Connective Tissue (most abundant type and diverse in types & functions)

Functions Binds structures Provide support and protection Serve as frameworks Fill spaces Store fat Produce blood cells Protect against infection Repair tissue damage

3 Elements 1. Matrix (the gel around cells and fibers) ­ like the jello around the fruit in a jello cup) ­ can vary greatly in its consistency (fluidy to solid, but majority is somewhere in the

middle like jello) 2. Fibers (strength, elasticity, and support) ­ in the matrix ­ like linty cat hairs) ­ helps you identify what type of Conn. tissue it is 3. Cells that usually divide ­ don’t divide as readily as epithelial (so less chance of cancer but take longer to heal)

4. Have varying degrees of Vascularity ­ degree of vascularity determines how long healing process takes ­ heals quicker with lots of blood vessels and vice versa

Cell Types

Fixed Cells ­ don’t move Fibroblasts (lots of fibers)

most common cell large and star shaped produce fibers

Mast cells release heparin (stops blood coagulation so that if an area is swelled up, the

blood won’t clot, and used on patients with potential blood clots) and/or histamine (compound released in response to an injury or allergic reaction that causes blood vessels to be more permeable to white blood cells)

Wandering Cells ­ Can move around Macrophages

phagocytic (cells that ingest harmful/foreign particles in the body)

important to an injury or infection

Fiber Types Collagenous Fibers (strongest but still stretchy)

thick composed of collagen great strength abundant in dense CT hold structures together tendons and ligaments (between bones like in your knees) has to be strong so it can hold up under lots of pressure like in between you knees

where all your body weight rests Elastic Fibers (extremely stretchy)

bundles of microfibrils embedded in elastin fibers branch elastic vocal cords and air passages

Reticular Fibers (medium stretch and strength) very thin collagenous fibers highly branched form supportive networks

Types of Connective Tissues ***Difference is in the matrix***

Connective Tissue Proper (LARDE) (general/basic category of Conn. tissue b/c their matrix is about the same/jello­like)

loose connective tissue adipose tissue reticular connective tissue Tells what fibers to look for dense connective tissue elastic connective tissue

Specialized Connective Tissue (have different matrixes) cartilage bone blood

Loose Connective Tissue (PROPER)

mainly fibroblasts collagenous fibers (strong) elastic fibers (stretchy) fluid to gel­like matrix

binds skin to structures (like muscle to bones) beneath most epithelial vascular to nourish epithelial cells nearby

between muscles (2=collagen fibers)

Adipose Tissue (PROPER) adipocytes (cells specialized in the storage of fat) cushions insulates stores fat beneath skin behind eyeballs around kidneys + heart protects organs without bone protection

Reticular Connective Tissue (PROPER) composed of reticular fibers supports internal organ walls walls of liver, spleen, and lymphatic organs

Dense Connective Tissue (PROPER) packed collagenous fibers elastic fibers few fibroblasts bind body parts together

tendons, ligaments, dermis poor blood supply

Elastic Connective Tissue (PROPER) abundant in elastic fibers some collagenous fibers fibroblasts attachments between bones walls of large arteries, airways, and heart

Bone/Osseous Tissue (SPECIALIZED) solid matrix supports protects forms blood cells attachment for muscles skeleton

(7=Osteocyte aka bone cells)

Cartilage Tissue (SPECIALIZED)

rigid matrix chondrocytes in lacunae (a hollowed area holding a cell or cells) poor blood supply

1. Hyaline most abundant ends of bones nose and respiratory passages embryonic skeleton

(9­Hyaline Cartilage; 10­Chondrocyte)

2. Elastic flexible external ear and larynx (voice box)

3. Fibrocartilage

very tough shock absorber intervertebral discs pads of knee and pelvic girdle

Blood Tissue (SPECIALIZED) fluid matrix called plasma red + white blood cells platelets transports defends involved in clotting

throughout body in blood vessels heart

(5­Leukocyte aka white blood cell)

Abnormalities Liver Fibrosis

collagen deposit increases ECM (extracellular secretions of cells)exceeds normal 3% value and may block

blood flow Heart Failure and Atherosclerosis

imbalances of collagen production and degradation ECM buildup may block blood flow in the arteries and the heart

Chondrodysplasia collagen chains are too wide stunted growth deformed joints

Hereditary osteoarthritis change in amino acid in collagen painful joints

Dystrophic epidermolysis bullosa breakdown of collagen that attaches skin layers stretchy skin lax joints

Lupus autoimmune disease destruction of collagen

GREEN BOXES

1. Release of histamine stimulates inflammation by dilating the small arterioles that feed capillaries: the tiniest blood vessels

a. results in swelling & redness i. inhospitable to infectious bacteria/viruses + dilutes toxins

b. Can be a result of inappropriate release like allergies c. allergy medication is called antihistamines

2. Skin exposed to prolonged intense sunlight can lead to fibers losing elasticity

a. skin stiffens and becomes leathery → in time it may sag or wrinkle i. collagen injections can be temporary fix but collagen cream does nothing

3. Surgeons use foam, powder, or sheet form elastin to prevent scar tissue adhesions from

forming on site of tissue removal a. elastin is produced in bacteria that have human genes b. this is cheaper than synthesizing elastin chemically + safer than cadavers

4. infants + young children have continuous layer of adipose (fat) beneath skin (baby fat) a. fat thins or remains thick in places as they age

i. women → breast, buttocks, and thighs ii. men → upper arms, lower back, and buttocks

Miscellaneous

Tendons → attaches MUSCLE → BONE Ligaments → attaches BONE → BONE