Group B7

Anatomy & Physiology Ashley, Nathan, Katherine, Shannon, Gentry

Hormones, The Perfect Storm?

Introduction

♦ How do the endocrine and nervous systems work

together? (1) The endocrine and nervous systems function to achieve homeostasis When the two systems work together, referred to as the neuroendocrine system, they perform the same general functions: communication, integration, and control.

♦ What is the method in which the endocrine system

undergoes its functions? (1) In the endocrine system, secreting cells send hormone molecules via the blood to specific target cells contained in target tissues of target organs Hormones- carried to almost every point in the body; can regulate most cells; effects work more slowly and last longer than those of neurotransmitters Endocrine glands are “ductless glands”; many are made of glandular epithelium whose cells manufacture and secrete hormones; a few endocrine glands are made of neurosecretory tissue Glands of the endocrine system are widely scattered throughout the body.

Hormones

♦ PROSTAGLANDS: PROSTAGLANDS: PROSTAGLANDS: PROSTAGLANDS: They are any member of a group of lipid compounds that

are formed enzymatically from fatty acids. These aren’t endocrine hormones

yet autocrine or paracrine which play a role of locally acting messenger tools.

The functions of the prostaglands are to serve as mediators and having nu-

merous physiological effects like the relaxation and contraction of small

muscle tissue. Also, they control cell growth, hormone regulation, induce

labor, cause aggression and disaggregation and so much more. Prostaglands

can be found in seminal fluid, the central nervous system, and microsomes.

(1)

♦ PITUITARY GLAND: PITUITARY GLAND: PITUITARY GLAND: PITUITARY GLAND: The pituitary gland is located at the base of the brain, and

is part of the endocrine system. It has the function of regulating growth, telling

your brain when to stop growing. Several Hormones that are associated with

the Pituitary gland would be FSH, in charge of the release of estrogen for

females and spermatogonia; LH triggers the completion of meiosis of an egg

and the release of the egg during the menstrual cycle, for the men LH acts on

the Leydig cells, stimulating them to release testosterone. (1

♦ Pineal Gland: Pineal Gland: Pineal Gland: Pineal Gland: It is located between the cerebral hemisphere and the third

ventricle also being a part of the diencephalon structure of the brain. The

pineal gland is what connects the endocrine system with the nervous system,

converting nerve signals into hormone signals. Hormones released from the

pineal gland are melatonin, influencing sexual development as well as sleep

wake cycles. (1)

♦ Thyroid Gland: Thyroid Gland: Thyroid Gland: Thyroid Gland: Located right above the hypothalamus, they thyroid gland plays

a major role in regulating the body’s metabolism. It controls how the body

uses energy, makes protein, and the body’s sensitivity to other hormones.

Hormones it works with are triiodothyronine and thyroxine, which are the ones

that regulate the metabolism and also affect the growth and rate of the func-

tions of many other body systems. (1)

♦ Parathyroid Gland: Parathyroid Gland: Parathyroid Gland: Parathyroid Gland: are located on the thyroid gland within the neck. The

function of the gland would be controlling the amount of calcium inside the

bones and controlling blood. Parathyroid hormone is used to regulate calcium

levels. When calcium levels are too low, there is more parathyroid hormone

produced and when there is too much calcium, a lesser amount of parathy-

roid hormone is produced. (1)

♦ Adrenal Glands: Adrenal Glands: Adrenal Glands: Adrenal Glands: They are located on top of both kidneys, and are responsible

for releasing hormones in response to stress through corticosteroids synthe-

sis. The hormones they work with which are those that are released are corti-

sol, decreasing bone formation and suppressing the immune system. Cate-

cholamine is another hormone being epinephrine, norepinephrine, and dopa-

mine for a fight or flight situation. There are also androgens which controls

the development of male characteristics such as their sex organs. (1)

♦ FUNCTION FUNCTION FUNCTION FUNCTION

Tropic hormones are hormones that target other endocrine

glands and stimulate their growth and secretion.

Sex hormones are hormones that target reproductive tissues.

