vitamin a

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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