6.6 Homeostasis Flashcards
Will the body always need to produce the same amount of ATP?
The body needs glucose to make ATP (via cell respiration), however the amount required will fluctuate according to demand
What can high levels of glucose in the blood do to an organism?
High levels of glucose in the blood can damage cells (creates hypertonicity) and hence glucose levels must be regulated
What are the two hormones controlling blood sugar concentration?
Two antagonistic hormones are responsible for regulating blood glucose concentrations – insulin and glucagon
Where are insulin and glucagon released from and where do they act?
These hormones are released from pancreatic pits (called the islets of Langerhans) and act principally on the liver
What is released when blood glucose levels are high?
Insulin is released from beta (β) cells of the pancreas and cause a decrease in blood glucose concentration
What does insulin promote?
This may involve stimulating glycogen synthesis in the liver (glycogenesis), promoting glucose uptake by the liver and adipose tissue, or increasing the rate of glucose breakdown (by increasing cell respiration rates)
What is released in response to low blood glucose concentration?
Glucagon is released from alpha (α) cells of the pancreas and causes an increase in blood glucose concentration
What is diabetes mellitus?
Diabetes mellitus is a metabolic disorder that results from a high blood glucose concentration over a prolonged period
What are the 2 different causes of diabetes mellitus?
It is caused by the body either not producing insulin (Type I) or failing to respond to insulin production (Type II)
How are the 2 different types of diabetes treated?
It is treated with either insulin injections (Type I only) or by carefully monitoring and controlling dietary intake (Type II)
When do the different types of diabetes develop?
1: usually occurs during childhood (early onset)
2: usually occurs during adulthood (late onset)
How do the different types of diabetes respond to insulin?
1:body does not produced sufficient insulin
2:body does not respond to insulin production
How do the two types of diabetes differ in terms of cause?
1: caused by the destruction of beta cells (autoimmune)
2: caused by down-regulation of insulin receptors
How do the two types of diabetes differ in treatment?
1: requires insulin injections to regulate blood glucose
2: controlled by managing lifestyle and diet
What is thyroxin?
Thyroxin is a hormone secreted by the thyroid gland in response to signals initially derived from the hypothalamus
Where does thyroxin act?
Thyroxin acts on nearly every tissue in the body and is essential to the proper development and differentiation of cells
What is the primary role of thyroxin?
The primary role of thyroxin is to increase the basal metabolic rate (amount of energy the body uses at rest)
How does thyroxin achieve its primary role?
This can be achieved by stimulating carbohydrate and lipid metabolism via the oxidation of glucose and fatty acids
What is the secondary role of thyroxin, as a side-effect of its primary function?
A consequence of increasing metabolic activity is the production of heat – hence thyroxin helps to control body temperature
When will thyroxin be released in regard to body temperature?
Thyroxin is released in response to a decrease in body temperature in order to stimulate heat production
A deficiency of what nutrient may lead to a thyroxine deficiency?
Thyroxin is partially composed of iodine and hence a deficiency of iodine in the diet will lead to decreased production of thyroxin
What disease will an iodine deficiency lead to?
Iodine deficiency will cause the thyroid gland to become enlarged, resulting in a disease known as goitre
What produces leptin and what is its role?
Leptin is a hormone produced by adipose cells that regulates fat stores within the body by suppressing appetite
Where does leptin bind and why?
Leptin binds to receptors located within the hypothalamus to inhibit appetite and thereby reduce food intake