Chapter 18C (18.8-18.10)

Leptin must be present for normal levels of GnRH and gonadotropin synthesis to take place this explains why

1. thin girls commonly enter puberty late 2. increase in body fat can improve fertility 3. women stop menstruating when their body fat content becomes very low

The lack of which hormones would inhibit skeletal formation?

A lack of GH, thyroid hormone, PTH, and the gonadal hormones would inhibit the formation and development of the skeletal system.

Why does a person with Type 1 or Type 2 diabetes urinate frequently and have increased thirst?

A person with Type 1 or Type 2 diabetes has such a high blood glucose level that the kidneys cannot reabsorb all the glucose; some glucose is lost in urine. Because the urine contains a high concentration of glucose, less water can be reclaimed by osmosis, so the volume of urine production increases. The water losses reduce blood volume and elevate blood osmotic pressure, promoting thirst and triggering the secretion of ADH.

4 types of cells of the pancreatic islets

Alpha cells Beta cells Delta cells Pancreatic polypeptide cells (PP cells)

Which pancreatic cells secrete glucagon? List the effects of glucagon.

Alpha cells secrete glucagon. Glucagon increases blood glucose level by (1) increasing the breakdown of glycogen to glucose in liver and skeletal muscle, (2) increasing the breakdown of fat to fatty acids in adipose tissue, and (3) increasing the synthesis and release of glucose by the liver.

What effect would an increased blood glucagon level have on the amount of glycogen stored in the liver?

An increased blood level of glucagon stimulates the conversion of glycogen to glucose in the liver, which would in turn decrease the amount of glycogen in the liver.

what is calcitriol synthesized from

Cholecalciferol (vitamin D3)

Why do levels of GH-RH and CRH rise during the resistance phase of the general adaptation syndrome?

During the resistance phase of the general adaptation syndrome, there is a high demand for glucose, especially by the nervous system. The hormones GH-RH and CRH increase the levels of GH and ACTH, respectively. Growth hormone (GH) mobilizes fat reserves and promotes the catabolism of protein; ACTH increases cortisol, which stimulates both the conversion of glycogen to glucose and the catabolism of fat and protein. Together, these metabolic processes conserve glucose for use by nervous tissue.

kidneys secrete what hormones

Erythropoietin and calcitriol

hormones involved in growth

GH thryoid hormones insulin PTH calcitriol reproductive hormones

Discuss the functional relationship between the endocrine system and the muscular system.

Hormones of the endocrine system adjust muscle metabolism, energy production, and growth; hormones also regulate calcium and phosphate levels, which are critical to normal muscle functioning. Skeletal muscles protect some endocrine organs.

Identify a hormone released by adipose tissue.

Leptin

Describe the action of renin in the bloodstream.

Once released into the bloodstream, renin functions as an enzyme, catalyzing the conversion of angiotensinogen to angiotensin I.

primary target of erythropoietin

Red bone marrow

Delta cells of pancreas secrete? function of this hormone?

Somatostatin =a peptide hormone identical to growth hormone-inhibiting hormone (GH-IH) which suppresses the release of glucagon and insulin by other islet cells and slows the rates of food absorption and enzyme secretion along the digestive tract

Identify the types of cells in the pancreatic islets and the hormones produced by each.

The cells of the pancreatic islets (and their hormones) are alpha cells (glucagon), beta cells (insulin), delta cells (GH-IH), and pancreatic polypeptide cells (pancreatic polypeptide).

Discuss the general role of the endocrine system in the functioning of other body systems.

The endocrine system adjusts metabolic rates and substrate use, and regulates growth and development, in all other body systems.

Identify two hormones secreted by the kidneys.

