Motivation

Question 1

What is motivation?

Answer 1

→ A physical need

→ Wanting/liking something

Question 2

What does the hypothalamus do?

Answer 2

→ Maintain homeostasis by regulating three interrelated functions

Question 3

What are the 3 things that the hypothalamus controls?

Answer 3

→ Endocrine secretion
→ Autonomic nervous system
→ Emotions and drive

Question 4

Describe anabolism?

Answer 4

→ glucose goes to the liver

→ Skeletal muscle stores glucose as glycogen

Question 5

Describe catabolism?

Answer 5

→ Glycogen gets broken down to glucose

Question 6

What is parabiosis?

Answer 6

→ Sharing of blood circulation between animals

Question 7

What do obese mice not produce?

Answer 7

→ leptin

Question 8

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

Answer 8

→ the ob/ob mouse will decrease in size

Question 9

Where does leptin bind?

Answer 9

→ Leptin receptors on the arcuate nucleus

Question 10

When is leptin released and why?

Answer 10

→ When you finished eating

→ to stop feeding

Question 11

Where is the hypothalamus?

Answer 11

→ At the base of the brain

Question 12

What happens when you lesion the VMH?

Answer 12

→ weight gain

Question 13

What happens during lateral hypothalamic syndrome?

Answer 13

→ Diminished appetite for food

→ Anorexia

Question 14

What happens during ventromedial hypothalamic syndrome?

Answer 14

→ Overeating

→ Obesity

Question 15

What are the anorectic peptides?

Answer 15

→ Alpha MSH

→ CART

Question 16

Describe the anorexic response?

Answer 16

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

Question 17

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

Answer 17

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

Question 18

Describe the orexigenic response?

Answer 18

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

Question 19

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

Answer 19

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

Question 20

What do alpha MSH and AgRP bind to?

Answer 20

→ MC4 receptor

Question 21

What does alpha MSH do to the MC4 receptor?

Answer 21

→ It activates the receptor

→inhibits feeding

Question 22

What does AgRP do to the MC4 receptor?

Answer 22

→ Inhibits the receptor

→ Increases feeding

Question 23

What are the 2 lateral hypothalamic peptides?

Answer 23

→ Melanin concentrating hormone (MCH)

→ Orexin

Question 24

What are the 3 functions of orexins?

Answer 24

→ Promotes meal initiation
→ Decreases sleep and increases arousal
→ Promotes drug addition

Question 25

What is the function of MCH?

Answer 25

→ Prolongs consumption

Question 26

What does disruption of the hypothalamus cause?

Answer 26

→ Hyperphagia → Anorexia → bulimia

Question 27

What happens during the cephalic phase?

Answer 27

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

Question 28

What happens during the gastric phase?

Answer 28

→ More secretion of saliva → More secretion of gastric juice → Distension signals via the vagus nerve

Question 29

What two other substances are released during the gastric phase?

Answer 29

→ CCK | → Insulin

Question 30

What is the connection between serotonin and food?

Answer 30

→ 5-HT rises in anticipation of food | → Spikes during a meal

Question 31

What are the natural rewards?

Answer 31

→ Sex → Food → Water → nurturing

Question 32

What is the reward pathway in the brain?

Answer 32

→ Dopaminergic neurons that project from the VTA to the nucleus accumbens

Question 33

What do nicotine, cocaine and heroin cause?

Answer 33

→ Activation of the mesolimbic pathway

Question 34

How does cocaine work?

Answer 34

→ Blocks dopamine transporters in the nucleus accumbens

Question 35

How does heroin work?

Answer 35

→ Activates new opioid receptors in the VTA

Question 36

How does nicotine work?

Answer 36

→ Activates nicotinic receptors in the VTA

Question 37

What is positive reinforcement?

Answer 37

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

Question 38

What is negative reinforcement?

Answer 38

→ A response or a behaviour that is strengthened by stopping, removing or avoiding a negative outcome

Question 39

What classifies someone as being an addict?

Answer 39

→ They suffer from physical and emotional withdrawal symptoms when the drug is taken away

Question 40

What do people who suffer from addiction have?

Answer 40

→ Suppressed reward systems

Question 41

What is wanting something driven by?

Answer 41

→ Dopamine

Question 42

What is liking something driven by?

Answer 42

→ Opioid system

Question 43

What is the prefrontal cortex involved in?

Answer 43

→ Willpower

Question 44

Why don't leptin injections work in humans?

Answer 44

→ Addiction is driven by many factors