Endocrine System
Tayelar Moscal
Period 5

Major Glands/Organs and their Functions:

Steroid/Non-Steroid Hormones

Major Functions:

Homeostatic Mechanisms

Diseases

The endocrine system uses hormones to communicate with cells to regulate "metabolic processes" (including: growth, sleeping, reproduction, and more). The local hormones can produce autocrine secretions that affects secretory cells or paracrine secretions that affect any adjacent cells.

Cranial Cavity

Pineal Gland:

  • Melatonin; controls the wake and sleep cycles

Pituitary Gland: controlled by the hypothalamus, the anterior controls the release and inhibition of hormones that get carried into the bloodstream by the hypophyseal portal veins; the posterior control holds the hormones made by the hypothalamus then releases them due to nerve impulses.

Thoracic Cavity

Thyroid Glands:

  • Thyroxine; increases energy released from carbohydrates, protein synthesis, and growth
  • Triiodothyronine; works the same as Thyroxine but fives times stronger
  • Calcitonin; lowers blood calcium

Parathyroid Glands:

  • Parathyroid hormones; increases blood calcium

Thymus Gland:

  • Thymosin; affects production of T lymphocytes

Abdominal Cavity

Kidneys:

  • Erythropoietin: helps blood cell production

Adrenal Gland:

  • epinephrine and norepinephrine: released into bloodstream, they stimulate stress and the "flight or fight" response

Pancreas:

  • Insulin; decreases blood glucose level
  • Glucagon; increases blood glucose level

Pelvic Cavity

Testes:

  • Testosterone; controls and maintains masculine physical characteristics

Ovaries:

  • Estrogen; controls menstrual cycle
  • Progestrogen; prepares the uterus to hold and care for a fertilized egg

Non-Steroid:

  • bind with receptors in the membranes of target cells
  • receptors hold an activity and binding site
  • hormones are called First Messengers
  • response chemicals are called Second Messengers
  • Signal Transduction is the series of processes that take place from the cell membrane to the inside, starting with the hormone binding

Steroid Hormones:

  • Can pass through cell membranes
  • inside target cells, there are protein receptors
  • hormone receptors bind with DNA to activate genes to direct the formation of proteins

Estrogen

Testosterone

Cortisol

Thyroid Hormones

Oxytocin

Prolactin

Diabetes Mellitus:

  • Diabetes Type 1: an autoimmune disorder stops production of insulin, this causes blood sugar levels to be too low, insulin is needed to to stand in for the missing glucose
  • Diabetes Type 2: Insulin is produced but is not acknowledged by cells, this leads to over production. Glucagon is needed for treatment to lower blood sugar

Adrenal Sex Hormones:

  • Addison Disease: lack of glucocorticoids and mineralocorticoids secretion
  • Cushing Syndrome: too much production of adrenal cortical hormones

Parathyroid Gland:

  • Hyperparathyroidism: Because of a tumor there could be an overproduction of PTH so then there is too much blood calcium
  • Hypoparathyroidism: due to damage of glands, there could be a lack of PTH this causes the blood calcium level to lower

Thyroid Gland:

  • Hyperthyroidism: over active thyroids causes high metabolism, overeating, restlessness, and exophthalmia
  • Hypothyroidism: under active thyroids causes fatigueness, low metabolism, and weight gain in adults; while in toddlers it causes abnormal mental development, sluggishness, and cretinism.

Negative Feedback: controls hormone release, it keeps the hormones in control with just minor shifts in secretion levels. When a hormone is over secreting the gland is inhibited by the negative feedback, then stops once the hormones are stable.

Positive Feedback: Opposite of negative feedback, when hormone levels drop in order to stabilize it, positive feedback stimulates glands to secrete hormones to become normal.

Posterior Pituitary Gland:

  • Antidiuretic hormone; conservation of water in kidneys
  • Oxytocin; contraction of smooth muscle in uterine wall

Anterior Pituitary Gland:

  • Growth Hormone; increases size of body cells, causes amino acids through membranes
  • Prolactin; produces milk after childbirth
  • Thyroid stimulating hormone; secretion of hormones from thyroids
  • Adrenocorticotropic hormone; secretion of hormones from adrenal cortex
  • Follicle-stimulating hormone; egg development and secretion of estrogen in females, sperm production in males
  • Luteinizing hormone; secretion of sex hormones

Adrenal Cortex:

  • Aldosterone; regulates concentration of electrolytes
  • Cortisol; decreases protein synthesis, increases fatty acid release, stimulates glucose synthesis
  • Adrenal androgens; supplements sex hormones