Chapt 18: Endocrine System

Describe EPO abuse

"Blood doping", Used to boost the number of oxygen carrying red blood cells in the bloodstream. This effect increases the oxygen content of blood which increases endurance.

Explain the mechanisms used by both lipid and nonlipid hormones to affect their target cells

1) Lipid Hormone: Being lipid soluble, steroid hormones can diffuse easily into their target cells. Once inside, they bind to a receptor located in the nucleus. The activated hormone-receptor complex then interacts with another receptor on the DNA. The result of this is to cause the transcription of certain genes, which leads to synthesis of the proteins coded for by the genes. These proteins may be enzymes that promote metabolic activity, structural proteins, or proteins exported from the cell. 2) Non-Lipid Hormone:The hormone is called the first messenger. To give the cell its message, the hormone attaches to a specific receptor in the cell membrane. Once attachment occurs there is an increase in the synthesis of cyclic AMP inside the cell. Cyclic AMP acts as the second messenger to alter cell function by activating enzymes inside the cell which go on to catalyze specific responses, such as inducing secretion, activating protein synthesis, and altering membrane permeability.

Define: Prostaglandins (include structure and function)

A group of eicosanoids (part of the lipid derivatives hormones). Functions: 1) Activation of the inflammatory response, production of pain, and fever. When tissues are damaged, white blood cells flood to the site to try to minimize tissue destruction. Prostaglandins are produced as a result. 2) Blood clots form when a blood vessel is damaged. A type of prostaglandin called thromboxane stimulates constriction and clotting of platelets. 3) Certain prostaglandins are involved with the induction of labor and other reproductive processes.

Define: Anabolic Steroids

A synthetic steroid hormone that resembles testosterone in promoting the growth of muscle

Describe Androgen abuse

Anabolic steroid used to increase muscle mass, endurance, and "competitive spirit".

Define: Adenohypophysis

Another name for the anterior lobe of the pituitary gland

Define: Hypophysis

Another name for the pituitary gland

Define: Neurohypophysis

Another name for the posterior lobe of the pituitary gland

Adrenal Medulla: Epinephrine, Norepinephrine

Collectively known as catecholamines Hormone: Epinephrine, norepinephrine Chemical Class: Proteins Target: MOST CELLS Hormonal Effect: INCREASES: heart rate, blood pressure, blood glucose, glycogen breakdown Regulated By: Sympathetic division of the CNS

Describe the chemical classification of human hormones

Lipids (Steroid Hormones): use intracellular receptors AND direct gene activation, pass through the cell wall without difficulty Proteins (Amino Acid Based Hormones): use membrane bound receptors AND second messengers. G proteins act as second messenger. Proteins are too large to go through the cell membrane

Compare and Contrast exocrine and endocrine glands

Endocrine: NO ducts!, makes hormones, releases hormones DIRECTLY into bloodstream Exocrine: Released through ducts, DO NOT make hormones Secretes substances into ducts which then leave the body (i.e. sweat/sebaceous glands) or into an internal space or lumen (i.e. digestive glands).

Describe GHB abuse

Gamma Hydroxybutyrate Can be used by body builders to stimulate muscle growth

Pituitary (ANTERIOR): ACTH

Hormone: Adrenocorticotropic Hormone Chemical Class: Protein Target: Adrenal Cortex Hormonal Effect: secretion of glucocorticoids (cortisol, corticosterone) Regulated By: Corticotropin Releasing Hormone (CRS)

Adrenal Cortex: Zona Glomerulosa

Hormone: Aldosterone Chemical Class: Lipids Target: Kidneys Hormonal Effect: Increase renal reabsorption of sodium and H2O (especially in the presence of ADH), accelerate urinary loss of potassium Regulated By: Stimulated by Angiotensin II, elevated plasma potassium levels or a fall in plasma sodium levels, inhibited by ANP and BNP

Adrenal Cortex: Zona Reticularis

Hormone: Androgens (testosterone) Chemical Class: Lipids Target: MOST CELLS Hormonal Effect: Encourages bone growth, muscle growth, and blood formation Regulated By: Stimulated by ACTH from the anterior lobe of the pituitary gland

