

1. INTRODUCTION: ANATOMY,
PHYSIOLOGY, IMPORTANCE OF
ENDOCRINE SYSTEM
Michael Angelo R. Nones
BSPCP5A

3. Endocrine– derived from Greek words “endo”, meaning within and “crinis”,
meaning to secrete.
It is made up of glands that produce and secrete hormones, chemical substances
produced in the body that regulate the activity of cells or organs. These hormones
regulate the body’s growth, metabolism, and sexual development and function; they
help maintain stable internal conditions or homeostasis.
Hormones – chemical messengers created by the body. They transfer
information from one set of cells to another to coordinate the functions
of different parts of the body.
Gland – is an organ that makes and puts out hormones that do a
specific job in your body. Endocrine glands release the substances
they make into your bloodstream.

4. 2 REGULATORY MECHANISMS:
A. Feedback Regulation
B. Circadian/Diurnal Rhythm

5. Hypothalamus
Releasing Hormones (RH)
Pituitary Gland
Trophic or Stimulating Hormones
Target Organs
A. Feedback Regulation
Target Organ Hormone
If excess
1. Negative Feedback

6. Example:
Hypothalamus
Thyrotropin Releasing Hormone
(TRH)
Pituitary Gland
Thyrotropin or Thyroid Stimulating Hormone
(TSH)
Thyroid Gland
T4, T3 hormones
If excess
Release of Thyroid Hormone

7. Hypothalamus
Gonadotropin Releasing Hormone (GnRH)
Pituitary Gland
Ovary
Progesterone
Gonadotropin
LH FSH
Estrogen
Positive Regulation
A. Feedback Regulation
2. Positive Feedback

8. B. Circadian Rhythm/ Diurnal Rhythm (Sleep-
wake cycle)
 Hormone secretion is entrained to sleep
Ex.
1. GH Secretion
- peaks at the height of deep sleep
2. Cortisol
- peaks 2 hours after waking up

9. The major glands of the endocrine system are:
 Hypothalamus
 Pituitary
 Thyroid
 Parathyroid
 Adrenal
 Thymus
 Pineal
 Reproductive Organs (Ovaries, Testes)
 Pancreas

10. HYPOTHALAMUS
Location: Lower central part of brain
Hormones: Vasopressin, Oxytocin, Somatostatin, GnRH, GHRH, TRH
Importance: Regulation of satiety, metabolism and body temperature.
Common diseases:
 Neurogenic diabetes insipidus
 Anorexia/Bulimia eating disorder
 Sleep disorders

11. PITUITARY
”Master Gland”
Location: Base of the brain beneath the hypothalamus
Hormones: Growth hormone, Luteinizing hormone, TSH, FSH, ACTH,
Prolactin
Importance: Most important because it produces hormones that control
or regulate many functions of other endocrine glands.
Common diseases:
 Acromegaly
 Cushing’s diseases
 Hyperprolactinemia

12. THYROID GLAND
Location: Lower front part of the neck
Hormones: Triiodothyronine (T3), Thyroxine (T4)
Importance: Produces thyroid hormones that regulates the body’s
metabolism, plays role in bone growth and development of the brain &
nervous system in children.
Common diseases:
 Graves’ Diseases
 Hashimoto’s Thyroiditis
 Goiter

13. PARATHYROID GLAND
Location: Two pairs of small glands embedded in the surface of thyroid
gland
Hormones: Parathyroid Hormone (Parathormone or Parathyrin)
Importance: Regulates calcium levels in the blood and bone metabolism
Common diseases:
 Hypercalcemia
 Hypocalcemia
 Primary hyperparathyroidism

14. ADRENAL GLAND
Location: Two adrenal glands are triangular-shaped glands located on top of each
kidney
Importance:
Outer Part: Adrenal Cortex – produces corticosteroids, which regulate the body’s
metabolism, balance of salt and water in the body, the immune system, and sexual
function. (Hormones: Cortisol, Aldosterone)
Inner Part: Adrenal Medulla – produces catecholamines, which help body cope with
physical and emotional stress by increasing heart rate and pressure. (Hormones:
Epinephrine, Norepinephrine)
Common diseases:
 Adrenal Gland Tumors
 Adrenocortical Carcinoma
 Addison’s diseases

15. THYMUS
Location: Upper anterior (front) part of chest behind sternum &
between the lungs
Hormone: Thymosin
Importance: Produces hormone called Thymosin, which stimulates the development of
disease-fighting T cells
Common diseases:
 Myasthenia gravis
 Pure red cell aplasia (PRCA)
 Hypogammaglobulinemia

16. PINEAL GLAND
Location: Middle of the Brain
Hormone: Melatonin
Importance: Secretes hormone called Melatonin, which helps
regulate the wake-sleep cycle of the body.
Common diseases:
 Depression
 Pineal Cell Tumor
 Alzheimer’s Disease

17. REPRODUCTIVE GLANDS
Location :
 Testes, in the scrotum (Males)
 Ovaries, both sides of the uterus (Females)
Importance:
 Testes produce Testosterone, responsible for male characteristics, sexual
development and sperm production.
 Ovaries produce Estrogen and Progesterone, responsible for female characteristics
and reproductive functions.
Common diseases:
 Sexually Transmitted Diseases (STDs)
 Prostate Cancer
 Breast Cancer

18. PANCREAS
Location: Back of the abdomen behind the stomach
Hormones: Insulin, Glucagon, Gastrin, Amylin, Secretin,
Importance: Digestive and hormonal functions; the exocrine pancreas
secretes digestive enzymes while the endocrine pancreas secretes
hormones called insulin and glucagon.
Common diseases:
 Pancreatic Cancer
 Cystic Fibrosis
 Pancreatitis

19. SOURCES
https://www.sciencedirect.com/topics/medicine-and-dentistry/hormonal-
rhythms
https://www.ck12.org/book/CK-12-Biology-Advanced-
Concepts/section/17.82/https://www.webmd.com/diabetes/endocrine-
system-facts#1
http://www.vivo.colostate.edu/hbooks/pathphys/endocrine/thyroid/contro
l.html
https://mcb.berkeley.edu/courses/mcb135e/fsh-lh.html
https://www.endocrineweb.com/endocrinology/about-endocrine-system

20. Thank you for listening!