Unit 14: Ingestive Behavior

Which of the following describes ghrelin? A. A peptide highly concentrated in the intestines that is released into the bloodstream when the intestines are empty B. A peptide highly concentrated in the stomach that is released into the bloodstream when the stomach is empty C. A peptide released by the magnocellular cells of the hypothalamus when the stomach is empty D. A peptide released by the magnocellular cells of the hypothalamus when the stomach is full

B. A peptide highly concentrated in the stomach that is released into the bloodstream when the stomach is empty

Which of the following is the process of breaking down complex macromolecules? A. Prandial state B. Catabolism C. Adiposity D. Anabolism

B. Catabolism

Which of the following describes the ventromedial hypothalamic syndrome? A. Hypothalamic lesions that cause overeating and weight gain B. Hypothalamic lesions that cause anorexia C. Reproductive incompetence with leptin deficiency D. Condition characterized by a decrease in adiposity

A. Hypothalamic lesions that cause overeating and weight gain

Which is a consequence of leptin deficiency? A. Increased NPY and AgRP in the arcuate nucleus B. Increased metabolism C. Decreased MCH in the lateral hypothalamic area D. Decreased NPY and AgRP in the arcuate nucleus

A. Increased NPY and AgRP in the arcuate nucleus

Which of the following describes the humoral response? A. Stimulating or inhibiting the release of pituitary hormones B. Inciting an appropriate somatic motor behavioral response C. Adjusting the balance of sympathetic and parasympathetic outputs of the ANS D. Regulating feedback to the central nervous system

A. Stimulating or inhibiting the release of pituitary hormones

Which neurons in the arcuate nucleus of the hypothalamus are activated by an increase in blood leptin levels? A. alphaMSH/CART neurons B. TSH/ACTH neurons C. NPY/AgRP neurons D. Adipocytes

A. alphaMSH/CART neurons

anabolism vs catabolism

Anabolism is the synthesis of complex molecules in living organisms from simpler ones together with the storage of energy; constructive metabolism. Catabolism is the breakdown of complex molecules in living organisms to form simpler ones, together with the release of energy; destructive metabolism

Which of the following represents the humoral response to a drop in leptin levels? A. Activate the sympathetic division of the ANS. B. Activate the parasympathetic division of the ANS. C. Decreased secretion of TSH and ACTH from the pituitary gland D. Increased secretion of TSH and ACTH from the pituitary gland

C. Decreased secretion of TSH and ACTH from the pituitary gland

When your stomach is full, mechanosensory neurons in the stomach wall sense the distension and transmit the sensation to the nucleus of the solitary tract in the medulla via which nerve? A. Hypoglossal B. Trigeminal C. Vagus D. Glossopharyngeal

C. Vagus

Identify the three phases that occur during short-term regulation of feeding

Cephalic, gastric, and substrate phases

Describe how feeding is regulated during the three phases by release of intestinal peptides, insulin and activation of sensory and hypothalamic neurons.

Cephalic-hunger: insulin release triggered by parasympathetic innervation of pancreas beta cells; ghrelin released when stomach is empty; activates NPY/AgRP containing neurons in arcuate nucleus Gastric-feeling full: gastric distension signals brain via vagus nerve; works synergistically with CCK released in intestines in response to certain foods; insulin also released by pancreas beta cells due to CCK, important in anabolism Substrate-food is absorbed: insulin release is maximal when food is finally absorbed in intestines; primary stimulus for insulin release is increased blood glucose levels; satiety stop eating

example of humoral and visceromotor response

Cold, dehydrated, loss energy → humoral and visceromotor response → shiver, blood moved away from surface to center of body, urine production stops, body fat reserves mobilized, etc

Anorexia can result from damage to which of the following parts of the brain? A. Dorsal thalamus B. Ventromedial hypothalamus C. Vascular organ of lamina terminalis D. Lateral hypothalamus

D. Lateral hypothalamus

explain homeostasis and its cycle

Homeostasis- process that maintain the internal environment of the body within a narrow physiological range (set point) Starts with sensory transduction Regulated parameter measure Deviations detected Response to bring parameters back (3 parts)

Explain the humoral response

Humoral: hypothalamic neurons respond to sensory signals by stimulating or inhibiting the release of pituitary hormones into the bloodstream.

Compare the mechanisms and circuitry involved in short and long-term regulation of feeding

Long period of time to maintain the body's fat reserves. Body fat and food consumption, leptin. Hypothalamus and feeding, lateral and ventromedial hypothalamus. Elevated or decreased leptin levels. Short period of time regulates meal size and frequency. Cephalic, gastric, and substrate phases. Ghrelin, gastric distension, CCK, insulin.

explain the effects Insulin has on the metabolism and feeding behavior

Released into blood by the beta (B) cells of the pancreas Glucose transport into other cells of the body (not neurons) requires insulin Imp for anabolic metabolism when glucose is transported into liver, skeleteal muscle, and adipose cells for catabolic metabolism Levels of glucose is regualted by insluin level Glucose levels fall when insulin rise Glucose levels rise when insulin falls

Cholecystokinin (CCK) is an ________ and grehlin is an ______

appetite suppressant; appetite stimulant

What ways can the hypothalamus responds to sensory input to maintain homeostasis ?

humoral, visceromotor, & somatic motor

explain the visceral response

hypothalamus neurons respond to sensory signals by adjusting balance of sympathetic and parasympathetic outputs of the ANS

what's the fastest and most effective way to correct deviations?

motivated behavior generated by somatic motor system ex. seek warmth, water, food, shelter

Insulin levels are maximal during which of the following phases of the body's reaction to feeding behavior? A. Cephalic B. Substrate C. Gastric D. Digestion

substrate

Discuss the circuitry in the hypothalamus (i.e. regions, neurons, and peptides) that is important for long term regulation of feeding

Rise in leptin levels → stimulate release of alpha-MSH and CART from arcuate nucleus neurons These anorectic peptides act on the brain by activating MC4 receptor to inhibit feeding and increase metaholbish Humoral- Increased secretion of TSH and ACTH. These pituitary hormones act on the thyroid and adrenal glands and have the effect of raising the metabolic rate of cells throughout the body. Visceromotor- Increases the tone of the sympathetic division of ANS, which also raises metabolic rate, in part by raising body temp. Intermediolateral gray matter of spinal cord (symp ANS) Somatic Motor- Decreases feeding behavior. The alpha MSH/CART neurons on the arcuate nucleus project their axons directly to the regions of the nervous system that orchestrate this coordinated response. Lateral hypothalamus --> decreased feeding motivated behaviors Fall in leptin levels --> stimulates release of NPY and AgRP from arcuate nucleus neurons, release of MCH and orexin from neurons in lateral hypotha area These orexigenic peptides act on brain to stimulate feeding and decrease metabolism Humoral- NPY and AgRP inhibit secretion of TSH and ACTH Visceromotor- activate parasympathetic division of ANS Somatic- stimulate feeding behavior

explain the somatic motor response

Somatic motor response- hypothalamic neurons (within lateral hypo.) respond to sensory signals by inciting appropriate somatic motor behavioral response