Explain
Sarcoma
Malignant tumors of the connective tissues and muscles
Arise from mesenchymal tissues
The most common adult soft tissue sarcoma is malignant fibrous histiocytoma, thought to derived from perivascular mesenchymal cells
What do connective tissues function in?
- Support
- Transport
- Storage
- Immune defence
- Thermoregulation
What are the 2 major groupings of connective tissue?
- Connective tissue proper - Includes loose & dense CT (arranged in irregular or regular conformation)
- Specialized connective tissue - Includes cartilage, bone, adipose tissue (fat), hemopoietic tissue, blood & lymph
Hemopoietic tissue - specialized tissue where new blood cells - including red blood cells, white blood cells, and platelets are formed through a process called hematopoiesis
Explain
Connective Tissue Proper
Includes a variety of cell types & fibers enmeshed in a ground substance that comprises an extracellular matrix
Explain
Loose Connective Tissue
(Areolar)
Found largely under the epithelium that forms the body’s surface & the epithelium that lines the body’s internal organ systems
LCT along with the skin is the first line of defence against infection
Explain
Dense Connective Tissue
Has many fibers, few cells & includes tendons, ligaments, the submucosa and reticular layers that offer support
What are the fibrous elements in connective tissue?
- Collagen fibers - numerous in CT, offer flexibility & strength
- Elastic fibers - interwoven fibers that offer flexibility & retain their shape if stretched
- Reticular fibers - thinner collagen fibers that provide strength & are the least common of the fibrous elements
True or False?
There are over 25 types of Collagen
True
List the types of collagen from I - IV
- I - accounts for 90 % of body’s collagen, most common in the skin, muscle tendons, ligaments & bones
- II - found in cartilage
- III - found in loose connective tissue & forms a loose reticular meshwork or supportive scaffold for the tissues and organs
- IV - found in the basement membrane supporting the epithelium
Define
Keloids
Occur when scar tissue of the skin grows well beyond the boundary of the initial wound & does not normally regress
Explain
Fibrosis
The deposition & overgrowth of fibrous connetive tissue that forms scar tissue
Occurs : laceration (cut), infection allergy or long-term inflammation
Define
Scleroderma
A chronic, degenerative disease resulting from an excessive production of collagen due to an autoimmune dysfunction
Define
Marfan Syndrome
Inherited connective tissue disorder caused by molecular defects in a gene which encode an extracellular protein that is component in microfibrils
Microfibrils serve as scaffolds for the deposition of elastic fibers
Define
Chronic Inflammation
Results in fibrosis & tissue necrosis
Linked to many autoimmune disorders
Define
Lipomas
Most common mesenchymal soft tissue tumors in adults that grow slowly & are usually found in proximal limbs, back, shoulder & neck
Can be removed by liposuction and surgical excision
Explain function
Plasma cells
Secrete immunoglobulins & are derived from B lymphocytes - white blood cells that are essential for the body’s adaptive immune response, primarily by producing antibodies to fight pathogens and toxins
Explain function
Macrophages
Phagocytic cells - specialized immune cells that engulf and eliminate foreign particles, pathogens like bacteria and fungi, and dead or damaged cells - derived from monocytes in the blood
Explain function
Lymphocytes
The principal cells of the immune system
Explain function
Mast cells
Respond early to immunologic challenges & secrete powerful vasoactive - substances or factors that cause the blood vessels to constrict (get narrower) or dilate (get wider), altering blood pressure and/or heart rate - and chemotactic substances
Explain function
Adipocytes
Store & release triglycerides - main type of fat in your body, stored for energy by converting unused calories from food, and they also come from dietary fats - as needed by the body and produce hormones & growth factors
Explain function
Fibroblasts
Abundant cells that sythesize all fibrous elements & elaborate the matrix
Explain function
Eosinophils
Phagocytes - white blood cells of the immune system that perform phagocytosis by engulfing and destroying foreign particles, pathogens like bacteria, and dead or damaged cells -that respond to allergens & parasitic infections
Explain function
Myofibroblasts
Capable of contraction & function in ways that are similar to fibroblasts and smooth muscle cells
Explain function
Neutrophils
Respond to injury & immunologic challenges and are capable of phagocytosis - phagocytes engulf other cells, particles and even pathogens