Anabolic hormones are hormones that stimulate anabolism in

target cells. (1)

♦ STRUCTURE STRUCTURE STRUCTURE STRUCTURE

Steroid hormones are synthesized from cholesterol. They are

lipid soluble and can easily pass through the phospholipid

plasma membrane or target cells. Examples of steroid hor-

mones include cortisol, aldosterone, estrogen, progesterone

and testosterone.(1)

Nonsteroid hormones are synthesized primarily from amino

acids. Protein hormones are long folded chains of amino

acids like insulin and parathyroid hormone. Also included are

Glycoprotein hormones which are protein hormones with a

carbohydrate groups attached to the amino acid chain. (1)

Peptide hormones are smaller than protein hormones, they

are a short chain of amino acids. Peptide hormones oxytocin

and antidiuretic hormone (ADH) (1)

Amino acid derivative hormones- each is derived from a

single amino acid. Amine hormones are synthesized by modi-

fying a single molecule of tyrosine, it is produced by neurose-

cretory cells and by neurons, epinephrine and norepineph-

rine. Produced by the thyroid gland and are synthesized by

adding iodine to tyrosine. (1)

Hormones signal a cell by binding to the target cells specific

receptors in a lock and key mechanism. Different Hormone

receptor interactions produce different regulatory changes

within the target cell through chemical reactions. (1)

Lock and key: A hormone acts only on cells that have recep-

tors specific to that hormone because the shape of the recep-

tors specific to that hormone because the shape of the recep-

tor determines which hormone can react with it. (1)

Function, Structure, Hormones

♦ PANCREATIC ISLETSPANCREATIC ISLETSPANCREATIC ISLETSPANCREATIC ISLETS---- The pancreatic islets are composed of endocrine

and exocrine tissues. pancreatic islets- endocrine portion. acini-exocrine

portion- secretes a serous fluid containing digestive enzymes into ducts

draining into the small intestine. each islet contains four primary types

of endocrine glands joined by a gap junctions. alpha cells (secrete

glucagon), beta cells (secrete insulin; account for up to 75% of all pan-

creatic islet cells), delta cells( secrete somatostatin), Pancreatic polypep-

tide cells (secrete pancreatic polypeptides). Pancreatic hormones work

as a team to maintain homeostasis of food molecules. Glucagon

(produced by alpha cells) tends to increase blood glucose levels; stimu-

lates gluconeogenesis in liver cells. Insulin (produced by beta cells)

lowers blood concentration of glucose, amino acids, and fatty acids and

promotes their metabolism by tissue cells. Somatostatin (produced by

delta cells) primary role is regulating the other endocrinie cells of the

pancreatic islets. Pancreatic polypeptide (produced by F cells) influences

the digestion and distribution of food molecules to some degree.(1)

♦ GONADSGONADSGONADSGONADS---- The Testes- paired organs within the scrotum in the male are

composed of seminiferous tubules and a scattering of interstitial cells.

testosterone ins produced by the interstitial cells and responsible for the

growth and maintenance of male sexual characteristics. testosterone

secretion is mainly regulated by gonadotropin levels in the blood. The

ovaries-primary sex organs in the female are a set of paired glands in

the pelvis that produce several types of sex hormones. estrogens- ster-

oid hormones secreted by ovarian follicles; promote development and

maintenance of female sexual characteristics. progesterone- secreted

by corpus luteum; maintains the lining of the uterus necessary for

successful pregnancy. ovarian hormone secretion depends on the

changing levels of FSH and LH from the adenohypophysis.(1)

♦ PLACENTAPLACENTAPLACENTAPLACENTA---- The placeta is the tissues that form on the lining of the

uterus as a connection between the circulatory system of the mother

and developing child. It serves as a temporary endocrine gland that

produces human chorionic gonadotropin, estrogens, and progester-

one.(1)

♦ THYMUSTHYMUSTHYMUSTHYMUS---- The thymus is the gland located in the mediastinum just

beneath the sternum. Thymus is large in children, begins to atrophy at

puberty, and, by old age, the gland is a vestige of fat and fibrous tissue.

It is Considered to be primarily a lymphatic organ, but the hormone

thymosin has been isolated from thymus tissue. Thymosin hormone-

stimulates the development of T cells(1)

♦ GASTRIC AND INTESTINAL MUCOSAGASTRIC AND INTESTINAL MUCOSAGASTRIC AND INTESTINAL MUCOSAGASTRIC AND INTESTINAL MUCOSA---- The gastric and intestinal mucosa is

the mucous lining of the GI tract contains cells that produce both endo-

crine and exocrine secretions. GI hormones such as gastrin, secretin,

and cholecystokinin- pancreozymin (CCK) play regulatory roles in coordi-

nating the secretory and motor activities involved in the digestive pro-

cess. Ghrelin- hormone secreted by endocrine cells in gastric mucosa;

stimulates hypothalamus to boost appetite; slows metabolism and fat

burning; may be a contributor to obesity(1)

♦ HEARTHEARTHEARTHEART---- The heart has a secondary endocrine role. Hormone-producing

cells produce atrial natriuretic hormone (ANH). ANH’s primary effect is to

oppose increases in blood volume or blood pressure’; also an antagonist

to ADH and aldosterone.(1)