際際滷

際際滷Share a Scribd company logo

Viatmin a , dr . jaswant kaur

Download as PPTX, PDF
J
jaswantkaur10

This document discusses vitamin A, including its recommended daily allowances, dietary sources, active forms, role in vision and the visual cycle, and deficiency manifestations. The RDA of vitamin A is 400-600 亮g/day for children, 750-1000 亮g/day for men, and 750 亮g/day for women and 1000 亮g/day during pregnancy. Animal sources like milk, liver, and fish liver oils as well as carotenoid-containing vegetables like carrots are good sources. Deficiency can cause night blindness, Bitot's spots, dry eyes, corneal softening and blindness as well as skin and immune system issues.

1 of 21
Download to read offline
Dr. Jaswant Kaur Assistant professor Department Biochemistry
Viatmin a , dr . jaswant kaur
Viatmin a , dr . jaswant kaur
Viatmin a , dr . jaswant kaur
Viatmin a , dr . jaswant kaur
Daily requirement of Vitamin A The recommended daily allowance (RDA) of Vitamin A for children = 400600 亮g/day, for men = 7501000 亮g/day, For women = 750 亮g/day pregnancy = 1000 亮g/day. quirement of Vitamin A
Dietary Sources Animal sources :- milk, butter, cream, cheese, egg yolk and liver. Fish liver oils (cod liver oil and shark liver oil) Vegetable sources contain the yellow pigment beta carotene. Carrot contains significant quantity of beta carotene. Papaya, mango, pumpkins and green leafy vegetables (spinach, amaranth) are other good sources of vitamin A activity.
Active form of viatmin A
Interconversion of vitamin A molecules.
Vitamin A metabolism.
Walds visual cycle
Mechanism of Dark Adaption
Dark adaption mechanism Person shifts from bright light to dim area- leads difficulty in seeing . Due to resynthesis of rhodopsin & vision is improved. Increased in Vit. A deficiency. Red light bleaches rhodopsin to a lesser extent. photosensitive cells Rods cones ( for dim light vision) ( bright light & color vision)
Vision Visual cycle Rods are for Vision in Dim Light Cones are for Color Vision Other Biochemical Functions Gene Regulation Immunological System Reproductive System Anti-oxidant Property Effect on Skin
Cont.
Deficiency manifestation of Vit. A Night Blindness or Nyctalopia Bitots Spots Xerophthalmia Keratomalacia Preventable Blindness Skin and Mucous Membrane Lesions growth retardation reduced immunity against infections.
Deficiency of vitamin A: Deficiency leads to a variety of disorders of the eyes and this affect the vision, some of the disorders are 1)Night blindness: The person cannot see the objects in dim light and in nights. Bitots spot:- seen as greenish white triangular plaques adherent to conjuctiva. 2)Xeropthalmia : conjuctiva becomes dry, thick, wrinkled. Losses its transperancy. Dryness spreads to cornea. 3) Keratomalacia ( softening of the cornea) :- Xeropthalmia persists for long time , leads Keratomalacia . Occur degeneration of corneal epithelium
Bitot spots Keratomalacia.
4)Skin become scaly, rough and is covered with papillae (Small eruptions). 5)Reproductive functions may also be effected in vitamin A deficiency. National Institute of Nutrition, Hyderabad has evolved a method giving a large dose (5 6 drops) of Vitamin-A once in six months to prevent blindness in children
Hypervitaminosis A or toxicity Excessive intake can lead to toxicity since the vitamin is stored. Symptoms of toxicity are anorexia, irritability, headache, drowsiness and vomiting, increased intracranial tension. Sometimes swelling over long bones (bony exostosis) may occur with painful bones. Enlargement of liver is also seen in children
Objectives List the different active forms of vitamin A State the dietary sources and RDA in children, adults, pregnancy and lactation Explain the role of vitamin A in vision and Walds visual cycle Describe the deficiency manifestations of vitamin A .

More Related Content

Viatmin a , dr . jaswant kaur

  • 1. Dr. Jaswant Kaur Assistant professor Department Biochemistry
  • 6. Daily requirement of Vitamin A The recommended daily allowance (RDA) of Vitamin A for children = 400600 亮g/day, for men = 7501000 亮g/day, For women = 750 亮g/day pregnancy = 1000 亮g/day. quirement of Vitamin A
  • 7. Dietary Sources Animal sources :- milk, butter, cream, cheese, egg yolk and liver. Fish liver oils (cod liver oil and shark liver oil) Vegetable sources contain the yellow pigment beta carotene. Carrot contains significant quantity of beta carotene. Papaya, mango, pumpkins and green leafy vegetables (spinach, amaranth) are other good sources of vitamin A activity.
  • 8. Active form of viatmin A
  • 12. Mechanism of Dark Adaption
  • 13. Dark adaption mechanism Person shifts from bright light to dim area- leads difficulty in seeing . Due to resynthesis of rhodopsin & vision is improved. Increased in Vit. A deficiency. Red light bleaches rhodopsin to a lesser extent. photosensitive cells Rods cones ( for dim light vision) ( bright light & color vision)
  • 14. Vision Visual cycle Rods are for Vision in Dim Light Cones are for Color Vision Other Biochemical Functions Gene Regulation Immunological System Reproductive System Anti-oxidant Property Effect on Skin
  • 15. Cont.
  • 16. Deficiency manifestation of Vit. A Night Blindness or Nyctalopia Bitots Spots Xerophthalmia Keratomalacia Preventable Blindness Skin and Mucous Membrane Lesions growth retardation reduced immunity against infections.
  • 17. Deficiency of vitamin A: Deficiency leads to a variety of disorders of the eyes and this affect the vision, some of the disorders are 1)Night blindness: The person cannot see the objects in dim light and in nights. Bitots spot:- seen as greenish white triangular plaques adherent to conjuctiva. 2)Xeropthalmia : conjuctiva becomes dry, thick, wrinkled. Losses its transperancy. Dryness spreads to cornea. 3) Keratomalacia ( softening of the cornea) :- Xeropthalmia persists for long time , leads Keratomalacia . Occur degeneration of corneal epithelium
  • 19. 4)Skin become scaly, rough and is covered with papillae (Small eruptions). 5)Reproductive functions may also be effected in vitamin A deficiency. National Institute of Nutrition, Hyderabad has evolved a method giving a large dose (5 6 drops) of Vitamin-A once in six months to prevent blindness in children
  • 20. Hypervitaminosis A or toxicity Excessive intake can lead to toxicity since the vitamin is stored. Symptoms of toxicity are anorexia, irritability, headache, drowsiness and vomiting, increased intracranial tension. Sometimes swelling over long bones (bony exostosis) may occur with painful bones. Enlargement of liver is also seen in children
  • 21. Objectives List the different active forms of vitamin A State the dietary sources and RDA in children, adults, pregnancy and lactation Explain the role of vitamin A in vision and Walds visual cycle Describe the deficiency manifestations of vitamin A .