Altered Cellular and Tissue Biology.ppt

1、1,Altered Cellular and Tissue Biology,Chapter 2,2,Cellular Adaptation,Physiologic vs. pathogenic Atrophy Hypertrophy Hyperplasia Metaplasia Dysplasia,3,Cellular Adaptation,4,Cellular Adaptation,5,Cellular Injury,Reversible Irreversible,6,Cellular Injury Mechanisms,Hypoxic injury Ischemia cut off of

2、blood flow circulation Anoxia insufficient oxygen can be due to lowered Hb, respiration effects, respiratory poisons Cellular responses Decrease in ATP, causing failure of sodium-potassium pump and sodium-calcium exchange Cellular swelling Reperfusion injury,7,Cellular Injury Mechanisms,Free radical

3、s and reactive oxygen species Electrically uncharged atom or group of atoms having an unpaired electron Lipid peroxidation Alteration of proteins Alteration of DNA Mechanisms for the inactivation of free radicals,8,Cellular Injury Mechanisms,Chemical injury Lead CNS toxin interferes with neurotransm

4、itters causing hyperactivity. Lead paints and children anemia & lead toxicity Carbon monoxide binds irreversibly to Hb Ethanol cellular toxin kills cells liver toxin- interrupts protein transport pickles cells can cause fetal alcohol syndrome Mercury neurotoxin can cause bone deformities Social or s

5、treet drugs,9,Unintentional and Intentional Injuries,Blunt force injuries Application of mechanical energy to the body resulting in the tearing, shearing, or crushing of tissues Contusion vs. hematoma bleeding in skin & underlying layers Abrasion removal of superficial skin layers Laceration rip, ye

6、ar or puncture of skin & layers Fractures broken bones,10,Contusions and Hematomas,11,Unintentional and Intentional Injuries,Sharp force injuries Incised wounds Stab wounds Puncture wounds Chopping wounds,12,Unintentional and Intentional Injuries,13,Unintentional and Intentional Injuries,Gunshot wou

7、nds Entrance wounds Contact range entrance wound Intermediate range entrance wound Tattooing and stippling Indeterminate range entrance wound Exit wounds Shored exit wound,14,Gunshot Wounds,15,Unintentional and Intentional Injuries,Asphyxial injuries Caused by a failure of cells to receive or use ox

8、ygen Suffocation Strangulation Hanging, ligature, and manual strangulation Chemical asphyxiants- carbon monoxide, cyanide Drowning,16,Infectious Injury,Pathogenicity of a microorganism gram neg or positive will determine which antibiotics will work best anti viral agents for viral infections Virulen

9、ce of a microorganism some strains are more dangerous than others Disease-producing potential Invasion and destruction Toxin production Production of hypersensitivity reactions,17,Immunologic and Inflammatory Injury,Phagocytic cells immune cells that engulf and destroy invading microbes and toxins I

10、mmune and inflammatory substances Histamine (chemical released by injured or infected cells that cause local vasodilation), antibodies (endogenous proteins that combat and identify invading cells and toxins), lymphokines (chemical produced by imune cells), complement, and enzymes Membrane alteration

11、s leakage of cell contents due to the presence of antibodies and histamines,18,Injurious Genetic Factors,Nuclear alterations mutations and damage to DNA Alterations in the plasma membrane structure, shape, receptors, or transport mechanisms Examples of genetic diseases Sickle cell anemia (substituti

12、on of one amino acid in Hb structure) and muscular dystrophy (muscle tissue does not function properly,19,Injurious Nutritional Imbalances,Essential nutrients are required for cells to function normally inadequate proteins, carbohydrates, fats, vitamins, minerals Deficient intake starvation and impr

13、oper diets protein deficiency “kwashiokor” most common, Vitamin B 12 deficiency leads to pernicious anemia Excessive intake - obesity,20,Temperature Extremes,Hypothermic injury Slows cellular metabolic processes Ice crystal formation and frostbite Hyperthermic injury Heat cramps Heat exhaustion Heat

14、stroke Protein denaturation,21,Atmospheric Pressure Changes,Sudden increases or decreases in atmospheric pressure Blast injury Nitrogen Narcosis or rapture of the deep Nitrogen gas has a narcotic effect (laughing gas) Decompression sickness or caisson disease “The bends”,22,Ionizing Radiation,Any fo

15、rm of radiation capable of removing orbital electrons from atoms X-rays, gamma rays, alpha and beta particles Amount of exposure measured in RADS. People who work with X-rays must wear badge that measures dosees of exposure over time Mechanism of damage ionization of chemicals and breakage of chemic

