Exam I (2.1)

Question 1

What is a biomaterial?

Answer 1

A nonviable material making up a medical device, participates in interactions with the body. (synthetics, biologics)

Question 2

How do biomaterials interact with the body?

Answer 2

Via proteins that absorb onto the surface of the biomaterial, from serum (soluble) proteins to tissue (insoluble) proteins. This absorption process is rapid, competitve, and dynamic.

Question 3

Proteins: structure

Answer 3

• Polymers of amino acids, connected by peptide bonds
• Defining differences in hydrophilicity/hydrophobicity
• Primary, secondary, tertiary, and quaternary structure (folding)
• Structural and functional, can be soluble or insoluble

Question 4

Cell receptors

Answer 4

Those with specific affinities can recognize adsorbed proteins

Question 5

Adsorption kinetics (phases)

Answer 5

1st Phase: Diffusion based, rapid, concentration-dependent/molecular weight-dependent
2nd Phase: Based on available surface, proteins adsorb in a monolayer

Question 6

Vroman Effect

Answer 6

Protein adsorption is dynamic. Small proteins, due to faster diffusion, may attach in greater concentrations at first. However, later on, proteins with more surface affinity (even if larger/slower), dominate.

Question 7

Protein Properties

Answer 7

Hydrophilicity, size, charge, and structural stability/rigidity (expand on each)

Question 8

Surface Properties

Answer 8

Hydrophilicity, charge, topography, chemistry (expand on each)

Question 9

Vivo vs. Vitro

Answer 9

In vivo, cells are constantly sensing and responding to the environment around them. By replicating the microenvironment in vitro, such as the pH levels, serum proteins, and temperature, can better study these interactions.

Question 10

Microenvironmental factors

Answer 10

Soluble factors expressed/received, extracellular matrix, oxygen stress, cell-cell contact, mechanical environment

Question 11

Mechanotransduction

Answer 11

• Cell adhesion allows for creation of a “bone structure” when integrin receptors bind to certain motifs in ECM proteins
• Actin cytoskeletal fiber can activate tensions within the cell, which leads to gene expression

Question 12

Homeostasis in the body

Answer 12

• Continual balance of molecular synthesis and degradation
• All types of cells, tissues, and organs

Question 13

Plasma membrane

Answer 13

Phospholipid bilayer! Expand on structure, and why it is protective and selective for the cell’s benefit.

Question 14

Glycocalyx

Answer 14

A ‘hairy’ structure on the outer membrane, composed of sugar chains, that produce a negative net charge.

Question 15

Active transport

Answer 15

• Specific receptors are needed, as well as ATP (energy)
• Often through vesicles
• Endocytosis, pinocytosis, transcytosis, phagocytosis, exocytosis

Question 16

Signal Transduction

Answer 16

• Soluble factors
• Paracrine: growth factors, cytokines, etc. from other cells
• Endocrine: systemic factors in the blood
  Synaptic: physical cell junctions

Question 17

Cell differentiation

Answer 17

• Mediated through pluripotent stem cells
• Blastocyst is first formation of varying cell types

Question 18

Blastocyst

Answer 18

• Endoderm, mesoderm, and ectoderm layers
• Leads to terminally differentiated cells that utilize different gene expression

Question 19

Cell Differentiation terms

Answer 19

• Totipotent/pluripotent
• Multipotent
• Progenitor
• Precursor
• Terminally differentiated cells

Question 20

How do tissues maintain homeostasis?

Answer 20

Old cells are regularly replaced

Question 21

Liable tissues

Answer 21

• Contain multipotent stem cells that are constantly regenerating
• Ex: skin, blood, bone

Question 22

Stable tissues

Answer 22

• Contain multipotent stem cells that can regenerate, but only if needed
• Ex: liver, pancreas

Question 23

Permanent tissues

Answer 23

• Do contain stem cells, but have limited regeneration capacity
• Ex: nervous/cardiac tissue

Question 24

Necrosis

Answer 24

• A cellular response to injury
• Occurs after trauma, chemical agent exposure, loss of blood, etc.
• Loses membrane integrity, ATP, then pH levels lower and acid builds up (swelling)
• No more protein production occurs, and the cell disintegrates

Question 25

Apoptosis

Answer 25

• A cellular response to injury
• Triggered by cancerous activity, growth factor/cytokine changes, or immune system instruction
• Signaling cascades activate proteases that chew up cell into pieces, which are then phagocytosed by WBC’s

Question 26

Tissue components

Answer 26

• Anisotropic!
• Arteries, arterioles, capillaries, venules, veins, lymphatic vessels
• Categories: epithelial, muscle, nerve bundle

Question 27

Lymphatic system

Answer 27

Circulates fluid throughout the body

Question 28

Extracellular Matrix (ECM)

Answer 28

• Deposited by cells during tissue development
• Fibroblasts, different proteins, basement membrane
• Fibrous structure via large adhesive proteins like collagen and fibronectin
• Has subunits, some of which can bind to integrins
• Elastin fibers allow for elasticity

Question 29

Proteoglycans

Answer 29

• ECM component that is constructed of a protein core with sugar chains
• Can trap water into tissue and help distribute growth factors

Question 30

ECM Functions

Answer 30

• Adhesion, mechanical support, cell orientation, cell differentiation and growth, work with soluble factors, and maintaining the microenvironment

Question 31

Tissue Response to Injury

Answer 31

-Inflammation occurs first
- If stimulus is removed, then regeneration or repair can occur
- Regular repair involves clotting, then neutrophils, macrophages/lymphocytes accumulating, formation of a new capillary, and new deposited ECM
- Otherwise… fibrosis can occur (foreign body reaction)

Question 32

Foreign Body Reaction

Answer 32

• After arrival/failure of neutrophils, giant cells form and attempt larger phagocytosis
• Upon failure, a fibrous capsule forms
• Essentially, this entails ECM very heavy in collagen to best ward off the foreign body