Pituitary (POSTERIOR): ADH

Hormone: Antidiuretic Hormone Chemical Class: Protein Target: Kidneys Hormonal Effect: Reabsorption of H2O, elevation of blood volume, and blood pressure Regulated By: NONE (in respect to hypothalamus regulation)

Thyroid: CT

Hormone: Calcitonin "BONE BUILDER" Chemical Class: Protein Target: Bone, Kidneys Hormonal Effect: DECREASES calcium concentrations in body fluids by stimulating calcium uptake by the bones Regulated By: Stimulated by elevated blood calcium levels, actions opposed by PTH (parathyroid hormone)

Adrenal Cortex: Zona Fasciculata

Hormone: Cortisol Chemical Class: Lipids Target: MOST CELLS Hormonal Effect: Glucose sparing Regulated By: Stimulated by ACTH from the anterior lobe of the pituitary gland

Pituitary (ANTERIOR): FSH

Hormone: Follicle Stimulating Hormone Chemical Class: Protein Target: Female- follicle cells of ovaries Male- nurse cells Hormonal Effect: Female- secretion of estrogen, follicle development Male- sperm maturation Regulated By: Gonadotropin Releasing Hormone (GnRH)

Pituitary (ANTERIOR): GH

Hormone: Growth Hormone Chemical Class: Protein Target: ALL CELLS Hormonal Effect: Growth, protein synthesis, lipid mobilization and catabolism Regulated By: Growth Hormone Releasing Hormone (GHRH) Growth Hormone Inhibiting Hormone (GHIH)

Pituitary (ANTERIOR): LH

Hormone: Luteinizing Hormone Chemical Class: Protein Target: Female- follicle cells of ovaires Male- interstitial cells of the testis Hormonal Effect: Female- ovulation, formation of corpus luteum, secretion of progesterone Male- secretion of testosterone Regulated By: Gonadotropin Releasing Hormone (GnRH)

Pineal Gland

Hormone: Melatonin Chemical Class: Protein Target: CNS- controls day/night cycles Gonads- decreases reproduction Regulated by: Light (more melatonin is produced in the dark)

Pituitary (POSTERIOR): OXT

Hormone: Oxytocin Chemical Class: Protein Target: Female- uterus, mammary glands Male- vas deferens, prostate gland Hormonal Effect: Female- labor contractions, milk ejections male- contractions of vas deferens and prostate Regulated By: NONE (in respect to hypothalamus regulation)

Parathyroid: PTH

Hormone: Parathyroid Hormone Chemical Class: Protein Target: Bone, Kidneys Hormonal Effect: INCREASES calcium concentrations in body fluids Regulated By: Stimulated by LOW blood calcium levels. PTH effects enhanced by calcitriol and OPPOSED by calcitonin

Pituitary (ANTERIOR): PRL

Hormone: Prolactin Chemical Class: Protein Target: Mammary glands Hormonal Effect: Production of milk Regulated By: Prolactin Releasing Factor (PRF) Prolactin Inhibiting Hormone (PIH)

Thyroid: T3 & T4

Hormone: T4 Thyroxine, T3 Triiodothyronine Chemical Class: Protein Target: MOST CELLS Hormonal Effect: Increases energy utilization, oxygen consumption, growth, and development Regulated by: Stimulated by TSH (Thyroid Stimulating Hormone) from the anterior lobe of the pituitary gland.

Thymus

Hormone: Thymosins Chemical Class: Proteins Target: Lymphocytes and stem cells of the immune system Hormonal Effect: Important in developing and maintaining immune defenses. Regulated By:

Pituitary (ANTERIOR): TSH

Hormone: Thyroid Stimulating Hormone Chemical Class: Protein Target: thyroid gland Hormonal Effect: secretion of thyroid hormone Regulated By: Thyrotropin Releasing Hormone (TSR)

Define: Tropic Hormone

Hormones who's targets are other endocrine glands

Define: Hormone

chemical messengers that are released in one tissue and transported in the bloodstream to alter the activities of specific cells in other tissues.

