Hormones

Steroid and Nonsteroid Hormones

Steroid hormones are manufactured by endocrine cells from cholesterol. They can easily pass through the phospholipid plasma membrane of target cells because they are lipid-soluable. EXAMPLES: cortisol, aldosterone, estrogen, progesterone, and

testosterone.

Nonsteroid hormones are synthesized from amino acids instead of cholesterol.

Protein hormones that have carbohydrate groups attached to their amino acid chains are classified as a whole separate group called glycoprotein hormones. EXAMPLES: Follicle-stimulating hormone, luteinizing hormone, thyroid-stimulating hormone, and chorionic gonadotropin.

Peptide hormones are smaller than protein hormones. They are made up of short chains of amino acids. EXAMPLES: Oxytocin, somatostatin, antidiuretic hormone, and melanocyte-stimulating hormone.

Amino acid derivative hormones are derived from a single amino acid molecule. Two major subgroups of amino acid derivative hormones are amine hormones and iodinated amino acids.

Amine hormones are synthesized by modifying a single molecule of the amino acid tyrosine. EXAMPLES: norepinephrine, epinephrine, and melatonin.

Some nonsteroid hormones are protein hormones. These hormones are made up of long, folded chains of amino acids. EXAMPLES (protein hormones): insulin, glucagon, calcitonin, prolactin, and growth

hormone.

Iodinated amino acids are produced by the thyroid gland and are synthesized by adding iodine atoms to the tyrosine molecule. EXAMPLES: thyroxine, triiodothyronine.

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***Directions: Find your way through the maze using the color blue to get to steroid hormones and red to get to nonsteroid hormones while passing each description (numbered on previous page) of each category of hormones.

Steriod and Nonsteroid Hormones

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Nonsteroid hormones are synthesized from amino acids instead of cholesterol.

Steroid hormones are manufactured by endocrine cells from cholesterol. They can easily pass through the phospholipid plasma membrane of target cells because they are lipid-soluable. EXAMPLES: cortisol, aldosterone, progesterone,

andestosterone. 1

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How do hormones work?• LOCK AND KEY: hormones bind to specific receptors on or in a cell.

Hormones will only bind to receptor molecules that "fit" them exactly.

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What happens when hormones combine? • Synergism is when different types of hormones combine and end up

having a greater effect on a target cell. Combined hormones may exhibit permissiveness. This occurs when the first hormone "permits" the full action of the second hormone. Antagonism may also occur when hormones combine. One hormone produces the opposite effect of another hormone. It can be used to "fine-tune" the activity of target cells.

Human BodyMaze

Lining of the gastrointestinal track contains cells that produce both endocrine and exocrine secretions. Hormones like gastrin, secretin, cholecystokinin-pancreozymin and

ghrelin.

A tissue that forms on the lining of the uterus as an interface between the circulatory systems of the mother and developing child.

I spy…I spy… a gland in the mediastinum. Its large in children until they hit puberty and it starts to shirk until its just fat and fibrous tissue. Two of the hormones are thymosin and thymopoietin

Thymus, Heart

I spy… has a specific area in its wall contains some hormone-producing cells. The hormone is atrial natriuretic. The Hormone deals with blood volume or blood

pressure.

Endocrine System

1. The endocrine system is responsible for the regulation of hormones in the body. It works with nervous system by stimulating the brain to release hormone to stimulate glands like thyroid glands to secrete thyroid hormones.

1. The endocrine system is made up of glands that produce and secrete hormones, chemical substances produced in the body that regulate the activity of cells or organs. These hormones regulate the body's growth, metabolism (the physical and chemical processes of the body), and sexual development.

Glands

• Pituitary Gland-Pea-sized gland located at the base of the skull between the optic nerves. The pituitary is sometimes referred to as the "master gland" as it controls hormone functions such as our temperature, thyroid activity, growth during childhood, urine production, testosterone production in males and ovulation and estrogen production in females.

• Pineal Gland-Pine cone shaped gland of the endocrine system located between cerebral hemispheres. A structure of the diencephalon of the brain, the pineal gland produces several important hormones including melatonin. Melatonin influences sexual development and sleep-wake cycles. The pineal gland connects the endocrine system with the nervous system in that it converts nerve signals from the sympathetic system of the peripheral nervous system into hormone signals.

Glands Cont.

• Thyroid Gland-The thyroid gland is located in the front of the neck, below the larynx. The small, two-inch gland consists of two lobes, one on each side of the windpipe, connected by tissue called the isthmus.

• Made up of two types of cells: follicular cells and Parafollicular cells. The thyroid plays an important role in regulating the body's metabolism and calcium balance. The harder the cells work, the harder the organs work. The calcitonin hormone works together with the parathyroid hormone to regulate calcium levels in the body.

• Levels of hormones secreted by the thyroid are controlled by the pituitary gland's thyroid-stimulating hormone, which in turn is controlled by the hypothalamus.

