Vitamin A

What Is Cancer Of The Pharynx? Cancer of the pharynx is a malignant growth of stratified squamous cells that line the pharynx, or throat. Q: What are stratified squamous cells that line the pharynx? A: Stratified squamous cells are thin, flat epithelial ...

What Is Xerophthalmia? Xerophthalmia is a serious condition of extreme drying and thickening of the conjunctiva following chronic inflammation and failure to make tears, characterized by hazy, dry cornea. Vitamin A is obtained from the diet and is required in ...

What Is Seborrhea Dermatitis? Seborrhea dermatitis is a recurring inflammatory disorder of sebaceous glands characterized by scaly patches of skin, often with bumps. Seborrhea dermatitis results from the body’s inflammatory reaction to invasion by pityrosporum yeast that naturally inhabits the ...

What Is Prurigo Nodularis (Hyde’s Prurigo)? Prurigo nodularis is a chronic dermatitis characterized by hard, dry, deep seated, intensely itchy papules (small bumps like pimples) and/or nodules (large bumps) that erupt most commonly on the arms, legs, and back. Papules ...

What Is Delayed Puberty in Boys? Delayed puberty in boys is characterized by lack of growth and functional activity of the male gonads, called testes or testicals, to produce testosterone by age 14 and failure to grow pubic hair by age 15. ...

What Is Non-Infectious Blepharitis? Non-infectious blepharitis is an inflammatory condition of the eyelids that is NOT caused by an invading organism but rather nutritional deficiencies. It is characterized by non-ulcerative inflammation of the hair follicles and lacrimal glands along the eyelid edges. Q: ...

What Is Delayed Puberty In Girls? Delayed puberty in girls is a concerning condition characterized by decreased functional activity of the ovaries resulting in late onset of ovulation and secondary sex characteristics. Q: When should puberty in girls begin? A: ...

What Is Failure To Thrive And Growth Retardation? Failure to thrive (FTT) and growth retardation are conditions affecting children characterized by weight consistently below the 3rd percentile for age or a decrease in the expected rate of growth based on ...

What Is Infertility in Males? Infertility in males is characterized by inability to either produce sperm or to produce viable sperm or mobile sperm resulting in prohibiting fertilization of the female ovum (egg). To the left is a false-colour scanning ...

What Is Unexplained Adult Male Hypogonadism? Hypogonadism in males is a distressing reproductive disorder characterized by inadequate production of male andogen hormones and/or spermatozoa by the testes. Q: How do andogens affect reproductive health? A: Male androgen hormones control the ...

What Is Inflammatory Vaginitis? Inflammatory vaginitis, also called desquamative inflammatory vaginitis, is a female genital disorder characterized by non-infectious tissue inflammation of the vagina (birth canal). Inflammatory vaginitis presents in females of any age including girls with a history of discomfort, ...

What Is A Bladder Infection? Bladder infection, or cystitis, is a urinary disorder characterized by pyuria (pus in urine) and dysuria (impaired urination). Cystitis is often simply called a UTI, although UTI (urinary tract infection) can affect any part of the ...

What Is Night Blindness? Night blindness is a visual defect caused by lack of rhodopsin in the rods of the retina located in the back of the eyeball due to inadequate vitamin A. Q: How does inadequate vitamin A cause ...

What Is Keratomalacia? Keratomalacia is a severe non-inflammatory eye condition characterized by a hazy, dry cornea that becomes softened and denuded (loss of protective layer), which when liquified is then irreversibly destroying the eyeball and causing blindness. The conjunctiva and ...

What Is Unexplained Blurred Vision? Unexplained blurred vision is unclear or distorted vision that is not caused by allergy, poor refraction (eye test), medication side effects, metabolic disorders, or defects in any part of the eyeball, optic nerve, or in ...