Week 4

Question 1

Carbs Energy Content

Answer 1

17.2 kJ/g

Question 2

Protein Energy Content

Answer 2

17.2 kJ/g

Question 3

Fat Energy Content

Answer 3

39 kJ/g

Question 4

Respiratory Quotient (RQ)

Answer 4

Ratio of CO2 produced to Oxygen consumed by the body (used for BMR)

Question 5

Carbs RQ

Answer 5

1

Question 6

Fat RQ

Answer 6

0.7 (16/23)

Question 7

Protein RQ

Answer 7

0.82 (2.5/3)

Question 8

Whole Body RQ

Answer 8

~ 0.85

Question 9

Total Energy Expenditure (TEE)

Answer 9

Net amount of Energy used by organism to maintain core physiological functions and to allow locomotion

Question 10

Measuring energy expenditure indirectly

Answer 10

~ 21kJ/L of O2 are liberated

Question 11

Basal Metabolic Rate

Answer 11

Energy expenditure at complete rest

Question 12

Diet Induced Thermogenesis (DIT)

Answer 12

Increase in energy expenditure after eating due to GI motility
(8 - 15% of TEE)

Question 13

TEE equation

Answer 13

TEE = BMR + DIT + EE
- measured in morning

Question 14

Normal BMR values

Answer 14

• M: 7000 kJ /Day
• F: 6000 kJ /Day

Question 15

Lateral Hypothalamic Area

Answer 15

“Hunger Center”
Stimulates eating

Question 16

What nuclei control eating

Answer 16

• PVN
• Arcuate Nuc.
• Nucleus Accumbens (reward)

Question 17

What external factors/drugs can enhance appetite

Answer 17

• Endogenous Cannabis
• Endogenous Opioids

Question 18

Nicotine effect on appetite

Answer 18

Suppression of Apetite

Question 19

I.C Ca2+

Answer 19

100 nM

Question 20

E.C Ca2+

Answer 20

• Free: 1.1 - 1.4 mM
• Total: 2.2 - 2.8 mM

Question 21

Types of Circulatory Ca2+

Answer 21

• Free ionized (45%, 1.0-1.3 mM)
• Protein bound (45%)
• Complexed with anions (~10%)

Question 22

E.C PO4 3-

Answer 22

0.8 - 1.5 mM

Question 23

Synthesis of PTH

Answer 23

1) Pre-pro-PTH (115a.a)
2) Pro-PTH (90a.a) in ER
3) PTH (84a.a) in secretory granules

Question 24

Regulation of PTH secretion

Answer 24

• Ca-SR (sensing-R), GPCR, Gq
• Calcitriol, more intestinal abs.
• Plasma PO4 3- binds and decreases free Ca2+

Question 25

What type of hormone is PTH

Answer 25

Peptide Hormone (doesn't require a BP for transport)

Question 26

Half life of PTH

Answer 26

4 minutes

Question 27

Target cells expressing PTH1R

Answer 27

- Kidney - Bones

Question 28

Kidney PTH1R

Answer 28

- Stimulation of Ca2+ reabsorption - TAL & Distal tubule (ECaC)

Question 29

How does PTH affect Pi absorption

Answer 29

PTH stimulates Endocytosis of Na/Pi symporter from Luminal side of Proximal tubules

Question 30

Calcitriol specs.

Answer 30

- Steroid Hormone - 1,25-dehydroxy-vitamin-D

Question 31

Biosynthesis of Calcitriol SKIN

Answer 31

7-dehydroxycholesterol reacts with UV light in skin = Cholecalciferol (D3/D2)

Question 32

Biosynthesis of Calcitriol LIVER

Answer 32

Cholecalciferol reacts with 25-a-hydroxylase = 2,5-hydroxy-vitamin-D

Question 33

Biosynthesis of Calcitriol Kidney

Answer 33

2,5-hydroxy-vitamin-D - 24-a-hydroxylase = 24,25-dehydroxy-vitamin-D - 1-a-hydroxylase = 1,25-dehydroxy-vitamin-D

Question 34

What forms the INACTIVE form of Vitamin D?

Answer 34

24-a-hydroxylase = 24,25-dehydroxy-vitamin-D

Question 35

What forms the ACTIVE form of Vitamin D?

Answer 35

1-a-hydroxylase = 1,25-dehydroxy-vitamin-D

Question 36

How is Calcitriol transported in blood

Answer 36

- Vitamin-D Binding Protein (DBP) (needed since its a steroid)

Question 37

Calcitriol Receptor

Answer 37

Nuclear Vitamin D receptor which forms a Heterodimer with the Retinoid X Receptor (RXR) - Binds genes and alters expression - More CaS-R & 24-a-hydroxylase

Question 38

Target organs of Calcitriol

Answer 38

- GI (small intestines) - Kidneys - Bones (osteoblasts)

Question 39

Vitamin D deficiency

Answer 39

Rickets - De-mineralization of bones due to impaired Ca and Pi absorption - Deformation of Bones

Question 40

What synthesizes Calcitonin

Answer 40

C-cells of Thyroid gland

Question 41

What type of hormone is Calcitonin

Answer 41

Peptide Hormone (32a.a)

Question 42

Calcitonin Receptor

Answer 42

- Only on Osteoclasts - Inhibits bone breakdown

Question 43

Paget's Disease

Answer 43

Abnormally high Osteoclast activity where Calcitonin is needed as a treatment (from salmon)

Question 44

What can cause Hypocalcemia

Answer 44

- No PTH (thyroid / PT removal) - No Vitamin-D - Hyperventilation (causes albumin to bind 2 Ca instead of H)

Question 45

Proteins secreted by Osteoblasts

Answer 45

- Collagen Type I - Osteocalcin (Gla) - Osteonectin

Question 46

Catabolic Bone enzymes

Answer 46

- Collagenase - Gelatinase

Question 47

Osteoid formation duration

Answer 47

10 - 14 days

Question 48

Bone mineralization duration

Answer 48

5 - 6 weeks - Formation of Hydroxyapatite

Question 49

Bone Nucleation

Answer 49

Hydroxyapetite formation and built into protein matrix to provide bone rigidity

Question 50

What is needed for Osteocalst activation

Answer 50

- M-CSF - RANKL - IL-6

Question 51

What is secreted into lacuna where Osteoclast is to help bone resorption

Answer 51

- TRAP (phosphatase) - Protons (H+)

Question 52

Bone Remodeling

Answer 52

1) Osteoclasts create micro-injuries with deep 20μm tunnels 2) Osteoblasts repair this damage

Question 53

Effects of PTH & Calcitriol on Bone remodeling

Answer 53

- Act on Osteoblasts only - RANKL & OPG secretion

Question 54

RANK-L

Answer 54

- Binds RANK activating nuclear factor Kappa B on Osteoclasts - Osteoclast activation - RANKL is TNF

Question 55

Osteoprotegnin (OPG)

Answer 55

Inhibits Osteoclasts

Question 56

Glucocorticoids effect on Bone remodeling (cortisol & synth.)

Answer 56

Increase RANKL/OPG ratio of Osteoblasts = Osteoclast activation

Question 57

Estrogens effect on Bone remodeling

Answer 57

Opposite of GC Decrease RANKL/OPG ratio of Osteoblasts = Osteoclast inhibition

Question 58

Inflammatory effect on Bone remodeling

Answer 58

Immune cells can express RANK-L leading to Osteoclast activation

Question 59

Tumor Cells effects on Bone remodeling

Answer 59

Tumor cells can also express RANK-L leading to Osteoclast activation