#6: histology (connective tissue)

connective tissue consists of…

cells that are separated from one another by a matrix

connective tissue cells include

1. blasts: form and secrete the matrix, eg. osteoblasts (builds)

2. cytes: maintains the matrix, eg. osteocytes

3. clasts: breakdown the matrix (so it can be built again)

matrix →

• is it extracellular or intracellular?

• what does it provide connective tissue with?

• how many primary components does it have?

• extracellular: surrounds the cells of the connective tissue

• provides the connective tissue with its characteristics

• three primary components

three primary components of the matrix

1. protein fibres (collagen for strength, elastin for stretch and recoil)

2. ground substances: unstructured material located between the cells. contains fibres

3. water

three primary characteristics of connective tissue

1. highly vascular (lots of blood) with some exceptions

2. lots of extracellular matrix (keeps cells far apart from one another)

3. primary function: support and connect tissues

types of connective tissue

1. connective tissue proper

2. cartilage

3. bone

two varieties of connective tissue proper

• loose connective tissue: adipose, areolar

• dense connective tissue: dense regular, dense irregular

what is areolar connective tissue called when it is found in mucous membranes?

lamina propria

dense regular connective tissue →

• what are the cells called?

• how much ground substance does it have?

• cells are fibroblasts

• very little ground substance

dense irregular connective tissue →

• what cells does it have?

• how much matrix does it have?

• what kind of fibres does it have, what direction do they run in?

• composed of fibroblast cells

• very little matrix

• composed of bundles of collagen fibres (larger and runs in more than one direction)

what does dense regular connective tissue form

tendons

• attaches muscle to bone

where is dense irregular connective tissue found

• in areas where there is pull in more than one direction

• eg. dermis

cartilage →

• what are the cells called and where are they found?

• what is the matrix like? what is it formed from?

• what is its vasculature?

• cells are called chondrocytes (found inside compartments called lacunae)

• firm matrixformed from tightly bound collagen fibres

• avascular

bone →

• what are the two types?

• what are its cells called?

• what is its vasculature?

• exists as spongy bone and compact bone

• cells are called osteocytes (located in organized structures called lacunae)

• highly vascular

what is the bone’s matrix made of

• densely packed collagen fibres

• inorganic calcium and phosphate salts → collectively called hydroxyapetite crystals

• water

blood →

• what are its cells?

• what is its matrix called?

• cells are red blood cells and white blood cells

• matrix is called plasma

what are the cells in adipose connective tissue

adipocytes (fat cells)

adipose connective tissue →

• how much matrix is in it?

• is it vascular?

• very little matrix

• highly vascular (allows for a lot of metabolic activity)

what does adipose connective tissue function in?

• shock absorption

• insulation

• energy & triglyceride storage

areolar connective tissue →

• how is it arranged?

• how vascular is it?

• loosely arranged

• highly vascular

areolar connective tissue →

• what does it contain?

• what is its ground substance?

• collagen and elastic fibres

• hyaluronic acid

what are the cells in areolar connective tissue?

fibroblasts

dense regular connective tissue →

• what kind of fibres does it have, what direction do they run in?

• how vascular is it?

• collagen fibrespacked together, running in same direction

• poor vasculature

cartilage →

• is it soft or firm? is it flexible?

• what is in its ground substance?

• how much water content does it have?

• firm and flexible

• ground substance: chondroitin sulfate, hyaluronic acids

• high water content (as high as 80%)