PATHO

First line physical barriers, second line innate immunity (phagocytosis and inflammation), third line adaptive immune response

the death of most or all of the cells in an organ or tissue due to disease, injury, or failure of the blood supply.

inadequate blood supply to an organ

sudden lack of oxygen leading to a death of tissue or necrosis

Redness, warmth, swelling, pain, and possible loss of function

Bradykinin

It causes capillary dilation and increases vascular permeability

Neutrophils and macrophages

They dilate and become permeable to allow immune cells, proteins, and fluid to enter damaged tissue

A rapid inflammatory response involving chemical mediators, vascular changes, and leukocyte migration

Capillary dilation increases blood flow and fluid movement into tissues

Leukocyte migration and phagocytosis of pathogens

A collection of interstitial fluid and proteins in the inflamed area

A localized collection of pus that forms when inflammatory fluid cannot be cleared

Long-term inflammation that occurs when the cause of injury is not removed

Scar tissue that forms around a necrotic or infected area during chronic inflammation

Resolution, regeneration, and replacement

Damaged tissue returns to normal with minimal damage

Replacement of damaged cells by identical cells through mitosis

Damaged tissue is replaced by fibrous scar tissue causing loss of function

Blood clot formation to seal the wound

They produce collagen to strengthen the healing tissue

Neat wound healing with minimal tissue loss

Healing involving more debris and larger tissue loss with greater scar formation

First degree, second degree, and third degree burns

Superficial skin damage with redness and pain that heals quickly

Partial thickness skin damage with blistering and sloughing

Full thickness tissue death with high infection risk and possible nerve damage

A foreign substance that triggers an immune response

A protein produced by lymphocytes that binds specifically to an antigen

Lymphoid organs, immune cells, and tissues involved in cell development

The first exposure to an antigen where immune memory begins forming

A faster and stronger immune response after re-exposure to the same antigen

An exaggerated immune response to a normally harmless substance

IgE mediated allergic reactions such as hay fever and rash

IgG antibodies attack body cells such as during incompatible blood transfusions

Immune complexes deposit in blood vessel walls causing inflammation

T cell mediated immune reaction causing tissue damage

A condition where the immune system attacks the body's own tissues

A reduced ability of the immune system to fight infections

A congenital failure in immune system development

Loss of immune function caused by factors such as infection or malnutrition

Through haematopoiesis from pluripotent stem cells in bone marrow

A condition where reduced red blood cells or haemoglobin decreases oxygen delivery to tissues

Insufficient dietary iron or chronic blood loss

Fatigue, pallor, tachycardia, dyspnoea, and delayed healing

Vitamin B12 deficiency or impaired absorption

A genetic disorder where abnormal haemoglobin causes red blood cells to become sickle shaped

An increase in red blood cell production leading to increased blood viscosity

A condition with low platelet numbers causing prolonged bleeding

A condition with excessive platelet production increasing clot formation risk

Absence or abnormal clotting factor VIII

A hereditary bleeding disorder caused by deficiency of von Willebrand factor

Reduced blood flow in coronary arteries usually caused by atherosclerosis

A condition where myocardial oxygen supply is less than oxygen demand

Chest pain caused by temporary myocardial ischaemia

Prolonged coronary obstruction causes irreversible death of heart muscle cells

A chronic condition where the heart cannot pump enough blood to meet body demands

Plaque formation in large and medium arteries causing narrowing and reduced blood flow

Persistent elevated blood pressure greater than 140/90 mmHg

High blood pressure with no identifiable underlying cause

High blood pressure caused by another medical condition

A state of inadequate tissue perfusion resulting in insufficient oxygen delivery to cells

Shock caused by severe loss of blood or fluids

Shock caused by failure of the heart to pump effectively

Shock caused by widespread vasodilation and poor tissue perfusion

Shock caused by physical obstruction of blood flow such as pulmonary embolism

A life threatening condition where the lungs cannot maintain adequate oxygenation or carbon dioxide removal

Barriers such as skin, tears, and mucous membranes

Phagocytosis and inflammation (innate immunity)

Immune system response (adaptive immunity)

