Chapter 4 - Altered Cellular and Tissue Biology Flashcards
When does cellular injury occur?
if a cell is unable to maintain homeostasis
What is the result of reversible cellular injury?
cells recover
What is the result of irreversible cellular injury?
cells die
Physiological Cellular Response
adaptive
Pathogenic Cellular Response
disease causing
What is cellular atrophy?
decrease in cellular size
What is cellular hypertrophy?
increase in cellular size
What is cellular hyperplasia?
increase in cellular number
What is cellular metaplasia?
replacement of one type of cell with another
What is cellular dysplasia?
deranged cellular growth
When does cellular metaplasia occur?
with chronic injury or irritation
What does “meta” mean?
after, behind
When does cellular dysplasia occur?
persistent severe injury or irritation
What does “dys” mean?
bad
What is the most common cause of cellular injury?
hypoxic injury
Ischemia
reduced or restricted blood flow leading to inadequate blood supply
What is the most common cause of hypoxia?
ischemia
What organelle is the main cellular consumer of oxygen?
mitochondria
What is the result of reduced oxygen to the mitochondria?
reduced ATP production resulting in reduced cellular energy and accumulation of H+
What can an accumulation of H+ in the mitochondria result in?
breakdown in the membrane leading to an increase intracellular H+ and loss of membrane potential
What does lost membrane potential lead to?
necrosis
Ischemia-Reperfusion Injury
additional injury caused by restoration of blood flow and oxygen
What are the mechanisms if ischemia-reperfusion injury?
oxidative stress, increased intracellular calcium, inflammation
Cellular response to hypoxic injury?
decrease in ATP leading to sodium-potassium pump and sodium-calcium exchange failure
What is the physical effect of hypoxic injury on cells?
swelling or shrinking
What are free radicals?
atoms missing an electron
What do free radicals do to healthy atoms?
attack them to obtain a replacement electron
Reactive Oxygen Species (ROS)
oxygen containing subset of free radicals created as a result of oxygen metabolism
Free Radicals are by-products of what?
normal metabolism
Oxidative stress results from…
not producing enough antioxidants to break down free radicals
Oxidative stress plays a major role in ______ and _________ ailments.
chronic and degenerative
What 3 things do free radicals cause?
- lipid peroxidation
- protein alteration
- DNA alteration
Lipid Peroxidation
damage to the lipid membrane
Protein Alteration
denaturation, breakdown, unfolding of proteins
DNA alteration
mutations in genes
What are xenobiotics?
substances foreign to the body (ie. lead, carbon monoxide, ethanol, mercury)
What chemical agent is most common in industry overexposure?
lead
Where is lead found?
houses with old paint that is chipped off and inhaled
How does lead affect humans?
lead poisoning, especially in fetus with immature BBB
Carbon monoxide is an _______, __________, __________ gas
odourless, colourless, nonirritating
How does carbon monoxide cause hypoxic injury?
oxygen deprivation by attaching to hemoglobin which has a higher affinity for CO
What is not able to store ethanol?
liver, unable to store the alcohol and becomes overwhelmed so it must make enzymes to break it down
Where is alcohol absorbed?
stomach
Nutritional deficiencies?
Alcohol consumption effects show a __-shaped curve
J-shaped
Light to moderate drinkers have a ______ mortality than non-drinkers
lower
Heavy drinkers have a ______ mortality
higher
What is the result of alcohol in light to moderate drinkers?
decreased LDL levels, decreased BP, decrease in atherosclerosis
Who does mercury threaten?
global and environmental health
What is the leading cause of child poisonings?
medications
What is a major limitation to medication therapy?
chemical injury
How do chemicals and medications cause direct damage to cells?
combine directly with critical molecular substances
On-Target Toxicity
direct damage to cells caused by chemotherapeutic and drugs of abuse
What do medications activate?
toxic metabolites and free radicals
What is a hypersensitivity reaction?
reaction to medication that ranges from a mild skin rash to immune-mediated organ failure
Asphyxiation
failure of cells to receive or use oxygen
Suffocation
aka systemic hypoxia resulting from no air exchange
Strangulation
results from compression or closure of airways and causes cerebral hypoxia
Drowning
when fluid fills the lungs and prevents oxygen exchange
Drowning lets fluid pass through the capillaries and results in…
fluid and electrolyte changes in blood
Chemical Asphyxiation
oxygen utilization and delivery is prevented
How is carbon monoxide poisoning treated?
hyperbaric chamber
What does cyanide do?
blocks oxygen at the ETC and leads to cardiac arrest
Contusion
crushing injury to muscle, bruising
Laceration
irregular cut with irregular edges
Incision
sharp straight wound
Fracture
broken or shattered bones
Incised Wounds
wound is longer than it is deep
Stab Wound
wound is deeper than it is long
Puncture Wound
sharp point but not edges
What is an infectious injury?
invasion of a pathogen that causes disease
What does the disease-producing ability of a pathogen depend on?
how the pathogen invades, destroys, produces toxins, initiates a hyper immune reaction
Apoptosis
cell death that occurs as a normal, controlled part of an organisms growth
Apoptosis is an ______ process
orderly
What happens during apoptosis?
the cell breaks up into sections that are taken away by the immune system
Autophagy
consumption of a cells own contents to be used as fuel in order to oppose starvation and disease
Necrosis
uncontrolled swelling and bursting of a cell membrane
Why does necrosis happen?
disease, injury, failure of blood supply
Necrosis occurs at the _____ level
cellular
What are examples of organs where coagulative necrosis occurs?
kidney, heart
What is the cause of coagulative necrosis?
ischemia or infarction
Infarction
obstruction of blood supply causing cell death
Ischemic cells can be revived if oxygen is restored within ___ minutes
20
What causes coagulation?
protein denaturation
Where does caseous necrosis occur?
lungs
What is the appearance of tissue affected by caseous necrosis?
clumped cheese
What causes caseous necrosis?
Tuberculosis (Mycobacterium tuberculosis)
What is the danger of TB?
dead cells become enveloped by other cells which increases their mass and decreases lung space
Where does liquefactive necrosis occur?
brain
What is the cause of liquefactive necrosis?
ischemic injury to neurons and glial cells
What does liquefactive necrosis do?
turns tissue into liquid and causes infarction (blocking blood supply = cell death)
Which bacteria may be responsible for liquefactive necrosis?
Streptococci or E. coli
Where does fatty necrosis occur?
breasts and abdominal organs
Fatty necrosis involved the action of what enzyme?
lipases
Is fatty necrosis harmful?
usually no, body absorbs
Gangrenous necrosis usually results from…
hypoxic injury (usually to major lower leg arteries)
Areas of gangrenous necrosis are mediums for _____ _____
anaerobic bacterial growth
Which bacteria causes gas gangrene?
Clostridium (anaerobic)
When is gas gangrene fatal?
when it enters the blood and diminishes RBC oxygen carrying capacity (clostridium produces other gases)
Oncosis
cell death due to swelling
Oncosis: When ATP production decreases due to hypoxia, sodium and water move OUT of the cell and then…
potassium moves INTO the cell causing the osmotic pressure to increase and water moves into the cell
What organelle is affected by oncosis?
Endoplasmic reticulum cisternae which distend, rupture, and form vacuoles
Vacuolation
formation of vacuoles
Cellular aging involves a_____, decreased function, and cell loss
atrophy
What is the result of tissue and systemic aging?
stiffness and rigidity
Sarcopenia
progressive loss of skeletal muscle mass and strength
