Homeostatic Feeding Regulation & Leptin

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Questions and Answers

Which of the following best describes the goal of a regulatory system?

To keep the system variable above the set point

To keep the system variable below the set point

To keep the system variable at a constant value

To keep the system variable near the set point (correct)

What is the process by which the effect of a correctional mechanism diminishes or terminates further corrective action?

Positive feedback

Negative feedback

Anticipation

Satiety (correct)

Which of the following is associated with satiety?

Anticipating food and water

Adequate supplies of readily available food and water (correct)

Losing water through sweat

Ingesting food and water

What triggers osmometric thirst?

Cells being too big Signup and view all the answers

Which region of the hypothalamus is responsible for the feeling of thirst?

AV3V region Signup and view all the answers

What type of neurons in the AV3V region of the hypothalamus are sensitive to angiotensin?

Osmoreceptors Signup and view all the answers

Which of the following best describes homeostasis?

A process by which substances in the body are regulated Signup and view all the answers

What happens when blood glucose levels are low?

The pancreas releases glucagon Signup and view all the answers

What is the purpose of ingestive behavior?

To survive Signup and view all the answers

Which cells in the body can use glucose without the need for insulin?

Brain cells Signup and view all the answers

What is a characteristic of a classic thermostat?

It is slow to warm up Signup and view all the answers

Why is it important for the body to maintain a set point for temperature?

To predict and prevent extreme temperatures Signup and view all the answers

Which neurons in the arcuate nucleus of the hypothalamus promote hunger?

AGRP/NPY neurons Signup and view all the answers

Which neurons in the arcuate nucleus of the hypothalamus inhibit hunger?

POMC/α-MSH neurons Signup and view all the answers

When leptin levels fall to critically low levels, what happens to the neurons in the paraventricular nucleus (PVN) of the hypothalamus?

They stop firing Signup and view all the answers

What is the term used to describe the elevated leptin set point and reduced response to leptin levels observed in overweight individuals?

Leptin resistance Signup and view all the answers

Which of the following is true about triglycerides?

Triglycerides are broken down into glycerol and fatty acids Signup and view all the answers

What is the function of ghrelin?

Ghrelin increases hunger and food intake Signup and view all the answers

Which of the following factors stops hunger after a meal?

Release of CCK and GLP-1 from the duodenum Signup and view all the answers

How does the liver signal satiety?

By measuring glucose and free fatty acid levels in the blood Signup and view all the answers

Which hormone is secreted by adipocytes and provides a negative feedback signal that decreases hunger?

Leptin Signup and view all the answers

What happens when the brain senses dangerously low blood glucose levels?

Insulin secretion increases Signup and view all the answers

What triggers the emergency feeding circuits when there is not enough body fat?

Low levels of leptin Signup and view all the answers

What can excess insulin signaling or drugs that inhibit glucose metabolism cause?

Hyperglycemia Signup and view all the answers

Which neuropeptides play an important role in regulating the motivational and hedonic effects of hunger?

GLP-1, NPY, orexin, and MCH Signup and view all the answers

What is the most effective form of bariatric surgery?

Roux-en-Y gastric bypass (RYGB) Signup and view all the answers

What is the purpose of bariatric surgery?

To reduce the amount of food that can be eaten Signup and view all the answers

What happens to the rewarding and reinforcing value of food when satiety is reached?

It decreases Signup and view all the answers

What happens to the rewarding and reinforcing value of food when hunger is experienced?

It increases Signup and view all the answers

What is the role of neurons in the medulla and hypothalamus in hunger regulation?

They regulate dopamine neuron activity Signup and view all the answers

Study Notes

Regulatory Systems

The goal of a regulatory system is to maintain a set point or homeostasis.

Thirst Regulation

Osmometric thirst is triggered by increased osmolality of the blood.
The region of the hypothalamus responsible for the feeling of thirst is the anteroventral third ventricle (AV3V).
Magnocellular neurons in the AV3V region of the hypothalamus are sensitive to angiotensin.

Hunger and Satiety Regulation

The purpose of ingestive behavior is to maintain energy homeostasis.
Red blood cells can use glucose without the need for insulin.
Leptin levels falling to critically low levels activates neurons in the paraventricular nucleus (PVN) of the hypothalamus.
Overweight individuals have an elevated leptin set point and reduced response to leptin levels, known as leptin resistance.
Neurons in the arcuate nucleus of the hypothalamus that promote hunger are AgRP/NPY neurons.
Neurons in the arcuate nucleus of the hypothalamus that inhibit hunger are POMC/CART neurons.

Glucose Regulation

When blood glucose levels are low, the brain senses it as a life-threatening emergency and triggers the emergency feeding circuits.
When the brain senses critically low blood glucose levels, it triggers the emergency feeding response to restore blood glucose levels.

Hormones and Metabolism

Ghrelin is a hormone that stimulates appetite.
Leptin is a hormone secreted by adipocytes that provides a negative feedback signal that decreases hunger.
The liver signals satiety through the release of insulin and other hormones.
Cholecystokinin (CCK) is a hormone that stops hunger after a meal.

Bariatric Surgery

The purpose of bariatric surgery is to restrict food intake and induce weight loss.
The most effective form of bariatric surgery is the Roux-en-Y gastric bypass.

Food Reward and Hedonics

When satiety is reached, the rewarding and reinforcing value of food decreases.
When hunger is experienced, the rewarding and reinforcing value of food increases.
The role of neurons in the medulla and hypothalamus is to regulate hunger by integrating sensory information and hormone signals.
Dopamine and opioid neuropeptides play an important role in regulating the motivational and hedonic effects of hunger.

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Description

Test your knowledge on the homeostatic regulation of feeding and the role of leptin in hunger and basal metabolic rate. Explore how leptin signaling affects hunger and the activity of specific neurons in the hypothalamus.

Homeostatic Feeding Regulation &amp; Leptin