vitamin a -SOURCES ,METABOLISM, FUNCTION &THEIR DEFICIENCY DISEASES

1. VITAMIN
DEFICIENCY
VITAMIN A - CHEMISTRY
RETINOL
RETINAL
RETINOIC
ACID

2. RDA(RECOMMENDED DAILY ALLOWANCE) -
MALE [ADULT] - 1000 ru/day
FEMALE (ADULT) -800 ru/day
PREFORMED
VITAMIN A
PRO VITAMIN

3. VITAMIN A - METABOLISM
SI
TRANSPORTABSORPTION
chylomicrons
STORAGE
LIVER
RBP

4. FUNCTIONS
VISION IN LOW LIGHT ANTIOXIDANT
DEVELOPMENT
OF TEETH &
SKELETAL TISSUE
EPITHELIAL CELL DIFFERENTIATION MAINLY
MUCUS SECRETING CELLS
ENHANCING
IMMUNITY

5. CAUSES ????
• Prolonged INADEQUATE INTAKE of vitamin A.
• IMPAIRED ABSORPTION. This may occur in a variety of
illnesses, including:
• Coeliac disease.
• Crohn's disease.
• Giardiasis - an infection of the gut (bowel).
• Cystic fibrosis-Diseases affecting the pancreas.
• Obstruction of the flow of bile from liver and gallbladder
into gut.

7. SQUAMOUS METAPLASIA
Vitamin A deficiency can lead to
replacement of lining of upper respiratory
passage & urinary tract by keratinizing
squamous cells.
Loss of mucociliary epithelium of the airway
predisposes affected patients to pulmonary
infection.

8. XEROPHTHALMIA

9. PRIMARY SIGNS ?????

10. NIGHT BLINDNESS
It’s a component of rhodopsin and other visual
pigments
WALD’S VISUAL CYCLE
Isomerization

11. ORAL MANIFESTATIONS
 Inadequate cell differentiation-impaired
healing & tissue regeneration;
 Desquamation of oral mucosa;
 keratosis;
 Increased risk of candidiasis;
 Gingival hypertrophy & inflammation;
 Leukoplakia;
 Decreased taste sensitivity;
 Xerostomia;

12. GINGIVAL
HYPERTROPHY
• Disturbed or arrested enamel
development;
• Irregular tubular dentine formation and
increased caries risk.
KERATOSIS

13. CANDIDIASAIS LEUKOPLAKIA

14. THANK YOU