Two hormones secreted by the kidneys are erythropoietin (EPO) and calcitriol.

effects of insulin

accelerating glucose uptake accelerating glucose Use and enhanced ATP production stimulating glycogen formation in skeletal muscle fibers and liver cells stimulating AA absorption and protein synthesis (helps to maintain glucose level by preventing conversion of AA to glucose) Stimulating triglyceride formation (adipocytes)

3 phases of general adaptation syndrome (GAS)

alarm, resistance, exhaustion

Insulin decreases the blood glucose level and glucagon increases the blood glucose level. This is an example of which type of hormonal interaction?

antagonism

what cells are insulin independent

cells in the brain, kidneys, lining of digestive tract and RBCs meaning they can absorb and use glucose without insulin stimulation

Type 1 diabetes

characterized by inadequate insulin production by the pancreatic beta cells DONT PRODUCE INSULIN insulin is required to live

exocrine pancreas

consists of clusters of gland cells called pancreatic acini takes up 99% of pancreatic flume secrete large quantities of an alkaline enzyme-rich fluid that reaches the lumen of the digest tract through secretory ducts

endocrine pancreas

consists of small groups of cells scattered among the exocrine cells endocrine clusters are known as pancreatic islets (islets of langerhans)

thymus secrete thymosin which have what effect

coordinate and regulate immune response target the lymphocytes and other cells of the immune response

renin

enzyme released by cells of the juxtaglomerular complex when renal blood flow decreases convertes angiotensinogen to angiotensin I

The pancreas is both an ________ and _______ gland

exocrine organ and an endocrine gland that produces hormones affecting the blood glucose level

overproduction of GH and signs/symptoms

gigantism, acromegaly excessive growth

alpha cells of the pancreas secrete

glucagon

angiotensin II

hormone that causes an increase in systemic blood pressure, stimulates the secretion of aldosterone, promotes thirst and causes release of antidiuretic hormone ACE converts angiotensin I to II

leptin target

hypothalamus

what happens when blood glucose levels increase/ when it decreases?

increases: beta cells secrete insulin which then stimulates transport of glucose across plasma membranes and into target cells decreases: alpha cells secrete glucagon which stimulates glycogen breakdown and glucose release by liver

pancreatic polypeptide (PP) function

inhibits gallbladder contractions and regulates production of some pancreatic enzymes helps control the rate of nutrient absorption by digestive tract secreted by pancreatic polypeptide cells (PP cells)

Somatostatin

inhibits insulin and glucagon secretion slows rates of nutrient absorption and enzyme secrretion along digestive tract secreted by delta cells of pancreas

Beta cells of the pancreas secrete

insulin and amylin

hormones that regulate blood glucose levels

insulin and glucagon

primary target of calcitriol

intestinal lining, bone and kidneys

renin-angiotensin-aldosterone system (RAAS)

involved with blood pressure regulation and electrolyte metabolism 1. renin converts angiotensinogen to angiotensin I 2. in the capillaries of the lungs angiotensin0converting enzyme (ACE) modified angiotensin I to the hormone angiotensin II

adipose tissue secretes what hormone

leptin

Erythropoietin is released in response to

low oxygen levels in kidney tissues EPO stimulates red bone marrow to produce RBCs which increase blood volume and therefore oxygen delivery because there are now more cells to carry O2

insulin effects

lowers the blood glucose level by increasing rate of glucose uptake by most cells and increasing glycogen production in skeletal muscles and liver secreted by Beta cells of pancreas

type 2 diabetes

most common produce normal amounts of insulin but their tissues do not respond properly (insulin resistance) associated with obesity and weight loss through diet and exercise can be effective treatment especially when coupled with oral meds

heart secretes what hormones

natriuretic peptides (ANP and BNP) which increase water and salt loss at kidneys, decrease thirst and supress secretion of ADH and aldosterone

pancreatic polypeptide cells (PP cells) produce

pancreatic polypeptide (PP)

amylin

peptide hormone whose level rises after a meal secreted by Beta cells of pancreas

underproduction of GH

pituitary growth failure

glucagon

raises blood glucose level by increasing the rates of glycogen breakdown and glucose release by the liver secreted by alpha cells of the pancreas

Effect of erythropoietin

red blood cell production

signs and symptoms of pituitary growth failure (underproduction of GH)

retarted growth abnormal fat distribution low blood glucose hours after meal

effect of calcitriol secreted by kidneys

stimulates calcium and phosphate absorption stimulates Ca release from bone inhibits PTH secretion

primary effects of glucagon

stimulating breakdown of glycogen stimulating breakdown of triglycerides stimulating production and release of glucose (gluconeogenesis: glucose synthesis by converting AA from bloodstream to glucose)

effect of leptin

suppression of appetite permissive effects on GnRH and gonadotropin synthesis

renin is released in response to

sympathetic stimulation or decline in renal blood flow

ACE inhibitors

used to treat hypertension