Describe the ways that hormone secretion is controlled

Nervous Stimuli:Nerve fibers stimulate hormone release. For example, catecholamines (epinephrine and norepinephrine) are released during times of stress by stimulation of the adrenal medulla by the sympathetic nervous system. Also, the hypothalamus stimulates the release of oxytocin and anti-diuretic hormone by neural stimulation. Humoral Stimuli: Hormone release is stimulated by substances dissolved in extracellular fluids. Usually changing blood levels or certain ions or nutrients stimulate hormone release. For example, the release of parathyroid hormone is prompted by decreasing blood calcium levels. Other examples are calcitonin, insulin, and aldosterone. Hormonal Stimuli: In some cases hormones stimulate other endocrine glands to secrete other hormones. For example, the release of anterior pituitary hormones is regulated by releasing and inhibiting hormones produced by the hypothalamus. Then, the anterior pituitary hormones in turn stimulate other endocrine glands to release their hormones. As the end-result hormones increase in the blood, they inhibit the release of anterior pituitary hormones and thus shut down their own release.

List the names and location of each major endocrine glands

Pineal Gland: attached to the roof of the third ventricle Hypothalamus: below the thalamus just above the brain stem Pituitary Gland: hangs inferior to the hypothalamus Thyroid Gland: lies inferior to the larynx Parathyroid Gland: embedded in the posterior surface of the thyroid gland Adrenal Gland: lies on top of each kidney Pancreas: located in the abdominopelvic cavity right below the stomach Gonads: testes for male, ovaries for females; both located in the groin area

List the hormones produced by each of the major endocrine glands, the structure, target of the hormone, action of each hormone, and the control mechanism of each hormone.

Proceed to next card :)

Pancreas: Glucagon

Produced by the ALPHA CELLS Hormone: Glucagon Chemical Class: Proteins Target: Liver, adipose tissue Hormonal Effect: ELEVATES blood glucose Regulated By: Stimulated by low blood glucose

Pancreas: Insulin

Produced by the BETA CELLS Hormone: Insulin Chemical Class: Proteins Target: MOST CELLS Hormonal Effect: DECREASES blood glucose by bringing in the extra glucose from the blood into muscle cells Regulated By: Stimulated by high blood glucose

Define: Neuroendocrine

Relating to or involving both nervous stimulation and endocrine secretion

Define: Infundibulum

The hollow stalk that connects the hypothalamus and the posterior pituitary gland

Causes and treatments of Diabetes Mellitus

This condition is characterized by the inability to control blood glucose levels. There will be glucose in the urine and a high solute concentration. Causes: Type 1- Autoimmune (body destroys own islets cells), improper insulin formation, improper insulin receptors (this will usually cause death) Type 2- Associated with obesity (caused by lifestyle and diet), there is a gradual decrease in tissue response to insulin with possible atrophy (reduction in size) of islets.

Causes and treatments of Diabetes Insipidus

This is a condition characterized by excessive thirst and excretion of large amounts of severely diluted urine, with reduction of fluid intake having no effect on the concentration of the urine. This is caused by a lack of ADH!! Causes: Either a problem with the production of antidiuretic hormone or kidney's response to antidiuretic hormone. Treatment: Depends on what form of the condition one has. Lack of ADH- treatment is with a synthetic hormone called Desmopressin. The synthetic hormone will eliminate the increase in urination. Kidneys not responding to ADH- Treatment might be a low-salt diet to help reduce the amount of urine your kidneys make. Also need to drink enough water to avoid dehydration

Describe the main differences in the causes and symptoms of Type 1 and Type 2 Diabetes Mellitus

Type 1 (5-10%) - Inherited, Juvenile onset diabetes, "insulin dependent" Causes: autoimmune (destroys on islets cells), improper insulin formation, improper insulin receptor <---- will usually end in death Type 2 (90-95%) - Non insulin dependent, adult onset, 40-45 years old or older when it first occurs, gradual decrease in tissue response to insulin with possible ATROPHY of islets (reduction in size of islets), can lead to Type 1 diabetes if not controlled!!