Pathophys and immuno review content

based on dr fish review recs

Necrosis vs autolysis

Necrosis = premature death of cells and living tissue due to injury or disease, requires inflammation

Autolysis = self-digestion of cells or tissues due to the action of enzymes, typically occurring after death.

Fat necrosis

Adipose tissue is necrosed by lipolytic enzymes with soap/calcium formation. Usually pancreatitis

Coagulative necrosis

Most common type of necrosis. Tissue structure is maintained but proteins are denatured. Usually happens with ischemic/anoxic injury to solid organs. Myocardial infarction

Caseous necrosis

Cheese-like form of coag. necrosis. Seen with tuberculosis granulomas in lungs and some fungal infections

Review pics?

YES

Hypertrophy

Tissue/organ size increases due to individual cell enlargement. Physiologic: weightlifter’s muscle, gravid uterus. Pathologic: LV hypertrophy in htn

Why cardiac htn → cardiac hypertrophy?

Increased cardiac workload due to elevated blood pressure → adaptive growth of cardiac muscle cells

Hyperplasia

Adaptive increase in number of cells, causing tissue enlargement. Ex) endometrial hyperplasia (driven by unopposed estrogen), hyperplastic polyps (benign mucosal proliferation in colon or stomach from polypoid mass)

Dysplasia

Disordered, atypical cell growth often arising in metaplastic epithelium with chronic irritation or infection; considered premalignant/precancerous. Ex) cervical intraepithelial neoplasia CIN (linked w/ HPV, pap smear checks for it)

Metaplasia

Reversible substitution of one mature cell type by another in order to tolerate stress of a certain environment. Ex) squamous metaplasia of bronchus (ciliated columnar epithelium of smoker is replaced by stratified squamous cells) leads to Barrett esophagus

Dystrophic vs metastatic calcifications

Dystrophic calcification = occurs in damaged or necrotic tissue, serum calcium is normal. Ex) Coronary artery calcification, aortic/mitral stenosis, breast cancer

Metastatic calcification = calcium deposits in normal tissues due to high serum calcium levels and disturbed metabolism. Ex) hyperparathyroidism, Vit D toxicity, chronic renal failure, calcium oxalate stones

Both processes involve abnormal calcium metabolism, but they present in different contexts.

Liquefactive necrosis

Enzymatic digestion converts tissue to liquid viscous mass. Seen with brain infarcts and abcesses (lungs, etc)

Anaplasia

Undifferentiated, uncontrolled cell growth. AKA Malignancy, cancer, carcinoma, neoplasm. Characteristics include pleomorphic cells (crazy nuclei), hyperchromatic nuclei (dark staining), high nuclear:cytoplasm ratio (1:1), mitotic abnormalities

Hypertrophy AND hyperplasia

Cell size and number increases. Ex) uterine smooth muscle in pregnancy, benign prostatic hyperplasia

Erythrocyte

RBC that carries O2 from the lungs to the body's tissues and returns CO2 to be exhaled. Produced in the bone marrow. No nucleus when mature. Biconcave disc shape increases surface area. No self motility or protein synthesis.

Hematocrit

Percentage of blood volume occupied by packed cellular elements (RBCs). Measures the proportion of red blood cells in whole blood, indicating oxygen-carrying capacity.

Buffy coat

Thin layer of WBCs and platelets that lies between the plasma and red blood cells in a centrifuged blood sample.

Plasma

Fluid portion of blood containing water, inorganic salts, proteins, hormones, etc. Aids in transportation of nutrients, waste products, and hormones throughout the body.

Serum

Clear fluid that remains after blood has clotted, containing water, electrolytes, proteins, and hormones. It differs from plasma by the absence of clotting factors.

Migration on electrophoresis of antibodies

Gamma globulin region. Movement of antibodies in a gel matrix based on their size and charge during protein separation.

How many antibody types are there?

5 main types of antibodies, aka immunoglobulins: IgA, IgD, IgE, IgG, and IgM.

Neutrophils

Most abundant leukocyte, 40-75%; multilobated nucleus (3-5); key cell of acute inflammation. Granulocyte. Purple granules are lysosomes aka specific granules. Dead neuts make pus. AKA polymorphonuclear leukocytes (PMNs), Polys, neuts, segs

Monocytes

Immature macrophages on their way to connective tissue. Phagocytic and have pseudopodia. Pale, indented nucleus. Circulate for 1-2 days then enter CT. Become macrophages once in CT

Macrophages

Phagocytes or histiocytes when in tissue. Horseshoe nucleus. Long lived and seen in chronic inflammation. AKA histiocytes, phagocytes

Kupffer cells

liver macrophage

Dust cells

heart failure macrophages in lungs

Microglial cells

brain macrophage

Eosinophils

Bilobed granulocyte with red-orange granules containing Histaminase. Combats parasites (when IgE is present) and modulates allergies and hypersensitivities. 1-6% of leuks. Highly phagocytic for antigen-antibody complexes and exhibit some phagocytic activity of neutrophils. Attracted to inflammation sites by substances that basophils and mast cells release. Located in blood and tissues

Original hematopoietic organs/tissues

Before bone marrow, blood formation begins in yolk sac/mesenchyme, liver, spleen, and lymph nodes

Granulocytes

Cytoplasmic granules are present. Neutrophils, eosinophils, and basophils.

Agranulocytes

No cytoplasmic granules. Lymphocytes (B and T cells), Natural killer NK cells, and monocytes.

T cell

Thymus-derived lymphocyte w/ long lifespan, mediating cell-mediated immunity. T helpers (secrete cytokines), cytotoxic T (antivirus and recruiter), or memory T cells based on surface receptors

B cell

Bone-marrow-derived lymphocyte that differentiates into antibody-secreting plasma cells and migrates to specific lymphoid tissues. Undergo proliferation when activated by a foreign antigen and mature into antibody secreting Plasma Cells which have the ability to secrete protein antibodies (IgG,IgA,IgM,IgE,IgD)

Natural killer NK cell

Large granular lymphocyte with IgG receptors that kills virus-infected or tumor cells without prior sensitization. Can secrete interferons to prevent healthy host cells from infection

Basophils

Circulate in blood and become mast cells once in tissue. Rare (less than 1%) bilobed granulocyte with dark blue granules containing histamine and heparin.

3 types of hemoglobin

HbA = 97%. 2 alpha 2 beta globin chains

HbA2 = 3%. 2 alpha 2 delta globin chains

HbF = fetal. 2 alpha 2 gamma globin chains

RBCs after 120 days

Removed from circulation by the spleen and liver, where they are broken down by macrophages into heme and globin components.

3 recycled RBC components

Iron, heme, and globin. Iron is reused for erythropoiesis, while heme is converted to bilirubin and globin is broken down into amino acids.

Platelets

Small, sticky cell fragments involved in blood clotting. Produced by megakaryocytes in the bone marrow. AKA thrombocytes. Contains serotonin! Release thromboplastin and plasmin

Thromboplastin

Enzymatically converts prothrombin in plasma to thrombin. Thrombin converts fibrinogen to fibrin to form clot.

Plasmin

Contractile protein released by platelets to cause clot retraction