Motivation

Hypothalamic Regulation. 3 steps

*1. Humural response:* Sensory input senses a change *2. Visceromotor response:* Neurons in hypothalamus adjust balance of sympathetic and parasympathetic outputs *3. Somatic motor response:* Hypothalamic neurons incite appropriate somatic motor behavioural response

Difference between abstract and concrete motivation

Abstract is "wanting" to. Concrete is needing to.

TSH (thyroid stimulating hormone)

Acts on thyroid gland, promoting release of thyroid hormones

Prandial state

Anabolism Energy stores replenished *during and right after a meal* Blood is filled with nutrients

Orexin peptides stimulate

Feeding behaviour. It's orexigenic

gastric distention

Feel full: stretching stomach wall is satiety signal

Sympathetic nervous system

Fight or flight. Exciting

Short term regulation of feeding behaviour

Ghrelin and Gastric distension

What nutrients to neurons use?

Glucose

What nutrients to all cells use?

Glucose, fatty acids and ketones.

What is broken down in postabsorptive state?

Glycogen (stored in muscles/liver) and triglycerides (stored in fat)

Insulin

Hormone produced by the pancreas. Transports glucose in other cells (other than neurons) of the body.

What part of the brain controls homeostasis of temperature, fluid balance and energy balance?

Hypothalamus

What part of the brain is important for homeostasis?

Hypothalamus

Activated arcuate nucleus contain peptides (neurotransmitters) which trigger humoral response:

Increased secretion of TSH and ACTH

What is homeostasis?

Maintaining a stable internal environment

Stomach wall is innervated by

Mechanosensory axons, ascend to brain via vagus

Self stimulation in septal area of forebrain

More alert and good feeling

ACTH (adrenocorticotropic hormone)

Stimulates adrenal cortex to release glucocorticoids (cortisol)

Insulin levels are maximal during which of the following phases of the body's reaction to feeding behavior? a. Cephalic b. Gastric c. Substrate d. Digestion

Substrate

Autonomic nervous system (ANS) skiptist í

Sympathetic og parasympathetic

What hormones act on thyroid and adrenal glands?

TSH and ACTH

How does the brain and body respond to leptin deficiency?

That the person is starving, despite massive obesity.

What is catabolism?

The breakdown of complex molecules (glycogen and triglycerides) to glucose, fatty acids and ketones.

Anabolism

When energy is assembled. Stored as glycogen and triglycerides.

Which of the following is the process of breaking down complex macromolecules? a. Catabolism b. Anabolism c. Adiposity d. Prandial state

a. Catabolism

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

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

substrate phase

absorption of nutrients

Lesions of lateral hypothalamus

anorexia

gastric phase

arrival of food in stomach

Warm- and cold-sensitive neurons are located in what part of the brain? a. OVLT b. Anterior hypothalamus c. Ventromedial hypothalamus d. Motor cortex

b. Anterior hypothalamus

How do neurons of the vascular organ of the lamina terminalis (OVLT) respond when the blood becomes hypertonic? a. Inhibit magnocellular neurosecretory cells that secrete vasopressin and inhibit osmotic thirst b. Excite magnocellular neurosecretory cells that secrete vasopressin and stimulate osmometric thirst c. Stimulate rise in blood levels of angiotensin II and inhibit thirst d. Stimulate rise in blood levels of angiotensin II and stimulate thirst

b. Excite magnocellular neurosecretory cells that secrete vasopressin and stimulate osmometric thirst

Which of the following is a symptom of diabetes insipidus? a. Glucose in urine b. Large volumes of pale, watery urine c. No urine production d. Hyperglycemia

b. Large volumes of pale, watery urine

Which of the following describes satiety signals responsible for short-term regulation of feeding behavior? a. Initiate a meal and maintain hunger during a meal. b. Terminate a meal and inhibit feeding for some time afterward. c. Initiate a meal when leptin levels are low. d. Initiate a meal when leptin levels are high.

b. Terminate a meal and inhibit feeding for some time afterward.

Which neurons in the arcuate nucleus of the hypothalamus respond to an increase in blood leptin levels a. NPY/AgRP neurons b. αMSH/CART neurons c. Adipocytes d. TSH/ACTH neurons

b. αMSH/CART neurons

lipostatic hypothesis

brain monitors the amount of body fat

Which of the following describes the ventromedial hypothalamic syndrome? a. Reproductive incompetence with leptin deficiency b. Hypothalamic lesions that cause anorexia c. Hypothalamic lesions that cause overeating and obesity d. Condition characterized by a decrease in adiposity

c. Hypothalamic lesions that cause overeating and obesity

Neurons in the lateral hypothalamus that receive a direct projection from leptin-sensitive cells in the arcuate nucleus contain which of the following peptide neurotransmitters? a. NPY and AgRP b. αMSH and CART c. MCH and orexin d. NPY and CART

