WEEK 1: Pigments and Lipids Flashcards
what is an artefact pigment?
Deposits produced as result of chemical reaction in tissue
what is an endogenous pigment?
Produced within tissue and have a physiological function or are a by-product of normal metabolic process
what is an exogenous pigment?
Gain access to body accidentally with no physiological function. Usually minerals, enter by inhalation or implantation in skin during industrial exposure
what are 3 artefact pigments?
formalin, malarial, mercury pigments.
what are 4 endogenous pigments? (8 altogether)
bile, lipofuscin, melanin, iron, calcium, copper, uric acid and urates pigments.
How is bile pigment produced? What colour?
breakdown of RBC’s, more specifically when Hb is recycled. Yellow (bilirubin), green (biliverdin). Liver diseases or haemolytic disease.
What is lipofuscin pigment? How is it produced?
‘wear and tear’ pigment due to lipid oxidisation. It is a normal process but excess is linked to PNS and CNS diseases.
Brown pigment.
where is lipofuscin pigment found?
found in heart muscle, liver and brain
How is lipofuscin stained?
Stained by Sudan black, Periodic Acid-Schiff (PAS), Schorl’s, Long Ziehl-Neelsen technique.
what is melanin?
the pigment that is a product of melanocytes. It is black/brown.
where is melanin pigment found?
Eye, skin, hair, brain and melanoma
what is iron pigment stored as?
It is stored as protein haemosiderin in ferric state Fe3+. Fine brown colour.
where is haemosiderin found in the body?
liver, spleen and marrow
what is haemosiderin?
an iron storage complex in cells/tissue as opposed to circulating in the blood. The iron is from the breakdown of erythrocytes.
how is iron, in the ferric state, stained?
it is stained with Perls Prussian Blue staining
how does Perls Prussian Blue stain work?
- dilute hydrochloric acid releases ferric ions from binding proteins by partial denaturation of protein.
- the metal reacts with potassium ferrocyanide to form ferric ferrocyanide, an insoluble bright blue pigment
what is the chemical equation for Perls Prussian Blue staining with ferric iron?
ferric iron + potassium ferrocyanide —> ferric ferrocyanide or Prussian Blue
what is haemochromatosis?
Haemochromatosis is a disorder in which the body can build up too much iron in the skin, heart, liver, pancreas, pituitary gland, and joints. Too much iron is toxic to the body. IT IS GENETIC
who is affected by haematochromatosis?
females after menopause or males aged 40-60
what are some initial symptoms of haemochromatosis?
- fatigue
- weakness
- arthropathy affecting various joints
- nonspecific abdominal problems
- erectile dysfunction
- heart problems
what are some advanced symptoms of haemochromatosis?
- diabetes
- bronzing of the skin !!
- hepatomegaly
- arthropathy
- impotence
- amenorrhoea or hypogonadism
- cirrhosis
- diabetes mellitus
- cardiac disease
- neurological or psychiatric symptoms
how is haemochromatosis investigated?
initially by assessing iron stores. Further investigation includes genetic testing, liver biopsy, MRI
what is haemosiderosis?
haemosiderosis is a term used to describe an overload of iron in your organs or tissues. Also referred to as secondary haemochromatosis. IT IS NOT GENETIC (acquired)
what causes haemosiderosis?
blood transfusion
- excessive iron medication
- thalassemia
- liver disease
- congestive heart failure
- repeated episodes of bleeding
