Histology: Connective Tissue (Exam 1) Flashcards
Where are most of the cells of connective tissue from
migrants of the vascular system
How is connective tissue classified
Type of cell
Nature of ECM
Where is connective tissue found
Under the epithelial tissues as a supporting tissue
What are the primary functions of connective tissue
Supportive
Space filling
What is the supportive role of connective tissue
mechanical function, bone, cartilage, dense, connective tissue
What is the space filling role
Fills in gaps between epithelium and muscle and other tissue
What fibers is the Extracellular matrix composed of
collagen
reticular
elastic
What is ground substance composed of
glycoproteins
glycosaminoglycans
proteoglycans
What is a proteoglycan composed of
protein core anchored to hyaluronic acid with GAG side chains
What is the basic unit of collagen
collagen fibrils
What are collagen Fibrils composed of
tropocollagen molecules
What are tropocollagen molecules composed of
3 glycoprotein alpha chains into a triple helix
How are the different types of collagen created
by changing the types/varieties of the alpha chains
How many different types of collagen are there
28
How many main types of collagen are there
4
What are the 4 types of collagen
Type I
Type II
Type III
Type IV
Where is Type I collagen found
bone, skin, tendons, ligaments
Where is Type II found
hyaline cartilage
Where is Type III found
Reticular fibers
Where is Type IV found
basement membrane
What type of collagen are reticular fibers composed of
Type III
Where are reticular fibers found
Lymphatic tissue
Supporting structure for adipocytes, muscle cells, small blood vessels, hemopoietic tissues
What stains are used to view reticular fibers
PAS
Silver Salts
Eosin
Where are elastic fibers found
elastic cartilage
elastic arteries
elastic ligaments
What cells produce elastic fibers
fibroblasts and smooth muscle cells
What are the components of elastic fibers
elastin core
fibrillin microfibrils around the core embedded into elastin
What is the cause of Marfan Syndrome
Lesion of the Fibrillin gene on chromosome 15
What is fibrillin in relationship to elastic fiber
an ECM protein that is important in maintaing elastic fibers
What is mutated in ehlers-danlos syndrome
Mutations in genes affecting the collagen polypeptide chains
Symptoms of Ehlers-Danlos syndrom
hyperelastic skin
hyperflexibility of joints
vascular and organ rupture
What causes osteogenesis imperfecta
Defect in synthesis of type I collagen
What are the symptoms of osteogenesis imperfecta
brittle bones
short stature
What is the most severe form of osteogenesis imperfecta
type 2
What occurs in type 2 osteogenesis imperfecta
abnormally small and fragile rib cage
What are the three categories of connective tissue
Embryonic
Connective tissue proper
Specialized connective tissue
What are the different types of embryonic connective tissue
mesenchyme
mucous connective tissue
What are the different types of connective tissue proper
Dense CT
Loose CT
What are the different types of specialized connective tissue
Adipose Blood Cartilage Hemopoietic tissue Lymphatic tissue
What is embryonic connective tissue
few star or spindle shaped cells forming a loose network
Extracellular space filled with huge amounts of viscous ground substance with few reticular fibers
What type of tissue is mesenchyme
Embryonic connective tissue
Where is mesenchyme CT found
mainly inside the embryo
What type of cells compose mesenchyme
pluripotent mesenchymal cells
What is the feature of pluripotent mesenchymal cells
can differentiate into other tissue types
Where is mucous connective tissue found
in the umbilical cord
What is another name for mucous connective tissue
Wharton’s jelly
What cells compose mucous connective tissue
Fibroblasts and few mesenchymal cells
What is the characteristics of mucous connective tissue
more space between cells and less reticular fibers in ground substance
creates a jelly like appearance
Mesenchyme cells develop into what cells
chondroblasts lipoblasts fibroblasts osteoblasts myoblasts
What do chondroblasts develop into
cartilage
What do lipoblasts develop into
fat cells
What do fibroblasts develop into
ligaments, tendons, capsules, supporting tissue
What do osteoblast develop into
bone
What do myoblasts develop into
skeletal muscle
What are the general characteristics of dense CT
few fibroblasts
little ground substance
large amounts of collagen fibers between them
