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