all come from mesoderm

adipose tissue branches off from mesenchymal tissue

mesenchymal tissue has blood, supportive tissues and CT

PROPER

loose and dense

SPECIAL

reticular, elastic and mucous

ADIPOSE

white and brown fat

cells: fibroblasts and fibrocytes

fibers

ground surface

Support

Protection

Defense

Nutrition and storage

repair and regeneration (scar tissue)

Collagen is the main fiber type

cells are not directly attached to each other like in epithelial

provides tensile strength

most abundant protein in the body

Type 1: fibrous tissue, bone

Type 2: hyaline and elastic cartilage

Type 3: meshwork in liver, hemotopoetic organs (RETICULAR)

Type 4: basement membrane

semi fluid, flexible gel

components:

proteoglycans

glycosaminoglycans (GAG) are hydrophilic

ex: haluronic acid, dermatan sulfate, chondroitin sulfate

adhesive glycoproteins: fibronectin, laminin osteonectin

loose and random fibers

thin fibers

abundant ground substance

soft and compliant

Examples:

gut lamina propria

perivascular

surrounding glands

skin

many fibroblasts

densely packed fibers

parallel arrangement

minimal ground substance

connects muscle to bone

examples:

tendons

ligaments

few fibroblasts

random orientation

minimal ground substance

usually covered by epithelium

concentrates where forces come from different directions

examples:

skin, organ capsules

proportions of cell/fiber/matrix (fibers and ground substance) is different than proper CT

types: reticular, elastic, mucous

type 3 collagen: reticular fibers

delicate, branched

need special silver stain to visualize

 lymphatic and hematopoetic organs

lymph nodes, spleen, thymus, lung, liver

elastic fibers

hard to see with H&E stain

functions: stretching, elastic recoil, resiliance

anatomic sites:

vessels, external ear, vocal chords, trachea, lung, skin

not found in mammalian adults

rare in non mammalian adults

predominant element is matrix/ground substance

scarce fibers and low cellularity

sites:

umbilical cord, subdermal embryo, chicken combs and turkey wattles

cell is spindle shaped

nucleus is flattened

cytoplasm is small

cell borders are indistinct

produce fibers, proteoglycans, glycoproteins

function in support, healing and repair

fibroblast is actively producing fibers and matrix

fibrocyte is inactive for maintenance and turnover

phagocytosis of infectious agents, foreign material, necrotic debris, RBC

antigen presenting cells

can be resident (kuppfer, langerhans cells) or transient

eccentric nuclei

eosinophilic / foamy cytoplasm (can contain materials)

lysosomes present

distinct cell margins

usually in low numbers (tumor possible)

associated w blood vessels

function in hypersensitivity (allergy)

granules have histamine, heparin, inflammatory mediators

sites: skin, respiratory, digestive

abundant cytoplasm with granules (basophilic)

distinct cell borders

lymphocytes

plasma cells

neutrophils

eosinophils

basophils

functions: energy storage, shock absorption, insulation and thermoregulation

nucleus is eccentric and flattened

cytoplasm is thin peripheral rim

cell is filled with a large single lipid droplet (primarily triglycerides)

sites: almost everywhere

can be individual cells, cluster, sheet

CT supporting muscle

subcutis, mesentary, surround kidneys

brown due to numerous mitochondria, vascularization

only function is to generate heat - oxidative phosphorylation

cells are smaller than white fat

nucleus is eccentric and peripheral; plump and oval, not flat

cytoplasm is eosinophilic w multiple discrete vacuoles (lipid droplets)

limited distribution:

axilla, perirenal, interscapular, mediastinum

well developed in rodents and hibernating animals

neonates have it