Cells of CT
What are their functions:
Fibroblasts
Mesenchymal Cells
Adipocytes
Chondrocytes
Osteoblasts
Hematopoietic Stem Cells
Produce Collagens, Proteoglycans, Glycoproteins
CT Stem Cells
Store/Release Fats
Produce/Maintain Cartilage Components
Produce Bone Components
Produce RBCs and Immune Cells
Fibroblast
Function?
- Produce:
- Collagen
- Elastin
- Reticular fibers
- Proteoglycans
- Glycoproteins
Adipocytes
Appearance?
Function?
Closely packed with nuclei pushed to side by large fat droplet
Removes lipids from blood, stores it, and releases into bloodstream when needed; Provides reserve energy source
ECM of CT - Fibrous Component
Collagens: What type is most common and function?
Elastin: What is it? Made up of what?
Reticular Fibers: Forms what?
Type 1 - Resists Tension
Stretchable Fiber (Tropoelastin, Fibulin-1, and Fibrillins 1 & 2)
Forms Supportive Meshwork
Type-I Collagen Fibers
They are aligned and crosslinked for what reason?
What two pathologic conditions are related to Collagen?
- Increase Tensile Strength
- Scurvy
- Vit. C Deficiency: co-factor in cross-linking collagen fibers; weakens CT
- Ehlers-Danlos Syndrome
- Abnormal collagen synthesis leading to weak collagen fibers
Marfan’s Syndrome
Autosomal dominant disorder causing weakness in what fiber?
Mutation in what?
What systems are principle targets?
How do patients present?
- Elastin
- Fibrillin-I gene (component of Elastin fibers)
- Ocular, Skeletal, Cardiovascular Systems
- Life threatening CV anomalies - dissecting aneurysms, mitral prolapse
- Tall with long arms/legs (skeletal defects)
ECM of CT - Amporphous Ground Substance
What is located here? (P.H.G.E.)
- Proteoglycans
- Chondroitin, Heparan, and Keratan Sulfates
- Hyaluronan
- Glycoproteins
- Cytokines, GFs, Structural Proteins
- Extracellular Proenzymes
Embryonic CT
Contain high amounts of what?
Reffered to as what in Umbilical Cord?
ECM and in Mesenchymal Stem Cells (Multipotent)
Warton’s Jelly
Adult Mesenchymal Stem Cells
Multipotent stem cells that can differentiate into what cell types?
Fibroblasts
Muscle Cells
Osteoblasts
Chondroblasts
Adipocytes
Fibrous CT Classes
What are the types of Loose CT?
What are the types of Dense CT?
- Loose
- Areolar (Fixed and wandering cells)
- Adipose (Fat containing)
- Reticular (Reticular fibers; open framework to create supportive mesh for holding free cells)
- Dense
- Dense Irregular CT (Random pattern - Dermis)
- Dense Regular CT (Regular pattern - Tendons)
- Elastic CT (Elastin Fibers)
Loose Areolar CT
What cell types are considered Fixed and Wandering Cells?
- Fixed (FAM)
- Fibroblasts, Adipocytes, Mesenchymal Cells
- Wandering Cells
- Macrophages, Mast Cells, WBCs/Lymphocytes, Plasma Cells
Loose CT
Function?
Location?
- Function
- Support/Bind other tissues
- Hold body fluids
- Defends against infection
- Location
- Immediately beneath membranous epithelia (referred to as lamina propria)
- Around BVs, Muscles, and Nerves
Adipose CT
Characterized by what?
Functions?
Location?
Difference between White and Brown fat?
- Adipocytes and Limited ECM
- Function
- Reserve energy; Insulation; Supports/protects organs
- Location
- Under Skin; Around Organs; Within Abdomen, Breast, and Buttocks
- White Fat: Energy Storage, Insulation, Cushioning Organs, Hormone Secretion
- Brown Fat: Thermogenic Tissue, Abundant in Newborns, Reduced in Adults
Reticular CT
Rich in what component?
Forms what?
Location?
- Reticular fibers
- Open framework for holding free cells
- BM & Lymph Nodes, Spleen & Liver
- Meshwork formed stores blood cells and immune cells outside blood and lymphatic vessels
Dense Irregular CT
What is it?
Principle Cell Type?
Location?
- ECM of tightly packed, interwoven collagen fibers running in random pattern
- Fibroblasts
- Location:
- Dermis; Fascia; Perichondrium and Periosteum; Capsules surrounding Internal Organs
Dense Regular CT
What is it?
Principle cell type?
Location?
Resists what?
Vascular status?
Appearance?
ECM of tightly packed, regularly arranged collagen fibers
Fibroblasts
Location: Tendons, Ligaments, Aponeuroses, Dense Fascia, Joint Capsules
Resists Pulling Forces
Poorly Vascularized
When not under tension, has Wavy appearance
Elastic CT
Has high proportion of what?
Allows for what to occur?
Location?
High proportion of Elastic Fibers
Allows recoil of tissue following stretching
Blood vessel walls, bronchiole tubes, special ligaments (ligamentum nuchae)
Macrophages
What are they differentiated from?
Function?
Blood Monocytes
Phagocytosis and destruction of bacteria, damaged or sick cells; Removal of cell debris; Antigen processing and presentation
Mast Cell
What do they secrete and what are there functions?
Histamine (mediate allergic response)
Heparin (anti-coagulant of blood)
Plasma Cells
What are they differentiated from?
Function?
B-Lymphocytes
Produce antibodies that mediate immunity
