Cellular Injury Flashcards
What are some mechanisms of cellular injury?
- Hypoxia and Ischemia: Hypoxia refers to a deficiency of oxygen, which can severely impair cellular function, especially in high-energy-demand tissues like the heart and brain. Ischemia, often caused by a blockage of blood supply, not only reduces oxygen but also nutrients, leading to cell injury and death.
- Chemical Agents: Various toxic chemicals, including pollutants, poisons, and some medications, can cause cellular damage. These agents might disrupt cellular membranes, interfere with enzyme systems, or damage DNA.
- Physical Agents: Mechanical trauma, extreme temperatures (burns or frostbite), and radiation can directly damage cellular structures or disrupt key molecular pathways.
- Infectious Agents: Bacteria, viruses, fungi, and parasites can induce cell injury either by directly damaging cells, producing toxins, or triggering immune responses that harm cells.
- Immunologic Reactions: Sometimes, the immune system can injure cells as part of an abnormal reaction (autoimmune diseases) or as an overly vigorous response to a pathogen.
- Genetic Defects: Abnormalities in the genome can lead to the production of dysfunctional proteins or enzymes that disrupt cellular operations or lead to the accumulation of harmful substances.
- Nutritional Imbalances: Deficiency or excess of essential nutrients (like vitamins, minerals, or amino acids) can impair cellular function and lead to injury.
What are some types of cellular adaptation?
- Atrophy: This is a decrease in cell size due to reduced metabolic demand or adverse environmental conditions. Atrophy can be caused by lack of nutrients, decreased hormonal stimulation, disuse, or reduced blood supply.
- Hypertrophy: This refers to an increase in cell size and volume, often in response to increased workload or hormonal stimulation. For example, muscle cells enlarge with exercise, and heart muscle cells may enlarge in response to high blood pressure or valve disease.
- Hyperplasia: This is an increase in the number of cells, usually in response to increased demand or hormonal stimulation. It can be physiological (such as the proliferation of glandular epithelium of the female breast at puberty) or pathological (like in wound healing where there’s an increase of skin cells to cover a wound).
- Metaplasia: Metaplasia is a reversible change where one type of cell is replaced by another type more suited to the environment. This can occur as an adaptive mechanism to chronic irritation and inflammation, such as in smokers where normal columnar ciliated epithelial cells of the bronchi can be replaced by stratified squamous epithelial cells.
- Dysplasia: Often occurring in epithelial tissue, dysplasia is a disorganized appearance of cells because of abnormal variations in size, shape, and organization. It is generally associated with chronic irritation or inflammation and can be a precursor to cancer, though it is not cancer itself.
- Anaplasia: This is characteristic of malignant tumors and involves a lack of differentiation, or a reversion to a more primitive cell type. It’s marked by variations in size and shape of cells, hyperchromatic nuclei, and the loss of normal cell features.
Reversible Cell Injury and characteristics of it
Reversible cell injury is the stage where cells can recover their normal structure and function if the damaging stimulus is removed promptly. This type of injury is typically characterized by:
- Cell Swelling: This is the most common early manifestation of reversible cell injury. Due to damage to the cell membrane’s ion pumps, there is an influx of sodium and water into the cell, leading to swelling.
- Fatty Change: Seen mainly in cells involved in fat metabolism, such as hepatocytes (liver cells), myocardial cells, and kidney cells. It involves the accumulation of lipid vacuoles in the cytoplasm due to impairment of the machinery needed for metabolizing fat.
Irreversible Cell Injury and characteristics of it
Irreversible cell injury is the point beyond which cells cannot recover, and it inevitably leads to cell death, either through necrosis or apoptosis. Characteristics include:
- Severe Membrane Damage: Damage to the plasma membrane leads to loss of cellular components and allows the influx of substances that can further damage the cell. Mitochondrial membrane damage also occurs, impairing energy production.
- Lysosomal Breakdown: Damage to lysosomal membranes releases enzymes that digest cellular components, contributing to cell death.
- Nuclear Changes: These include pyknosis (nucleus shrinkage), karyorrhexis (nucleus fragmentation), and karyolysis (dissolution of the nucleus).
Irreversible injury usually involves more severe and sustained stresses, such as prolonged hypoxia, persistent toxic chemical exposure, or overwhelming infections.
Tell me about Genetic Mutations and their relationship with cancer.
Cancer typically begins with genetic mutations in a single cell. These mutations can be inherited or acquired due to environmental exposures and lifestyle factors. Mutations in oncogenes (genes that promote cell division), tumor suppressor genes (genes that control cell division and repair damaged DNA), and genes involved in DNA repair can lead to cancer. These genetic changes cause the cells to proliferate uncontrollably.
Tell me about Metastasis
Metastasis is the process by which cancer cells spread from the place where they first formed (primary site) to other parts of the body. Cancer cells break away from the original tumor and travel through the bloodstream or lymphatic system to form new tumors (metastatic tumors) in other organs. This process is facilitated by changes in cell adhesion and the ability of cancer cells to invade other tissues.
What are some Risk Factors for cancer
- Lifestyle factors: Smoking, excessive alcohol consumption, poor diet, and lack of physical activity.
- Environmental exposures: Exposure to carcinogens such as asbestos, benzene, and certain pollutants.
- Biological factors: Certain viruses (e.g., HPV, hepatitis B and C), bacteria, and chronic inflammation.
- Genetic predispositon: Family history of cancer and genetic disorders such as BRCA1 and BRCA2 mutations.
- Age: Most cancers become more prevalent with increasing age.
Give me some Clinical Manifestations of Cancer
The signs and symptoms of cancer vary depending on the type and location of the cancer but may include:
- Unexplained weight loss
- Fever
- Fatigue
- Pain
- Skin changes (e.g., hyperpigmentation, jaundice, reddened skin)
- Changes in bowel or bladder habits
- Unusual bleeding or discharge
- Persistent cough or hoarseness
- Lumps or tissue masses
What are some treatments for cancer?
The treatment of cancer depends on the type, location, and stage of the cancer, as well as the overall health of the patient. Common treatments include:
- Surgery: Removal of the tumor and surrounding tissue.
- Radiation Therapy: Using high doses of radiation to kill cancer cells.
- Chemotherapy: Using drugs to kill cancer cells. It can be systemic (affecting the whole body) or localized to the area of the tumor.
- Immunotherapy: Boosting the body’s own immune system to fight cancer.
- Targeted Therapy: Using drugs or other substances to specifically target cancer cells without harming normal cells.
- Hormonal Therapy: Used for cancers that are sensitive to hormones, such as breast and prostate cancer.
