Lecture 1-3 Flashcards
What is the definition of a nucleus?
The central and most important part of a cell.
What type of tissue is characterized by providing support and structure?
Connective tissue.
What is collagen?
A structural protein found in connective tissues.
What are fibroblasts?
Cells that produce collagen and other fibers in connective tissue.
What are fibrocytes?
Premature fibroblasts that have differentiated.
What color are healthy blood vessels typically described as?
Bright red.
What do endothelium cells line?
Blood vessels.
What does hypoxia refer to?
Oxygen deprivation.
Define ischaemia.
Loss of blood to a tissue due to impeded arterial supply.
What is infarction?
Death to tissue, usually due to ischaemia.
What can cause blockage leading to ischaemia?
- Vessel
- Thrombus (blood clot)
- Embolism (object fully blocking)
What is thrombosis?
Formation of a clotted mass of blood (thrombus) in a cardiovascular system.
What is pneumonia characterized by?
Inadequate oxygenation and obliteration of alveolar spaces.
What are necrosis and apoptosis?
Types of cell death; necrosis is due to irreversible injury.
What occurs during atrophy?
An organ diminishes in size while cells remain alive but have diminished function.
Define hypertrophy.
Increase in cell size and organ size which can be physiological or pathologic.
What is hyperplasia?
Increase in the number of cells, leading to an increase in organ size.
What does metaplasia refer to?
Change in cell type due to damage.
What happens if cells cannot adapt?
They die, leading to necrosis or apoptosis.
What is necrosis?
Cell death where cells die together due to loss of oxygen/blood supply.
What is apoptosis?
Individual cell death triggered by external signals.
What characterizes necrosis?
Cell wall dissociates, releasing cellular material and triggering an immune response.
How is apoptosis different from necrosis?
Apoptosis is orderly and maintains cellular membrane integrity.
What factors does necrosis depend on?
- Cell type
- Type/severity of injury
What is pyknosis?
Shriveling of the nucleus in necrosis.
What is karyorrhexis?
Breaking apart of the nucleus.
What is karyolysis?
Dissolution of the nucleus, often with a ruptured membrane.
What is coagulative necrosis?
Necrosis characterized by protein denaturation.
What is liquefactive necrosis?
Necrosis that results in the formation of pus.
What is caseous necrosis?
Necrosis associated with tuberculosis infections.
What is gangrenous necrosis?
Necrosis resulting from a lack of blood supply.
What is inflammation?
The immune system’s reaction to injury.
What are the two types of inflammation?
- Acute (short term)
- Chronic (long term)
What type of immune system is involved in acute inflammation?
Innate immune system.
What type of immune cells are primarily involved in chronic inflammation?
- Lymphocytes
- APC
- Macrophages
What are local signs of inflammation?
- Heat
- Redness
- Tumor
- Pain
- Loss of function
What are systemic signs of inflammation?
Whole body effects, such as increased neutrophils.
What is histamine?
A chemical mediator involved in inflammation.
What does vasodilation refer to?
The widening of blood vessels.
What is margination in the context of inflammation?
WBC slow down as the vessel dilates.
What is adhesion in inflammation?
Joining of WBC to the vessel wall.
What is chemotaxis?
Movement of WBC towards the site of damage due to chemical signals.
What occurs during resolution of inflammation?
Return to homeostasis after inflammation.
What is chronic inflammation?
Long-term inflammation characterized by tissue destruction.
What are labile cells?
Cells that are always proliferating, e.g., epithelial cells.
What are permanent cells?
Cells that do not proliferate, e.g., neurons and myocardium.
What are stable cells?
Cells that only proliferate with proper stimulation.
What is scarring formation?
Involves new blood vessel formation, fibroblast migration, ECM deposition, and organization of fibrous tissue.
What is angiogenesis?
Growth/sprouting of new blood vessels from existing ones.
What is remodelling in tissue healing?
Breaking down of ECM to strengthen connections.
What is primary union in wound healing?
Healing of clean incisions with minimal effort.
What is secondary union in wound healing?
Healing of larger tissue defects requiring more inflammation and granulation tissue.
What is contracture?
Tissue shortening that limits mobility, often across joints.
What is acute inflammation?
The immediate and early response to harmful stimuli, aimed at eliminating the cause, clearing debris, and initiating repair.
List the causes of acute inflammation.
- Infections (bacterial, viral, fungal, parasitic)
- Tissue necrosis (ischemia, burns, physical trauma)
- Chemical & physical injury (radiation, toxins, frostbite, burns)
- Foreign bodies (splinters, sutures, dirt)
- Immune reactions (autoimmune diseases, allergies)
What are the 5 R’s of acute inflammation?
- Recognition
- Recruitment
- Removal
- Regulation
- Repair
Define the recognition phase in acute inflammation.
Immune cells detect injury via pattern recognition receptors (PRRs) that identify microbial products and damaged cells.
What happens during the recruitment phase of acute inflammation?
Leukocytes (mainly neutrophils) and plasma proteins move to the site of injury.
Explain the removal phase in acute inflammation.
Phagocytosis by neutrophils and macrophages removes debris and pathogens.
What is the purpose of the regulation phase in acute inflammation?
Ensures inflammation resolves appropriately to prevent excessive tissue damage.
What occurs during the repair phase of acute inflammation?
Tissue healing via regeneration or fibrosis.
What are the components of the vascular response in acute inflammation?
- Vasodilation mediated by histamine and prostaglandins
- Increased permeability allowing plasma proteins and leukocytes to exit the bloodstream
What is the role of leukocyte migration in acute inflammation?
Neutrophils and macrophages move toward the site of injury via chemotaxis.
Name key chemical mediators of acute inflammation.
- Histamine
- Prostaglandins
- Leukotrienes
- Cytokines (TNF, IL-1)
- Complement system
What is the outcome of complete resolution in acute inflammation?
Healing with minimal damage in tissues that regenerate.
What does healing by fibrosis entail?
Scar formation occurs when tissue damage is extensive or the tissue cannot regenerate.
Define chronic inflammation.
Long-lasting inflammation characterized by macrophages, lymphocytes, and plasma cells.
What are the common causes of chronic inflammation?
- Persistent infections
- Prolonged exposure to toxic agents
- Autoimmune diseases
List the systemic effects of chronic inflammation.
- Fever
- Weight loss
- Anemia
- Fatigue
What is primary intention healing?
Occurs in clean wounds with opposed edges, resulting in minimal granulation tissue formation.
Describe secondary intention healing.
Occurs in large, open wounds, resulting in more granulation tissue and scarring.
List the stages of healing of bone fractures.
- Hematoma formation
- Soft callus formation
- Hard callus formation
- Remodeling
What factors affect healing?
- Poor blood supply
- Infections
- Diabetes
- Nutritional deficiencies
- Steroid medications
