Short Notes on Hormones and Their Functions

1. Classification of Hormones

• Peptide Hormones: Insulin, glucagon, growth hormone, FSH, LH.

• Steroid Hormones: Cortisol, testosterone, estrogen, progesterone.
• Amino Acid Derivatives: Epinephrine, thyroxine.
• Iodothyronines: Triiodothyronine (T3), thyroxine (T4).

2. Human Endocrine System: Glands, Hormones, and Functions

Glan Target
Hormones Functions
d Organs
Hypo
Releasing/Inhibiting Regulates pituitary hormones (stimulates Pituitary
thala
hormones (e.g., GnRH) or inhibits secretion). gland
mus
Growth regulation,
GH, TSH, ACTH, FSH, Various
Pituit thyroid/adrenal/gonadal activity,
LH, Prolactin, (e.g., liver,
ary lactation, uterine contraction, water
Oxytocin, ADH kidney)
balance.
Pinea Regulates sleep-wake cycles and Brain and
Melatonin
l circadian rhythms. body
Thyro Metabolic rate regulation, calcium
T3, T4, Calcitonin Various
id homeostasis.
Parat
Increases blood calcium levels (bone Bone,
hyroi PTH
resorption, renal reabsorption). kidney
d
Adre
nal Stress response, metabolism regulation,
Cortisol, Aldosterone Various
Corte electrolyte balance.
x
Adre
nal Adrenaline, Fight or flight response (increased heart Heart,
Medu Noradrenaline rate, glucose release). liver
lla
 Pancr Regulates blood sugar levels (insulin Liver,
Insulin, Glucagon
eas decreases, glucagon increases). muscles
Male
Testi Male secondary sexual characteristics,
Testosterone reproducti
s spermatogenesis.
ve system
Female
Estrogen, Female secondary sexual characteristics,
Ovary reproducti
Progesterone menstrual cycle, pregnancy maintenance.
ve system
Thym Immune
Thymosins T-cell differentiation, immune function.
us cells
Blood
Heart ANF Lowers blood pressure by vasodilation.
vessels
Kidne Bone
Erythropoietin Stimulates RBC production.
y marrow
GI Gastrin, Secretin, Regulates digestive enzymes, gastric acid Digestive
Tract CCK, GIP secretion, bile secretion. system

3. Summary of Functions

• Growth and Development: GH, T3, T4, androgens, estrogens.

• Metabolism Regulation: Insulin, glucagon, cortisol, thyroid hormones.
• Stress Response: Adrenaline, cortisol.
• Reproductive Functions: LH, FSH, testosterone, estrogen, progesterone.
• Homeostasis: ADH (water balance), aldosterone (electrolytes), PTH (calcium).

This table and summary encapsulate the essential details for quick understanding and
efficient learning. Let me know if you'd like further simplifications or elaborations!

Short Notes on Hormones and Human Endocrine System

1. Hormones

• Definition: Chemical messengers secreted by endocrine glands into the

bloodstream to regulate target organ functions.
• Types:
 o Peptides/Proteins: Insulin, glucagon, growth hormone.
o Steroids: Cortisol, testosterone, progesterone.
o Amino Acid Derivatives: Epinephrine, thyroxine.
o Iodothyronines: T3 (Triiodothyronine), T4 (Thyroxine).

2. Endocrine Glands and Hormones

• Hypothalamus:
o Produces releasing/inhibiting hormones (e.g., GnRH, somatostatin).
o Controls pituitary gland activity.
• Pituitary Gland:
o Anterior Pituitary: Secretes GH, TSH, ACTH, LH, FSH, and Prolactin.
o Posterior Pituitary: Stores and releases Oxytocin (uterine contractions) and
ADH (water balance).
• Pineal Gland:
o Secretes Melatonin.
o Regulates circadian rhythm (sleep-wake cycle).
• Thyroid Gland:
o Produces T3, T4 (metabolism regulation) and Calcitonin (lowers blood
calcium).
• Parathyroid Gland:
o Secretes PTH.
o Increases blood calcium by bone resorption and renal absorption.
• Adrenal Glands:
o Medulla: Adrenaline and Noradrenaline for "fight or flight" response.
o Cortex: Cortisol (stress, metabolism), Aldosterone (electrolyte balance).
• Pancreas:
o Secretes Insulin (lowers blood glucose) and Glucagon (raises blood
glucose).
• Testes:
o Produces Testosterone.
o Regulates male sexual characteristics and spermatogenesis.
• Ovaries:
o Produces Estrogen (female characteristics) and Progesterone (pregnancy
maintenance).
• Thymus:
 o Secretes Thymosins for immune system function.