Where is dense regular connective tissue found
in tendons, aponeuroses, ligaments
How is the connective tissue of the ligamentum flavum different than other ligaments
contains a lot of elastic fibers = elastic connective tissue
What are characteristics of dense regular CT
fibers of collagen arranged in parallel
rod shaped nuclei
What type of collagen is in dense CT
type 1
Where is dense irregular connective tissue found
submucosa of hollow organs, connecting mucous membrane to underlying muscle layer
What type of cells compose dense irregular connective tissue
fibroblasts
Describe dense irregular connective tissue
fibers of type 1 collagen arranged in bundles running in all directions
What is a fibroblast do
synthesize fibers and ground substance
What do fibroblasts look like
star shaped cells with elongated disc-like nucleus
Why do fibroblasts stain basophilic
developed rER in the cytoplasm for protein synthesis
How do myofibroblasts differ from fibroblasts
similar to fibroblast but contain contractile elements
How do myofibroblasts differ from smooth muscle
lack basal lamina
Where are myofibroblasts found
located in loose CT
What is the function of myofibroblasts
regulate the shape and emptying of flands and wound contraction and closure
What is loose connective composed of
Collage Type I
Elastic fibers
Where is loose connective tissue found
mostly beneath the epithelial
What is loose CT role in inflammation
undergo significant swelling
What are the two cell populations found in loose Connective tissue
resident cells
migrant cells
What are resident cells
fibroblasts macrophages mast cells adipose cells mesenchymal cells
What are migrant cells
lymphocytes plasma cells neutrophils eosinophils basophils
What are the two different types of adipose
white and brown
What are white adipose cells
single fat drop filling the cytoplasm
ring shaped cytoplasm and flat peripheral nucleus
What are brown adipose cells
several fat droplets in the cytoplasm
brown pigment
Where is brown adipose cells found
in newborns as they need a lot of energy fast
What are macrophages derived from
blood monocytes
Describe macrophages
round nucleus
ingested material in cytoplasm
large golgi and rER
What is the function of macrophages
antigen presenting cell: use MHC2 molecules to present antigens for CD4 lymphocytes
What are Langhans giant cells
Multiple macrophages fused together
What are mast cells
large rounded cells with spherical nucleus
basophilic granules
Where are mast cells located
next to small vessels in CT, capsule of organs
What stain is used to view mast cells
tuloidin blue stain
What is the function of mast cells
Antibodies bind to mast cells to release contents of granules
Mast cells play a role in what clinical scenario
anaphylactic reactions
What do the granules of mast cells contain
histamine
heparin
eosinophil and neutrophil/chemotactic factor
What is the function of histamine
vasodilation, edema
What is the function of heparan
blocks coagulation, responsible for basophilia
What is the function of eosinophil and neutrophil chemotactic factor
cell attraction
Where are mesenchymal cells found in adults
around vessels
What do mesenchymal cells
they are pluripotent and form various things
What structure do mesenchymal cells have
star or spindle shaped cells
What structure do lymphocytes have
intensely staining slightly indented spherical nucleus
cytoplasm is pale basophilic ring
How are lymphocytes classified
T lymphocytes
B lymphocytes
Natural Killer cells
Where did T lymphocytes differentiate from
thymus
What percentage of lymphocytes are T-lymphocytes
60-80%
What percentage of lymphocytes are B-lymphocytes
20-30%
Where did B lymphocytes differentiate from
bone marrow
What percentage of lymphocytes are natural killer cells
5-10%
Where did natural killer cells originate from
bone marrow
What are plasma cells derived from
B cells
What is the function of plasma cells
antibody producing
What is the life span of plasma cells
10-30 days
Describe plasma cells
heterochromatin in the nucleus with cartwheel or clock face pattern
What are the types of blood cells seen in connective tissue
neutrophils, eosinophils, basophils
Describe neutrophils
pale pink cytoplasm
fine granules
nucleus is multilobed and stains basophilic
Describe eosinophils
large eosinophilic granules in the cytoplasm
bilobed nucleus
Describe basophils
large basophilic granules
nucleus obscured by granules
closely related to mast cells of CT