Pigments Flashcards
Pigments are coloured substances, some of which accumulate in the cell under special circumstances.
● They could be:
○ Normal e.g. ______ or abnormal e.g. ____
melanin; tatoo
________ is the most common exogenous
pigment.
Carbon (Coal dust)
Carbon(coal dust)
- is inhaled daily as an ______
• When inhaled, it is ingested by the _______ in the ____ which transport them via _______ to the regional _____
air pollutant
macrophages; alveoli
lymphatic channels
lymph nodes
Carbon dust is ubiquitous
T/F
T
Coal dust
This pigments forms the ___ coloured patches seen on the _____ surface of the lungs and ______ in the ________
dark; pleural; lymph nodes; tracheobronchial tree.
Coal worker’s pneumoconiosis is a disease condition where there is a ______ reaction to the large amounts of coal dust inhaled by workers in this
profession.
fibroblastic
Endogenous:
•______ (wear and tear
pigment)
• Hemosiderin
•___________ – deposited in the connective tissues, skin in patients with alkaptonuria. The pigmentation is known as _______.
• Melanin
• Bilirubin
Lipofuscin
Homogentisic acid
ochronosis
Lipofuscin
• Granules composed of _______ complexes.
● Found in _______ diseases and are the end products of oxygen radical mediated membrane damage which are not eliminated by intracellular ______
● They subsequently persist in the ______ as collections of _______.
lipid-protein
ageing or debilitating
lipid peroxidation.
Lysosomes; indigestible material
Lipofuscin is injurious to the cell
T/F
F
Not injurious to the cell
Lipofuscin has no gross features
T/F
T
Melanin
• ______ pigment.
● Normally seen in the skin, hair etc
● Synthesized in the _____ and _____ cells by the action of _____ on ______ to form
__________(DHPA).
Brown-black
melanocytes; dendritic
tyrosinase on tyrosine
dihydroxyphenylalanine
Melanin is derived from hemoglobin
T/F
F
Melanin
Disorders of melanin pigmentation can cause generalised and localised _______/_______
hyperpigmentation/hypopigmentation
Generalised hypopigmentation (Albinism)
● Genetic defect in ______
●_______ cases have almost no pigment in the skin and hair and complain of severe ________.
● Chronic sun exposure may lead to ______
tyrosinase
Oculocutaneous; photophobia
skin cancer
Focal hypopigmentation
●_________: localised loss of skin pigmentation.
●_____: More common
● Acquired focal hypopigmentation: healing of wounds,_______,_____ etc.
Leucoderma
Vitiligo
leprosy, lupus
Alkaptonuria
● Autosomal (dominant or recessive?) disorder
● Deficiency of ____ enzyme which is required to break down ________ which therefore accumulates in the tissues
and is excreted in the urine.
● Urine turns ____ if allowed to stand for a few hours in the air ( ______ of _______).
Recessive
oxidase
homogentisic acid.
black
oxidation of homogentisic acid
black pigment in alkaptoneuria is called ______ and is deposited _____cellularly. E.g. Joints, ligaments, skin
tissue.
ochronosis
both inter and intra
● Iron in tissues can be stored either as
○________
○________
Ferettin
Haemosiderin