Hormones and Diseases

Growth Hormone

• Location: Anterior Pituitary

• Function: Body and bone growth

• Growth Hormone Releasing Hormone

• Growth Hormone Inhibiting Hormone

Growth Hormone Homeostatic Imbalance

• Hypo secretion: Dwarfism

• Hyper secretion: Gigantism or Acromegaly

Prolactin

• Location: Anterior Pituitary

• Function:

  • Stimulates breast development

  • Stimulates & maintains milk production following childbirth

• Prolactin releasing hormone

• Prolactin inhibiting hormone (dopamine)

Prolactin Homeostatic Imbalances

Hypersecretion: can be caused by a tumor in the adenophypophyseal and includes lack of menses and infertility in females and breast enlargement and importency in males

Thyroid Stimulating hormone/ Thyrotropin

• Function: Stimulates the release of the thyroid hormone and influence the growth and activity of the thyroid

• Stimulated by: Hypothalamic hormone called thyrotropin releasing hormone

• High blood levels of the thyroid hormones act on the pituitary and hypothalamus to inhibit TSH release

Adrenocorticotropic hormone

• Function: stimulates the release of cortisol and other glucocorticoids to help the body resist stress

  • regulates adrenal cortex activity

• Regulated by : Hypothalamic corticotropin-releasing hormone (CRH)

  • Rising levels of glucocorticoids block CRH and ACTH

  • Stressors such as a fever can trigger CRH and ACTH

Gonadotropic hormones

• absent in boys and girls before puberty

• release is prompted by hypothalamic hormone gonadotropin releasing hormoe (GnRH)

Follicle-stimulating hormone

Females: Stimulates follicle development in the ovaries, as follicle mature they produce estrogen and eggs that are readied for ovulation.

Males: Stimulates sperm development in testes

Luteinizing hormone

Females: Triggers ovulation and causes ruptured follicles to produce progesterone and some estrogen, also it causes the follicle to become corpus luteum

Males: Stimulates testosterone production, refferes to as interstitial cell-stimulating hormone (ICSH) because it causes hormone production by the interstitial testes cells

Gonadotropic hormone Homeostatic Imbalance

Hypo secretion: sterility

Hyper secretion: no problems, can be even used to promote fertility

Oxytocin

• stimulates contractions of the uterus during labor

• causes milk ejection (positive feedback)

• used to speed up a normal but slow pregnacy

Antidiuretic hormone / Vasopressin

• inhibits urine production causing the kidneys to reabsorb more water so there is more water in the blood

• Drinking diuretic substances inhibits ADH (coffee, alcohol)

Antidiuretic Hormone Homeostatic Imbalance

Hyposecretion: diabetes insipidus, can be caused by blow to the head

Hypersecretion: when there's too much ADH in the body, it makes the kidneys hold onto too much water, which can cause problems like headaches, confusion, and weight gain. This can happen because of infections (meningitis), brain surgery or injury, certain cancers, or certain medications.

Thyroid hormone (THYROID GLAND)

• contains 2 active iodine contain hormones thyroxine and triiodothyronine that act on all body cells to increase basal metabolic rate and heat production

• produced by iodinated thyroglobulin

Calcitonin (THYROID GLAND)

• location: Parafollicular cells lying in the follicular epithelium protruding into connective tissue that surronds the follicle produce calcitonin hormone

• Function: inhibits osteoclasts and lowers blood calcium by stimulating Ca2+ uptake

Goiter

Iodine deficiency (Hypothyroidism) the TSH needs thyroxine so the Glands grows and negative feed back fails

Cretinism

Hypothyroidism due to the lack of stimulation by TSH, form of dwarfism. The adult like propotions stay child like. ONLY IN INFANTS

Myxedema

physical and mental sluggishness due to hypothyroidism. Oral thyroxine is prescribe to fix the condition. In adults

Graves’ disease

body produces antibodies that mimic TSH thus the TH continue releases

• eyes bulge

  • tissue behind the eye becomes fibrous (exophthalmos)

• can be treated surgically of chemically

Parathyroid hormone

• stimulated by: blood calcium levels dropping

• stimulates osteoclasts the breakdown bone matrix and release calcium

• stimulates kidneys and intestines to absorb calcium

• promotes activation of vitamin D

  • vitamin D is useless until activated

Parathyroid hormone Homeostatic Imbalance

Hypo-

• Causes of hypocalcemia: Trauma to parathyroid glands, low dietary magnesium.

• Consequence: Neurons become overactive, leading to rapid muscle spasms (tetany).

• Symptoms: Uncontrollable muscle spasms.

