1
Q

What is motivation?

A

β†’ A physical need

β†’ Wanting/liking something

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2
Q

What does the hypothalamus do?

A

β†’ Maintain homeostasis by regulating three interrelated functions

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3
Q

What are the 3 things that the hypothalamus controls?

A

β†’ Endocrine secretion
β†’ Autonomic nervous system
β†’ Emotions and drive

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4
Q

Describe anabolism?

A

β†’ glucose goes to the liver

β†’ Skeletal muscle stores glucose as glycogen

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5
Q

Describe catabolism?

A

β†’ Glycogen gets broken down to glucose

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6
Q

What is parabiosis?

A

β†’ Sharing of blood circulation between animals

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7
Q

What do obese mice not produce?

A

β†’ leptin

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8
Q

What happens if you connect an ob/ob mouse and a normal mouse via parabiosis?

A

β†’ the ob/ob mouse will decrease in size

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9
Q

Where does leptin bind?

A

β†’ Leptin receptors on the arcuate nucleus

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10
Q

When is leptin released and why?

A

β†’ When you finished eating

β†’ to stop feeding

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11
Q

Where is the hypothalamus?

A

β†’ At the base of the brain

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12
Q

What happens when you lesion the VMH?

A

β†’ weight gain

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13
Q

What happens during lateral hypothalamic syndrome?

A

β†’ Diminished appetite for food

β†’ Anorexia

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14
Q

What happens during ventromedial hypothalamic syndrome?

A

β†’ Overeating

β†’ Obesity

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15
Q

What are the anorectic peptides?

A

β†’ Alpha MSH

β†’ CART

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16
Q

Describe the anorexic response?

A

β†’ Leptin increases in circulation
β†’ Leptin binds to receptors on the arcuate nucleus
β†’ Alpha MSH and CART neurons in arcuate nucleus are activated which project to the lateral hypothalamus
β†’ These neurons release alpha MSH and CART peptides
β†’ Peptides inhibit feeding

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17
Q

Describe how the basal metabolic rate is increased during the anorexic response?

A

β†’ Leptin stimulates the Alpha MSH and CART neurons of the Arcuate Nucleus.
β†’ These neurons extend from the Arcuate Nucleus to the Paraventricular Nucleus.
β†’ The Paraventricular Nucleus is stimulated and stimulates the release of ACTH and TSH from the Anterior Pituitary.
β†’ ACTH and TSH increases the basal metabolic rate.

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18
Q

Describe the orexigenic response?

A

β†’ Leptin levels are low.
β†’ CART and alpha MSH neurons of the Arcuate Nucleus are inhibited.
β†’ NPY and AgRP neurons in Arcuate Nucleus are activated which project to the lateral hypothalamus.
β†’ These neurons release NPY and AgRP peptides.
β†’ Peptides stimulate feeding.

19
Q

Describe how the basal metabolic rate is decreased during the orexigenic response?

A

β†’ Low Leptin levels inhibits the Alpha MSH and CART neurons of the Arcuate Nucleus whilst activating the AgRP and NPY neurons.
β†’ These neurons extend from the Arcuate Nucleus to the Paraventricular Nucleus.
β†’ AgRP and NPY inhibit the Paraventricular Nucleus thus it cannot stimulate the release of ACTH and TSH from the Anterior Pituitary.
β†’ A lack of ACTH and TSH means a decreased basal metabolic rate.

20
Q

What do alpha MSH and AgRP bind to?

A

β†’ MC4 receptor

21
Q

What does alpha MSH do to the MC4 receptor?

A

β†’ It activates the receptor

β†’inhibits feeding

22
Q

What does AgRP do to the MC4 receptor?

A

β†’ Inhibits the receptor

β†’ Increases feeding

23
Q

What are the 2 lateral hypothalamic peptides?

A

β†’ Melanin concentrating hormone (MCH)

β†’ Orexin

24
Q

What are the 3 functions of orexins?

A

β†’ Promotes meal initiation
β†’ Decreases sleep and increases arousal
β†’ Promotes drug addition

25
Q

What is the function of MCH?

A

β†’ Prolongs consumption

26
Q

What does disruption of the hypothalamus cause?

A

β†’ Hyperphagia
β†’ Anorexia
β†’ bulimia

27
Q

What happens during the cephalic phase?

A

β†’ Secretion of saliva
β†’ Gastric juices secreted in the stomach in preparation for food
β†’ Activated NPY/AgRP

28
Q

What happens during the gastric phase?

A

β†’ More secretion of saliva
β†’ More secretion of gastric juice
β†’ Distension signals via the vagus nerve

29
Q

What two other substances are released during the gastric phase?

A

β†’ CCK

β†’ Insulin

30
Q

What is the connection between serotonin and food?

A

β†’ 5-HT rises in anticipation of food

β†’ Spikes during a meal

31
Q

What are the natural rewards?

A

β†’ Sex
β†’ Food
β†’ Water
β†’ nurturing

32
Q

What is the reward pathway in the brain?

A

β†’ Dopaminergic neurons that project from the VTA to the nucleus accumbens

33
Q

What do nicotine, cocaine and heroin cause?

A

β†’ Activation of the mesolimbic pathway

34
Q

How does cocaine work?

A

β†’ Blocks dopamine transporters in the nucleus accumbens

35
Q

How does heroin work?

A

β†’ Activates new opioid receptors in the VTA

36
Q

How does nicotine work?

A

β†’ Activates nicotinic receptors in the VTA

37
Q

What is positive reinforcement?

A

β†’ Anything added that follows a behaviour and makes it more likely that the behaviour will occur again in the future

38
Q

What is negative reinforcement?

A

β†’ A response or a behaviour that is strengthened by stopping, removing or avoiding a negative outcome

39
Q

What classifies someone as being an addict?

A

β†’ They suffer from physical and emotional withdrawal symptoms when the drug is taken away

40
Q

What do people who suffer from addiction have?

A

β†’ Suppressed reward systems

41
Q

What is wanting something driven by?

A

β†’ Dopamine

42
Q

What is liking something driven by?

A

β†’ Opioid system

43
Q

What is the prefrontal cortex involved in?

A

β†’ Willpower

44
Q

Why don’t leptin injections work in humans?

A

β†’ Addiction is driven by many factors