Nikki Delgado and Joy Hochstetler Homeostasis Day 2 Nikki Delgado and Joy Hochstetler Intro:

Stamp Homework

Homework Answers

Concept Check 41.5 Explain how people can become obese even if their intake of dietary fat is relatively low compared with carbohydrate intake. After reviewing Figure 41.21, explain how PYY and leptin complement each other in regulating body weight.

Concept Check 45.2 In a glucose tolerance test, periodic measurements of blood glucose level are taken after a person drinks a glucose-rich solution. In a healthy individual, blood glucose rises moderately at first but falls to near normal within 2 - 3 hours. Predict the results of this test in a person with diabetes mellitus. Explain the answer. If a hormone pathway provides a transient response to a stimulus, how would shortening the stimulus duration affect the need for negative feedback?

Digestion and Appetite

Digestion Regulation of Digestion Many animals do not need their digestive systems to be active continuously When the food arrives it triggers secretion of substances such as gastric juices, that promote the next stage of chemical digestion and muscular contractions that move food along the canal Endocrine system plays a huge role in controlling digestion series of hormones released by the stomach and duodenum help ensure that digestive secretions are present only when needed. They are transported through the bloodstream like all other hormones Connection to Energy Storage: The two sites where humans store energy is the liver and muscle cells Within these cells, excess energy from the diet is stored in glycogen. Then once the glycogen depots are full, the additional excess energy is stored in fat in adipose cells Adipose tissue provides the most space efficient way for the body to store large amounts of energy

Appetite Relays info from the digestive system to regulate hormone release Leptin and the leptin receptor Levels rise when the amount of body fat increases ---> suppresses appetite Loss of fat decreases leptin levels ---> increase appetite Ghrelin, Insulin, Leptin, PYY ob gene codes for leptin db gene encodes the leptin receptor Researchers have discovered homeostatic mechanisms and these operate as feedback circuits and they control the storage and metabolism of fat Several hormones regulate long-term and short-term appetite by affecting a satiety center in the brain indicating when you are hungry or “full” A network of neurons relays and integrates information from the digestive system to regulate hormone release This neuronal network functions independent of inputs from the central nervous system Leptin and the leptin receptor are major components to regulating appetite B/c leptin is a product of adipose cells, levels rise when the amount of body fat increases, cuing the brain to suppress appetite Loss of fat decreases leptin levels, signaling the brain to increase appetite. In this way, the feedback signals provided by leptin maintain body fat levels within a set range Most obese people have an abnormally high leptin level, which somehow fails to elicit a response from the brain’s satiety center ob gene led to the demonstration that it codes for the hormone leptin db gene encodes the leptin receptor

Glucose Homeostasis and Diabetes

Simple Endocrine Pathway endocrine cells respond directly to an internal or environmental stimulus by secreting a particular hormone negative feedback

Simple Neuroendocrine Pathway the stimulus is received by a sensory neuron, which stimulates a neurosecretory cell positive feedback

Insulin and Glucagon blood glucose concentration: 70 - 110 mg/100 mL blood glucose rises above normal range = release of insulin blood glucose drops below the normal range = release of glucagon

Glucose Homeostasis Activity

Diabetes Mellitus deficiency of insulin or a decreased response to insulin in target tissues cells are unable to take up enough glucose two type of diabetes http://www.nanomegamedical.com/medical/background.html

Type 2 Diabetes Type 1 Diabetes high blood pressure insulin-dependent immune system destroys beta cells of pancreas destroys person’s ability to create insulin cause: hereditary generally appears in childhood high blood pressure non-insulin-dependent failure of the target cells to respond normally to insulin in the blood cause: excess body weight and lack of exercise; can be hereditary generally after 40 years old 90% of people with diabetes have this type of diabetes

Type 2 Diabetes Type 1 Diabetes Treatments daily insulin shots blood sugar monitoring healthy diet spread carbohydrates throughout the day regular physical exercise no smoking blood sugar monitoring healthy diet spread carbohydrates throughout the day regular physical exercise possibly diabetes medication or insulin therapy no smoking

Quiz What are the main appetite suppressors? What is the product of adipose cells? What is the normal range for the blood glucose concentration? What does each pancreatic islet have?

Homework Due 1/29/16 Read 45.3 Diagram “Hormone Cascade” of Thyroid Regulation