TR3.5

Diseases, an Overview

Houjun Liu 2021-09-27 Mon 12:00

1 Diseases, an overview

\definition{**Disease**}{an abnormal condition that causes impairment in/loss of function of an organism (a.k.a. decreased fitness) that is not due to immediate external injury.}

1.1 Causes of Disease

  • Infectious agents
  • Deficiency disorders
  • Heritable factors
  • Physiological disorders (immunodeficiency, autoimmune disorders, allergies, etc.)

1.2 Types of Diseases

1.2.1 Congenital Disease

Diseases present at birth due to DNA abnormalities / pregnancy pathological issues

1.2.2 Acquired Disease

Diseases that begin during the lifetime due to exposure to some environmental factors…

  • Microrganism Invasion => "infectious disease"
  • Autoimmune reaction => your body fighting your body
  • Nutrient deficiency => not eating good
  • Mechanical wear => wear and tear of physical body parts
  • Ingestion of noxious chemicals => eating poison

An aside…

Infectious diseases actually smaller on the causes of death in the US

  • Heart disease => wear + deficiency
  • Cancer => heritable + DNA
  • Unintentional injuries => not a disease
  • Chronic respitory disease => wear
  • Stroke => not a disease
  • Alhetimer disease => wear
  • Diabetes => autoimmune, nutrient, wear
  • Influenca <= here, finally, an infections disease. *

1.3 Measuring diseases: pathogenicity + virulence

1.4 Disease-causing Agents

  • Protozoan => single-celled eukaryotes
  • Fungal => single/multi-celled eukarotyes
  • Bacteria => single-celled prokaryotes
  • Viral => acellular parasitic infectious agent
  • Helminuthus => multicellular worms
  • Prions => acellular misfolded proteins
  • Viroids => infections nucleic acids w/o protein coat to make virus

1.4.1 Protozoan

  • Protozoan factors => direction pathogenisis leading to tissue damage
  • Host-mediated factors => immune evation + escape mechnisms + immunalsupression

Adaptable!!

1.4.2 Fungal

  • Fungal factors => many shapes and very adaptable, colud produced specialized enzymes to take root in body
  • Host-mediated factors => cause immunocomprimzation, acquired though inhalation, etc.

1.4.3 Bacteria

1.4.4 Viruses