Hormone source target Principal action

Growth hormone-releasing hormone (GRH)

Hypothalamus Adenohypophysis (somatotrophs)

Stimulates secretion (release) of growth hormone

Growth hormone- inhibiting hormone (GIH), or somatostatin

Hypothalamus Adenohypophysis (somatotrophs)

Inhabits secretion of growth hormone

Corticotropin- releasing hormone (TRH)

Hypothalamus Adenohypophysis (corticotrophs)

Stimulates release of adrenocorticotropic hormone (ACTH)

Thyrotropin- releasing hormone (TRH)

Hypothalamus Adenohypophysis (thyrotrophs)

Stimulates release of thyroidstimulating hormone (TSH)

Gonadotropin- Releasing Hypothalamus Adenohypophysis (gonadotrophs)

Stimulates release of gonadotropins (FSH and LH)

Prolactin- releasing hormone (PRH)

Hypothalamus Adenohypophysis (corticotrophs)

Stimulates secretion of Prolactin

Prolactin- inhibitingHormone (PIH)

Hypothalamus Adenohypophysis (corticotrophs)

Inhibits secretion of prolactin

       

Growth hormone (GH) (somatotropin [STH])

Adenohypophysis (somatotropin [STH])

General Promotes growth by stimulating protein anabolism and fat mobilization

Prolactin (PRL) (lactogenic hormone)

Adenohypophysis (lactotrophs) Mammary glands (alveolar secretory cells)

Promotes milk secretion

Thyroid- stimulating hormones (TSH)

Adenohypophysis (thyrotrophs) Thyroid gland Stimulates development and secretion in the thyroid gland

Adrenocorticotropic hormone (ACTH)

Adenohypophysis (corticotrophs)

Adrenal cortex Promotes development and secretion in the adrenal cortex

Follicle- stimulating hormone (FSH)

Adenohypophysis (gonadotrophs)

Gonads (primary sex organs) Female: promotes development of ovarian follicle; simulates estrogen secretion Male: promotes development of testis; stimulates sperm production

Luteinizing hormone (LH) Adenohypophysis (gonadotrophs)

Gonads Female: triggers ovulation; promotes development of corpus luteum

Antidiuretic hormone (ADH) Neurohypophysis Kidney male: stimulates production of testosterones promotes water retention by kidney tubules

Oxytocin (OT) Neurohypophysis Uterus and mammary glands Stimulates uterine contractions; stimulates ejection of milk into mammary ducts

Aldosterone Adrenal cortex (zona glomerulosa)

kidney Stimulates kidney tubules to conserve sodium, which, in turn, triggers the release of ADH and the resulting conservation of by the kidney

Cortisol (hydrocortisone) Adrenal cortex (zona fasciculata)

General Influences metabolism of food molecules; in large amounts, it has an antinflammatory effect

Adrenal androgens Adrenal cortex (zona reticularis)

Sex, organs, other effectors

Exact role uncertain, but may support sexual function

Adrenal estrogens Adrenal cortex (zona reticularis)

Sex organs Thought to be physiologically insignificant

Epinephrine (adrenaline) Adrenal medulla Sympathetic effectors Enhances and prolongs the effects of the sympathetic division of the autonomic nervous system

Norepinephrine Adrenal medulla Sympathetic effectors Enhances and prolongs the effects of the sympathetic division of the autonomic nervous system

Triiodothyronine (T3) Thyroid gland (follicular cells)

General Increase rate of metabolism

Tetraiodothyronine (T4), or thyroxine

Thyroid gland (follicular cells)

General Increase rate of metabolism (usually converted to T3 first)

calcitonin (CT) Thyroid gland (parafollicular cells)

Bone tissue Increase calcium storage in bone, lowering blood Ca ++ levels

Parathyroid hormone (PTH) or parathormone

Parathyroid glans Bone tissue and kidney Increase calcium removal from storage in bone and produces the active form of vitamin D in the kidneys, increasing absorption of calcium by intestines and increasing blood Ca ++ levels

Glucagon Pancreatic islets (alpha [a] cells or A cells)

General Promotes movement of glucose from storage and into the blood.

Insulin Pancreatic islets (beta [b] cells or B cells)

General Promotes movement of glucose out of the blood and into cells

Somatostatin Pancreatic islets (delta [d] cells D cells)

Pancreatic cells and other effectors

Can have general effects in the body, but primary role seems to be regulation of secretion of other pan pancreatic hormones

Pancreatic polypeptide Pancreatic islets (Pancreatic polypeptide [PP] or F cells)

Intestinal cells and other effectors

Exact function uncertain, but seems to influence absorption in the digestive tract.

The adrenal glands are also called suprarenal glands. These are endocrine glands that lie like caps on top of the kidneys. The adrenal medulla secretes both adrenalin and noradrenalin, also known as epinephrine and norepinephrine respectively. These hormones are involved in the body’s “fight or flight” response. Can you find them?

Parathyroid glands are small glands of the endocrine system which are located in the neck behind the thyroid. Parathyroid glands control the calcium in our bodies--how much calcium is in our bones, and how much calcium is in our blood.

The gonads pertain to the anatomical part of the body where sex cells (gametes) are synthesized. For instance, the gonads in females are the ovaries whereas in males are the testes.

Male Testes

The pancreas is a gland organ in the digestive and endocrine system of vertebrates. It is both an endocrine gland producing several important hormones, including insulin, glucagon, and somatostatin, as well as an exocrine gland, secreting pancreatic juice containing digestive enzymes that pass to the small intestine. These enzymes help in the further breakdown of the carbohydrates, protein, and fat in the chyme.

Works Cited

• Thibodeau, Gary A. Anatomy & Physiology. seventeenth. St. Louis: Library Of Congress Cataloging In Publication Data, 2003. 1106. Print.

• N.p., E-mail. <http://www.news-medical.net/health/What-Does-the-Adrenal-Gland-Do.asp&xgt;.

• http://www.cartage.org.lb/en/themes/sciences/zoology/animalphysiology/endocrinesystem

• http://www.emedicinehealth.com/anatomy_of_the_endocrine_system/article_em.htm