Objective 58: Hormones and Digestion

Relay structure and function of the endocrine system to digestion...........

These two pictures from the Anatomy and Physiology textbook*  along with time in both lab discovery and lecture gave a full understanding of the role that the endocrine system plays in digestion.  The pancreas is labeled as both and endocrine and exocrine gland.  Its exocrine functions include the release of enzymes that aid in digestion and its endocrine functions include the release of both insulin by the beta cells and glucacon by the alpha cells.  These two secretions work antagonistically to one another to maintain the proper amount of glucose in both the blood and the cells.

 I had an "AHA" moment while listening to one of the podcasts regarding glucagon and insulin.  It was so "AHA" and had me so turned around that I actually had to get Jeremy to explain it to me again!  While listening to the podcasts on the endocrine system the question was posed "What would be the result of too much insulin in the blood stream"?  I know the answer to this, I thought!  High blood sugar!  WRONG, so WRONG!  The answer was hypoglycemia.  What?  How can that be?  I was so perplexed that I actually had to grab Jeremy in the parking lot at school, make him listen to that section of the podcast and then pretty much force him to repeatedly explain it to me.  He laughed as he explained that I apparently had the functions of insulin and glucagon backwards.  Insulin actually moves the glucose into the cell while glucagon breaks down glycogen from the liver and puts glucose back into the blood stream. 

Thank you, Jeremy for setting me straight!

Nurse's Note: Diabetes Mellitus occurs when there is too little insulin in the blood and glucose can not be effectively moved into the cells.  There are three cardinal signs of Diabetes Mellitus.  These include polyuria or excessive urine output, polydipsia or excessive thirst, and polyphagia or excessive hunger.

Objective 15 - The Adrenal glands and stress

Discuss how the adrenal glands respond to stress....

http://www.interactivephysiology.com/ip10/endocrine/response/topic1.html

Love the interactive physiology website.  It gives a great in-depth explanation of the objectives that we're covering in class.  More importantly it offers creative ways to learn the information; whether its through videos, crossword puzzles, labeling, matching games or quizzes; they're all really useful tools to learn and understand the information. 

Objective 14 - Endocrine glands: function and histology

     Describe the location, histology, hormones and functions of the thyroid gland, the parathyroid glands,the adrenal glands,the pancreas, the ovaries, the testes,the pineal gland and the thymus. 

This picture gave me a great overview of the different endocrine glands and helped me to classify which hormone was produced by that gland, how it affects the body. Simple pictures like this one help me to break down my learning by starting with a broad overview of the subject at hand.  Once I get the basics down pat it allows me to go into the fine details with a better understanding.

