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Flashcards in Motivation Deck (31)
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1
Q

What is motivation?

A
  • Driving force
  • Physical need
  • Wanting,liking
2
Q

What does the hypothalamus maintain?

A

Maintains homeostasis by regulating three interrelated functions:

  • Endocrine secretions
  • ANS
  • Emotions and drive/behaviour
3
Q

What is parabiosis and its effect?

A

Parabiosis is the sharing of blood circulation between animals
This means blood borne signals are shared and can effect the hypothalamus

4
Q

What is the effect of parabiosis?

EXAMPLE

A
  • A genetically obese mouse ob/ob fat cells do not produce leptin
  • When connected to a normal mouse of whoms fat cells do produce leptin, this will lead to a reduction of obesity in the ob/ob mouse
5
Q

What is the feedback mechanism of fatty tissues?

A
  • Fatty tissue produce leptin when satisfied

- Leptin travels to the brain and signals to the arcuate nucleus to stop eating

6
Q

What are the VMN and LH important for the regulation of?

A

VMN and LH important for the regulation of:

  • Body weight/food intake
  • Blood volume/osmolarity
7
Q

What does a VMH lesion cause?

A

Causes a dramatic increase in food intake and body weight

8
Q

What role does VMH play in?

A

VMH plays a role in controlling the cessation of eating

9
Q

What does a LH lesion cause?

A

Causes a decrease in food intake

10
Q

What signalling are both VMH and LH related to?

A

VMH and LH both are related to leptin signalling

11
Q

What is the arcuate nucleus important for?

A

It’s important for control of feeding

12
Q

What is the response to elevated leptin levels?

A
  • Leptin activates arcuate neurons that release alphaMSH and CART peptides
  • Neurons then project to regions that orchestrate coordinated responses of humoral, visceromotor and somatic responses
    • PVN
    • Intermediolateral grey matter of spinal cord
    • Lh
13
Q

Why are alphaMSH and CART anorectic peptides?

A

Are anorectic peptides because they diminish appetite

14
Q

What is the response to decreased leptin levels?

A

-NPY/AgRP neuron of the arcuate nucleus are activated
-These neurons inhibit neurons in the PVN that control the release of TSH and ACTH from the pituitary
-The neurons in the LH are then activated that stimulate feeding behaviour
-Some of the activated LH neurons contain the peptide
MCH

15
Q

What receptor do both alpha MSH and AgRP act on?

A

Both act on the MC4 receptor

16
Q

What do alphaMSH and AgRP do to the MC4 receptor?

A
  • alphaMSH stimulates MC4 receptor

- AgRP inhibits MC4 receptor

17
Q

What does the MC4 receptor do when activated?

A

Activation of MC4 receptor inhibits feeding behaviour

18
Q

What do LH neurons stimulating feeding behaviour contain?

A

Contain MCH and Orexin

19
Q

What does MCH do?

A

Prolongs consumption

20
Q

What does Orexin do?

A

Orexin promotes meal initiation

21
Q

What are the 3 phases of digestion?

A
  • Cephalic
  • Gastric
  • Substrate
22
Q

What happens in the cephalic phase?

A
  • Ghrelin is released when stomach is empty

- Ghrelin then activates NPY/AgRP containing neurons in arcuate nucleus

23
Q

What does the removal of ghrelin secreting cells do?

A

Removal of ghrelin secreting cells of stomach are thought to cause loss of appetite

24
Q

What happens in the gastric phase?

A
  • Gastric distension
  • CCK release in intestines
  • Insulin also released by beta cells of the pancreas
25
Q

What signals does gastric distension and CCK release send and what does this cause?

A

Gastric distention and CCK release signals the nucleus of the solitary tract via the vagus nerve to cause satiety

26
Q

What happens to levels of 5HT in the hypothalamus in the anticipation of food or a meal?

A

They rise

27
Q

What is 5HT levels associated with?

A

Associated with anorexia nervosa and bulimia with depression

28
Q

What are examples of natural rewards?

A
  • Food
  • Water
  • Sex
  • Nurturing
29
Q

What are the stages in the addiction cycle?

A

Acute reinforcement/social drug taking –>Escalating and compulsive use–>Dependence–>Withdrawal–>Protracted withdrawal–>Recovery

30
Q

What is positive reinforcement?

A

It is anything added that follows a behaviour that makes it more likely that the behaviour will occur again in the future

31
Q

What is negative reinforcement?

A

It is a response or behaviour that is strengthened by stopping, removing or avoiding a negative outcome or aversive stimulus