Pathophysiology chapter 2

Abrasion

(scrape) removal of the superficial layers of the skin caused by friction between the skin and the injuring object

Common biochemical themes of cell injury

-ATP depletion -oxygen and oxygen-derived free radicals -intracellular calcium and loss of calcium steady state -defects in membrane permeability

Cellular death processes

-Pyknosis -Karyolysis -Karyorrhexis

Free Ca++ causes

-activation of protein kinases -activation of phospholipases with phospholipid degradation and loss -activation of proteases -activation endonuclease

postmortem changes

-algor mortis -livor mortis -rigor mortis -postmortem autolysis

where does fat necrosis occur?

-breast, pancreas, and other abdominal organs

Cellular responses of hypoxic injury

-decrease in ATP causing failure of sodium-potassium pump and sodium-calcium exchange -cellular swelling -vacuolation (formation of vacuoles)

Cellular accumulations (infiltrations)

-water: most common degenerative change -lipids and carbohydrates: metabolic disorders (liver fatty change) -pigments -calcium -urate

Unintentional and Intentional Injuries

1. Unintentional -falls, motor vehicle, poisonings 2. Intentional -homicide, suicide 3. Injuries -blunt force -sharp force -gunshot wounds -asphyxial injuries 4. errors in health care

Major types of necrosis

1. coagulative necrosis 2. liquefactive necrosis 3. caseous necrosis 4. fatty necrosis 5. gangrenous necrosis 6. gas gangrene

Sharp-Force Injuries

1. incised wounds 2. stab wounds 3. puncture wounds 4. chopping wounds

Causes of cell injury

1. lack of oxygen (hypoxia) 2. free radicals 3. caustic or toxic chemicals 4. infectious agents 5. unintentional and intentional injury 6. inflammatory and immune responses 7. genetic factors 8. genetic factors 9. insufficient nutriets 10. physical trauma from many causes

A patient sustained a fracture of his right arm 2 months ago, requiring a cast placement. What kind of adaption has occurred in the skeletal muscles?

ATROPHY

Asphyxial Injuries

Failure of cells to receive or use oxygen 1. suffocation 2. strangulation 3. Chemical Asphyxiants 4. Drowning

Which of the following is the most common cause of cellular injury?

HYPOXIA

Hypoxic injury

Hypoxia= lack of sufficient oxygen -ischemia -anoxia reperfusion injury

Immunologic and Inflammatory injury found where

MEMBRANE

Triggers for hypertrophy

Mechanical (stretch) Trophic (growth factors, hormones, vasoactive agents muscular hypertrophy tends to diminish with removal of excessive workload (use em or lose em)

Cellular death

Necrosis -cell death leading to cellular dissolution

Metaplasia

REVERSIBLE replacement by 1 mature cell type to another less mature cell

Free Radicals-Reactive Oxygen Species Injury

ROS=reactive oxygen species -oxidative stress occurs when excess ROS overwhelms antioxidant systems

Incised wound

a cut that is longer than it is deep -edges are sharp without abrasion -produce significant external bleeding with minimal internal hemorrhage

Laceration

a tear or rip resulting when the tensile strength of the skin or tissue is exceeded

Drowning

alteration of oxygen delivery to tissues resulting from the breathing in of fluid, usually water

Anoxia vs Hypoxia

anoxia= total lack of oxygen hypoxia= partial lack of oxygen

Blunt Force injuries

application of mechanical energy to the body resulting in tearing, shearing, or crushing of tissues -MVAs and calls are most common causes -contusion vs. hematoma -abrasion -laceration -fractures

Characteristics cellular aging

atrophy, decreased function, and loss of cells -frailty -tissue and systemic aging

Chemical cell injury

biochemical interaction between toxic substance and the cell's plasma membrane (leads to increased permeability) -carbon tetrachloride -lead -ethanol -mercury -social or street drugs

Contusion (bruise)

bleeding into the skin or underlying tissues as a consequence of a blow that squeezes or crushes the soft tissues and ruptures blood vessels without breaking the skin

algor mortis

body slowly cools once hurt stops beating -measuring body ten can approximate time of death (once ambient temp reached, TOD no longer determined)

Fractures

bone break or shatter

Hemosiderin accumulation

bruising -extravasated red cells -phagocytosis of red cells by macrophages ->hemosiderin and iron free pigments

Calcium infiltration

calcium stores in mitochondria and endoplasmic reticulum pumped to extracellular space bound to calcium-binding proteins -released after cell damage -free Ca++

Gas gangrene

caused by Clostridium sp -anaerobic bacteria produce hydrolytic enzymes and toxins that destroy connective tissue and cellular membranes -Bubbles of gas forms in muscle, soft tissue -death caused by shock

Puncture wounds

caused by instruments or objects with sharp points but without SHARP edges -abrasion of wound edges

Hydropic Degeneration

cell starts to shrink and it dies

fat necrosis

cellular dissolution by action of LIPASES -lipases break down triglycerides, releasing free fatty acids, which combine with calcium, magnesium, and sodium ions, creating soaps (saponification) -necrotic tissue appears opaque an chalk-white

Immunologic and Inflammatory Injury (not tested on first exam)

cellular membranes are injured by direct contact with cellular and chemical components of the immune and inflammatory responses -phagocytic cells= lymphocytes, macrophages -immune and inflammatory substances= histamine, antibodies, lymphokines, complement, and proteases

