Podcast
Questions and Answers
What is a characteristic sign of classical apoptosis?
What is a characteristic sign of classical apoptosis?
Which pathway is primarily associated with death receptor-mediated apoptosis?
Which pathway is primarily associated with death receptor-mediated apoptosis?
What type of necrosis is characterized by the tissue dissolving and losing all structural integrity?
What type of necrosis is characterized by the tissue dissolving and losing all structural integrity?
What is a common effect of immune-related cell death?
What is a common effect of immune-related cell death?
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Which type of necrosis is often associated with tuberculosis?
Which type of necrosis is often associated with tuberculosis?
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What process is primarily involved in DNA fragmentation during apoptosis?
What process is primarily involved in DNA fragmentation during apoptosis?
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What type of necrosis is usually observed in the brain during severe infections?
What type of necrosis is usually observed in the brain during severe infections?
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Which type of necrosis can occur as a result of significant blood supply loss and is commonly seen in diabetic patients?
Which type of necrosis can occur as a result of significant blood supply loss and is commonly seen in diabetic patients?
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What is the primary mechanism behind hypertrophy in tissues?
What is the primary mechanism behind hypertrophy in tissues?
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Which type of epithelium lines the kidneys and thyroid glands?
Which type of epithelium lines the kidneys and thyroid glands?
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What is the main characteristic of metaplasia in tissues?
What is the main characteristic of metaplasia in tissues?
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Which of the following is NOT a macroscopic change in tissues?
Which of the following is NOT a macroscopic change in tissues?
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What does physiological atrophy refer to?
What does physiological atrophy refer to?
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Which of the following changes is characterized by the increase in cell numbers in tissues?
Which of the following changes is characterized by the increase in cell numbers in tissues?
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Alcohol abuse can lead to which type of inclusions in liver cells?
Alcohol abuse can lead to which type of inclusions in liver cells?
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Which of the following best describes apoptosis?
Which of the following best describes apoptosis?
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During which type of stress does a cell shrink in size?
During which type of stress does a cell shrink in size?
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Which of the following conditions results from chronic irritation, leading to metaplasia?
Which of the following conditions results from chronic irritation, leading to metaplasia?
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Study Notes
Mechanisms of Tissue Injury
- Pathological diagnosis relies on macroscopic and microscopic tissue changes.
- Living cells adapt to environmental changes; failure leads to cell injury or death.
- Cellular changes can be observed at both organ and cellular levels, influencing diagnosis.
Tissue Changes
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Macroscopic changes (Organ level):
- Hypertrophy: increased cell size; organs may grow.
- Atrophy: shrinkage of cell or organ size.
- Dysplasia: abnormal development.
- Pigmentation and calcification: abnormal color and hardening changes.
- Fatty change: deposits of fat in tissues.
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Microscopic changes (Cellular level):
- Pigmentation: visible changes due to substance accumulation.
- Inclusions: e.g., iron (hemosiderin), fat, or lipofuscin.
- Multi-nucleation: presence of multiple nuclei in a cell.
- Apoptosis: programmed cell death; necrosis: uncontrolled cell death.
Macroscopic and Microscopic Liver Changes
- Normal liver structure vs. fatty liver distinguishable via imaging.
- Hyaline inclusions in the liver, referred to as Mallory bodies, associated with alcohol-related liver damage.
Tissue Responses to Stress
- Increased demand leads to hypertrophy and hyperplasia (cell number increase).
- Decreased demand causes atrophy (cell shrinkage).
- Chronic injury can result in metaplasia (cell type change).
Key Definitions
- Hypertrophy: Increases in cell size; can occur in both dividing and non-dividing cells.
- Hyperplasia: Increase in cell number; applies only to dividing cells.
- Atrophy: Reduction in size of cells or organs due to decreased stimulation.
- Metaplasia: Transformation of one cell type into another.
Physiological vs. Pathological Hypertrophy
- Physiological hypertrophy occurs, for example, in the uterus during pregnancy.
- Pathological hypertrophy exemplified in benign prostatic hyperplasia (BPH), linked to hormonal changes.
Atrophy
- Physiological atrophy: uterine shrinkage post-pregnancy due to loss of hormonal signals.
- Pathological atrophy seen in muscle wasting after fractures or neurodegenerative diseases like Alzheimer's.
Epithelial Cell Types
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Simple Epithelium: Covers surfaces as single layers.
- Squamous Epithelium: Found in body cavities, vessels, alveoli.
- Cuboidal Epithelium: Lines nephrons and thyroid glands.
- Columnar Epithelium: Lines intestines, uterine tubes, respiratory tract.
Metaplasia Types
- Squamous metaplasia occurs in the upper airways of smokers, replacing columnar cells with squamous cells.
- Intestinal metaplasia (Barrett’s esophagus) occurs at the gastro-esophageal junction due to GERD.
Causes of Cell Death
- Oxygen deprivation, physical injury, chemicals, infectious agents, genetic factors, immune reactions, and nutritional deficiencies can lead to cell death.
Apoptosis vs. Necrosis
- Apoptosis: Controlled, programmed cell death, often silent; characterized by DNA laddering and caspase activation.
- Necrosis: Violent cell death that causes inflammation, leading to visible tissue damage.
Types of Necrosis
- Coagulative Necrosis: Basic tissue architecture preserved; often seen in heart muscle post-infarct.
- Liquefactive Necrosis: Complete tissue dissolution; typical in severe infections, notably in brain.
Clinical Types of Necrosis
- Gangrene: Indicates loss of blood supply, may be dry or wet; often seen in conditions such as diabetes leading to foot ulcers.
- Caseous Necrosis: Characteristic of tuberculosis, the tissue appears cheeselike.
- Fat Necrosis: Associated with tissue damage and fat destruction, often from pancreatitis.
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Description
Explore the mechanisms of tissue injury in this clinical medicine lecture. Understand how pathological diagnoses are made based on cellular changes and the impact of environmental stress on living cells. This session will delve into adaptations, injuries, and the critical aspects of cellular health.
