Fibrous Connective Tissue Flashcards
What are the 4 major types of connective tissue?
Fibrous CT, Cartilage CT, Bone CT, Blood CT
What are the functions of connective tissue?
Structural framework for body, protection, defense against microorganisms, supports and interconnects other tissues, energy storage, transports fluids, cells, and dissolved chemicals throughout the body
What are the 3 basic fibers found in the ECM?
Collagen, Elastic fibers and Reticular fibers
What type of collagen is the most common?
Type 1
What is the main job of collagen?
Resist tension
List the properties of type 1 collagen
Fibrils are aligned and crosslinked to increase the tensile strength; made of 2 alpha1 chains and 1 alpha2 chain that are processed and then crosslinked on the surface of the cell
How does scurvy affect collagen?
Scurvy is a vitamin C deficiency, and vitamin C is needed in order to crosslink collagen fibers. This deficiency results in weakened collagen and CT
What are the symptoms of scurvy?
Bleeding gums, loss of teeth, easy bruising and poor healing
What is Ehlers Danlos Syndrome?
ABnormal collagen synthesis due to mutations in the collagen or collagen synthesis genes = overly flexible joints
It results in weakened collagen fibers
What are elastic fibers?
Protein fibers that are elastic and recoil back to original state when stretched
What are elastic fibers made up of?
Tropoelastin, fibulin 1, fibrillin 1, fibrillin 2
What are reticular fibers?
They form a meshlike supportive network around structures
What is something reticular fibers connect?
Connective tissue to basement membranes
What is ground substance?
An amorphous, gel-like substance in the extracellular space that contains all components of the ECM BESIDES the fibrous materials (collagen, elastin)
Why is ground substance important?
It carries oxygen, carbon dioxide, nutrients and waste
What are the fixed cell types found in loose areolar CT?
Fibroblasts, adipocytes, mesenchymal cells
Function of fibroblasts?
Produce collagens, proteoglycans, and glycoproteins
Function of adipocytes?
Stores and releases fats
Function of mesenchymal cells?
CT stem cells
What are the wandering cell types found in loose areolar CT?
Macrophages, mast cells, leukocytes/lymphocytes, plasma cells
Difference between fixed and wandering cells?
Fixed are permanent and wandering cells are actively migrating
What is the function and location of loose CT?
Support and bind other tissues, hold body fluids, defense against infection
Found beneath membranous epithelia
Principle cell type of Dense connective tissue?
Fibroblasts
What is the purpose of proteoglycans and hyaluronans?
Sugar molecules in the ground substance that hold water and are responsible for resisting compressive forces
What is the purpose of glycoproteins?
In the ground substance, can protect proteins from destruction, serve as signaling molecules and serve as structural molecules for the ground substance to be built
Subclasses of loose CT?
Areolar, Adipose, and reticular
Describe loose adipose CT
Abundant adipocytes and sparse ECM, provides energy reserve and insulates against heat loss, also provides protection to organs by cushioning
What are the 2 types of loose adipose CT?
White fat and brown fat
Purpose of white fat?
Energy storage, insulation, cushion for vital organs and hormone secretion
Purpose of brown fat?
Thermogenic tissue (produces heat), abundant in newborns and reduced in adults
Describe loose reticular CT?
Rich in reticular fibers, creates a supportive mesh for holding free cells
Found in the liver, bone marrow, lymph nodes and spleen where meshwork it forms houses blood cells and immune cells
2 types of Dense CT?
Regular and irregular
Describe Dense irregular CT?
High fibrous density with fibers in a RANDOM pattern
ex. dermis of skin, fascia, surrounding internal organs
Describe Dense regular CT?
ECM tightly packed with fibers REGULARLY arranged, resists tension, poorly vascularized, wavy appearance when not in tension
ex. tendons, ligaments, aponeuroses, dense fascia, joint capsules
Describe elastic CT?
High number of elastic fibers that allow stretching
ex. blood vessel walls, bronchiole tubes, nuchal ligament
Marfan’s syndrom
Autosomal dominant disorder = elastin is weak! due to mutation in fibrillin 1 gene
Targets ocular, skeletal (long arms and legs) and cardiovascular (life threatening aneurysms)
Difference between embryonic and adult CT?
Embryonic is high in mesenchymal cells and ECM but low fibril count
Adult is high in fibrils and their mesenchymal cells are differentiated into other cell types
How do cells interact with the ECM?
Integrin receptors, syndecans, CD44, growth factor receptors, cytokine receptors
What are integrin receptors?
Transmembrane receptors that bind ECM components and initiate signaling cascades using RTK mechanisms
Epithelia and CT combine to form membranes, list the 4 types
Mucous, serous, cutaneous, synovial