Pyknosis

clumping of the nucleus

Hematoma

collection of blood in soft tissues or an enclosed space -subdural hematoma= between dura mater and surface of brain -epidural hematoma= between skull and dura

caseous necrosis

combination of coagulative and liquefactive necrosis -tissues resemble clumped cheese -usually from tuberculous pulmonary infection

liquefactive necrosis

commonly from ischemic injury to neurons and glial cells of the brain -brain cells are rich in digestive hydrolytic enzymes and lipids -cells digested by their own hydrolases -tissue becomes soft, liquefies -walled off from healthy tissue -bacterial infection

Physiologic hyperplasia

compensatory: adaptive mechanism that enables certain organs to regenerate ex) liver, skin callus hormonal: occurs chiefly in estrogen-dependent organs ex) uterus, breast (prego)

Strangulation

compression and closure of the blood vessels and air passages resulting from external pressure on the neck -causes cerebral hypoxia or anoxia secondary to the alteration or cessation of blood flow to and from the brain

Somatic death

death of an entire person

gangrenous necrosis

death of tissue from severe HYPOXIC injury

Atrophy

decrease in cell size most common in skeletal muscle, heart, secondary sex organs, brain

Dysplasia

deranged cell growth abnormal changes in size, shape, organization of mature cells not a true adaptive process -often called: atypical hyperplasia

Free radical

electrically uncharged atom or group of atoms having an unpaired electron that damage: -lipid peroxidation -alteration of proteins -alteration of DNA -mitochondria

Gunshot wounds

entrance wounds -contact range entrance wound (blow back and muzzle imprint) -intermediate range entrance wound (tattoing and stippling) Exit wounds=shored exit wound (larger than exit wounds)

Where is dysplasia associated?

epithelial tissue of the cervix, lung (respiratory tract)

Karyorrhexis

fragmentation of the nucleus

Which of the following terms best describes death of a cell from hypoxia, generally as a result of ischemia in the lower extremities?

gangrenous necrosis

Chopping wounds

have combination of sharp and blunt force characteristics -associated crushing of wound edges and underlying tissues

single most common cause of cell injury

hypoxic injury

When do hyperplasia and hypertrophy occur together?

if cells can synthesize DNA -nondividing cells: only hypertrophy occurs

Where does hyperplasia occur?

in cells which can regenerate

Hyperplasia

increase in cell number resulting from an increased rate of cellular division -compensatory= adaptive mechanism that enable certain organs to regenerate (ex. liver, skin, callus)

Hypertrophy

increase in cell size most common in heart and kidneys increased cell size from increased accumulation of protein in the cellular components and not with an increase in cellular fluid

ischemia

lack of blood flow

A patient with severe drowning was admitted 5 days ago an has been declared brain dead. What kind of cell death would you expect to find on autopsy of his brain?

liquefactive necrosis

rigor mortis

loss of ATP from body muscles after death causes limbs of corpse to STIFFEN -2 to 3 hours death starts

morbidity vs mortality

morbidity= illness/complications mortality= death

Necrosis vs Apoptosis

necrosis= group of cells apoptosis= single cell -cell breaks apart and is absorbed or phagotized by macrophages

Wet gangrene

neutrophils invade site, causing LIQUEFACTIVE necrosis -usually occurs in internal organs -site becomes cold, swollen, black, foul odor -systemic symptoms associated with HIGH MORTALITY

Karyolysis

nuclear dissolution and chromatin lysis

Manifestations of Cellular Injury

occur in both injured and normal cells cellular accumulations (infiltrations) -water: most common degenerative change -lipids and carbohydrates: metabolic disorders (liver fatty change)

Cellular injury

occurs if cell is unable to maintain homeostasis -reversible (recovery) -irreversible (death) -classified as acute or chronic and reversible or irreverseible

Suffocation

oxygen failing to reach the blood -can result from a lack of oxygen in the environment or blockage of external airway

Infectious Injury

pathogenicity of a microorganism disease-producing potential -invasion and destruction -toxin production -production of hypersensitivity reactions

Stab wounds

penetrating sharp-force injury that is DEEPER than it is long -depths of the wound are clean and distinct, without underlying or associated crush injury -depending on size, location of stab wound, may have only small amount of external bleeding but copious internal bleeding

Chemical asphyxiants

prevent the delivery of oxygen to the tissues or block its use

coagulative necrosis

primarily occurs in kidneys, heart, adrenal glands -commonly results from hypoxia -coagulation caused by protein denaturation

Apoptosis

programmed cellular death -affects scattered, SINGLE cells -"dropping off"

Tissue and systemic aging

progressive stiffness and rigidity -Sarcopenia: "poverty of flesh" degenerative loss of skeletal muscle mass and strength due to aging

livor mortis

setting of the blood in the lower portion of the body -heavy blood cells sink through the serum by gravity

Autolysis

sum of cellular changes after local cell death and the process of cellular auto digestion

Reperfusion injury

tissue damage caused when blood supply returns to the tissue after a period of ischemia or lack of oxygen

Dry gangrene

usually the result of COAGULATIVE necrosis -skin becomes very dry and shrinks (wrinkles) -color changes to dark brown or black

Avulsion

wide area of tissue pulled away creating large skin flap