Sequence Of Events for Vascular Cellular Repair and the Inflammation Response A break in the skin occurs Bacterial reproduction increases Macrophages engulf bacteria Macrophages secrete cytokines Activated mast cells secrete histamine Histamine and cytokines increase dilation of blood vessels White blood cells (WBCs) adhere to capillary lining (pavementing) WBCs migrate to injured site via endothelial cellular gaps via diapedis movement Monocytes turn into macrophages Macrophages and neutrophils engulf pathogens (phagocytosis) Red Blood Cells increase in concentration causing redness and head An increased amount of fluid migrates to the area causing swelling and pain. Tissue repair commences and systemic responses may be evident e.g. fever What is involved in the tissue repair response? Resolution – the toxin is neutralized, oedema decreases, capillary permeability decreases and vasoconstriction occurs Regeneration & replacement – proliferation...
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Vascular & Cellular Changes Produced By Chemical Mediators Causing Inflammation Inflammation is a vascularised response to injury, mostly an immune response to infectious organisms, trauma, surgery, chemicals and extreme heat and cold. The suffix "itis" e.g. appendicitis characterises inflammation, therefore appendicitis is inflammation of the appendix. Acute inflammation Symptoms Includes vascular and cellular phases including: Redness due to hyperemia (increased blood flow) Heat due to hyperemia Swelling due to increased capillary permeability and filtration Pain due to inflammatory chemicals (bradykinin) and fluid pressure on nerves or nerve injury. The purpose of inflammation is to decrease the spread of pathogens giving the body an increased chance of removing them and damaged tissue debris and to repair the tissue damage. The sequence of acute inflammation Change in vascular calibre and blood flow Change in vascular blood flow Cellul...
How to Distinguish Between Hyperplasia, Hypertrophy, Necrosis, Atrophy & Apoptosis Topic 1 - Cellular Changes in Disease What is Hyperplasia? An INCREASE in the NUMBER of cells due to an adaptive change e.g. the removal of a kidney What is Hypertrophy? An INCREASE in the SIZE of cells due to an adaptive change e.g. half a heart not functioning What is Atrophy? A DECREASE in the SIZE of cells, failure to adapt to change, loos of cytoskeleton and organelles e.g. muscular dystrophy What is Metaplasia? One adult cell is replaced with a different adult cell What is Dysplasia? An abnormal change in size, shape and organisation (not adaptive) What is Necrosis? Necrosis is cell death caused by injured cells, usually by enzymes or denatured proteins. Types of necrosis include Coagulative, Liquefaction or Casseous Coagulative necrosis - Occurs in the heart, kidney and adrenal glands. Results from ischemia or hyp...
Cellular change in disease are often non-specific or adaptive changes to injury. Cellular disease can be identified if there are: External indicators Physical measurement changes Biochemical changes Changes in the pathology of the cell Cell damage depends on type of agent or stress, type and duration of injury or type of tissue involved. Cellular changes which are all adaptations to stressors include: Hypertrophy Atrophy Hyperplasia Metaplasia Dysplasia Handy Hint! How can you memorize the above? MADHH ( MAD H airy H ead) M etaplasia, A trophy, D ysplasia, H ypertrophy, H yperplasia How does the lack of oxygen affect cells? Hypoxia is the lack of oxygen in cells which is the most common cause of cell injury and most commonly caused Ischemia (reduced blood supply) however can also be caused by any of the following: Decrease of oxygen in the air Loss of haemoglobin or loss of Hb (Haemoglobin) function Decr...