Fundamentals of Pathology - Soft Tissue Healing and Immune System

Vocabulary flashcards covering key concepts of pathology, the immune system, physical signs and fluids of inflammation, cell types, and the soft tissue healing process based on PHTY20070 lecture notes.

Pathology

The study (logos) of suffering (pathos).

Disease

A consequence of a failure of haemostasis (e.g., osteoarthritis, rheumatoid arthritis).

Injury

The medical term for cellular damage (e.g., soft tissue injuries, fractures, nerve injuries of the upper limb).

Immune System

A network of biological systems that protects an organism (i.e., human body) from infection, injury, and disease due to foreign macromolecules or invading organisms.

Immunity

The ability to distinguish between self and non-self.

Antigen

A foreign substance capable of initiating an immune response when it enters the body.

First Line Defence

Surface barrier tissues (e.g., skin, coughing and sneezing, tears, urine, and GI/respiratory mucus) that stop or expel foreign pathogens from entering the body.

Innate Immune System

The body's second line of defence providing a nonspecific and immediate response through humoral, chemical, and cellular barriers.

Physical Signs of Inflammation

Heat (Calor), Redness (Rubor), Pain (Dolor), Swelling (Tumor), and 'loss of function'.

Oedema

Excess fluid in the extravascular space.

Transudate

An inflammatory fluid of low protein content.

Exudate

An inflammatory fluid of high protein content, which can be fibrinous, serous, purulent, fibropurulent, or haemorrhagic.

Platelets

Blood components playing a fundamental role in haemostasis and blood clot formation, serving as a natural source of connective tissue growth factors like PDGF and TGF-$\beta$.

Neutrophils

First responders to acute inflammatory processes and bacterial infections that perform phagocytosis, with their activity and death forming pus.

Basophils

Polymorphonuclear leucocytes responsible for allergic and antigen responses that release histamine.

Eosinophils

Polymorphonuclear leucocytes that primarily deal with parasitic infections.

Macrophages

Cells differentiated from monocytes in tissues that remove cell debris, spent neutrophils, and bacteria via phagocytosis while stimulating new tissue growth, fibroblast ingrowth, and angiogenesis.

Mast Cells

Cells located in tissues near blood vessels (especially skin) activated by inflammation to degranulate and release histamine ($2-5\,\text{pg/cell}$), serotonin, heparin, prostaglandins, and leukotrienes.

Adaptive Immune System

The third line of defence activated by the innate immune system that develops immunological memory for specific antigens to launch faster and stronger responses upon repeated exposure.

Passive Memory

Short-term immunological memory (lasting days to months) naturally acquired by infants via placental IgG antibodies or colostrum/breast milk.

Active Memory

Long-term adaptive immunity generated naturally by infection (activating B and T lymphocytes) or artificially through vaccination.

B Cells

Lymphocytes derived from bone marrow stem cells that mediate humoral immunity by producing antibodies.

T Cells

Lymphocytes that mature in the thymus and mediate cell-mediated immune responses.

Immunoglobulins (Ig)

Antibody proteins (IgG, IgM, IgA, IgD, IgE), collectively known as gammaglobulins, that recognize and bind to specific antigens.

Major Histocompatibility Complex (MHC)

Cell surface proteins that bind self-proteins or pathogen-derived antigens and present them on the cell surface for recognition by T cells.

Killer T Cells

T cells that eliminate damaged, dysfunctional, or infected cells by recognizing antigens coupled to Class I MHC molecules.

Helper T Cells

T cells that control innate and adaptive immune responses by recognizing antigens coupled to Class II MHC molecules.

$\gamma\delta$ T Cells

T cells combining characteristics of killer T cells, helper T cells, and natural killer cells that recognize antigens not coupled to MHC molecules.

Autoimmunity

An overactive immune response resulting from a breakdown in tolerance where the body fails to distinguish self from non-self, leading to excessive tissue damage.

Inflammatory Phase

The initial soft tissue healing phase (immediate to $2-5\,\text{days}$ post-onset) involving haemostasis, vasoconstriction, platelet aggregation, clot formation, vasodilation, and phagocytosis.

Proliferative Phase

The second soft tissue healing phase ($2\,\text{days}$ to $3\,\text{weeks}$) involving granulation tissue formation, fibroblast ingrowth, angiogenesis, re-epithelialisation, and wound contraction.

Remodelling Phase

The final soft tissue healing phase ($3\,\text{weeks}$ to $2\,\text{years}$) where new collagen forms and aligns along lines of stress, restoring tensile strength up to $80\%$ of original tissue.

PRICE Protocol

The clinical management strategy for the acute inflammatory phase, standing for Protection, Rest, Ice, Compression, and Elevation.