16、al bonds Effects of ionizing radiation,23,Ionizing Radiation,24,Cellular Injury,Illumination injury Eyestrain, obscured vision, and cataract formation Caused by light modulation Mechanical stresses Physical impact or irritation Noise sound can cause tisse and organ trauma Acoustic trauma and noise-i

17、nduced hearing loss tinnitus very common among performing rock band members,25,Manifestations of Cellular Injury,Cellular accumulations (infiltrations) Water Lipids and carbohydrates Glycogen Proteins,26,Hydropic Degeneration,27,Manifestations of Cellular Injury,Cellular accumulations (infiltrations

18、) Pigments Melanin, hemoproteins, bilirubin (aging brown spots) Calcium can cause hardening of cells and altered membrane permeability Urate example is gout where urate crystals form in joints and is very painful,28,Calcium Infiltration,29,Cellular Death,Necrosis local cell death by autodigestion Su

19、m of cellular changes after local cell death and the process of cellular autodigestion Processes Karyolysis Nuclear dissolution and chromatin lysis Pyknosis Shrinking & Clumping of the nucleus Karyorrhexis Fragmentation of the nucleus,30,Cellular Death,31,Necrosis,Coagulative necrosis Primarily foun

20、d in Kidneys, heart, and adrenal glands Protein denaturation and increased intracellular level of Ca,32,Coagulative Necrosis,33,Necrosis,Liquefactive necrosis common after ischemic events in CNS (stroke) Neurons and glial cells of the brain die and are rich in digestive enzymes Hydrolytic enzymes ca

21、uses brain tissues to become soft and liquefy sometimes walled off and form cysts These types of cysts also form after bacterial infection due to actions of phagocytic neutrophils and fluid in cyst is called pus.,34,Liquefactive Necrosis,35,Necrosis,Caseous necrosis Found in Tuberculous pulmonary in

22、fection Combination of coagulative and liquefactive necrosis Necrotic debris not completely digested thus tissues appear granular like clumped cheese,36,Caseous Necrosis,37,Necrosis,Fat necrosis Common in Breast, pancreas, and other abdominal organs breakdown of fats create soaps and referred to as

23、saponification and tissue is opaque or white chalky Action of lipases break down fats to FA and glycerols,38,Fat Necrosis,39,Necrosis,Gangrenous necrosis Clinical term Dry vs. wet gangrene Gas gangrene,40,Gangrenous Necrosis,41,Apoptosis a type of cell death different from Necrosis in that it is act

24、ive self destruction of normal and pathologic tissue,Programmed cellular death- found mostly to occur during development of embryo Mechanisms- specific signaling chemicals send message to cells programmed to die Necrosis vs. apoptosis- while necrosis usually effects all cells in an area apoptosis ef

25、fects scattered cells killing the cells shrink quickly and disappear neatly while necrotic cells swell and lyse,42,Apoptosis,43,Aging and Altered Cellular and Tissue Biology,Aging vs. disease tissues all have accumulaion of toxic chemicals and mutation damage over time. Disease can damage and destro

26、ys cells quickly due to some pathogenic cause Normal life span - brain cells live as long as you do and the neurons in CNS once formed by age 6 do not divide. RBC live only 120 days Gender differences - women live longer than men 78 vs 81 years may be due to genetic superiority,44,Theories of Aging,

27、Accumulation of injurious events the more exposure to dangerous chemicals and pathogens the faster you age Genetically controlled program some of us are destined to live longer due to the genetic program in our cells Theories Genetic and environmental lifestyle factors Alterations of cellular contro

28、l mechanisms decreased protein synthesis as you age Degenerative extracellular changes nutrients and free radicals important,45,Theories of Aging,46,Aging,Cellular aging all cells can replicate 40 60 times max and may be why clones do not live as long as parents Tissue and systemic aging immune func

29、tion goes down with age and free radicals damage cells speeding aging Frailty wastin syndrome of aging due to decreased protein synthesis and reduced muscle mass and lowered bone density,47,Somatic Death,Death of an entire person Somatic death with no respiration or circulation Postmortem changes Al

30、gor mortis drop in body temp such that in 24 hrs same as room temp Livor mortis blood settles on lowest tissues due to gravity causing discoloration Rigor mortis 6 12 hours post somatic death stiffening of body due to muscle protein breakdown Postmortem autolysis bloating and swelling of body due to autolysis,