microanatomy - tissue types

Question 1

a. name the main groups tissues

Answer 1

• Epithelia -
• Muscle
• Nerve
• Connective tissue

Question 2

name the main groups of connective tissues and describe their composition

Answer 2

Loose connective tissue
Dense regular connective tissue
Dense irregular connective tissue

Question 3

b. describe the general characteristics of connective tissues and apply these to their functional roles

Answer 3

Fibres –collagen, elastic, reticularGround substance –material that fills the space between cells
Cells

Question 4

describe the composition of connective tissue

Answer 4

• contain collagen, reticular and elastic and a gel like matrix
• Contains fibroblasts, macrophages, mast cells and some white blood cells
• Location –widely distributed under epithelia of the body

Question 5

how does this relate to the function of loose connective tissue

Answer 5

Function –wraps and cushions organs; its macrophages phagocytize bacteria; plays important role in inflammation; holds and conveys tissue fluid

Question 6

describe the composition of dense regular connective tissue

Answer 6

Primarily parallel collagen fibres; a few elastin fibres; major cell type is the fibroblast

Question 7

function of dense regular connective tissue

Answer 7

Function –attaches muscles to bones or to muscles; attaches bones to bones; withstands great tensile stress when pulling force is applied in one direction
Location –tendons and ligaments

Question 8

describe the composition of dense irregular connective tissue

Answer 8

• dense woven network of collagenous (and some elastic) fibres in a viscous matrix.
• the collagen fibres are densely packed, and arranged in parallel.
• found in ligaments and tendons. These are powerfully resistant to axially loaded tension forces, but allow some stretch.
• Dermis periosteum capsules of organs -Protection

Question 9

c. name and describe the special characteristics, distributions and functions of bone

Answer 9

Bone

Rigid connective tissueSupports and protects the body
Collagen fibres make up 95% of the matrix, they are imbedded in GAGs and calcium phosphate hydroxyapatite

Question 10

c. name and describe the special characteristics, distributions and functions of cartilage

Answer 10

Cartilage

Semi-rigid, strong but slightly flexible, it withstands compression forces
Major role during development and growth of long bones
It is Avascular –cells have to get their oxygen and nutrients by diffusion

Question 11

Hyaline cartilage

Answer 11

Found in embryonic skeleton, articular ends of long bones, nose, trachea
The matrix –amorphous gel composed of GAGs provides smooth surfaces, enabling tissues to move/slide easily over each other

Question 12

Fibrocartilage

Answer 12

Prominent collagen fibre bundles arranged in parallel to resist stretchFound in tendon insertionsProvides tensile strength, absorbs compression shock

Question 13

Elastic cartilage

Answer 13

Withstands repeated bending, is flexible maintains shape and can spring back into original position

Question 14

elements of connective tissue

Answer 14

Fibres –collagen, elastic, reticularGround substance –material that fills the space between cells
Cells

Question 15

Collagen Functions

Answer 15

Function depends on the type of collagen
Type I –tensile strength
Type II –hyaline and elastic cartilage
Type III –Reticular limina, first collagen secreted in wound healing
Type IV –Basal lamina

Collagen is thick, unbranched, tough and provides high tensile strength (stretch resistant

Question 16

elastin

Answer 16

Provides elasticity
Found in the vocal cords, aorta, pulmonary arteries, lungs and skinIt is thin and branched and requires special staining to be seen

Question 17

Reticular Fibres

Answer 17

Support for capillaries, nerve and muscle fibres Found in basement membrane and capsules surrounding organs

Question 18

Ground substance

Answer 18

highly hydrated semi-solid gel-like substance in the extracellular space (interstitial fluid) that contains all components of the extracellular matrix except for collagen and elastin

Question 19

Glycosaminoglycans (GAGs)

Answer 19

Unbranched polysaccharide chains of repeating disaccharide unitsThey are highly polar and thisattract water, so can be used as a lubricant or shock absorber

Question 20

connective tissue cells

Answer 20

Fibroblasts -major cell in ordinary connective tissue –actively producing fibres
Plasma cells
Adipocytes - Uptake, synthesis, storage and mobilization of lipid
Used as fuel for cells, cushion, insulation
Pericytes
Endothelial cells

Question 21

adipose tissue

Answer 21

Similar to loose connective tissue, packed with adipocytes