Topic 6.6

Question 1

What are the 3 sources of energy in the body?

Answer 1

• carbs
• fat
• proteins

Question 2

How do we measure energy content?

Answer 2

joules or calories

Question 3

Relationship bw calories and joules

Answer 3

1 calorie = 4.2 joules

Question 4

How do we measure the energy content of molecules?

Answer 4

with a calorimeter

Question 5

Energy content of carbohydrates + RQ

Answer 5

17,24 kJ/g

RQ = 1

Question 6

Energy content of fats + RQ

Answer 6

39 kJ/g

RQ = 0,7

Question 7

Energy content of proteins + RQ

Answer 7

17 kJ/g

RQ = 0,82

Question 8

What is the respiratory quotient and its value in humans?

Answer 8

VCO2 / VO2 (ratio of produced CO2 to consummed 02)

RQ = 0,85

Question 9

What is the total energy expenditure?

Answer 9

the total energy content of food intake when in neutral energy balance

Question 10

Direct method of measuring TEE

Answer 10

measuring a person’s heat production (rate of metabolism)

Question 11

TEE = ? (2)

Answer 11

TEE = Heat production + external work 
TEE = BMR + DIT + Energy expenditure in physical activity

Question 12

What principle does the indirect method for TEE rely on?

Answer 12

It relies on the principle that nearly all E released in our body is derived from reactions in which O2 participate

Question 13

Relationship bw O2 consumed and kJ of E released

Answer 13

1L of O2 consumed = 21 kJ of E released

Question 14

What is the BMR?

Answer 14

The minimal energy expenditure required to exist

Question 15

Requirements for measurement of BMR (6)

Answer 15

1. usually measured in the morning
2. no physical activity
3. neutral temperature (20)
4. no food 8-12 hours before
5. No emotional stress / stimuli
6. no drugs

Question 16

BMR value based on surface area

Answer 16

170 kJ/ square meter / hour

Question 17

BMR women

Answer 17

6000 kJ / day

Question 18

BMR men

Answer 18

7000 kJ / day

Question 19

Which hormones can increase BMR?

Answer 19

thyroid hormones and catecholamines

Question 20

How much of the TEE do BMR, DIT , and E in physical activity represent?

Answer 20

• BMR : 50 - 70%
• DIT : 8-15%
• E in phys ac : 15-30%

Question 21

Which tissue specializes in heat production?

Answer 21

Brown adipose tissue

Question 22

How are brown adipocytes better at heat production?

Answer 22

Because they have UCP1 protein, which allows H+ ions to flow from the intermembrane space to the matrix and thus decreases the proton gdt necessary for ATP synthase

Question 23

What type of adipose tissue do aadult humans have?

Answer 23

beige adipose tissue (also with UCP 1)

Question 24

What factor increase cell differentication to beige adipose tissue? (2)

Answer 24

• cold

- catecholamines (beta)

Question 25

What is the role of the satiety center?

Answer 25

inhibit apetite even in the presence of food

Question 26

What is the role of the feeding center?

Answer 26

Increase apetite

Question 27

What are the 2 centers that regulate feeding?

Answer 27

Satiety and feeding center

Question 28

where are the regulatory centers located?

Answer 28

in the hypothalamus

Question 29

Where do the regulatory centers recieve information from?

Answer 29

from the arcuate nucleus

Question 30

What are the 2 types of neurons that project from the arcuate nucleus to the regulatory centers?

Answer 30

Anorexigenic neurons and orexigenic neurons

Question 31

What do anorexigenic neurons do?

Answer 31

they release POMC, which decreases apetite

Question 32

What do orexigenic neurons do?

Answer 32

They release neuropeptide Y, which leads to increased apetite

Question 33

What 3 factors affect the arcuate nucleus and regulate hunger and feeding?

Answer 33

- Increasing adipose tissue mass, release of leptin - Insulin - Neuropeptides from the GI

Question 34

What does Leptin do? (4)

Answer 34

- Decreases hunger by stimulating anorexigenic neurons - Increases thermogenesis - Increases energy expenditure - Restore the adipose tissue to an appropriate set point

Question 35

What does insulin do? (3)

Answer 35

- Stimulates anorexigenic neurons - Inhibits orexigenic neurons - Indirectly supports leptin secretion

Question 36

Which neuropeptides from the GI decrease hunger? (4)

Answer 36

- GLP-1 (glucagon-like peptide 1) - Peptide YY - CCK - CART (cocaine and amphetamine related transcript)

Question 37

Which neuropeptides from GI increase hunger? (2)

Answer 37

- Ghrelin | - Orexins

Question 38

What is the function of GLP-1?

Answer 38

stimulates insulin secretion

Question 39

Function of peptide YY? (2)

Answer 39

- decrease ghrelin production | - directly acts on hypothalamus

Question 40

Role of orexins (2)

Answer 40

stimulate hunger and awakeness