T/F The vertebrate body is mostly extracellular space

True. Connective tissues mainly and extracellular matrix mainly fill this space

ECM is ______ in cartilage and bone, but ______ in brain and spinal cord

plenty, scarce

What are the functions of the ECM?

• Determines the form an shape which leads to its function
• Mechanical support (hold shape and resist outer forces)
• Helps cells with adhesion and migration
• Control cell signaling and differentiation

What exactly is an ECM?

A combo of polysaccharides and proteins that support the cells and tissues in the body

What is responsible for ECM secretion?

Fibroblasts!

What are epithelial cells?

Cells that line the inside and outside of the body

What is a basal lamina?

A thin layer of ECM that sits between the connective tissue and the epithelial cell. Acts kinda like glue. A felt like sheet

What are the 2 types of proteins that make up the ECM?

• Fibrous
  • Collagen and Elastin
• Adhesive
  • Fibronectin and Laminin

What is the role of polysaccharides?

To help resist compression (Glycosaminoglycans)

Collagen fibrils provide the ECM with _______ strength

Tensile

• long, stiff triple helix
• 3 of them wind together like a rope
• Rich in proline and glycine

What are the properties of Fibrillar (I, II, III, V, XI)?

• 1,2,3,5,11

Connective tissues, bone, skin, tendons, ligaments, eyes, internal organs

T/F Collagen fibrils are the most abundant proteins in vertebrates

True! The most abundant as it is expressed in many tissues

What are the properties of Fibril associated (IX, XII) collagen good for?

• 9, 12

Found on the surface of collagen fibrils and help with linking fibrils and ECM together (Cartilage)

What are the properties of Network forming (IV, VII) collagen good for?

• 4, 7

Type IV

• the basal lamina!

Type VII

• Dimers to anchor the basal lamina to the connective tissue

Describe the biosynthesis of fibrillar collagen

Each helix is formed separately extra pro-peptides to prevent it from assembling just yet. When there are 3, the triple strand helix starts to form and the pro-peptides are cleaved off. This happens outside the cell

Why are collagen fibrils so strong?

They have covalent and noncovalent bonds as well as stacking of the molecule

What is and what caused the Ehlers-Danlos syndrome?

A mutation in the Type III collagen

• Fragile and Hyperextensible skin, hypermobile joints

What is and what caused the Osteogenesis imperfecta?

Mutations in Type I collagen

• Fragile bones that fracture easily

What is and what caused the Chondrodysplasia?

Mutations in Type II collagen

• Bone and joint deformities; mutations in cartilage collagens

What is and what caused Scurvy?

Lack of vitamin C

• Loss of collagen so gums are too weak to hold teeth and blood vessels are fragile

What is Feline cutaneous asthenia?

A cat's version of Ehler-Danlos syndrome which gives cat's wings!!

What are Proteoglycans?

Glycosaminoglycans (GAGs) linked to proteins. The point is to take up space. Think Pine needle trees

What are the functions of Glycosaminoglycans and Proteoglycans?

The resist compression due to lots of negative charge. Allows lots of water. Allows a matrix for the molecules to travel through. The "space" is technically not empty

What does the Basal Lamina (basement membrane) consist of?

Type IV collagens, perlecan, laminin and nidogen

What does the Basal Lamina do?

It acts like a filter only letting certain molecules through. Selective barrier and provides a scaffold for regenerating cells to migrate

T/F Cells can live if they are connected to the wrong place

False! Cells must be attached to the correct place in order to live: Anchorage dependence