Pathophysiology 1: basics of disease

3 steps of Patho

1. Etiology: Cause of disfunction

2. Signs/Symptoms

3. Implications: why does it matter

Cell reactions to injury/stress

1. Adaptive (main homeostasis)

2. Maladaptive (deragements: structure, function)

3. Necrosis (cell death)

Atrophy

Cellular shrinkage

Causes of atrophy

• Decreased metabolic support (blood, nutrients)

• Less use (ex: paralysis)

• Less stimulation (nerve/hormonal)

• Increased age

Hypertrophy

Cellular enlargement

• Cause: stress/resistance

• Positive or negative (exercise vs thickened heart walls)

Hyperplasia

Increased number of cells

• Normal: breast gland cells lactation

• Dysfunctional scar healing: keloids

Metaplasia

Replacing one cell type with another

• Ex: changing esophagus cells to handle acid from reflux

• cancer risk

Dysplasia

Deranged cellular growth

• cancer risk

Neoplasia

New growth (of abnormal cells): tumor (benign or malignant)

What drives cellular changes?

(acronym)

T: toxic injury

I: infectious/inflammatory

P: physical injury

D: deficit injury

Types of toxic injury

Endogenous: inside body (metabolites, hormones)

Exogenous: external (alcohol, lead, drugs etc)

Types of infectious/inflammatory injury

Viral

Fungal

Protozoal

Bacterial

types of physical injury

Thermal

Mechanical

Types of deficit injury

Oxygen

Water

Nutrients

Temperature

Inadequate waste disposal

what is deficit of oxygen called

hypoxia

Apoptosis vs necrosis

Apoptosis: programmed, packages within membrane

Necrosis: not programmed, messy, contents get everywhere (tissues, blood)

Impact of necrosis

• Function loss

• Release of contents

• Infection risk

Congenital

Present at birth

Two types

• Genetic

• Non-genetic