Homeostasis and Blood Glucose Regulation

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Questions and Answers

What is the primary mechanism by which homeostasis is maintained in humans?

Negative feedback loops (correct)

Positive feedback loops

External environmental changes

Random fluctuations

Which of the following is NOT considered a homeostatic variable in humans?

Body temperature

Blood glucose concentration

Blood pH

External humidity (correct)

What role does insulin play in homeostasis?

Regulates blood pH

Increases blood glucose concentration

Decreases blood glucose concentration (correct)

Stimulates brown adipose tissue

What physiological response involves the narrowing of blood vessels to conserve heat?

Vasoconstriction Signup and view all the answers

Which of the following hormones is secreted by pancreatic endocrine cells to balance blood glucose levels?

Insulin Signup and view all the answers

Which mechanism is an example of thermoregulation involving the body's response to cold?

Shivering Signup and view all the answers

Which part of the brain is primarily responsible for regulating body temperature?

Hypothalamus Signup and view all the answers

How does the body respond to overheating?

Vasodilation and sweating Signup and view all the answers

What type of cells in the pancreas release glucagon?

Alpha cells Signup and view all the answers

Which hormone decreases blood glucose levels?

Insulin Signup and view all the answers

What distinguishes endocrine glands from exocrine glands?

Endocrine glands do not have ducts. Signup and view all the answers

What is the primary function of glucagon?

To raise blood glucose levels Signup and view all the answers

Which of the following correctly describes insulin's role in the body?

Facilitates the conversion of glucose to glycogen. Signup and view all the answers

How are insulin and glucagon transported to their target cells?

By the bloodstream Signup and view all the answers

Which of the following statements about pancreas function is true?

The pancreas functions as both an endocrine and exocrine gland. Signup and view all the answers

What effect does insulin have on muscle cells?

Enhances glucose uptake. Signup and view all the answers

What is the primary treatment method for Type I diabetes?

Insulin injections, diet and exercise Signup and view all the answers

How does the hypothalamus respond to keep body temperature regulated?

By secreting hormones that adjust metabolic rate Signup and view all the answers

Which of the following is an important factor in Type II diabetes management?

Diet and exercise Signup and view all the answers

What role does thyroxin (T4) play in thermoregulation?

Increases metabolic reactions to generate heat Signup and view all the answers

Which method is NOT associated with the treatment of Type I diabetes?

Carbohydrate-rich diet Signup and view all the answers

What is the primary function of thermoreceptors in the body?

To monitor body temperature Signup and view all the answers

What hormone does the hypothalamus secrete to increase metabolic rate?

Thyrotropin releasing hormone (TRH) Signup and view all the answers

What primarily causes Type I diabetes?

Autoimmune destruction of beta cells Signup and view all the answers

Which organ is primarily responsible for heat generation through metabolism?

Brain Signup and view all the answers

Which of the following is a symptom associated with Type II diabetes?

Fatigue and slow healing Signup and view all the answers

Which factor is NOT associated with the development of Type II diabetes?

Autoimmune disease Signup and view all the answers

What is a physiological consequence of consistently elevated blood glucose levels?

Presence of glucose in urine Signup and view all the answers

How does insulin function in the body?

It stimulates the absorption of glucose into cells. Signup and view all the answers

What age group is most affected by Type I diabetes?

Children and young people Signup and view all the answers

What can lead to insulin receptor deficiency in Type II diabetes?

Obesity and lack of exercise Signup and view all the answers

Which statement about the treatment of Type I and Type II diabetes is correct?

Type I diabetes requires insulin therapy for management. Signup and view all the answers

What is the primary mechanism by which homeostasis operates?

Negative feedback loops Signup and view all the answers

Which statement about positive feedback is true?

It amplifies initial stimuli. Signup and view all the answers

What normal blood glucose level is typically maintained in human blood?

90 mg/100ml Signup and view all the answers

What happens during negative feedback in homeostasis?

Conditions return to a set value. Signup and view all the answers

Which of the following is an example of positive feedback?

Release of FSH during the menstrual cycle Signup and view all the answers

What is the role of negative feedback in homeostasis?

To keep internal conditions stable. Signup and view all the answers

What can cause an increase in blood sugar levels?

Diet high in carbohydrates Signup and view all the answers

Which factor does NOT play a role in maintaining homeostasis?

Tissue damage Signup and view all the answers

Study Notes

Homeostasis

Homeostasis is the maintenance of a stable internal environment despite external fluctuations.
It works through negative feedback loops, monitoring variables and making adjustments to maintain set points.

Negative Feedback Loops

Negative feedback loops counteract changes, bringing variables back to their set points.
They form the basis of homeostatic control, keeping internal conditions within narrow limits.
They require energy to maintain stability.

Regulation of Blood Glucose

Blood glucose levels are maintained within a normal range (around 90mg/100ml).
Insulin and glucagon, produced by the pancreas, regulate blood glucose levels.
Insulin lowers blood glucose by promoting glucose uptake by cells and glycogen storage in the liver.
Glucagon raises blood glucose by stimulating glycogen breakdown in the liver and glucose release into the blood.

Pancreas & Hormone Secretion

The pancreas has both endocrine and exocrine functions.
Endocrine glands secrete hormones directly into the bloodstream.
The pancreas contains alpha (α) cells that release glucagon and beta (β) cells that release insulin.

Diabetes

Diabetes is a condition characterized by consistently elevated blood glucose levels, even during fasting.
Type 1 diabetes is caused by the destruction of pancreatic beta cells, leading to insulin deficiency.
Type 2 diabetes is characterized by insulin resistance, where the body cannot properly utilize insulin.

Thermoregulation

Thermoregulation is the control of body temperature, maintaining a set point through negative feedback mechanisms.
Thermoreceptors in the skin and hypothalamus monitor body temperature.
The hypothalamus acts as the regulatory center, initiating responses to maintain core body temperature.

Adjusting Body Temperature

To increase body temperature, the hypothalamus secretes thyrotropin-releasing hormone (TRH), which stimulates the pituitary gland to release thyroid-stimulating hormone (TSH).
TSH stimulates the thyroid gland to produce thyroxin (T4), which increases metabolic rate and heat production.
To decrease body temperature, the body can use mechanisms like vasodilation, sweating, and uncoupled respiration in brown adipose tissue.

Thermoregulation: Mechanisms

Vasodilation increases blood flow to the skin, promoting heat loss.
Vasoconstriction reduces blood flow to the skin, conserving heat.
Shivering generates heat through muscle contractions.
Sweating cools the body by evaporative heat loss.
Uncoupled respiration in brown adipose tissue produces heat without ATP production.
Hair erection traps a layer of warm air, reducing heat loss.

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Description

This quiz focuses on the concept of homeostasis and the essential role of negative feedback loops in maintaining stable internal conditions. It specifically examines the regulation of blood glucose levels by insulin and glucagon, highlighting the functions of the pancreas. Test your understanding of these biological processes and their significance in human physiology.