Podcast
Questions and Answers
Which of the following statements about fat-soluble vitamins is true?
Which of the following statements about fat-soluble vitamins is true?
Which vitamin is synthesized by the host in amounts adequate to meet normal physiological needs?
Which vitamin is synthesized by the host in amounts adequate to meet normal physiological needs?
What is the main route of absorption for fat-soluble vitamins?
What is the main route of absorption for fat-soluble vitamins?
What is the characteristic of fat-soluble vitamins that increases the risk of toxicity with high intakes?
What is the characteristic of fat-soluble vitamins that increases the risk of toxicity with high intakes?
Signup and view all the answers
What is the main distinguishing factor of vitamins from fats, carbohydrates, and proteins?
What is the main distinguishing factor of vitamins from fats, carbohydrates, and proteins?
Signup and view all the answers
Which fat-soluble vitamin is known to be primarily obtained through exposure to sunlight?
Which fat-soluble vitamin is known to be primarily obtained through exposure to sunlight?
Signup and view all the answers
What is the principle function of vitamin D?
What is the principle function of vitamin D?
Signup and view all the answers
What is the active form of vitamin D?
What is the active form of vitamin D?
Signup and view all the answers
What happens when blood Ca levels drop?
What happens when blood Ca levels drop?
Signup and view all the answers
What is the consequence of vitamin D deficiency in children?
What is the consequence of vitamin D deficiency in children?
Signup and view all the answers
What is the role of active vitamin D at the intestine?
What is the role of active vitamin D at the intestine?
Signup and view all the answers
What is the consequence of over-supplementation of vitamin D?
What is the consequence of over-supplementation of vitamin D?
Signup and view all the answers
What is the form of vitamin D synthesized in the skin?
What is the form of vitamin D synthesized in the skin?
Signup and view all the answers
What is the first product formed in the liver from vitamin D?
What is the first product formed in the liver from vitamin D?
Signup and view all the answers
Which form of vitamin A is crucial for light perception in the eye?
Which form of vitamin A is crucial for light perception in the eye?
Signup and view all the answers
What are the two main categories of vitamin A compounds?
What are the two main categories of vitamin A compounds?
Signup and view all the answers
How are retinoids and carotenoids transported to the liver from the intestine?
How are retinoids and carotenoids transported to the liver from the intestine?
Signup and view all the answers
What is the most common plant precursor of vitamin A?
What is the most common plant precursor of vitamin A?
Signup and view all the answers
Which deficiency poses a threat to the health and sight of millions of children worldwide?
Which deficiency poses a threat to the health and sight of millions of children worldwide?
Signup and view all the answers
In which cycle does vitamin A combine with opsin to form rhodopsin?
In which cycle does vitamin A combine with opsin to form rhodopsin?
Signup and view all the answers
Which vitamin is known to be primarily obtained through exposure to sunlight?
Which vitamin is known to be primarily obtained through exposure to sunlight?
Signup and view all the answers
What is the characteristic of fat-soluble vitamins that increases the risk of toxicity with high intakes?
What is the characteristic of fat-soluble vitamins that increases the risk of toxicity with high intakes?
Signup and view all the answers
What happens by the absence or underutilization of a specific vitamin?
What happens by the absence or underutilization of a specific vitamin?
Signup and view all the answers
Which form of vitamin A plays a role in gene expression and regulates the production of proteins?
Which form of vitamin A plays a role in gene expression and regulates the production of proteins?
Signup and view all the answers
What is the main cause of blindness in resource-poor countries?
What is the main cause of blindness in resource-poor countries?
Signup and view all the answers
What is the primary function of vitamin A in the visual cycle?
What is the primary function of vitamin A in the visual cycle?
Signup and view all the answers
What happens when blood calcium levels drop?
What happens when blood calcium levels drop?
Signup and view all the answers
What is the consequence of over-supplementation of vitamin D?
What is the consequence of over-supplementation of vitamin D?
Signup and view all the answers
What is the main function of active vitamin D at the intestine?
What is the main function of active vitamin D at the intestine?
Signup and view all the answers
What is the principle function of vitamin D?
What is the principle function of vitamin D?
Signup and view all the answers
Study Notes
Vitamin A: Sources, Functions, and Deficiency
- Vitamin A can be obtained from animal products, supplements, or plant foods, with the most common plant precursor being beta-carotene.
- Vitamin A is essential for night vision, cell differentiation, and growth regulation.
- Preformed vitamin A compounds are known as retinoids, while plant precursors are called carotenoids, with beta-carotene being the most common.
- Retinoids and carotenoids are transported to the liver from the intestine in chylomicrons.
- Different forms of vitamin A, such as retinol, retinal, and retinoic acid, have distinct functions in the body.
- In the visual cycle, vitamin A, particularly retinal, combines with opsin to form rhodopsin, which is crucial for light perception in the eye.
- Retinoic acid, a form of vitamin A, plays a role in gene expression and regulates the production of proteins.
- Retinoic acid binds to specific protein receptors in the nucleus and alters the level of mRNA, thus regulating gene expression.
- Vitamin A deficiency poses a threat to the health and sight of millions of children worldwide and is a major cause of blindness in resource-poor countries.
- Vitamin A deficiency can result from insufficient intake of vitamin A, fat, protein, or zinc.
- Excessive intake of preformed vitamin A can be toxic, and medications made from vitamin A can have serious side effects.
- Vitamin A plays a crucial role in maintaining immune function and is involved in cranio-facial development, nervous system patterning, and organogenesis.
Vitamin A: Sources, Functions, and Deficiency
- Vitamin A can be obtained from animal products, supplements, or plant foods, with the most common plant precursor being beta-carotene.
- Vitamin A is essential for night vision, cell differentiation, and growth regulation.
- Preformed vitamin A compounds are known as retinoids, while plant precursors are called carotenoids, with beta-carotene being the most common.
- Retinoids and carotenoids are transported to the liver from the intestine in chylomicrons.
- Different forms of vitamin A, such as retinol, retinal, and retinoic acid, have distinct functions in the body.
- In the visual cycle, vitamin A, particularly retinal, combines with opsin to form rhodopsin, which is crucial for light perception in the eye.
- Retinoic acid, a form of vitamin A, plays a role in gene expression and regulates the production of proteins.
- Retinoic acid binds to specific protein receptors in the nucleus and alters the level of mRNA, thus regulating gene expression.
- Vitamin A deficiency poses a threat to the health and sight of millions of children worldwide and is a major cause of blindness in resource-poor countries.
- Vitamin A deficiency can result from insufficient intake of vitamin A, fat, protein, or zinc.
- Excessive intake of preformed vitamin A can be toxic, and medications made from vitamin A can have serious side effects.
- Vitamin A plays a crucial role in maintaining immune function and is involved in cranio-facial development, nervous system patterning, and organogenesis.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge of Vitamin A with this quiz on its sources, functions, and deficiency. Learn about the importance of retinoids, carotenoids, and different forms of Vitamin A, as well as the potential health risks associated with deficiency and excessive intake.
