Problem 7

Question 1

ghrelin

Answer 1

Neuropeptide which is released when the stomach is empty

Question 2

Glucoseprivation

Answer 2

A dramatic fall in the level of glucose available to cells; can be caused by a fall in the blood level of glucose or by drugs that inhibit glucose metablosim

Question 3

Lipoprivation

Answer 3

A dramatic fall in the fatty acids available to cells; usually caused by drugs that inhibit fatty acid metabolism

Question 4

CEPHALIC PHASE

Answer 4

® Begins with sight, smell or thought of food and ends with food starting to be absorbed into bloodstream.
® Insulin released in anticipation of glucose arrival in blood.
® Digestive phase – Food entering
stomach causes release of gut hormones and stimulates pancreas to release insulin.

Question 5

ABSORPTIVE PHASE

Answer 5

Period where the energy absorbed into bloodstream meets body’s immediate energy needs
Glucodetectors – Enter liver to detect glucose entering bloodstream and signal pancreas to release insulin ->Minimizes high levels of bloodborne fuels by using, storing them.

Question 6

FASTING PHASE

Answer 6

Period where all unstored energy from previous meal has been used and body is withdrawing energy from its reserves to meet immediate energy requirements.
® High levels of glucagon and low levels of insulin in blood.

Question 7

Osmometric thirst

Answer 7

Happens when the solute concentration of the interstitial fluid increases, draws water out of the cells and they shrink in volume
o The detectors respond to this change

Question 8

Osmoreceptors

Answer 8

neurons whose firing rate was influenced by the level of hydration, when they shrink they firing less, located in the OVLT SFO and the supraoptic nucleus of the hypothalamus

Question 9

Hypolimnetic thirst

Answer 9

refers to the measuring of the volume of the blood plasma (Hypovolemia)
o The kidneys recognize lack of water and secrete an enzyme renin which becomes to the enzyme angiotensinogen which then tells the kidneys to conserve water and sodium

Question 10

median preoptic nucleus

Answer 10

a fiber bundle that connects the amygdala and anterior temporal lobe, acts as integrating system for most or all of the stimuli for osmometric and volumetric thirst

Question 11

digestive behaviour

Answer 11

Regulatory system of the body for e.g. isotonic

Question 12

system variable

Answer 12

A variable that is controlled by regulatory mechanisms, for example, temperature in a heating system

Question 13

Set point

Answer 13

the optimal value of the system variable in a mechanism

Question 14

Detector

Answer 14

In a regulatory process, a mechanism that signals when the system variable deviates from its set point

Question 15

correctional mechanisms

Answer 15

In a regulatory process, the mechanism that is capable of changing the value of the system variable (restores the value to the set point)

Question 16

Negative feedback

Answer 16

When the value falls below or above the given set point it signals this to the Detector

Question 17

Satiety mechanisms

Answer 17

A brain mechanism that causes cessation of hunger and thirst, produced by adequate and available supplies of nutrients or water
o Stops the correctional mechanism and so protects the body against to much water or food

Question 18

Interstitial fluid

Answer 18

The fluid that bathes the cells filling the space between the cells (seawater) (has to be kept at a precise limit)

Question 19

Intravascular fluid (blood plasma)

Answer 19

the fluid found within the blood vessels (has to be kept at a precise limit)

Question 20

Isotonic

Answer 20

The solution of both cell fluids is the balanced

Question 21

Hypertonic

Answer 21

The characteristic of a solution that contains enough solute that it will draw water out of a cell placed in it, inhibits the function of the cell

Question 22

Hypovolemia

Answer 22

Reduction of the volume of the blood caused by a lack of water

Question 23

Brian parts involved

Answer 23

• The brain stem contains neural circuits that detect hunger and satiety
• The medulla receives taste information from the tongue and a variety of sensory information from the internal organs, including signals from detectors in the stomach, duodenum and stomach
 all this goes to the forebrain where the eating and metabolism is regulated

Question 24

Hypothalamus

Answer 24

o Lateral hypothalamus eating and drinking behaviour

o Ventromedial hypothalamus satiety and hunger control

Question 25

Neuropeptides

Answer 25

signalling substance

Question 26

Leptin

Answer 26

Produced in fat cells – Once produced, it is secreted into the bloodstream by these cells.
Signals current long-­‐term energy stores in fat.
FUNCTION
-> Brain monitors leptin levels to measure and regulate body’s energy reserves in form of fat.

Question 27

Ghrelin

Answer 27

produced by cells of the stomach and duodenum – Once produced, released into bloodstream by endocrine cells.
Provides ‘fasting’ signal – Indicates to arcuate system that digestive system is empty ® Increase appetite.
Circulating levels rise during fasting and drop after meal is eaten.
Powerful appetite stimulant.

Question 28

PYY

Answer 28

produced in In cells of the ileum (= small intestine) and colon and then it is secreted into the circulation.
Provides rapid signal that food has been consumed, prompting arcuate system to suppress appetite.
Acts on hypothalamic appetite control mechanisms to suppress appetite.

Question 29

CCK

Answer 29

produced in he cells of the duodenum and then it is secreted into the circulation after ingestion of food high in protein and/or fat.
Signaling molecule in the brain
Suppresses appetite via direct action on vagus nerve (cranial nerve X)

Question 30

Insulin

Answer 30

produced in cells of the pancreas and then it is secreted into the circulation
Provides appetite controller with information about blood glucose level

Question 31

Melanin-Concentrating-Hormone

Answer 31

produced in a system of lateral hypothalamic neurons that stimulate appetite and reduce metabolic rate.
Regulating changes
in skin
pigmentation in fish and other non-­mammalian vertebrates.

Question 32

Orexin

Answer 32

produced in system of lateral hypothalamic neurons that stimulate appetite and reduce metabolic rate.
Keeping the brain’s sleep-­‐waking switch in the ‘waking’ position.
Plays role in regulation of sleep cycles

Question 33

Homeostasis

Answer 33

Process by which the body’s substances and characteristics (e.g. temperature and glucose level) are maintained at their optimal level