Connective Tissue Flashcards
o Found throughout the body; most abundant and widely distributed of the tissues
o Includes: Connective tissue proper, cartilage, bone, blood
o Functions: Binding and support, protection, insulation, transportation
Connective Tissue
o Found below dermis and epidermis
o Between muscles and surrounds blood vessels, nerves and joints
o Function: wraps and cushions organs
o Macrophages – hunt and destroy invaders
o Fibroblasts make fibres
♣ Collagen (strength), elastin (flexibility), reticular fibres (network)
o cO6Mast cells – produce the anticoagulant heparin and the histamine
♣ Heparin limits internal clotting at wounds
♣ Histamine causes edema; also appears to attract macrophages (chemotaxis)
Loose (Areolar) Connective Tissue
o extracellular matrix (mixture of these) = ________
o fluid/gel like substance that acts as protective barrier that absorbs shock =
Cells, fibres, ground substance
Ground substance
5 classic symptoms of acute inflammation
o Swelling – histamine response o Redness – increased blood flow o Pain – swelling impinges on nerves o Heat – due to increase blood flow o Loss of function – area immobilized by swelling
EXAMPLES
Acute
Chronic
o a sprain, ingrown toenail, a sliver
o rheumatoid arthritis, Crohn’s disease, silicosis
Purpose (4)
o Limit damage at the site and/or isolate irritant
o Prevent spread of injury
o Surround and possibly remove irritant (may involve fibrosis (scarring) – collagen bridges openings or surrounds irritant, rendering harmless
o Allow repair
o Inflammatory Response is a case of two Simultaneous Processes:
o Destruction of damaged tissue and/or irritant
o Rebuilding of new tissue
o Found under skin, around kidneys, within abdomen (around organs or between), in breasts, yellow bone marrow
o Functions: energy stores, insulation, support and protection – a cushion.
o Menses: menstruating normally, monthly
o Amenorrhea: Lowering body fat to below 6% to naturally stop menstruation
o Formed like areolar tissue with fibers, cells, adipocytes
o Cells have a nucleus marginalized by a large droplet of fat (triglycerides)
o Cell numbers stay constant, but amount of fat within fluctuates
o Hypertrophy to store fat – stages = newborns pack on fat,
Adipose Connective Tissue
o Found in lymph nodes, bone marrow, liver, and the spleen (think filtering)
o Function: trap blood cells (spleen) and bacteria (lymphatics) for destruction; a “soft skeleton” to support other cell types (macrophages are ‘fixed’ in liver, forms support for red bone marrow in trabeculae of bone)
o Reticular fibres with cells (macrophages and lymphocytes) interspersed in fibre network
Reticular Connective Tissue
o Parallel collagen fibers with a few elastic fibers
o Major cell type is fibroblasts
o Attachment
o Muscles to bone = tendons
o Bone to bone = ligaments
o Forms a tough sheet of tissue to which muscles attach
♣ Aponeurosis – muscle to muscle “head to toe”. Sheet of tissue that allows muscle to muscle without bulk
♣ Ex.) galea, palmar, abdominal, plantar
o Function: provide strong attachments and strength in one direction
o Structure: parallel collagen fibres – very strong in the direction of the fibres
o Cells – fibroblasts to make more collagen
o Collagen fibres of a tendon actually mesh with the collagen fibres in the tissue that surrounds the bones (periosteum)
o Pull the tissue, it resists the pull
o Dense Regular Connective Tissue - ELASTIC
Dense Regular Connective Tissue
o High proportion of elastin
♣ Easily deformed and then resumes original shape (rebounds)
♣ Not as common as Dense Regular
o Found in:
♣ Respiratory tubing – bronchi, bronchioles
♣ Circulatory tubing – larger arteries
♣ Spinal ligaments
Dense Regular Connective Tissue - ELASTIC
o Found in dermis, submucosa of the digestive tract, fibrous organ and joint capsules, periosteum and perichondrium, fasica around muscles
o Structures: Irregularly arranged collagen fibers with some elastic fibres
o Major cell type is fibroblasts
Function: structural support and protection
Dense Irregular Connective Tissue
o Red and white blood cells in a fluid matrix (plasma) (shapeless = amorphous)
o Cells produced in red bone marrow
o Contained within blood vessels
o Functions in the transport of respiratory gases (O2 and CO2), nutrients, and wastes
o RBC’s = erythrocytes
o WBC’s = leukocytes
o Platelets = thrombocytes, thrombus = clot
o Plasma is more frequent in women
o Neutrophil are most common WBC’s, lymphocytes = ~20%
o Fibrinogen connects and creates fibrin. Fibrinogen dissolves unless it is needed for blood clotting.
o Polymerization = connecting the same thing again and again. (think DNA)
Connective Tissue: Blood
o Supports, reinforces, cushions, and resists compression
o Forms the costal cartilage
o Found in embryonic skeleton, the end of long bones, nose, trachea, and larynx
o Cartilage is the SLOWEST healing tissue in the body (blood vessels are far, low diffusion)
o Amorphous, gel-like matrix
o Imperceptible network of collagen fibers
o Water (80%)
o Proteoglycans (mucopolysaccharides) – slippery, slimy
♣ Proteins + carbohydrates
♣ Chondroitin sulfates (shock absorber)
♣ Hyaluronic acid (low friction)
o Chondrocytes lie in lacunae (“little lakes”)
o Chondroblasts secrete matrix
o CHRONDRO = CARTILAGE
o When surrounded by matrix – chondrocytes
o Also secrete substance to limit blood vessel growth (anti-angiogenesis factor) – poor blood supply
o Angio = blood vessel, angiogenesis = creation of blood vessels
o No blood vessels, so no diffusion hence longer healing time for cartilage
Connective Tissue: Hyaline Cartilage
o Similar to hyaline cartilage but with more elastic fibers
o Maintains shape and structure while allowing flexibility
o Supports external ear (pinna) and the epiglottis
Connective tissue: Elastic Cartilage