Swelling, redness, warmth, pain, and possible loss of function

Injured cells release bradykinin

Stimulates pain receptors

Causes release of histamine

They cause capillary dilation

Neutrophils and macrophages

Allow immune cells to move into damaged tissue and remove debris

Net hydrostatic pressure

Acute is short-term with chemical mediators; chronic persists if the cause is not eradicated

Pyrexia, shivering, cool skin

Scar tissue that forms around necrotic tissue

Resolution, regeneration, replacement

Minimal tissue damage; cells return to normal quickly

Tissue regrows by mitosis from edges, function maintained

Tissue replaced by fibrous scar tissue; function may be lost

Produce collagen to strengthen tissue

First intention is neat, second intention involves more debris and scarring

Red and painful; heal quickly

Partial thickness; skin sloughs off; healing occurs from outside in

Full-thickness; tissue death; high infection risk; charred appearance

A foreign substance or unique human protein that induces an immune response

A protein produced by lymphocytes that binds to a specific antigen

Lymphoid structures, immune cells, tissues involved in cell development

Primary is first exposure; secondary is rapid re-exposure response

An inappropriate immune response to an innocuous substance

IgE-mediated allergic reactions like rash or hay fever

IgG antibodies react with normal or foreign antigens causing cytotoxicity

Immune complexes deposit in vessel walls causing inflammation

T-cell mediated response; delayed hypersensitivity

The body attacks its own cells due to faulty signaling

Inadequate immune response increasing infection or cancer risk

Developmental failure in the immune system

Infections, malnutrition, stress, endocrine disorders

By negative feedback or hypothalamic-pituitary system

Insulin secretion triggered by blood glucose

Hypothalamus → pituitary → target gland → hormone release

Defect in the hormone-producing gland

Defect in the pituitary

Defect in the hypothalamus

Dwarfism

Giantism or acromegaly

Increase basal metabolic rate and energy availability

Decreased metabolism, dry skin, weight gain, goiter

Increased metabolism, weight loss, heat intolerance, elevated BP

Stress response; increases available energy, suppresses non-essential systems

Long-term steroid use or pituitary/adrenal tumors

Conn’s syndrome, certain medications

Addison’s disease, autoimmune conditions, adrenal crisis

Adrenaline

Benign adrenaline-secreting tumor causing episodic hypertension

Formation of blood cells from pluripotent stem cells

Low platelet count, risk of bleeding

High platelet count, risk of thrombi formation

Deficiency of clotting factor VIII; X-linked recessive

Deficiency of von Willebrand factor affecting platelet adhesion

Plasmin

Structural heart abnormality developing in first 8 weeks of embryonic life

Ventricular septal defect (VSD)

Left-to-right shunt (acyanotic)

Shunt reversal (right-to-left) causing cyanosis

Narrowing of valve restricting forward flow

Valve fails to close, causing backflow

Cyanotic congenital heart defect with VSD, pulmonary stenosis, RV hypertrophy, overriding aorta

Chronic condition where heart cannot pump enough blood

Sympathetic nervous system activation, RAAS, ventricular hypertrophy/dilation

Left = pulmonary congestion; Right = systemic venous congestion

Thickening and hardening of arteries

Plaque formation in large and medium arteries

Transports cholesterol to tissues; contributes to plaque

Removes cholesterol from tissues; protective

Age, male gender, family history, genetics

High-fat diet, smoking, sedentary lifestyle, obesity, hypertension, diabetes

Persistent elevated blood pressure >140/90 mmHg

Primary = no identifiable cause; Secondary = due to underlying condition

Severely elevated BP >180/120 mmHg with organ damage

Impaired coronary blood flow, often due to atherosclerosis

Myocardial oxygen supply-demand imbalance causing ischaemia

Reduced coronary blood flow → myocardial ischaemia

Heart failure, cardiogenic shock, arrhythmias

Shock due to loss of blood or fluids

Shock due to heart failing to pump effectively

Shock due to widespread vasodilation

Shock due to physical obstruction of blood flow

Tachycardia, increased contractility, peripheral vasoconstriction

Increased respiratory rate

RAAS activation → sodium and water retention, decreased urine output

Subtle tissue hypoperfusion, mild tachycardia, cellular hypoxia begins

Worsening hypoperfusion, hypotension, confusion, oliguria, edema

Severe cellular/organ damage, persistent hypotension, multi-organ failure