connective tissues Flashcards
what is connective tissue?
the most abundant tissue in the human body
what are example of connective tissues?
- bone (structural integrity)
- cartilage (protects joints)
- tendons/ligaments (connects muscle to bone)
- adipose tissue (store energy)
- mesentery (connects intestine to abdomen
- layers under skin/around organs (support)
what is the structure of tendons (connective tissue)?
- dense fibrous tissue
- fires run parallel, which increases strength to help transfer the force of muscle contractions to bone
what are the components of connective tissue?
- ground substance
- fibres
- cells
what makes up the extracellular matrix and what is its function?
ground substance and fibres
it provides structural and biochemical support for cells
what is ground substance?
- provides biochemical support
- clear, semi-solid gel
- composed of glycoproteins and complex carbohydrates (hyaluronic acid and glucosamine)
- water binding ability
- provides tissue volume
- supports intracellular exchange of substances
what are the two main types of fibres in connective tissue?
collagen and elastin
what is the role of fibres in connective tissue?
- provides structural support and tensile strength
describe collagen fibres
- strongest fibres
- most abundant fibres
- provide tensile strength
- secreted by ECM by connective tissue cells
- around 28 different types
- type 1- found in fibrous tissues eg dermis of skin
- type 2- hyaline cartilage contains this
- type 3- found in highly cellular organs eg liver- has a delicate branched reticular network
describe elastin fibres
- long and branched
- wavy to provide stretch and recoil ability
- secreted into ECM by connective tissue cells
- found in the skin, lungs, blood vessels, bladder etc.
what do - blast cells do?
synthesise the extracellular matrix
what do -cyte cells do?
maintain the extracellular matrix
what do -clast cells do?
breakdown the extracellular matrix
what is the most common connective tissue cell?
fibroblasts- secrete fibres and components of ground substance
what do odontoblast cells do?
synthesise dentine in the teeth
what do adipocyte cells do?
maintain the ECM in adipose tissue
what do osteoclast cells do?
recycle (breakdown) ECM in bone
what makes connective tissue highly vascularised?
- blood vessels and lymphatics
- immune cells which survey tissues for invading pathogens/cell damage
- exceptions are cartilage, tendons and ligaments
what is loose connective tissue proper mostly made up of?
ground substance (fewer fibres)
what is dense connective tissue proper mostly made up of?
fibres
what are examples of loose connective tissue proper?
- areolar
- adipose
- reticular
describe areolar loose connective tissue
can be found beneath the skin, submucosa and surrounding capillaries
- universal packing material
describe adipose loose connective tissue
can be found in isolation or in small clusters deep beneath the skin , breasts, abdomen and pads of fingers/toes
- energy storage, shock absorption and insulate
what are examples of highly cellular organs?
liver, lymph nodes, spleen
what are examples of dense connective tissues?
- dense regular
- dense irregular
- elastic
describe regular dense connective tissue
closely packed collagen fibres running in the same direction, providing tensile strength
- found in tendons and ligaments
describe irregular dense connective tissue
closely packed interwoven fibres fibres running in different directions
- found in dermis of skin and forming a protective capsule around organs
describe dense elastic connective tissue
it is the only dense regular tissue dominated by elastic fibres- allows stretch and recoil
- found in arteries, skin, lungs and underlying epithelium
what is scurvy?
- a disease caused by a lack in vitamin C
- defective collagen formation
- leads to loose teeth, skin haemorrhages and even death
- treated with vitamin C
- symptoms include fatigue, gum disease, anaemia, poor wound healing etc.
what is vitamin C required for?
collagen synthesis
- it has a triple helix structure arising from collagens unusual abundance of amino acids, glycine, proline and hydroxyproline
- without the structural support from collagen, blood vessels, tendons and skin become fragile
what is SLE?
systemic lupus erythematosis
- autoimmune disease
- target tissues which antigens attack include skin, bones, tendons and kidney
- oral symptoms include dry and painful oral cavity
- oral manifestations are the buccal and palatal lesions
what is sjogren’s?
an autoimmune disease
- affects the glands which produce tears and saliva
- symptoms include dry eyes and mouth
- oral manifestations are increased dental caries and candidiasis
- can occur independently or accompany other disorders eg SLE
