Fibrous Connective Tissue Flashcards
What are some characteristics of connective tissues? (4)
- CT is never exposed to the outside environment
- CT cells are separated by ECM
- Contains ECM, which is embedded in protein fibers, carries O2, CO2, nutrients and waste
- There is embryonic and aduct CT
What are the main functions of CT? (6)
- Structure
- Protection
- Support/interconnection
- Energy storage (adipose tissue)
- Transports fluids
- Defense against microorganisms
What do fibroblasts do?
produce collagens, proteoglycans and glyocproteins
What are mesenchymal cells?
connect tissue stem cells (multipotent)
What do adipocytes do?
Store and release fats
What do chondrocytes/chondroblasts do?
produce and maintain cartilage components
What do osteoblasts/osteocytes/clasts do?
Produce bone components
What do hematogpoeitic cells do?
Produce red blood cells and immune cells such as macrophages and mast cells
What are the 3 types of fibrous components in CT, and what do they do?
Collagens (type 1 most common): resists tension
Elastin : stretchable fiber
Reticular fibers: forms supportive meshwork (bone marrow)
What cross-links collagen (2 A1 helical, 1 A2 helical) to form the tensile tetromere collagen strands?
Vitamin C
What disease can occur if vitamin C is low?
Scurvy, which is due to weakened CT by weaked/malformed collagen
What is Ehlers-Danlos Syndrome?
Abnormal collagen synthesis leading to weak collagen fibers. Hereditary disease in enzymes to make vitamin C
What autosomal dominant disorder occurs when there is a mutation in the fibrillin-I gene of elastin fibers, making the elastin weak?
Marfan’s Syndrome
What are some common signs of marfan’s syndrome?
skeletal problems: patients are tall with long arms/legs
cardiovascular problems (dissecting aneurysms/ mitral prolapse)
Chondoitin, heparan, and keratan sulfates are all part of what group of the ECM?
They are all proteoglycans which are linked together by hyaluronan (hyaluronic acid).
Cytokines, Growth factors, and structural proteins such as fibronectin and laminins are all examples of what part of ECM?
Glycoproteins
What is unique of embryonic connective tissue (3)?
- rich in ECM (not in density of cells)
- rich in mesenchymal stem cells
- Not many collagen/reticular fibers (wharton’s jelly)
What can adult mesenchymal stem cells differentiate into (bone marrow) (5)?
fibroblasts muscle cells (skeletal/smooth) osteoblasts chondroblasts adipocytes all depend on location and signaling to become the above
What are the 3 types of loose and dense connective tissues?
Loose: Areolar, Adipose, Reticular
Dense: Dense irregular CT, dense regular CT, elastic CT
Loose areolar CT
Have both fixed (fibroblasts/adipocytes) and wandering cells from circulation such as macrophages/mast cells.
What do loose connective tissues do and where can they be found?
They support and bind tissues, hold body fluids, defends against infection
Found beneath membranous epithelia, around blood vessels, muscles and nerves
What is specific to adipose CT?
Abundant adipocytes and sparse ECM
Provides energy and insulates against heat loss
Found under skin and around organs
What does white fat do?
Functions in energy storage, insulation, cusioning vital organs and hormone secrection
What does brown fat do?
Key thermogenic tissue due to abudance of mitochondria, abundant in newborns and reduced in adults
What is specific to reticular connective tissue?
Rich in reitcular fibers (looks like spider web)
open framework to hold most free cells
Found in liver, BM, LN, and spleed where mesh forms to hold blood cells
What is specific of dense irregular connective tissue?
ECM is tightly packed (ALOT) and running in random pattern
Fibroblasts are principle cell type
Found in dermis of skin, perichondrium and periosteum
What is specific of dense regular connective tissue?
ECM tight packed and all in same order, fibroblast are cell type
Resists pulling forces and poorly vascularized
Found in tendons, ligaments, aponeuroses, dense fascia
What is specific of elastic CT?
Contains lots of elastic fibers, allows recoil of tissue following stretching
found in blood vessel walls, bronchiole tubes, and special ligaments (ligamentum nuchae)
What is the main function of fibroblasts?
To produce collagen, elastin, reticular fibers, proteoglycans and glyocproteins in ECM
What is the function of macrophages?
From blood monocytes, function in phagocytosis and destruction of bacteria, damages or sick cells
What is the function of mast cells?
Release chemicals like histamine that mediate the allergic response, and heparin.
important in wound healing and angiogenesis
What is unique of plasma cells and what is their function?
Differentiated from B-lymphocytes, function is to produce antibodies that mediate immunity, contain golgi aparatus