3. Hormones from Non-Endocrine Organs

• Heart: ANF reduces blood pressure via vasodilation.

• Kidneys: Erythropoietin stimulates red blood cell production.
• GI Tract: Gastrin (stimulates HCl), Secretin (bicarbonate secretion), CCK (bile
secretion).

4. Hormonal Regulation

• Metabolism: Insulin and glucagon maintain glucose homeostasis.

• Growth: GH stimulates overall growth; thyroid hormones support development.
• Reproduction: LH and FSH regulate gonads; estrogen and progesterone manage
menstrual cycles.
• Stress: Adrenaline and cortisol manage acute and chronic stress responses.
• Homeostasis: ADH (water balance), Aldosterone (electrolytes), PTH and Calcitonin
(calcium balance).

Diseases and Disorders Related to Endocrine Glands

1. Hypothalamus

• Disorders:
o Hypothalamic Dysfunction: Can cause irregular secretion of
releasing/inhibiting hormones affecting the pituitary gland, leading to various
hormonal imbalances (e.g., growth hormone deficiency, secondary
hypothyroidism).

2. Pituitary Gland

• Diseases:
 o Gigantism: Excess growth hormone (GH) in children, leading to abnormal
height.
o Acromegaly: Excess GH in adults causing disfigurement of the face, hands,
and feet.
o Pituitary Dwarfism: GH deficiency, leading to stunted growth.
o Diabetes Insipidus: ADH deficiency, resulting in excessive water loss
through urine.

3. Pineal Gland

• Disorders:
o Insomnia: Low melatonin levels disrupting sleep-wake cycles.
o Seasonal Affective Disorder (SAD): Abnormal melatonin levels, leading to
mood disturbances during certain seasons.

4. Thyroid Gland

• Diseases:
o Hypothyroidism: Insufficient thyroid hormone production causing fatigue,
weight gain, and cold intolerance.
▪ Cretinism: Hypothyroidism in infants, causing stunted growth and
mental retardation.
o Hyperthyroidism: Excessive thyroid hormones causing weight loss, tremors,
and increased heart rate.
▪ Graves’ Disease: An autoimmune disorder causing hyperthyroidism
and exophthalmic goiter.
o Goiter: Enlarged thyroid gland, often due to iodine deficiency.
o Thyroid Cancer: Malignant growth affecting hormone production.

5. Parathyroid Gland

• Diseases:
o Hyperparathyroidism: Excessive PTH, leading to hypercalcemia, kidney
stones, and bone weakening.
 o Hypoparathyroidism: Low PTH causing hypocalcemia, leading to muscle
cramps and spasms.

6. Adrenal Glands

• Diseases:
o Addison’s Disease: Insufficient cortisol and aldosterone, causing fatigue,
weight loss, and low blood pressure.
o Cushing’s Syndrome: Excess cortisol causing weight gain, hypertension,
and moon-shaped face.
o Pheochromocytoma: Tumor of adrenal medulla, leading to excessive
adrenaline and severe hypertension.

7. Pancreas

• Diseases:
o Diabetes Mellitus:
▪ Type 1: Insulin deficiency due to autoimmune destruction of beta
cells.
▪ Type 2: Insulin resistance, leading to high blood sugar levels.
o Hypoglycemia: Low blood sugar due to excessive insulin secretion.

8. Testes

• Disorders:
o Hypogonadism: Low testosterone causing reduced secondary sexual
characteristics and infertility.
o Androgen Insensitivity Syndrome: Genetic condition causing resistance to
male hormones.

9. Ovaries

• Diseases:
 o Polycystic Ovary Syndrome (PCOS): Hormonal imbalance leading to
irregular cycles, infertility, and cysts in ovaries.
o Ovarian Insufficiency: Low estrogen causing infertility and early
menopause.

10. Thymus

• Disorders:
o Immunodeficiency: Reduced thymosin production in older age weakens the
immune system.

11. Heart

• Disorders:
o Hypertension: Imbalance in ANF secretion affecting blood pressure
regulation.

12. Kidneys

• Disorders:
o Anemia: Low erythropoietin production, leading to reduced RBC count.

13. Gastrointestinal Tract

• Disorders:
o Peptic Ulcers: Excess gastrin leading to overproduction of gastric acid.
o Malabsorption Syndromes: Imbalance in secretin or CCK affecting
digestion.

This comprehensive list covers disorders associated with each gland and their hormonal
dysfunctions. Let me know if you'd like details on specific diseases!