Connective Tissue

Question 1

What are the 4 types of tissue in the body?

Answer 1

Epithelial, Muscle, Nerve, Connective

Question 2

What are the 3 substances found in General CT Proper?

Answer 2

Cells, Fibres, Ground substance

Question 3

What is the molecular make up of ground substance? How does this affect its function?

Answer 3

Made up of PROTEOGLYCANS, which consists of a core protein, covalently bonded by GLYCOSAMINOGLCANS. These are hydrophilic molecules, forming a hydrated gel which resists compression within losing flexibility.

Question 4

Extracellular matrix = X + X

Answer 4

Ground substance and fibres

Question 5

What are some of the functions of CT?

Answer 5

CONNECTS - cells to tissues to organs
TRANSPORTATION - diffusion of nutrients and waste, blood
PROTECTION - cushioning and insulation
STORAGE - Adipose tissue (fat)
DEFENCE - blood, lymph, fixed/wandering white blood cells
WOUND HEALING - e.g. Macrophages

Question 6

What are the 3 types of fibres and their properties?

Answer 6

COLLAGEN - gives flexibility and strength
ELASTIN - Gives recoil e.g. Skin
RETICULAR - Gives spongey framework

Question 7

What are the two types of connective tissue?

Answer 7

Loose and dense

Question 8

Describe loose CT.

Answer 8

Many cells (fibroblasts, macrophages, elastic fibres etc), sparse collagen, lots of Ground Substance, gel like. Lies just under the epithelium and blood vessels - first line of defence so prone to swelling e.g. Dermis.

Question 9

What is the difference between a -blast and a -cyte cell? Gives examples.

Answer 9

Blast cell - immature ‘forming’ cells. Secrete ground substance and fibres to extracellular matrix e.g. Fibroblasts, osteoblasts.
Cyte cell - when a blast cell has matured, finished forming e.g. Osteocyte.

Question 10

What are the 2 types of dense CT? Describe.

Answer 10

Regular - collagen fibres orientated in a parallel fashion, with fibroblasts in between. Can withstand stress in one direction e.g. Tendons, ligaments.
Irregular - collagen fibres bundled in different directions and can withstand stress in multiple directions e.g. Dermis, intestine.

Question 11

What type of tissue is in the dermis?

Answer 11

Dense irregular, can withstand force in many directions, elastic fibres allow recoil after stretch.

Question 12

What are the two types of cell in CT?

Answer 12

Fixed and wandering

Question 13

Give me some examples of fixed cells.

Answer 13

Fibroblasts - secrete ground substance and fibres - important in wound healing.
Myofibroblasts - contain ACTIN which causes wound contraction when tissue loss occurs.
Macrophages - ‘ingesting’ white blood cells
Mast cells
Melanocytes - melanin producing cells
Adipocytes - far cells

Question 14

Explain how Mast cells work.

Answer 14

Mast cell ‘granules’ are rich is Histamine (increase blood wall permeability) and Heparin (an anti-coagulant).
Coated in IMMUNOGLOBIN (IgE) molecules which bind to to allergens, causing cell granules to be released.
Cause allergic reactions and anaphylaxis.

Question 15

What are some examples of wandering cells?

Answer 15

Leukocytes, monocytes, eusinophils, basophils - WBC

Question 16

What are the 2 types of collagen?

Answer 16

Type I - makes up 90% of collagen, fibrils make up fibres which make up fibre bundles e.g. Tendons. Triple alpha helix.
Type II - formed in muscle and nerve cells, lymphatic tissue. Reticular fibres.

Question 17

How does Scurvy come about? What is it a deficiency of?

Answer 17

Fibroblasts secrete PROCOLLAGEN which converts to collagen OUTSIDE the cell. Vitamin C is needed for the production of intracellular procollagen, therefore collagen cannot be made. This leads to poor wound healing and bone formation. Common in homeless people.

Question 18

What is Osteogenesis Imperfecta?

Answer 18

When there is too little Type I collagen in the body (makes up 90%) - leads to fragile bones (not adequately protected).

Question 19

What is the make up of elastin?

Answer 19

Elastin fibres are made up of FIBRILLIN e.g. Dermis, artery walls, lungs. All areas of the body needed for recoil (blood, air e.g.)

Question 20

Tell me about Marfan’s Syndrome.

Answer 20

An autosomal dominant trait. Abnormal fibrillin leading to abnormal elastic tissue. Patients are abnormally tall,thin, arachnodactyly. Bone dislocation common, risk of aortic rupture. Should keep blood pressure low, heart surgery can be performed including hypothermic circulatory arrest to slow down blood flow.

Question 21

What are the 2 types of fat cells and their properties?

Answer 21

White - most common. Used as a fuel reserve, insulation, shock absorption. Cells are almost entirely fat with nucleus and cytoplasm squeezed to one side.
Brown - many droplets found in one cells with lots of mitochrondrian, used for respiration capacity to generate heat. Highly vascularised hence brown colour. Found in newborns to keep warm.