http://www.connecticutvalleybiological.com/endocrine-system-p-9247.html



Endocrine System Gland	Hormone Produced	Endocrine System Function
Pituitary gland	Antidiuretic hormone (vasopressin)	Helps kidneys to retain water and in presence of aldosterone it helps control blood pressure.
	Corticotropin (ACTH)	Controls production and secretion of hormones of the adrenal glands.
	Human growth hormone	Controls growth and development and promotes protein production.
	Luteinizing hormone and follicle-stimulating hormone	Controls reproductive functions that includes the production of sperm and semen, egg maturation, and menstruation. It also controls male and female sexual characteristics that includes hair distribution, muscle formation, skin texture and thickness, voice, and may even control personality traits.
	Oxytocin	It causes muscles of the uterus and milk ducts in the breast to contract.
	Prolactin	It starts and maintains milk production in the mammary glands.
	Thyroid-stimulating hormone	It causes stimulation, production and secretion of hormones of the thyroid gland.
Parathyroid glands	Parathyroid hormone	It controls formation of bones and the excretion of calcium and phosphorus.
Thyroid gland	Thyroid hormone	It regulates metabolic rate of the body.
	Calcitonin	The function of calcitonin in humans is still unclear but in other species, it regulates calcium balance.
Adrenal glands	Aldosterone	It helps in regulation of salt and water balance by retention of salt and water and excretion of potassium. Read more on functions of adrenal gland.
	Cortisol	It has widespread effects in the whole body. It mainly has anti-inflammatory action, maintaining blood sugar level, blood pressure, and muscle strength. It also helps control salt and water balance.
	Dehydroepiandrosterone (DHEA)	It affects the bones, mood, and the immune system
	Epinephrine and norepinephrine	Stimulates the heart, lungs, blood vessels, and nervous system.
Pancreas	Glucagon	It helps in raising the blood sugar level.
	Insulin	It helps in lowering the blood sugar level, affects the metabolism of sugar, protein, and fat throughout the body.
Kidneys	Erythropoietin	Stimulates red blood cell production.
	Renin	It controls blood pressure.
Ovaries	Estrogen	It controls the development of female sex characteristics and the reproductive system.
	Progesterone	Prepares the lining of the uterus for implantation of a fertilized egg and readies the mammary glands to secrete milk.
Testes	Testosterone	It controls the development of sexual characteristics in men and the reproductive system.
Digestive tract	Cholecystokinin	It controls the gallbladder contractions that cause bile to enter the intestine and stimulates release of digestive enzymes from the pancreas.
	Glucagon-like peptide	it increases insulin release from the pancreas.
	Ghrelin	It controls the growth hormone release from the pituitary gland and causes sensation of hunger.
Adipose (fat) tissue	Resistin	It blocks the effects of insulin on muscle.
	Leptin	It controls appetite.
Placenta	Chorionic gonadotropin	Stimulates the ovaries to continue releasing progesterone during early pregnancy.
	Estrogen and progesterone	It helps keep the uterus receptive to the fetus and placenta during pregnancy.

http://www.buzzle.com/articles/endocrine-glands-and-functions.html

Objectives 5 & 12 - Hypothalamus and Hypothalamus-Pituitary Complex

¨Is the hypothalamus a true endocrine gland?  Hmmm, debatable I guess.  True endocrine glands are not supposed to have ducts, yet the hypothalamus does.  It has ducts connecting it to the posterior pituitary.  So instead of releasing hormones directly to the blood stream it releases hormones directly to the pituitary.  The pituitary then stores these hormones until it receives a signal from the hypothalamic neurons.  Either way you look at it, there’s a lot of information to remember here, its amazing that something as small as the hypothalamus and the pituitary gland can have such DRASTIC effects on your body and your overall wellbeing!  This picture helped me to wrap my brain around all of the hormones that were involved in this in-depth process!

 http://www.scholarpedia.org/article/Models_of_hypothalamus

Objective 11 - Structure and function of endocrine system

Understand structure and function of the endocrine system in relation to growth and homeostasis.

I enjoyed this video that I found on YouTube because it gave a great overview of both the structure AND function of the endocrine system.  It covers structure by talking about the different classes of endocrine hormones, specifically the thyroid or steroid type hormones, and delves into the function with a great in-depth animation on how the glands actually work inside the cell.  The animations on target cells, negative feedback , and positive feedback help me to wrap my brain around the concepts.  Sometimes simply reading or hearing the information is just not enought to get a full comprehension.

Objective 10 - Identifying the classes of hormones

¨Identifying the classes of hormones was an objective that I had a relatively strong understanding of based on the information that we learned in Bio-100.  Realizing that the steroid hormones were lipid based and could therefore easily traverse a plasma membrane while the amine hormones were amino acid based and therefore required the help of a carrier protein to cross the membrane was more like a review of what we spent MONTHS on in BIO-100! 

Objective 4 - Endocrine and Exocrine glands

¨Differentiating between endocrine and exocrine glands is pretty easy.  Endocrine glands release their products into the blood stream or interstitial fluid, while exocrine glands release their product to the surface of an organ or the body itself.  The prefix of these words prevents their from being any confusion between the two.

¨ENDO = INTO

¨EXO = OUT OF