Pigments

Question 1

What are the two groups of pigments?

Answer 1

exogenous and endogenous

Question 2

name and describe some exogenous pigments

Answer 2

1. pneumoconiosis: dust inhaled and retained in lung
   anthracosis: carbon inhalation. carbon is phagoctosed and transported by macrophages into the lymph nodes and to the lungs
   silicosis: inhalation of silicon
2. tattoos -pigment introduced into the dermis and doesn’t cause an inflammatory response
3. carotenoid pigments - pigments from plants. when animal has vegetable oil in its diet the tissues fat is yellow orange color

Question 3

name and describe some endogenous pigments

Answer 3

1. melanin - brown-black pigments that are produced by melanocytes in the epidermis. requires copper containing tyrosinase therefore a lack of copper or tyrosinase will effect coat colour
2. liofusion - brown pigment that accumulates over time
3. hemoglobin -multiple problems that may arise
4. bilirubin - icterus - yellow staining of tissue bilirubin because there is an excess amount of bilirubin in the plasma because it isn’t being broken down

Question 4

What are some situations where hemoglobin are affected

Answer 4

• cyanide poisoning - venous blood will appear as artial blood
• methemoglobin - poisoning by nitrates will cause red brown or chocolate brown blood tissue
• carbon monoxide poisoning - blood will appear cherry red
• intravascular hemolysis - RBC lyse and stain plasma, kindeys and liver red
• myoglobin - damage to muscle causing red muscle
• hemosiderin -golden yellow-brown pigment because of excess iron

Question 5

what are the 3 types of icterus?

Answer 5

• prehepatic icterus: hemolytic crisis that produces high plasma concentration of unconjugated bilirubin that exceeds uptake capacity
• hepatic icterus: hepatocellular damage of canaliculus allowing the bilirubin to leak into circulation
• posthepatic icterus: secondary obstruction of biliary system so bile isn’t flowing and get a build up in the blood

Question 6

Describe replicative senescense

Answer 6

-when somatic cells have arrested and are not dividing anymore. This is regulated by telomeres (short repeated sequences of DNA). With each replication, the telomeres become shorter and once it is too short then the cell cycle arrests and new cells are formed.
If the telomeres are maintained then the cells will not stop replicating