9/10 Fibrous Connective Tissue Flashcards
Connective is covered by which structure that isolated CT from the outside environment?
CT cells are separated from each other by?
epithelium
ECM
Three subgroups of fibrous CT
Loose (areolar CT)
dense regular CT
dense irruglar CT
Functions of CT (6)?
structural framework
protection
supports and interconnects other work
energy storage
transports fluids
defense
cells of CT (6)
– Fibroblasts—produce collagens, proteoglycans and glycoproteins (produce most of CT)
– Mesenchymal cells– connective tissue stem cells
– Adipocytes—store and release fats
– Chondrocytes—produce and maintain cartilage components
– Osteoblasts—produce bone components
– Hematopoietic stem cells—produce red blood cells and immune cells (e.g., macrophages, mast cells, lymphocytes, plasma cells)
Three major fibrous components ECM of CT
- Collagens (several different types, type-I most common) – resists tension
- Elastin—stretchable fiber – Assembly of tropoelastin, fibulin-1, and fibrillins1/2
- Reticular fibers—forms supportive meshwork
- Type-I collagen fibrils are aligned and crosslinked to increase?
- In electron micrographs, banding of collagen fibers is observed due to ____ alignment
- due to vitamin C deficiency; co-factor in cross-linking collagen fibers; weakens CT?
- abnormal collagen synthesis leading to weak collagen fibers (multiple forms)
- tensile strength
- fibril
- scurvy
- Ehlers-Danlos syndrome
Marfan’s Syndrome, autosomal dominant disorder where ____ is weak (mutation in ____ gene—component of elastin fibers)
Where has a great amount of elastin?
- Principle targets ocular, skeletal, and cardiovascular systems
- Life-threatening cardiovascular anomalies (e.g. dissecting aneurysms, mitral prolapse)
- Patients tend to be tall with long arms/legs (skeletal defects)
- Incidence 2-3/10,000
elastin, fibrillin-I
great arteries
Extracellular Matrix of Connective Tissues
Amorphous Ground Substance
There are 4?
- Proteoglycans – Chondroitin sulfates – Heparan sulfates – Keratan sulfates
- Hyaluronan
- Glycoproteins – Cytokines – Growth factors (TGF-ß) – Structural proteins (e.g., fibronectin, laminins, tenascins, link proteins)
- Extracellular proenzymes
Cell-ECM interaction
Embryonic CT is rich in which two components/cells? and low in what component?
In umbilical cord, it’s referred as what?
- Rich in ECM
- Rich in mesenchymal stem cells
- Some but not many collagen or reticular fibers
- In umbilical cord, sometimes referred to as “Warton’s jelly”
Adult mesenchymal cells are multipotent stem cells that differentiate into a variety of cell types including (5)?
– fibroblasts
– muscle cells (skeletal and smooth muscle)
– osteoblasts
– chondroblasts
– adipocytes
There are three classes of loose CT?
Areolar— low-density tissue with both fixed and wandering cells; widespread
Adipose— fat containing tissue
Reticular— rich in reticular fibers; forms an open framework to create a supportive mesh for holding free cells
There are three classes of dense CT?
Dense irregular connective tissue— fibers are deposited in a random pattern • Dermis of the skin
Dense regular connective tissue—fibers are deposited in a highly regular pattern • Tendons connecting skeletal muscle to bone
Elastic connective tissue—rich in elastin fibers
Loose areolar CT (columnar cells), two categories of cell types?
What are each specific cells?
Fixed and wandering cells
- Fixed Cells – Fibroblasts – Adipocytes – Mesenchymal Cells
- Wandering Cells (immune cells) – Macrophages – Mast Cells – Leukocytes/Lymphocytes – Plasma Cells
Loose CT
- Functions to support and bind other tissues; hold body fluids; defends against infection
- Found immediately beneath membranous epithelia (where it is referred to as the lamina propria) and around BVs, muscles, and nerves
loose areolar CT
Adipose CT
- Characterized by abundant adipocytes and sparse ECM
- Provides reserve energy source and insulates against heat loss • Supports and protects organs (by padding and cushioning organ or filling space)
- Found under skin; around organs (e.g. kidney, eyeballs, etc.), within abdomen, breasts and buttocks
Two types of fat?
as the age increases, which type of fat decreases?
White and brown fat
brown fat
White fat—functions in energy storage, insulation, cushioning vital organs, and hormone secretion
Brown fat—key thermogenic tissue, abundant in newborns; greatly reduced in adults
Reticular Connective Tissue
- Rich in _____ fibers
- what is the main function of the open framework forms by reticular CT?
- Found in liver, bone marrow, lymph nodes and spleen where the meshwork it forms houses blood cells and immune cells outside the blood and lymphatic vessels
reticular
Forms an open framework to create a labyrinth for holding free cells
Dense Irregular Connective Tissue
- ECM of tightly packed, interwoven collagen fibers running in a _____ pattern
- ______ are the principal cell type
- Found in: – dermis of skin – capsules that surround internal organs – perichondrium and periosteum – fascia
random
Fibroblasts
Dense Regular CT
- ECM of tightly packed, regularly arranged collagen fibers
- _____ are the principal cell type
- Resists pulling forces
- ______ vascularized
- When not under tension, has _____ appearance • Found in: – Tendons – Ligaments – Aponeuroses – Dense fascia, joint capsules
Fibroblasts
Poorly
wavy
Elastic CT
- Contains a high proportion of _____ fibers
- Allows recoil of tissue following stretching
- Found in _____ walls, bronchiole tubes, and special ligaments (e.g., ligamentum nuchae)
elastic
blood vessel
Fibroblast
The function is to produce the which 5 elements in the extracellular matrix?
collagen, elastin, reticular fibers, proteoglycans, and glycoproteins
(CERPG)
Adipocytes
- Closely packed with their _____ pushed to the side by large fat droplet
- Removes _____ from blood, stores it, and releases it into the bloodstream when needed
- Provides reserve ______
nuclei
lipids
energy source
Macrophages
- Differentiate from blood _______
- The function is ______ and destruction of bacteria, damaged or sick cells, removal of cell debris, and antigen processing and presentation
monocyte
phagocytosis
Mast cells
Mast cells secrete chemicals such as ______ that mediate the allergic response and heparin (an anticoagulant of blood)
Lots of granules
histamine
Plasma Cells
Differentiate from ______
Function is to produce _____ that mediate immunity
B cells
antibodies