Hyper -

• massive bone destruction, large punched out holes in the bony matrix

• bones become very fragile and spontaneous fractures occur

Pancreas Islet cells

insulin, glucagon and somatostatin

Insulin

1. Proinsulin is broken down into active insulin in secretory vesicles before release from beta cells into the blood.

• Elevated blood glucose levels trigger the release of insulin from beta cells.

• Insulin acts on all body cells, enhancing their ability to uptake glucose across their plasma membranes.

Glucagon

When blood sugar is low, special cells called alpha cells release a hormone called glucagon. Glucagon signals the liver to release glucose into the bloodstream. This process helps raise blood sugar levels.

Somatostatin

released by the Delta cells (δ-cells or D cells) of islets, inhibits the release of insulin by Beta cells and glucagon from alpha cells.

Type II Diabetes

Typically seen in adults, where the body makes enough insulin, but the cells don't respond properly, a condition called insulin resistance. Treatment involves special diets or oral medications to stimulate the insulin-producing cells and make the body's tissues more sensitive to insulin.

Type I Diabetes

Also known as juvenile or insulin-dependent diabetes, it's characterized by a lack of insulin production. Treatment involves continuous insulin infusion via an external pump or carefully planned insulin injections throughout the day to manage blood sugar levels.

Melatonin (PINEAL GLAND)

• sleep trigger

• coordinate the hormone of fertility and to inhibit the reproductive system until adult body size is reached

Thymus Hormones

The thymus gland makes hormones like thymulin, thymopoietins, and thymosins that guide the development of T lymphocytes, which are important in the immune system. During childhood, the thymus helps these white blood cells, called T cells, mature properly.

Adrenal glands

• Positioned above the kidneys.

• Structurally and functionally two parts: adrenal cortex (glandular) and adrenal medulla (neural).

• Adrenal cortex has three layers of cells producing different hormones.

Hormones of the Adrenal Cortex

• Mineralocorticoids (zona glomerulosa) regulate sodium and potassium levels in blood.

• Glucocorticoids (zona fasciculata) regulate metabolism and help in stress response.

• Gonadocorticoids (zona reticularis) produce sex hormones contributing to puberty and sexual characteristics.

Homeostatic Imbalances of Hormones of the Adrenal Cortex

• Hyposecretion leads to Addison’s disease with symptoms like skin discoloration, weight loss, electrolyte imbalance, and low blood sugar.

• Hypersecretion results from tumors.

  • Outermost cortical area: causes high blood pressure and potassium loss, muscles weakness, and paralysis

  • Middle cortical are: excess glucocorticoids lead to Cushing’s syndrome with symptoms like obesity and weakened immune system

  • Sex Hormones: Masculinization regardless of sex

Hormones of the Adrenal Medulla

• Made of nervous tissue releasing catecholamines like epinephrine and norepinephrine.

• Enhance "fight-or-flight" response, increasing heart rate, blood pressure, and blood glucose levels.

Homeostatic Imbalance of the Adrenal Medulla

Hypersecretion of catecholamines causes symptoms like rapid heart rate, high blood pressure, and irritability, often due to a tumor called pheochromocytoma. Surgical removal corrects this condition.

Estrogens

Two hormones: estrone and estradiol

Functions:

1. Stimulate development of secondary sex characteristics in females (reproductive organs, pubic and axillary hair).

2. Work with progesterone to prepare uterus for fertilized egg.

3. Help maintain pregnancy and prepare breasts for lactation.

Progesterone

• Acts with estrogen in menstrual cycle.

• During pregnancy, prevents miscarriage by relaxing uterine muscles and prepares breast tissue for lactation.

• Hyposecretion impairs fertility.

Hormones of the Testes

• Testes produce sperm and androgens, primarily testosterone.

• Testosterone:

  1. Promotes growth and maturation of reproductive organs.

  2. Causes male secondary sex characteristics (facial hair, muscle growth, deep voice).

  3. Stimulates sex drive.

  4. Required for sperm production in adults.

• Stimulated by LH from anterior pituitary.

• Hyposecretion causes sterility, treated with testosterone injections.

atria of the heart

atrial natriuretic factor/peptide - decrease blood volume, blood pressure, and blood sodium concentration

gastrointestinal tract

enteroendocrine cells through the mucosa- secrete hormones to regulate digestive function

placenta

secretes estrogens, progesterone, and human chorionic gonadotropin which acts on the uterus to influence pregnancy

Kidneys

produce erythropoietin, which signals the bone marrow to produce red blood cells

Skin

produces cholecalciferol, inactive Vitamin D

• helps body absorb calcium from food

Adipose tissue

• produces leptin - acts on the CNS to produce the feeling of satiety

• produces resistin - insulin antagonist