Intrscellular accumulation and Pathological Calcification/ Causes of cell injury

Lect 2 pt 2/3

Intracellular Accumulations

The buildup of various substances inside cells that cant immediately be used or eliminated

• Can be temp or permanent

Mechanisms of intracellular accumulations

• Excessive production of endogenous substance

• Impaired removal of endogenous substances

• Abnormal disposition of exogenous substances

Excessive production of endogenous substance

• Substances that originate from within the body

• Ex: Steatosis

Steatosis

• Abnormal intracellular accumulation of triglycerides (fat) in the cytoplasm of the hepatocytes (cells in the liver)

• Result of excessive and prolonged alcohol consumption

• Condition is reversible after stoppage of consumption

• Signat ring

Impaired removal of endogenous substances

• Can occur in people with genetic or acquired disorders that disrupt metabolism

• Ex : Von Gierke disease

Von Gierk Disease

• Large amounts of glycogen accumulate in the liver and kidneys, reduction in blood glucose levels resulting in weakness and stunted growth '

• Diagnosed between 3-6 months

• Most common form of glycogen storage disorders

Abnormal disposition of exogenous substances

• Can occur in people who are exposed to heavily polluted environments

  • Ex: Coal workers Pneumoconiosis

Coal workers Pneumoconiosis

• Macrophages lining the alveoli engulf coal dust and release cytokines that stimulate inflammation of the surrounding tissues

• Include distortion of the lung architecture (scarring) and airflow obstruction

• Lungs look black instead of pink- "Black lung disease”

Pathologic Calcification

Refers to the deposition of calcium salts, along with smaller amounts of iron, mag, and other minerals, in tissues other than where they are normally found (bones/teeth)

• Alt name: Heterotypic calcification

Forms of Pathologic Calcification:

• Dystrophic

• Metastatic

Dystrophic Calcification

• Abnormal deposition of calcium salts in injured, dying, or dead tissue despite normal blood levels of calcium

• Seen in damaged heart valves or arterial walls

• Appear macroscopically as fine, white clumps and feels gritty

Metastatic Calcification

• Abnormal deposition of calcium salts in normal tissue following elevated blood levels of calcium (Hypercalcemia)

What calcification is this?

Dystrophic

Causes of hypercalcemia:

• Destruction of bone tissue due to tumors of the bone marrow or following prolonged immobilization

What calcification is this?

Metastatic

Cell Injury: Exposure of physical agents

• Mechanical trauma can tear soft tissue, fract bones and injure blood vessels

• Extreme heat can damage cell mem and other structures, accelerate cell metabolism, etc

• Extreme cold can induce vasoconstriction, which deprives tissues of oxygen

What example of cell injury is this?

Exposure of physical agents

• Electrical burn

Cell Injury: Exposure to radiation

• Ionizing radiation incudes high energy waves (gamma rays, X rays)

  • Can kill cells immediately or interrupt cell division by interfering with DNA synthesis)

• Non-ionizing radiation includes low energy waves (visible light, microwaves)

  • Can cause sunburn, increase the risk of skin cancer depending on exposure and melanin in the skin

  • Rarely has a big effect

Cell Injury: Exposure to chemicals

• Strong acids/bases can injure cell and other structures

• Led exposure can interfere with brain development in children

• Mercury exposure can result in neurotoxicity, manifesting as slurred speech, tremors and paralysis

Cell Injury: Exposure to biologic agents

• Viruses, bacteria, fungi

• Can replicate inside humans and continue their damaging effect until adequately treated

• Viruses can enter cell and damage DNA

• Bacteria release toxins that can interfere with cellular ATP production

• Fungi can cause an immune response, resulting in hypersensitivity (allergic) reactions

What example of cell injury is this?

Exposure to biologic agents

Cell Injury: Nutritional Imbalances

Both nutritional excesses and deficiencies predisposed cells to injury

What is this?

Petechiae

(Puh-tee-key-uh)

What is this?

Purpura

(pur-pry-uh)