CONNECTIVE & ADIPOSE Basics Flashcards
What are 6 functions of connective tissue?
“Connective Tissue Will Do Plenty Stuff”
Protect - cushion between tissues and organs and shock absorber/insulation (adipose)
Transport - diffusion of nutrients and waste (loose CT)
Defence/Immune - against infection - (blood/lymph/wandering cells)
Connects - bone to bone, muscle to bone (cartilage, tendons)
Storage - fuel storage (adipose)
Wound Healing - fibroblasts, macrophages, myofibroblasts
What are the 3 general components of CT?
Cells
Fibres
Ground Substance
What is ground substance made up of?
A watery lubricating substance made of proteogylcans (long polysaccharide chains). GAGs bind to a core protein e.g. Along a hyaluronan molecule in hyaluronic acid which is a common GAG found in cartilage
What is extracellular matrix made of?
Fibres and ground substance.
What is loose CT formed of and what is it useful for?
Many cells, sparse collagen, lots of ground substance, it’s gel-like consistency good for Transportation - diffusion.
What types of cells might you find in loose CT?
Many - fibroblasts, plasma cells, mast cells, endothelial cells, adipose cells, lymphocytes, eosinophils
What 3 things/structures is loose connective tissue usually associated with? How does this help with it’s function?
1) Beneath epithelia for diffusion
2) Associated with epithelium of gland
3) Located around small BVs
These are all areas where pathogens can infiltrate - Loose connective tissue can swell during inflammation
What kind of tissue is elastic fibres found in?
Most kinds of CT but where and how densely is different - e.g. Major component of Dermis, artery walls, lungs, elastic cartilage
What are the 7 fixed cells and 5 wandering cells that can be present in connective tissue?
Fixed: macrophages, fibroblasts, myofibroflasts, mast cells, melanocytes, adipocytes, mesenchymal stem cells.
Wandering: monocytes, eosinophils, basophils, leucocytes, plasma cells
What is the role of fibroblasts and myofibroblasts? What are their roles in wound healing?
Fibroblasts secrete ground substance and the fibres within it e.g. Procollagen - major role in wound healing and scar tissue formation
Myofibroblasts contain actin and play a major role in closing wounds ‘purse string’
What are macrophages and two major roles?
Are migrated monocytes from blood to connective tissue - phagocytose foreign bodies and debris and also are professional antigen presenting cells (present antigens to T cells)
What are mast cells, what coats them and name 2 things they release
Mast cells are found in CT near blood vessels. They release Histamine, Heparin They coat with IgE molecules that release their granule content on binding with an allergen. Role in allergic reaction/anaphylaxis.
How is regular dense CT structure useful for it’s function?
It has dense parallel bundles of collagen fibres that withstand stress in a single direction.
How is irregular dense CT suited to it’s function?
Dense irregular bundles of collagen fibres in all different directions - can withstand stress from many different directions e.g. Skin.
What are Ghrelin and Leptin and where are they secreted from?
Ghrelin - appetite stimulant released from stomach
Leptin - appetite suppressor released from fat cells
Give 3 examples of regular dense CT and 2 examples of irregular dense CT
Regular - tendons, ligaments, aponeuroses(e.g. Alba Linea)
Irregular - deep layers of dermis of skin, submucosa of intestine
How many types of collagen are there? What is the main type?
28
90% is type I
Describe and explain 4 common types of collagen
I - 90% - form fibres - tendons, capsules of organs, dermis
II- fibrils do not form fibres - hyaline and elastic cartilage
III - form fibres round muscle and nerve cells and within lymphatic tissues and organs (reticulin)
IV - Unique form found in basal lamina of basement membrane
What are 3 common types of fibre found in connective tissue?
Collagen, reticular, elastic fibres
What are reticular fibres? Where do they get secreted from?
Made of irregular network of collagen type III secreted by reticular cells
What are elastic fibres?
Made of elastin which is enfolded and surrounded by fibrillin.
What are 3 functions of adipose?
Fuel reserve, thermal insulation, shock absorber
What is the different between unilocular and multilocular adipose?
Unilocular - white fat - one large lipid droplet inside, cytosol and nucleus pushed to periphery
Multilocular - brown fat - many small lipid droplets with central nucleus. Brown due to many mitochondria and blood vessels- high respiratory capacity to make heat - non shivering thermogenesis
Where is brown fat found?
In babes - mainly scapula, sternum, axillae. In the adult there is some in the upper chest and neck.
Give 4 examples form the lecture of what happens when CT can go wrong (disease)
Scurvy - lack of vit C that is needed to make procollagen
Osteogenesis imperfecta - Abnormal type I collagen
Marphans - autosomal dominant - abnormal expression of fibrillin gene so abnormal elastic fibres. Present as abnormally tall, arachnodactyly, dislocations, at risk of aortic rupture.
AAA - loss of elastin
What does GAG stand for?
Glycosaminoglycan
What are two functions of the ground substance gel made with GAGs and water
allow diffusion resist compression
What are two main roles of loose connective tissue?
Diffusion - lots of Ground Substance
Can swell in immune response
Which is the most common type of collagen in body?
Collagen I
90%
How is type I collagen arranged, where in the body would you see it (4)?
Arranged in fibres, in tendons, bones, round organs and skin dermis
How is type II collagen arranged? Where in the body is it found (2)
NOT in fibres, found in elastic and hyaline cartilage
How is type III collagen arranged? Where in the body is it found?
Arranged in fibres. E.g.
muscle, nerves, and within lymphatic tissue and organs
