Connective Tissue Flashcards
What are the 4 types of connective tissues?
- Propper connective tissue
- Cartilage connective tissue
- Bone connective tissue
- Blood connective tissue
What are the main 3 components of connective tissue?
- Three types of fibres
- Ground substance
- Main featured cells
What is the main constituent of connective tissue?
Mostly constituted of extracellular matrix rather than cells
What is the extracellular matrix made up of?
Consists of different combinations of ground substances and protein fibres
Why is there such a large variety of connective tissues in the body?
Due to the differences in composition of cells, fibres and ground substances
What are all connective tissues formed from?
Mesenchyme
- From the middle later of the embryo - the mesoderm
What is the function of ligaments?
Join bone to bone
What are the three types of fibers within connective tissue?
- Collagen fibers
- Elastic fibers
- Reticular fibers
What are collagen fibers?
The strongest and most abundant type of fiber.
What are collagen fibers made from?
Created by fibroblast cells
What is type 1 collagen?
Tendons, ligaments, skin and bone
What is type 2 collagen?
= Cartilage
What are the structure and function elastic fibers?
Stretch and recoil like rubber bands
Have a rubber like quality
Form a branching framework
What are elastic fibers made from?
Made out of the protein elastin
Where are elastic fibers found?
Found in skin, lungs and large blood vessel walls
What is the structure of reticular fibers?
Short, finer collagen fibers
Have a sponge like network
Where are reticular fibers found?
Found in long bones and immune tissue.
What is the function of reticular fibers?
Suspends growing erythrocytes and plasma cells from its network. e.g. bone marrow, spleen, lymph nodes
It is supportive to areas with rapidly changing populations of proliferating cells
Overall what are the 5 key points of collagen fibers?
- Most abundant
- Flexible
- Tensile strength
- Collagen fibrils
- Wavy
Overall what are the 4 key points of elastic fibers?
- Thinner
- Arranged in a branching pattern
- Allow tissues to stretch and distend
- Interwoven with collagen
Overall what are the 3 key points of reticular fibers?
- Thin and short
- Form fine meshwork
- Type 3 collagen
What is ground substance?
The background around where fibres and cells are located
An amorphous (shapeless) gelatinous material. Transparent and colourless, fills the space between fibres and cells.
What 3 molecules make up most of the ground substance?
- Hyaluronic acid
- Proteoglycans
- Glycoproteins
=> all good at absorbing water - 90% of ECM is made up of water - allows tissue to return to original shape when compressed or deformed
What cells are found in the ECM?
- Fibroblasts
- Macrophages
- Adipocytes
- Mast cells
- Stem cells
What does the suffix ‘blast’ mean?
= form tissue
What does the suffix ‘cyte’ mean?
= maintain tissue
What does the suffix ‘clast’ mean?
= erode tissue
What are osteoblasts?
The blast cells of bone - bone forming cells
What are osteocytes?
Mature bone cells that monitor and maintain bone matrix.
Remodel bone
What are do fibroblasts do ?
They secrete collagen and elastin.
What is the function of fibroblasts?
Least specialised connective tissue cell and can differentiate into other types of cell found in the ECM.
What is the structure of fibroblasts?
Spindle shaped with an actively secreting matrix.
Cytoplasm is basophilic - stains purple with H&E stain
Adults have less active fibroblasts - fibrocytes - have paler stained cytoplasm.
What are adipocytes?
Fat cells
2 types: - White fat cells
- Brown fat cells
What are white fat cells?
- Unilocular - have a single large lipid droplet
- Have a large diameter and are found in
subcutaneous, omentum and mesentry
regions - Most common in adults
What are brown fat cells ?
- Multilocular - have multiple large lipid
droplets - Smaller than white adipocytes
- Present in new borns + hibernating animals
- Located around kidney, aorta and regions of
the neck and mediastinum in adults.
What are macrophages and what is their function?
Phagocytes - that ‘eat’ particles such as bacteria
What do macrophages derive from?
From wite blood cells called monocytes
What are mast cells?
Cells containing large secretory granules of heparin proteoglycan - a weak anticoagulant
- also contain histamine - promotes an
inflammatory reaction when secreted - Histamine also causes constriction of
bronchioles and vasodilation
Where are mast cells located?
Found close to small blood vessels in loose connective tissue.
What are 3 examples of loose connective tissue?
- areolar
- reticular
- adipose
What are 3 examples of dense connective tissue?
- regular
- irregular
- elastic
What is 4 features of loose connective tissue and what is an example of it?
- Little collagen
- Lots of ground substance
- Viscous and gel like
- Inflammatory and immune reactions
e.g. => Spleen - key immune system organ
What 3 cells and fibres is areolar tissue made up of?
- Fibroblast cells
- Collagen fibers
- Elastic fibers
What 3 cells is adipose tissue made up of?
- Adipocytes
- Nucleus
- Lipid vacuole
What 2 cells and fibres is reticular tissue made up of?
- Developing blood cells
- Reticular fibres
What are the 5 key features of dense regular connective tissue?
- Ordered
- Densely packed
- Little ECM
- Parallel
- Maximum strength
What are the 5 key features of dense irregular connective tissue?
- Mostly collagen
- Cells are sparse
- Fibroblast
- Strength
- Resistance to tearing and stretching
What type of tissue is blood?
= a connective tissue
What is the main functions of blood?
Transport gases, nutrients, waste, cells and hormones throughout the body.
Regulate pH, temperature, water content of cells and protect against disease via phagocytic white blood cells and antibodies.
What 4 cells make up blood?
- Erythrocytes (red blood cells)
- Leukocytes (white blood cells)
- Platelets
- Plasma
What % of blood volume is plasma?
about 55%
What is plasma made up of?
- A solution of water (92%), proteins, lipids,
inorganic ions (salts) and glucose. - Proteins include hormones
- Salts include urea - waste products of cells
extracted by the kidneys
What is the function of cartilage?
Cartilage = connective tissue
Strong, flexible and semi-rigid supporting tissue. Can withstand compression forces and can bend.
What is cartilage made up of?
- Chondroblasts
- Chondrocytes
- Extracellular matrix
What are the 3 types of cartilage?
Hyaline
Fibrocartilage
Elastic cartilage
What is hyaline cartilage and what is an example of it?
Most common - has glassy appearance. Sparse collagen.
E.g. articular cartilage
What is fibrocartilage and what is an example of it?
- Reinforced with parallel bundles of collagen fibres
- The strongest
e.g. tendon insertions and invertebral disks
What is elastic cartilage and what is an example of it?
Flexible and resilient - has elastic fibres as well as collagen fibres
E.g. external ear and epiglottis
What is the main function of bone?
= support
What is the structure of bone?
A strong, flexible and semi rigid supporting tissue. Can withstand compression forces and can bend.
What is bone made up of?
Osteoblast, osteoclasts and osteocyte cells as well as extracellular matrix.
ECM is made up of an organic matrix, collagen fibres and proteins.
Only 25% of bone is water.
How does bone calcify?
Before the ECM is calcified the tissue is called osteoid.
When calcium and phosphate ion concentration rises high enough they are deposited into the ECM calcifying the bone.
What are bone forming cells called?
Osteoblasts
What are bone breaking down cells called?
Osteoclasts
What are bone re-modelling cells called?
Osteocytes
