L11: Connective Tissue 1 (alyaa) Flashcards
What are the 3 characteristics of CT?
- They all have mesenchyme as their cell of origin
- They have varying degrees of vascularity
- They’re made up of non-living material called the extracellular matrix
What is the most abundant Tissue in the Human body?
connective tissue
What does the nonliving extracellular matrix consist of?
ground substance and fibers
CT have good __________ and _____________ supply
Nerve
Blood
(except dont foget that cartilage is avascular and has no nerve supply, those are found in its perichondrium)
What are functions of the CT?
- Anchors the epithelium to the rest of the body (basement membrane & basal reticularis)
- Provides structure (bone)
- Stores energy (fat)
- Transports materials (blood)
What is the ground substance?
Rubbery, Unstructured material that fills the spaces between cells and protects them from the surroundings
What makes up the CT?
cells, fibers, ground substance
What are the three types of fibers in connective tissue?
collagen, elastic, reticular
What are the cell types in connective tissue?
- Fibroblasts
- Chondroblasts
- Osteoblasts
- Hematopoietic stem cells
What are the types of connective tissue?
- CT proper (loose & dense)
- Supportive CT: cartilage & bone
- Fluid CT: blood
The most abundant cell type in all connective tissue proper?
fibroblast
What do fibroblasts secrete?
proteins and hyaluronan (cellular cement)
Macrophages
- Large, amoeba-like cells of the immune system
-Eat pathogens and damaged cells
-Fixed macrophages stay in tissue
-Free macrophages migrate
Adipocytes
- Fat cells
- Each cell stores a fat droplet
mesenchymal cells
- stem cells that respond to injury or infection
- differentiates into fibroblast, macrophages etc.
Melanocyte
Cells that synthesize and store the brown pigment melanin
Mast cells
Cells that stimulate inflammation after injury or infection
What do mast cells secrete?
heparin and histamine
Basophils
Mast cells carried by blood
Lymphocytes
Specialized immune cells in the lymphatic system
(Eg: plasma cells which produce antibodies)
microphages
- phagocytic blood cells
- respond to signals from macrophages and mast cells
(Eg: neutrophils, eosinophils)
What is the most abundant fiber?
collagen fiber
Which fiber is most abundant in dense connective tissue?
collagen fiber
Characteristics of collagen fibers?
- thick & flexible
- composed of collagen
- holds structures together
- ligaments & tendons
Characteristics of elastic fibers?
- made up of protein elastins that allow them to stretch
- bundles of microtubules embedded in elastin
- vocal cords and air passages
Characteristics of reticular fibers?
-Short and finer collagenous fibers
- highly branched
- form supportive networks
- Acts as a supporting mesh in soft tissues such as, liver, bone marrow, and the tissues and organs of the lymphatic system
What are the sub classes of Cartilage
- Hyaline cartilage
- Fibrocartilage
- Elastic Cartilage
What are the sub classes of connective tissue proper?
- Loose connective tissue
Areolar
Adipose
Reticular - Dense connective tissue
Regular
Irregular
Elastic
What are the sub classes of bone?
- Compact bone
- Spongy (cancellous) bone
Define mesenchyme
- Irregularly shaped cells
- Are in semifluid ground substance with reticular fibers
- They give rise to other types of connective tissue
Define mucous connective tissue (or wharton’s jelly)?
1.Star shaped cells in jelly like ground substance
- Contain very few cells or fibers
Where would you find mucous connective tissue?
Found only in the umbilical cord
What is the shape of fibroblast?
They are elongated or discoid (shaped like a disc)
Fibroblasts remain in close proximity to what?
Collagen fibers
What are the differences between fibrocytes and fibroblasts?
What is the difference between loose connective tissue and dense connective tissue?
Loose CT:
> ground substances
cells
< fibers
Dense CT:
< ground substances
< cells
> fibers
Areolar tissue contains all?…
Cell types and the 3 fibers
Areolar tissue holds?
Blood vessels and capillary beds (eg. under the skin -> subcutaneous layer)
What are the cell types in areolar connective tissue?
Fibroblasts, plasma cells, macrophages, mast cells, and a few white blood cells
In adipose tissue, what are the functions of white fat?
- Most common
- Stores fat
- Stores energy
- Slows down heat loss (insulation)
- Cushions vital organs
Where can white adipose be located?
- CT under the skin (hypodermis)
- Buttocks, abdomen, thighs (external)
- Omentum, mesentery
In adipose tissue, define brown fat?
- More vascularized
- Breaks down fat
- Produces heat
Which cells develop from a lipoblast?
- Unilocular adipocyte (white fat)
- Multiocular adipocyte (brown fat)
Why are the nuclei peripheral in adipocytes?
Due to large fat storage droplet
Where is adipose tissue found?
- In the deeper layer of the skin
- Organ padding
- Yellow marrow
What are the functions of adipose tissue?
- Reduce heat loss
- Stores energy
- Protection
Brown fat found in infants?…..
-Has more blood vessels and mitochondria
-Responsible for heat generation
Multiocular consists ib shkthr in a newborn?
2-5%
What is reticular connective tissue?
Network of fibers in cells that produce the framework of organs
What is dense regular connective tissue?
They are collagen fibers in parallel bundles with fibroblasts between bundles of collagen fibers
Shlon shakil il dense connective tissue?
White, tough, and pliable when unstained (forms tendons)
What is dense regular connective tissue also known as?
White fibrous connective tissue
How is irregular dense connective tissue characterized?
- They have collagen fibers which are irregularly arranged
- The tissue can resist tension from any direction- They have collagen fibers which are irregularly arranged
- The tissue can resist tension from any direction
Where can you find dense CT irregular?
In the white of the eyeball and the dermis of the skin
How are the fibers arranged in dense connective tissue irregular?
Fibers are haphazardly arranged
What are the characteristics of the Elastic connective tissue?
- It has branching elastic fibers and fibroblasts
- It can stretch and still return to original shape
Where can you find elastic connective tissue?
walls of large arteries, lung tissue, vocal cords, ligament between vertebrae
what do you call the fibers in the aorta?
elastic lamellae
in dense elastic, what are the fiber types found and what are they for?
Elastin (for elasticity)
Collagen (for strength)
Why is ground substance in the CT flexible?
Bc it’s made up of starch and proteins mixed with water
What is heparin?
An anticoagulant released by mast cells
Compare white and brown adipose tissue?
White fat:
- most common
- stores fat
- slows heat loss (insulation)
Brown fat:
- more vascularized
- breaks down fat
- produces heat
Which type of adipose tissue is more vascularized?
Brown fat
Which type of adipose tissue is more common?
White fat
