AGRP Hypothalamus Quiz and Flashcards: Regulation of Hunger and Satiety

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Questions and Answers

What is the primary function of neuropeptide Y (NPY) neurons in the arcuate nucleus?

Inhibit the release of melanocortin hormones

Decrease food intake and increase energy expenditure

Stimulate insulin secretion and metabolism

Increase food intake and reduce energy expenditure (correct)

Which neurotransmitter stimulates the release of orexin and melanin-concentrating hormone (MCH) in the lateral hypothalamus?

Ghrelin

Leptin

Glucagon-like peptide-1 (GLP-1)

Endocannabinoids (correct)

What is the primary function of POMC neurons in the arcuate nucleus?

Decrease food intake and increase energy expenditure (correct)

Inhibit the activity of melanocortin receptors

Increase food intake and reduce energy expenditure

Stimulate the release of NPY and AGRP

What is the primary target of α-MSH released by POMC neurons?

Melanocortin receptors in the paraventricular nucleus Signup and view all the answers

What is the primary function of AGRP in the arcuate nucleus?

Inhibit the activity of melanocortin receptors Signup and view all the answers

Which nucleus plays a role in controlling insulin secretion and metabolism?

Paraventricular nucleus Signup and view all the answers

What is the primary role of insulin in the long-term control of body weight?

Insulin inhibits the NPY-secreting cells of the arcuate nucleus, suppressing further food intake. Signup and view all the answers

What is the main function of the nucleus tractus solitarius (NTS) in the short-term control of meals?

The NTS processes afferent inputs from the digestive tract, such as signals indicating stomach distension, to contribute to the feeling of being full. Signup and view all the answers

How does cholecystokinin (CCK) act as a satiety signal for regulating meal size?

CCK is released from the duodenal mucosa during digestion of a meal and signals the feeling of being full, regulating meal size. Signup and view all the answers

Which of the following is NOT a mechanism by which the nucleus tractus solitarius (NTS) contributes to the short-term control of meals?

The NTS directly stimulates the release of cholecystokinin, a key satiety signal from the gastrointestinal tract. Signup and view all the answers

How does the increase in insulin secretion that accompanies nutrient abundance affect the NPY-secreting cells of the arcuate nucleus?

The increase in insulin secretion inhibits the NPY-secreting cells, suppressing further food intake. Signup and view all the answers

What is the primary role of the hypothalamus in maintaining energy balance?

The hypothalamus plays a key role in maintaining energy balance by regulating the activity of the satiety center in the brain stem. Signup and view all the answers

What is the primary role of insulin during the fed state?

Facilitate uptake of glucose by body cells Signup and view all the answers

Which of the following accurately describes the fasting phase?

Fatty acids are the primary energy source for most body cells Signup and view all the answers

What is the primary function of glycerol during the fasting phase?

It is converted to glucose by the liver for use by the brain Signup and view all the answers

Which of the following statements about melanin-concentrating hormone (MCH) is correct?

It stimulates appetite and reduces metabolic rate Signup and view all the answers

During the fed state, what happens to excess carbohydrates and amino acids?

They are converted to fatty acids and stored in adipose tissue Signup and view all the answers

Which of the following accurately describes the role of the sympathetic nervous system during the fasting phase?

It stimulates the release of glucagon from the pancreas Signup and view all the answers

What is the primary function of ghrelin?

Stimulate appetite Signup and view all the answers

Which peptide signals fullness or satiety?

PYY3-36 Signup and view all the answers

What is the primary function of leptin?

Suppress appetite Signup and view all the answers

Which peptide is considered the dominant factor responsible for the long-term matching of food intake to energy expenditure?

Leptin Signup and view all the answers

Which nucleus in the hypothalamus is the major site for leptin action?

Arcuate nucleus Signup and view all the answers

Which peptide is produced by the stomach and stimulates appetite by activating the hypothalamic NPY-secreting neurons?

Ghrelin Signup and view all the answers

What is hunger?

A signal indicating the need for food intake and energy Signup and view all the answers

Where are the hunger and satiety centers located?

Hypothalamus Signup and view all the answers

What is satiety?

The suppression of hunger for a period after a meal Signup and view all the answers

Which nervous system is more active during the absorptive phase?

Parasympathetic nervous system Signup and view all the answers

What is the function of the Dorsomedial hypothalamus (DMH)?

Controlling hunger and satiety centers Signup and view all the answers

Which neurotransmitters and hormones influence hunger and satiety centers in the hypothalamus?

Orexinergic and anorexinergic Signup and view all the answers

Study Notes

Regulation of Hunger and Satiety

Hunger is a feeling caused by lack of food, signaling the body's need for food intake and energy.
Satiety is the feeling of fullness, suppressing hunger for a period of time after a meal.
Appetite is the desire for food.

Short-Term Eating Behavior

Ghrelin, the "hunger hormone," is produced by the stomach, stimulating appetite by activating hypothalamic NPY-secreting neurons.
Peptide YY3-36 (PYY3-36) is produced by the small and large intestines, signaling satiety by inhibiting appetite-stimulating NPY-secreting neurons in the arcuate nucleus.

Long-Term Maintenance of Energy Balance

Leptin, an adipokine, suppresses appetite, promoting weight loss by inhibiting hypothalamic output of appetite-stimulating NPY and stimulating melanocortins.
Insulin, secreted by the pancreas, stimulates cellular uptake, use, and storage of nutrients, suppressing further food intake.

Satiety Center in Brain Stem

The nucleus tractus solitarius (NTS) in the brain stem processes signals important in the feeling of being full, contributing to short-term control of meals.
The NTS receives input from higher hypothalamic neurons involved in energy homeostasis and afferent inputs from the digestive tract.

Cholecystokinin (CCK) as a Satiety Signal

CCK is released from the duodenal mucosa during digestion, regulating meal size.
CCK is secreted in response to the presence of nutrients in the small intestine.

Neuronal Connections and Energy Balance

The arcuate nucleus is the major site for leptin action, regulating energy balance.
Neurons in the arcuate nucleus, such as POMC and NPY/AGRP neurons, play a crucial role in controlling food intake and energy expenditure.

Metabolic Pathways

During the absorptive phase, glucose, amino acids, and fats are received from the intestines, and insulin levels are high, permitting all cells to metabolize glucose.
During the fasting phase, the liver converts glycogen to glucose, and fats are broken down into glycerol and fatty acids, which are used by the body for energy.

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Description

Explore the concepts of hunger, satiety, and appetite in relation to food intake and energy regulation. Learn about the feeling of fullness after a meal and the importance of recognizing signals from the body for maintaining a healthy diet.

6)Regulation of Hunger and Satiety