Connective Tissue Flashcards
Connective Tissue Equations
CT = Cells + ECM ECM = GS + Fibres
ECM Function
Determines properties of CT types
Binds/Supports/Strengthens other tissues
Transport
Energy Storage
Ground Substance Components
Water
Proteins
Polysaccharides
Marfan’s Syndrome
Mutation in Chromosome 15 alters coding for Fibrillin
- alters structural scaffolding for Elastin, leading to weakened heart valves, arterial walls and irregular BP
- Transforming Growth Factor beta (TGFb) unable to be inactivated by binding to Fibrillin, resulting in hypergrowth such as elongated limbs/digits, chest deformity
Cells in Solid CT
Fibroblasts Adipocytes Macrophages Plasma Mast Leukocytes
Fibroblast Function
Secrete ECM components (GS and fibres)
Migratory
Widely Distributed
Adipocyte Function
Fat (Triglyceride) storage (central triglyceride droplet)
‘Cushioning’ under skin/around organs
Macrophage Function/Characteristics
Phagocytic
Fixed Location: “dust cells” in lungs, “kupffer cells” in liver, “langerhans cells” in skin
Wandering Location: sites of inflammation/infection/injury
Plasma Cell Function/Location
Antibody production
Gut; Lung; Salivary Glands; Lymph Nodes; Spleen; Red Bone Marrow
Mast Cell Function/Location
Histamine Production
Swelling/Inflammation Response
Alongside Blood Vessels in CT
Function/types of Leukocytes (in blood)
Immune Response
Granular: Easinophils; Basophils/Mast cells; Neutrophils
Agranular: Monocytes; T-/B-Lymphocytes
Hyaline Cartilage: Structure Function Characteristics Location
- Resistance gel with subtle fibres present; Prominent chondrocytes in lacunae surrounded by perichondrium
- Flexibility/Movement
- Weakest cartilage
- Anterior end of ribs (between ribs/sternum); respiratory cartilage (nose/trachea/bronchi); Nasal septum; ends of long bones
Elastic Cartilage: Structure Function Characteristics Location
- Chondrocytes in thread-like network of elastic fibres; perichondrium (‘fibrous’) surround chondrocyte surface (provide blood supply)
- Strength/Elasticity; maintains shape of certain structures
- Epiglottis; Auricle (external ear); Eustachian (auditory tubes)
Fibrocartilage: Structure Function Characteristics Location
- Chondrocytes scattered in visibly thick collagen fibre bundles; has lacunae but no perichondrium
- Strength/Rigidity; Support; Joining structures
- Strongest cartilage
- Pubic Symphysis (anterior hip-bone joint); Intervertebral discs; menisci (cartilage pads) of knee; parts of tendons that insert into (hyaline) cartilage
Perichondrium
Coating of dense irregular CT around chondrocytes
Provides blood to avascular cartilage
Cartilage: General Structure/Characteristics
Dense Collagen/Elastic fibre network
Mature Supporting CT
CT Classifications
- Embryonic: Mesenchyme; Mucous
- Mature:
Proper CT (Loose - Areolar/Adipose/Reticular; Dense - Regular/Irregular/Elastic)
Fluid CT (Blood; Lymph)
Supporting CT (Cartilage/Bone)
Mesenchyme CT Structure/Function
Very few mesenchymal cells; semi-fluid GS; reticular fibres
Embryonic
Gives rise to all other CT
Mucous CT Structure/Function
Widely scattered fibroblasts; jelly-like GS
Embryonic
Supports foetal umbilical cord
Areolar Tissue Structure/Location/Function
Cartilage/Elastin/Reticular Fibres present
Widely distributed around almost every structure (i.e. subcutaneous layer)
Strength/Elasticity/Support
Adipose Tissue Structure/Location/Function
Dominated by Adipocytes; includes fibroblasts
Found with Areolar Tissue
White - energy storage; Brown - heat production (very important in newborns)
Insulation/Thermoregulation/Heat Production
Reticular Tissue Structure/Location/Function
Interlacing network of reticular fibres and reticular cells (from mesenchymal cells)
Stroma (support framework) of organs; binds SmM tissue cells (___mysium); filters/removes worn-out blood cells in spleen/microbes in lymph nodes
Collagen Fibres
Secreted by fibroblast cells in ECM; Parallel, thick bundles of collagen
Strong but inflexible; most abundant in body
Resist pulling forces
Bone; Cartilages; Tendons/Ligaments
Reticular Fibres
Secreted by fibroblasts in ECM; thinner collagen fibres with glycoprotein coat bundled together; branch throughout tissue
Structure; Support
Elastic Fibres
Thinner, fibrous network; Protein elastin surrounded by glycoprotein fibrillin
Strength; Stability; Stretching Capacity 150%
Skin; Blood Vessels; Lungs; Sites of increased movement/abrasion
Perichondrium
Coating of dense irregular connective tissue; source of new chondrocytes; contains blood vessels/nerves
Dense Regular CT
Collagen with fibroblasts arranged along rows; Shiny white colour; some avascular
Slow-healing
Attachments (Tendons, Ligaments, Aponeuroses)
Dense Irregular CT
Collagen with few fibroblasts
Often arranged in ‘sheets’
Tensile (multi-directional) strength
Found in fasciae (tissue under skin/around muscles/other organs); reticular dermis; fibrous pericardium; periosteum; perichondrium; joint capsules (synovial); membrane capsules of kidneys/liver/testes/lymph nodes; heart valves
Elastic CT
Predominantly Elastic fibres with fibroblasts; yellowish when unstained Strength/recoil Lung tissue (exhalation); elastic artery walls (blood flow); trachea; bronchial tubes; true vocal cords; suspensory ligaments of penis; ligaments between vertebrae
Blood Structure/Function
Yellow plasma (contains lipids); 'formed elements': - RBC - WBC - Platelets Nutrient/hormonal/gas exchange/transport
Stapedius
Smallest muscle (1.25mm) Performs tympanic reflex; prevents hyperacusis
Sartorius
Longest muscle (around 60cm); hip flexor/abductor/lateral rotator; knee flexor; ‘checking for gum’
Bell’s Palsy
Paralysis in facial nerve causes muscular weakness on one side of face; tympanic reflex is weakened; causes hyperacusis
Epimysium
Surrounds anatomical muscle
Perimysium
Surrounds fascicles (bundles of myocytes)
Endomysium
Surrounds muscle fibres; capillary/nerve supply around cell
Sarcolemma
Plasma membrane of myocyte; surrounds sarcoplasm
Myofibrils
Contractile threads within myocytes:
- actin
- myosin
Sarcomere
Contractile unit of skeletal/cardiac muscle cells
Z-line
Links filaments of adjacent sarcomeres; passes through center of I band; actinins
Titin
Links z-discs and M-line; creates resting tension in I-band; acts as ‘molecular spring’