c. MCH and orexin

Hypothalamic neurons maintain homeostasis by responding to a sensory stimulus with humoral, visceromotor, and somatic motor responses. Which of the following describes the humoral response? a. Adjusting the balance of sympathetic and parasympathetic outputs of the ANS b. Inciting an appropriate somatic motor behavioral response c. Stimulating or inhibiting the release of pituitary hormones d. Regulating feedback to the central nervous system

c. Stimulating or inhibiting the release of pituitary hormones

Opposite of anabolism

catabolism

Neurons that contain MCH have widespread connections in the

cerebral cortex, makes it perhaps conscious

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 released by the magnocellular cells of the hypothalamus when the stomach is full c. A peptide released by the magnocellular cells of the hypothalamus when the stomach is empty d. A peptide highly concentrated in the stomach that is released into the bloodstream when the stomach is empty

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

Which is a consequence of leptin deficiency? a. Decreased NPY and AgRP in the arcuate nucleus b. Decreased MCH in the lateral hypothalamic area c. Increased metabolism d. Increased NPY and AgRP in the arcuate nucleus

d. Increased NPY and AgRP in the arcuate nucleus

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

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. Trigeminal b. Hypoglossal c. Glossopharyngeal d. Vagus

d. Vagus

anorectic peptides

diminish appetite mimics response to elevated leptin levels activate sympathetic ANS

Ghrelin activates neurons of the arcuate nucleus, same neurons that are activated by

drop in leptin

CCK is released in response to certain type of food

fatty food

Orexin stimulates

feeding behaviour

hyperglycemia

high blood sugar

Overdose on Insulin

hypoglycemia, starves neurons in the brain

Injection of drugs that block the actions of anorectic peptides

increase feeding behaviour

Neurons that incite (+) feeding behavior are in the:

lateral hypthalamus

Level of glucose in blood is regulated by:

level of insulin

If intake consistently fails to meet body's demands:

loss of fat

Vagal sensory neurons activate neurons in nucleus in

medulla: inhibit feeding behaviour

Self stimulation in hippocampus

mild pleasure

Destruction of dopamine axons

no motivation to seek food

If intake and storage consistently exceed usage:

obesity

Lesion to ventromedial hypothalamus

obesity

low level of leptin activate

orexigenic peptides

Insulin release controlled by

parasympathetic innvervation during anticipation of food. Blood glucose levels fall.

CCK (cholecystokinin)

protein that inhibits meal frequency and size. Present in neurons of ENS, that controls gastrointestinal system

After a meal, glucose levels in blood

rise

orexigenic peptides

stimulate feeding behavior Inhibit secretion of TSH and ACTH Activate parasympathetic ANS

cephalic phase

the earliest phase of digestion, in which the brain thinks about and prepares the digestive organs for the consumption of food

ob gene

the gene that codes for the hormone leptin

MCH motivates

the search for food

Neurons that reduce (-) feeding behavior are in the:

vetromedial hypothalamus

Adiposity

A condition of being severely overweight, or obese.

Ghrelin

A hunger-arousing hormone secreted by an empty stomach

Levels of peptides in _______ correlate with level of leptin.

Arcuate nucleus

high levels of leptin activate neurons of

Arcuate nucleus Anorectic peptides

Central Nervous System (CNS)

Brain and spinal cord

Triglyceride is stored in

Capacity adipose (fat) tissues. Unlimited capacity

3 phases of body reactions to a meal

Cephalic phase Gastric phase Substate phase

Self stimulation provides a rewards. Most effective in

Dopaminergic Axons in ventral tegmental area

True or False Glycogen reserves are found in adipose tissue.

False

Hormone leptin

Is released by adipose tissue (fat cells) and acts directly on neurons of hypthalamus. *Decrease appetide and increase energy expenditure*

hedonic

It feels good, so we do it

What peptides do lateral hypothalamic neurons contain?

Leptin and Orexin

Glycogen is stored in

Liver and muscles Limited capacity

Highest vs lowest level of behaviour.

Lowest is unconscious, automatic movement. Highest is conscious, we control them.

Neurons in the lateral hypothalamus that receive a direct projection from leptin-sensitive cells in the arcuate nucleus contain which of the following peptide neurotransmitters?

MCH

ENS (enteric nervous system)

Part of ANS brain of the gut

Fasting between meals, what state?

Postabsorptive

What do TSH and ACTH do?

Raise metabolic rate of cells throughout the body. If we eat too much, metabolic rate is increased.

parasympathetic nervous system

Rest and digest. Relaxing

True or False CCK is a gastrointestinal satiety peptide released by cells of the intestines in response to the presence of fatty food.

True

True or False CCK trigger insulin release

True

True or False Dopamine-depleted animals appear to lack the motivation to seek food even though they seem to enjoy it when it is available.

True

True or False Serotonin levels in the hypothalamus spike during a meal, especially in response to carbohydrates.

True

True or False Leptin deficiency inhibits reproductive competence

True Adaptive responses when food is scarce and energy reserves are low