Week 3- Injury, Inflammation, Healing and Repair Flashcards
The structural and functional changes in the body caused by disease or trauma
Pathology
What do the structural and functional changes produced by pathology start with?
Injury to the cells that make up the tissues
What does mild injury produced by stressors leads to?
Sublethal alterations of the affected cells that may be reversible
What does moderate/severe injury leads to?
Lethal alterations that are likely irreversible and can lead to cell death
True or false: Cell injury may be reversible or irreversible
True
What determines if an injury is reversible?
The cell’s ability to withstand the derangement of homeostatic mechanisms and its adaptability
What is reversing the injury and achieving homeostasis determined by?
-Mechanism of injury
-Length of time the injury is present without intervention
-Severity of the injury
When does ischemia occur?
Blood flow is insufficient to maintain cell homeostasis and metabolic function
What are the causes of cell injury?
-Ischemia
-Infectious agents
-Immune reactions
-Genetic factors
-Nutritional factors
-Physical factors
-Chemical factors
What does insufficient blood flow result in?
-partial/total reduction in oxygen supply
-decreased delivery of nutrients
-decreased removal of waste products from the tissue
What does lack of oxygen lead to?
Loss of aerobic metabolism
True or false: The resulting reduction in ATP synthesis leads to accumulation of ions and fluid intracellularly, causing the cells to swell.
True
Ischemia resulting in _______ or __________ can cause ________ and accounts for two of the three leading causes of mortality in industrialized nations
-myocardial infarction
-stroke
-necrosis (death of tissue)
What are responsible for most infections?
Bacterial and viral agents
How do bacterial infections cause cell injury?
Invading tissue and releasing exotoxins and endotoxins that can cause cell lysis and degradation of extracellular matrix and aid in the spread of the infection
Term for involuntary muscle contractions
Tetanus
Endotoxins released from gram-negative bacteria induce the synthesis of _________and ________ that are responsible for many of the systemic
manifestations of sepsis.
-cytokines
-interleukins
Cardiovascular collapse may lead to a condition called ______________.
Septic shock
True or False: The detection of an infectious agent initiates an
inflammatory reaction designed to contain and inactivate the pathogen, but the magnitude of this defensive response by the host may also cause
cellular or tissue destruction in the infected area.
True
What are two ways viruses kill cells?
-Kill from within by disturbing various cellular processes or by disrupting the integrity of the nucleus and/or plasma membrane
-Virally encoded proteins become inserted into the plasma membrane of the host cell (forming a channel) and alter the permeability of the cell membrane to ions
True or false: Viruses do not integrate themselves into the cellular genome
False
What happens when the immune system is compromised or if the number of invading microorganisms overwhelms the immune system?
Disease
What are the mechanisms by which the immune system can lead to cell injury/death?
-antibody attachment
-complement activation
-activation of the inflammatory cells
What are some ways the immune system can cause cell injury and disease?
-Allergies
-Severe hypoxia
-Cross reactivity between foreign and host antigens
How are toxic substances divided?
-Substances than can injure cells directly
-Substances that require metabolic transformation into the toxic agent
Example of drug-induced chemical toxicity
Suicide via drug overdose
Another term for reactive oxygen species
Free radicals
A variety of normal and pathologic reactions can lead to the activation of _______ by the sequential addition or subtraction,
respectively, of one electron at a time.
Oxygen
True or false: Free radicals only exert positive effects
False
(they exert positive or negative effects)
True or false: Free radicals are an integral part of metabolism and formed continuously
True
What happens when a normal oxygen atoms lose one of their four paired electrons?
A chain reaction occurs
True or false: The cellular enzymes always scavenging the body to protect cells from
injury normally inactivate radicals and convert the free
radical back to usable oxygen.
True
True or false: Some unstable oxygen molecules (i.e., free
radicals) enable the body to fight inflammation, kill bacteria, and help regulate the autonomic nervous system.
True
Situation when radicals are produced in excess amounts
Oxidative stress
Research has
shown that oxidative stresses caused by ROS are factors in more than ______%
of lifestyle-related diseases
90%
Oxidation as a by-product of metabolism damages _________, leading to intrinsic cellular damage, a part of the normal aging process
Cell membranes
Other causes for free radical formation
-Exposure of toxic chemicals
-Exposure to high level of oxygen
-Irradiation
-Ultraviolet
-Fluorescent light
-Pollutants
-Tobacco smoke
-Pesticides
-Drug overdose
-Heat stress
-Reperfusion injury
-Prolonged exercise
What neutralizes extra free radicals and stop chain reactions?
Antioxidants
A variety of enzymatic and nonenzymatic
defense mechanisms are present within cells to perform the function of
antioxidants detoxifying ROS and protecting the cells from this type of
injury.
Endogenous antioxidants
This can be obtained from outside the body through diet (in food and plant substances)
Exogenous antioxidants
True or False: Moderate physical activity and exercise strengthen the antioxidant defense system
True
True or false: Intense or prolonged, strenuous exercise (especially in person with a sedentary lifestyle) does not lead to oxidative stress
False
This molecule is present in all mammals including humans and is one of the few gaseous signaling molecules known
NO (nitric oxide)
What are the three primary ways genetic alterations lead to cellular injury/death?
-Alterations in the structure or number of chromosomes that
induce multiple abnormalities
-Single mutations of genes that cause changes in the amount or functions of proteins
-Multiple gene
mutations that interact with environmental factors to cause multifactorial
disorders
Examples of alterations in the structure or number of chromosomes that induce multiple abnormalities
Down syndrome: 3rd chromosome in 21st pair
Examples of single mutations of genes that cause changes in the amount or functions of proteins
Sickle cell anemia, low-density lipoprotein receptor deficiency, and α-antitrypsin deficiency
Examples of multiple gene mutations that interact with environmental factors to cause multifactorial disorders
Hypertension and type 2 diabetes
Proposes that changes in the relative level of physical stress cause a predictable adaptive response in all biologic tissue
Physical stress theory