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What is a hormone?
A chemical that is secreted into extracellular fluid and carried by the blood
What are Paracrine Regulators?
Do not travel in blood; allow cells of organs to regulate each other
What are Pheromones?
- Chemicals released into the environment to communicate among individual of a single species
- Ex. Ants follow each others pheromones
What are neurohormones?
Neurotransmitters distributed by the blood
What does norepinephrine control? What gland is is controlled by?
- Coordinates the activity of the heart, liver, and blood vessels during stress; fight or flightControlled by the adrenal gland
What is the difference between endocrine and exocrine glands?
Endocrine: internal secretions
into a duct
for transport externally
Saliva, breast milk, sweat
What is the master gland?
What are the two basic characteristics that hormones must exhibit?
1. Must be sufficiently complex to convey regulatory information to their target cells
2. Must be adequately stable to resist destruction before reaching their target cells
What are the four classes of hormones?
- 1. Peptides and ProteinsEx. Glycoproteins2. Amino Acid (Fatty Acid) DerivativesEx. Melatonin3. Steroids (made of cholestrol)Ex. Sex Steroids4. Monoamines (Amines)Ex. Typtophan and Tyosine
What are the two categories of hormones?
Explain liphophillic hormones
- Steroid and Thyroid hormones
- Bind to intracellular receptors
Explain hydrophillic hormones
- Water-SolubleAll other hormones
- Bind to extracellular receptors
What regulates growth in most organs? What are the different growth factors?
- Paracrine Regulation
- Epidermal = Skin
- Nerve = Neurons
- Insulin = Bone
- Cytokines = Immune System
What are a rich source of Paracrine Regulators?
Endothelium of blood vessels
What promotes vasodilation? What promotes vasoconstricion?
Vasodilation: Nitric Oxide (NO) and Brady Kinin
What are prostaglandins? What do they regulate?
- Diverse group of fatty acids that are produced in almost every organ
- Regulate a variety of functions including smooth muscle contraction, lung function, labor, and inflammation
What are the two parts of the pituitary gland?
- Anterior (adenohypophysis)
- Posterior (neurohypophysis)
How does the hypothalamus regulate the anterior pituitary gland?
Produces releasing hormones that stimulate anterior pituitary secretion and inhibiting hormones that suppress anterior pituitary secretion
What are the hormones that the anterior pituitary releases?
- Follicle Stimulating Hormone (FSH)Luteninzing Hormone (LH)Thyroid Stimulating Hormone (TSH)Adrenocorticotropin (ACTH)
- Prolactin (PRL)Growth Hormone (GH)
What are the hormones that the posterior pituitary releases?
Oxytocin and Antidiuretic Hormone (ADH)
What are the main Endocrine Glands?
- Pituitary Gland (Anterior and Posterior)
- Pineal Gland
What does the pineal gland produce?
It produces the monoamines serotonin and melatonin
What does the thymus do? What is its primary hormone?
- It plays a role in the endocrine, lymphatic, and immune systems. It is the site of maturation for white blood cells, the T lymphocytes
- The primary hormone is thymosin
What hormones does the thyroid produce? What does the thyroid regulate?
- Thyroxine (T4) and Triiodonthyronine (T3)T3 contains three iodides and T4 contains four iodides. Thyroid hormones increase metabolism and stimulate growth and maintain the nervous systemBetween the follicles are clusters of C (parafollicular) cells that secrete calcitonin, that lowers blood calcium.
What is the parathyroid? What does it do?
The parathyroid glands are four small glands usually found on the posterior side of the thyroid glands. PTH increases blood calcium
Where are the adrenal glands located? What are the two main sections?
The adrenal glands are attached to the superior aspect of each kidney. The two distinct portions are the adrenal cortex and the adrenal medulla
What hormones does the adrenal medulla produce? What are these hormones in response to?
The medulla makes catecholamines epinephrine (adrenaline), norepinephrine, and a small amount of dopamine. The secretion occurs in response to stress.
What does the adrenal cortex do?
The adrenal cortex synthesizes more than 25 corticosteroids (corticoids). All are synthesized from cholesterol
What are the three categories of the corticosteroids?
- 1. Mineralcorticoids - The main mineralcorticoid is aldosterone
- 2. Glucocorticoids - An example is cortisol which helps the body respond to chronic stress and tissue damage and increases blood glucose3. Sex Steroids
What does the pancreas do?
The pancreas is mainly an exocrine digestive gland (that produces digestive enzymes)
What are the five classes of the Islets of Langerhans?
- 1. Alpha Cells - Glucagon2. Beta Cells - Insulin3. Delta Cells - Somatostatin4. PP (Pancreatic Polypeptide Cells) - a hormone that inhibits gall bladder contraction and secretion of digestive enzymes5. G Cells - Gastrin
Are the gonads endocrine or exocrine? What are the products?
The gonads are both endocrine and exocrine glands. Exocrine products are eggs and sperm, while endocrine products are steroid hormones.
What do the ovaries contain/produce? What do the testes produce/consist of?
- The ovary contains follicles; produces estradiol and progesteroneThe testes consist largely of tubules that produce sperm. They also produce testosterone, small amount of androgens, and estrogen
What does the intermediate lobe of the pituitary produce?
Melatonin Stimulating Hormone (MSH) is responsible for production and secretion of melanin in skin and hair
What hormone is produced in the heart?
Atrial Natriuretic Peptide (ANP) has the overall effect of lowering blood pressure
What hormone is produced in the skin?
Keratinocytes perform the first step in the production of calcitriol, a form of vitamin D that promotes calcium absorption
What hormone is produced in the liver?
- Erythropoietin (EPO), a hormone that stiumlates red blood cell production.
- Also the second step of calcitriol production takes place in the liver
What hormone is produced in the kidneys?
Erythropoietin (EPO) , they also secrete renin, that converts angiotensinogen to angiotensin I, and they carry out the final step of calcitriol syntesis
What hormones do the stomach and small intestine produce?
Gastrin and cholecystokinin that promote aspects of digesion
What hormones do the placenta produce?
Progesterone, estrogen, and other hormones that regulate pregnancy
Chemical messengers that are secreted into the blood by endocrine glands
Lipid hormones synthesized from cholesterol
Small molecules that are synthesized fro the amino acids tyrosine and tryptophan
Chains of 3 to 200 amino acids that may be proteins.
Posterior part of the pituitary gland that is connected to they hypothalamus via the stalk (infundibulum). It stores and releases two hormones that are synthesized in the hypothalamus
Anterior part of the pituitary gland that secretes six main hormones
Define Neuroendocrine Cells
Neurons that secrete their product into the blood
Define Hypophyseal Portal System
Network of blood vessels that surround the hypothalamus and the anterior pituitary gland. Hormones released by the hypothalamus travel through the vessels to target cells in the anterior pituitary gland.
Define Tropic (trophic) Hormones
Hormones whose targets are other endocrine glands
Inadequate hormone release
A hormone excess