72: Dietary Balances, anorexia, Vitamins and minerals

Question 1

Which signaling system has been implicated as causing weight loss associated with severe infections, uremia, or cancer tumors?

Answer 1

Melanocortin system

Question 2

In summary, what effects does leptin exert in the body?

Answer 2

1. decreases hypothalamic appetite stimulator production
2. Activate POMC neurons (suppress appetite)
3. Increased hypothalamic CRH production to decrease food intake
4. Increase SNS activity to increase energy expenditure and metabolic rate
5. Decreased insulin secretion to reduce energy storage

Question 3

What is retinol necessary for, and what are symptoms of deficiency?

Answer 3

Vit A is needed to form retinal pigments of the eye.
Deficiency seen as:
-Scaly skin
-Skeletal growth retardation
-Interrupts female cycle, atrophies testicles
-corneal keratinization
-Infection of damaged epithelium

Question 4

What are the main results of thiamine deficiency?

Answer 4

Needed for CHO and AA metabolism.
-Chromatolysis + swelling of CNS neurons
-Myelin sheath degeneration
-Cardiac failure due to peripheral vasodilation
-Peripheral edema and ascites
-Many GI disturbances

Question 5

What is the crucial role of niacin, and how does deficiency manifest?

Answer 5

-Hydrogen acceptor (NAD and NADP)
Deficiency:
-Muscle weakness, poor glandular secretion
-Then tissue death
-Pigmented, cracked skin cannot repair self
-GI hemorrhage

Question 6

What are the major functions of riboflavin, and how does deficiency manifest?

Answer 6

Vit B2.
Need for forming FMN and FAD for hydrogen carriers.
Deficiency =
-Dermatitis
-Vomiting, Diarrhea
-Muscle spasticity
-Weak, coma, cold, dead
-Mental depression

Question 7

What are the main functions of, and manifestations of deficiency in cobalamin?

Answer 7

Vit b12
Need for cobalt functions
H+ receptor coenzyme

**Coenzyme for gene replication
Deficiency:
-Pernicious anemia
-SC and large fiber demyelination, esp posterior columns.

Usually deficiency due to lack of intrinsic factor from parietal cells of the gastric glands

Question 8

What are the main functions of, and manifestations of deficiency in folic acid?

Answer 8

Pteroylglutamic acid

Synthesis of purines and thymine for DNA formation.
Defic = macrocytic anemia

Question 9

What are the main functions of, and manifestations of deficiency in pyridoxine ?

Answer 9

Vit B6
Coenzyme for amino acid and protein metabolism. **Transamination
Lack = dermatitis, decr growth rate, fatty liver, anemia

Question 10

What are the main functions of, and manifestations of deficiency in ascorbic acid?

Answer 10

Vit C
Activates enzyme for collagen formation

Deficiency = wounds can’t heal, bones can’t grow, fractures can’t heal, blood vessels are fragile, petechiae,

Question 11

What are the main functions of vitamin D?

Answer 11

Increases calcium absorption from GIT and controls Ca deposition in bones.
Promotes active transport of Ca from the ileum

Question 12

What are the main functions of, and manifestations of deficiency in vitamin E?

Answer 12

Sterility, fetal resorption, and can lead to renal tubular cell and myocyte degeneration. Protects against oxidation of unsaturated fats

Question 13

What are the main functions of, and manifestations of deficiency in vit K?

Answer 13

Cofactor for clotting factors II, VII, IX, and X

Made by bacterial flora of GIT