vitamin a
TRANSCRIPT
VITAMIN DEFICIENCY
VITAMIN A - CHEMISTRY
RETINOL
RETINAL
RETINOIC ACID
RDA(RECOMMENDED DAILY ALLOWANCE) - MALE [ADULT] - 1000 ru/day FEMALE (ADULT) -800 ru/day
PREFORMED VITAMIN A
PRO VITAMIN
VITAMIN A - METABOLISM
SI
TRANSPORTABSORPTION
chylomicrons
STORAGE
LIVERRBP
FUNCTIONS
VISION IN LOW LIGHT ANTIOXIDANT
DEVELOPMENT OF TEETH &
SKELETAL TISSUE
EPITHELIAL CELL DIFFERENTIATION MAINLY MUCUS SECRETING CELLS
ENHANCING IMMUNITY
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.
DEFICIENCY DISEASE
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.
XEROPHTHALMIA
PRIMARY SIGNS ?????
NIGHT BLINDNESS
It’s a component of rhodopsin and other visual pigments
WALD’S VISUAL CYCLE
Isomerization
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;
GINGIVAL HYPERTROPHY
• Disturbed or arrested enamel development;
• Irregular tubular dentine formation and increased caries risk.
KERATOSIS
CANDIDIASAIS LEUKOPLAKIA
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