Lecture 10- Connective Tissue And Adipose Tissue Flashcards
List common types of cells found in connective tissue
- macrophages
- mast cells
- fibroblasts
- adiposcytes
- recticular cells
- mesnechymal cells
What is the function of fibroblasts ?
- they help lay down scar tissue.
- they secrete and produce fibres that lie in the extracellular matrix.
What occurs to fibroblasts when there is a wound in the body ?
They change into myofibroblasts which contain actin and myosin which helps with contraction of the wound.
Where are mast cells usually found - in what type of connective tissue?
-aerolar connective tissue near the blood vessels.
Where are mast cells absent from - what part of the body ?
- the CNS in order to prevent Oedema because histamines in the cytoplasm of the mast cells will increase permeability of the blood vessels
What is contained within the cytoplasm of mast cells ?
1) histamines which increase permeability of blood vessels making them similar to sinusoids.
2) heparin : act as anticoagulants preventing blood clots
3) cytokines which attract neutrophils and eosinphils to site of the wound.
What is the role of macrophages ?
- they are phagocytictic
- professional antigen presenting cells to T lymphocytes
How many cell types does loose connective tissue contain ?
-multiple cell types for example fibroblasts , mast cells , macrophages and adipocytes
What are the twomain fibres that are within loose connective tissue !
?
- collagen and elastin
What is the fuel like substance found in loose connective tissue called and is it in large or small amounts ?
- proteoglycans which is made up of glycoaminoglycans such as hyaluroic acid. It is an important component in moving substances , especially in epithelial cells where blood vessels are not present.
Where is loose connective tissue mainly found ?
- lamina propia
- surrounds capillaries , nerves and sinusoids.
- lymph nodes too
- around gland .
What are two forms of loose connective tissue ?
Blood and adipose tissue
Are there many type of cells in dense connective tissue ?
A- no , mainly fibroblasts cells and collagen make up a lot of tissue present.
Is there more or less ground substance in dense connective tissue ?
Less , as the fibres are closely packed together.
Wwhat are the two types of dense connective tissue ?
1) irregular
2) regular
What are the functions of loose connective tissue ?
1) packaging around organs
2) involved in inflammation pathways
3) generally hold everything in place
4) cushions and stabilises organs.
Describe characteristics of irregular dense connective tissue ?
- interwoven bundles of collagen which criss cross each other in many directions in order to counteract the multidirectional forces they experience.
Where is dense irregular connective tissue usually found ?
- dermis of the skin AND SUBMUCOSA OF INTESTINE
- deep fascia of muscles
- periosteum around bone
- dura meter around brain and spinal cord
-
What stain is usually required to see elastin in irregular dense connective tissue ?
Van goesen. Which is silver stain
What are examples of regular dense connective tissue ?
- tendons
- ligaments
- aponeuroses ( flattened tendons)
Why do tendons have such high mechanical strength?
- due to myotendinous junctions
- which are junctions that connect tendons with skeletal muscle
- collagen passes from the tendon to the muscle fibres were it interacts with the collagen fibres coating muscle fibres.
- cross links occur between these fibres.
What is the main function of regular dense connective tissue ?
- provides mechanical strength
What types of collagen ar e tendons made up of ?
70% type 1 and 30% type 111 ( recticulin)
Powhatan are tendons mainly made up of ?
30% collagen ( type 1 and type 3)
- 68% water
- 2% elastin
Name one difference between regular and irregular dense connective tissue ?
- irr gulag can resist stress in all directions due to collagen 1 fibres scattered in all directions whereas regular dense connective tissue can only resist stress in one direction because collagen 1 fibres are in parallel .
What is fascia ?
Sheet of connective tissue containing closely packed bundles of collagen orientated in a wavy pattern parallel to direction of pull.
- primarily found beneath the skin.
how is collagen fibril produced outside the cell ?
- fibroblasts secrete procollagen that is converted to collagen molecules outside the cell. the collagen molecules are then aggregated to form the final collagen fibrils.
Why is vitamin c important for collagen fibrin production ?
- vitamin C is required for the production of procollagen intracellularly , where it hydroxylates proline and lysine which helps to form procollagen that is packed , released and modified into collagen outside the cell.
OUTLINE OUTLINE THE CAUSE OF SCURVY
- vitamin C deficiency
What are symptoms of scurvy ?
- gum disease
- bruising of the skin
- bleeding
- poor wound healing
Outline the cause of Marfan’s syndrome
- mutation of the fibrillin 1 gene which prevents production of normal elastic tissue.
Wha are symptoms of mar fans syndrome
- wing span greater than height
- abnormally tall
- aortic rupture
- frequent joint dislocation
- exhibit arachnodactylyl ( long fingers , long limbs)
WCA’s elastic be regenerated ?
No, it is laid down only during fatal development. Not replaced in the adult.
What is the cause of osteogenesis imperfecta?
Mutation in the collagen 1 and collagen 2 gene.
What are the symptoms of osteogenesis imperfecta ?
- hearingnloss
- blue sclera
- arched / flat feet
- weakens bones
- poor teeth development.
What type of adipocytes are found in loose connective tissue ?
- white adipocytes
What are the functions of white adipocytes ?
- shock absorber
- insulation
- padding
- energy reserve
What are features of white adipocytes ?
- thei- they have one single enormous fat droplet
- nucleus , cytoplasm , organelles are all squeezed to one side of the cell
Which of the adipose tissues are found in neonates( infant less than 4 weeks old ) ?
- brown adipose tissue
What are features of brown adipose tissue ?
1) they have greater number of mitochondria
2) they have multiple small lipid droplets
3) nucleus , cytoplasm , organelles squeezed to the centre of the cell.
What is the function of brown adipose tissue ?
- provides insulation and fuel storage in neonates.
- lipid breakdown is accelerated.
What is the most common type of collagen ?
Type 1 collagen - where fibrils aggregate into fibres and fibre bundles in the tendons , skinndermis and capsules of organs
What type of collagen does not form fibres ?
Type 2;: found in cartilage and hyaline
What type of collagen is considered to be recticulin ?
Type 3 - it is found in lymphatic organs such as the spleen , liver and tendons
What type of collagen is found in the basement membrane ?
Type 1V
What does the extraceullar matrix consist of ?
Ground substance and fibres.
QWhat is a ground substance contained in connective tissue
- composed of proteoglycans which are LARGE macromolecules consisting of glycoaminoglycans which are long chained polysaccharides.
What is an example of glycoaminoglycans ?
hyaluronic acid
How how are mast cells responsible for allergic reactions ?
- mast cells become coated with IgE , which then bind with allergens. The allergen forms cross links with the surface bound IgE molecules , the contents of the granules are rapidly released = allergic response.
Where can mucoid connective tissue be found ?
Umbilical cord - ground substance is Wharton’s jelly in extracellular matrix.
What is found in mucous connective tissue in the umbilical cord ?
- macrophages
- lymphocytes
- stellate fibroblasts
How many blood vessels are there in the umbilical cord and what is their role ?
- there are 3 blood vessels
- 2 arteries
- 1 vein
- arteries are used to transport deoxygenated away from the baby, whereas veins are used to carry oxygenated blood from the placenta to foetus
What is brown adipose tissue required for
- non shivering thermogenic regulation
