Unit 1: Connective Tissue Flashcards
What are the 5 types of connective tissue?
- Loose
- Dense
- Cartilage
- Bone.
- Blood
*most abundant tissue in the body
- Depend on relative proportions of ground substance, cells, and fibers
What is connective tissue made of?
Matrix and cells
What is matrix made of?
Ground substance mixed and fibers (collagen, elastic, and reticular)
- Extracellular substance, a product of the cells
- Proportion of matrix to cells varies, usually mostly matrix
Function: provides strength and support to tissue
What are the 6 cell types?
- Fibroblasts (secrete matrix).
- Macrophages (phagocytes).
- WBC
- Plasma (secrete antibodies)
- Mast cells (produce histamine)
- Adipocytes (store lipids)
CT general features
Never on an exposed surface
Vascularized (has blood supply) but varies (lots in adipose, poor in bone)
Fixed and wandering types
CT functions
Binds/supports other tissues
Protects organs
Compartmentalizes structures
Transports
Energy reserve
Healing/fighting infection
Matrix ground substance
Amorphous, homogenous
Liquid, gel, or calcified
Contains glycoproteins
Function: medium for nutrient/waste exchange, shock-absorber, physical barrier against bacteria
3 types of matrix fibers
- Collagenous (white)
- Reticular
- Elastic (yellow)
Collagenous matrix fiber
Most common
Long, thick bundles of collagen in varying amounts (loose in fat, dense in ligaments). Wavy when not stretched
- Thick, strong, flexible, non-elastic
- Excess production of these fibers during healing = scars
- If they attach to tissues abnormally = ‘adhesions’
- When meat is cooked collagen breaks down (tender) when leather is tanned it toughens
Reticular matrix fiber
Networks of very fine threads of collagen
Delicate framework for cells in spleen, liver, lymph, endocrine glands
- May also support vessels, nerves, muscle fibers
Elastic (yellow) matrix fiber
Found in CT of organs that change shape (vocal cords, lungs, skin, blood vessel walls)
- Have elastin protein in coiled bundles
- Typically branched
- Not as strong as collagenous, but stretchy
Fibroblasts (fixed cell)
Produce the fibers and ground substance that make the matrix
- Different types for each type of tissue:
Chondroblasts (cartilage), osteoblasts (bone), fibroblasts (bone)
Fibroblasts (fixed cell)
Large, irregular shaped cells that can reproduce themselves.
- Tend to convert to chondrocytre, osteocyte, fibrocyte when mature (less active, but reversible)
Adipocytes (fixed cell)
Store fat (if in groups = ‘adipose tissue’)
Most common SC, abdominal wall, around kidneys
Reticular cells (fixed cell)
Flat, star-shaped, long
- Form a net if contact each other
- Common in lymp nodes, spleen, bone
- Function: immunity, making reticular fibers
3 types of wandering cells?
- Mast
- Leukocytes
- Macrophages
- Move in and out of CT.
- Protection & repair
Mast cells (wandering)
- Contain large granules of histamine and heparin
- Release these and cause inflammation
- Found near blood vessels
Leukocytes/WBC (wandering)
Circulate in blood, enter tissue in response to infection
- 5 types, some phagocytize (eat) bacteria, other make antibodies to help w/infection
Macrophages (fixed OR wandering)
Very large phagocytes, eat bacteria/dead cells/debris
- Tend to congregate around infection & inflammation
- Different names in different tissues
What are the 2 types of CT proper?
Loose (areolar, adipose, reticular)
Dense (regular, irregular, elastic)
What are the 3 types of specialized CT?
Cartilage (hyaline, elastic, fibro)
Bone (compact, cancellous)
Blood
CT proper
- Most CT in the body.
- Loose/dense
- Fibers differ in protein, but mostly collagen & elastin
- Basic support framework of organs
Areolar CT (Loose)
Most abundant CT
Loosely organized cells & extracellular substances
- Cells: fibroblasts (mostly), macrophages, mast cells, adipocytes, plasma
- Extracellular: collagen, elastic and reticular fibers, ground substance
Location: SC skin, mucous membranes, blood vessels, nerves, muscles, stroma of many organs
- Can tear easily, stretch too much when extracellular fluid is present (‘pitting edema’)
Areolar CT (loose) functions
Cushioning
Elasticity
Strength, continous network within organs.
Nutrition to nearby cells through capillary network
Area for immune system to work
Attachment of skin to underlying tissues
Adipose CT (loose)
- Made of adipocytes and fine network of reticular fibers
- Large and rounded (up to 95% of mass stored as fat -> pushes cytoplasm and nucleus to the side)
- Highly vascularized
- Usually look white, can be yellow
- 2 types: brown & white
Location: SC skin, heart, kidneys, yellow marrow, joint padding, behind eye
Function: energy reserves (store triglycerides), insulation, cushioning