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

2. Stamp Homework

3. Homework Answers

4. 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.

5. 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 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?

6. Digestion and Appetite

7. 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

8. 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

9. Glucose Homeostasis and Diabetes

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

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

12. 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

13. Glucose Homeostasis Activity

14. 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

15. 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

16. 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

17. 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?

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