Histology of Connective Tissue Flashcards
Connective tissue is derived from _ germ cell layer
Connective tissue is derived from mesoderm germ cell layer
* Mesoderm also gives rise to muscle tissue
Two categories of connective tissue include _ and _
Two categories of connective tissue include connective tissue proper and specialized connective tissue
* Connective tissue proper is protecting and supporting organs/tissues/structures
* Specialized connective tissue has additional roles
Four types of connective tissue proper
Connective tissue proper provides resistance to pulling, stretching
Four types:
1. Dense regular connective tissue
2. Dense irregular connective tissue
3. Loose (areolar) connective tissue
4. Reticular connective tissue
Four main types of specialized connective tissue:
Four main types of specialized connective tissue:
1. Blood transports nutrients and oxygen
2. Cartilage provides template for bone growth
3. Bone home for hematopoietic precursor cells
4. Adipose tissue stores energy in form of lipids
How does the composition of connective tissue differ from epithelial, muscle, and nerve tissue?
Connective tissue (especially connective tissue proper) has abundant extracellular matrix
* The ECM carries out its main functions
* ECM is composed of fibers and amorphous ground substance
Fibers in the ECM are made of _ and they are really good at resisting _ forces
Fibers in the ECM are made of proteins and they are really good at resisting tensile forces
* Fibers run parallel in tendons to resist forces in the direction that the muscle produces force
Two types of fibers are _ and _
Two types of fibers are elastic and collagen
Elastic fibers are thin, structural proteins that allow for incredible elasticity due to a protein called _
Elastic fibers are thin, structural proteins that allow for incredible elasticity due to a protein called elastin
* Elastin forms the inner core of elastic fibers
* It is composed of short peptide chain that are cross-linked in a way that allows for extension and retraction
The cross-links of elastin are composed of two amino acids, _ and _
The cross-links of elastin are composed of two amino acids, desmosine and isodesmosine which are only found in elastin
Elastic fibers are found in tissues that need to stretch, expand, and return their shape such as _
Elastic fibers are found in tissues that need to stretch, expand, and return their shape such as walls of arteries, bronchi, bronchioloes, ligaments
The most common type of fiber found in the ECM is _
The most common type of fiber found in the ECM is collagen
Type _ collagen is found in bone, skin, tendons, dentin, ligaments, fascia, scar tissue, fibrocartilage, organ capsules, cornea
Type I collagen is found in bone, skin, tendons, dentin, ligaments, fascia, scar tissue, fibrocartilage, organ capsules, cornea
Type _ collagen is the most common among the collagen subtypes and makes up about 90% of the collagen in our body
Type I collagen is the most common among the collagen subtypes and makes up about 90% of the collagen in our body
The key function of type I collagen is to _
The key function of type I collagen is to resist tension
The stripy appearance to collagen is due to a complex, staggered arrangement of small molecules called _
The stripy appearance to collagen is due to a complex, staggered arrangement of small molecules called tropocollagen
Type _ collagen is found in the hyaline cartilage matrix
Type II collagen is found in the hyaline cartilage matrix
The nucleus pulposus of vertebral discs and the vitreous body of the eye is type _ collagen
The nucleus pulposus of vertebral discs and the vitreous body of the eye is type II collagen
The primary function of type II collagen is to _
The primary function of type II collagen is to resist pressure
* These fibers are thin
Hyaline cartilage appears smooth and glassy due to a blend between type II collagen and _
Hyaline cartilage appears smooth and glassy due to a blend between type II collagen and glycosaminoglycans
Type III collagen fibers are extremely fine and delicate; they provide structural support to _
Type III collagen fibers are extremely fine and delicate; they provide structural support inside hematopoietic organs like bone marrow, spleen, lymph nodes
Collagen III fibers are also called _
Type III collagen fibers are also called reticulin or reticular fibers
* Latin for network
* * Can be seen seen with silver stain
Type IV collagen’s main function is to form _
Type IV collagen’s main function is to form meshwork of fibers in the basal lamina of basement membranes
* Functions to support and anchor epithelial cells
* Also aids filtration
* Scaffold for cell migration
We find dense regular connective tissue proper mainly in _ and _
We find dense regular connective tissue proper mainly in ligaments and tendons
* Parallel orientation makes dense regular good at withstanding tension in one direction
What are the key histologic features of dense regular?
Dense regular:
* Densely packed
* Parallel bundles of Type I
* Few fibroblasts and scant ground substance
What are the key histologic features of dense irregular?
Dense irregular:
* Densely packed
* Randomly oriented bundles of type I
* Few fibroblasts and scant ground substance
* Collagen bundles are in random/irregular directions
Where do we mostly find dense irregular connective tissue proper?
Dense irregular is normally found in organ capsules and the deep dermis of the skin
* Places that are susceptible to multidirectional pulling forces
What are the key histologic features of loose (areolar) connective tissue?
Loose (areolar) connective tissue:
* Numerous fibroblasts and fine collagen fibers interspersed with areas of clear ground substance
* Contains numerous cell types (fibroblasts, plasma cells, macrophages)
Where do we find reticular connective tissue?
Reticular connective tissue is found in the bone marrow, lymph nodes, and spleen
* Delicate, supportive framework
