Exam 1 Flashcards
Chap 1-5, 13
Totipotent
potential of a single cell to develop into an entire organism (stem cell)
Pluripotent
ability to develop into all cell types of the body, but not supporting structures (placenta, amnion, etc) [stem cell]
Multipotent
ability to give rise to a small number of different cell types (stem cell)
Unipotent
capacity to give rise to a single cell type
Where do you find pluripotent stem cells?
found in early embryos
Which stem cells are you more likely to find in adults?
Induced Pluripotent Stem Cells (IPSC) - Adult stem cells that are reprogrammed to embryonic state
What are some examples of cells that can develop from hematopoietic stem cells?
blood cells: RRC’s, B lymphocytes, T lymphocytes, natural killer cells, neutrophils, basophils, eosinophils, monocytes, macrophages, platelets
What are progenitor cells?
are early descendants of stem cells that can differentiate to form one or more kinds of cells, but cannot divide and reproduce indefinitely. They are often more limited than a stem cell in the kinds of cells it can become.
Asymmetric vs Symmetric cell division?
An asymmetric cell division produces two daughter cells with different cellular fates. This is in contrast to symmetric cell divisions which give rise to daughter cells of equivalent fates. (Stem cell > stem cell / differential cell) vs. (stem cell > 2 stem cells or stem cell > 2 differential cell)
_______ of ______ cell divison leads to cancer
dysregulation, asymmetric
What are proteoglycans made of?
Masses of GAGs and protein
What are GAGs
Glycosaminoglycans (disaccharides of acidic sugar and amino sugar)
“sulfated” glycosaminoglycans - dermatan, chondroitin, keratan, and heparan
What impact does the negative structure of GAGs have on its function?
Attracts water but repulses other GAGs (this is what gives it the “bottle brush” structure)
What is the difference between a proteoglycan monomer and aggregate?
Monomer: protein core with GAGs attached to it (except hyaluronic acid), repulsion of GAGs causes it to have “bottle brush” appearance
Aggregate: protein core with hyaluronic acid
Where are proteoglycans located in the body?
mucus and synovial fluid
How is collagen assembled (in general)?
“chains” of repeating amino acids
note: need for Vitamin C
three chains form helix, exocytose to exterior of cell
assembled into fibrils
How might collagen be organized in skin vs. tendons?
Multi-directional in skin, to stretch in different directions. Stretch in one direction in tendons in muscles attached to bones
There is ____ ECM in epithelial cells
little
Epithelial tissue is also known as ______ or ______
basement membrane, basal lamina
What separates epithelial cells from connective tissue
Basement membrane
Components of ECM
Proteoglycans, fibrous proteins and adhesive proteins
Types of fibrous proteins in ECM
collagen, elastin
Fibrous proteins provide ____, and are made up of _____.
structure, amino acids
Collagen type I
most abundant, located in bones, skin and tendons (also, found in scar tissue)
Collagen type II
location: hyaline cartilage
body specific location: end of ribs, larynx, trachea and bronchi, & articular surface of bone
Collagen type III
made during wound healing
location: artery walls, intestine and uterus
collagen type IV
component for filtration in kidneys
location: basement membrane and eye lens
Collagen gets attacked by ______
free radicals
Collagen vs. Elastin
Collagen: resist force, different types vary for structural role, ECM function- support and strength
Elastin: rubber-like connective tissue (stretch and relax without ripping)
Fibrous proteins and disease
Scurvy osteogenesis imperfecta Ehlers - Danlos syndrome Marfan syndrome a1 - Antitrypsin deficiency
Osteogenesis Imperfecta
“brittle bone”
inherited (mutation in collagen gene which causes decreased synthesis)
Type 1 (most common)
type 2 (lethal around birth)
Ehlers-Danlos syndrome
genetic defect of fibril collagen (defect in structure, synthesis or processing)
6-types (all affect joints and some affect skin)
Marfan Syndrom
Autosomal dominant (mutation in gene necessary for ELASTIN)
a1 - Antitrypsin Deficiency
WBC in lungs elastase (Elastase digest elastin & is inhibited by the protein a1 - Antitrypsin)
a1 - Antitrypsin Deficiency
WBC in lungs elastase (Elastase digest elastin & is inhibited by the protein a1 - Antitrypsin)
Which cell junction and proteins seals epithelial cells together?
tight junctions (also prevents leakage [prevents leaky gut])
What do integrins bind to for cell-cell or cell-ECM interactions?
Ligands (molecule that binds to another molecule)
cell to cell: binds to members of the immunoglobulin superfamily
cell to ECM: binds to arginine-glycine-aspartic acid residue in collagen and fibronectin (or may bind to laminin)
What it the main adhesive protein in epithelial tissue?
Laminin
• What is the main adhesive protein in connective tissue?
Fibronectin
What are desmosomes?
anchors filaments between cells
Which cell junction protein joins cells by binding actin bundles?
Adherens
Which cell junction and proteins are involved with anchoring to the basement membrane?
Hemidesmosomes
How are adhesion molecules related to cancer?
involved with the progression of cancer and metastasis
E-cadherin activity is lost in most epithelial tumors
How are adhesion molecules related to leukocyte?
Genetic defect
results in recurrent bacterial infections
most cases do not live past 2 years old
How are adhesion molecules related to pemphigoid?
Autoimmune condition, causes disruption of cadherin cell-cell adhesion, and gets a lot of blistering because epidermal cells are not allowed to adhere to one another
Which molecules are overexpressed during asthma?
increased ICAM-1 expression, causes excessive migration of WBC to respiratory tract, leads to chronic inflammation
Which molecules are overexpressed during rheumatoid arthritis?
Autoimmune disease, bone cells overexpress adhesion molecules (integrin LFA-1 & ICAM-2), increased leukocyte adhesion which causes synovial inflammation
What does selectin do?
-Short term
-cell to cell adhesions
Functions: mediate WBC migration to areas of inflammation and important for the immune system
Selectin on one cell binds to lectin on another cell
What is extravasation?
Migration of cells from circulation into the tissue
How are cell adhesion molecules involved in the 4 steps of extravasation?
- Selectin on the WBC (leukocyte) binds to ligand (immunoglobulin superfamily) on the surface of the endothelial cell causing rolling of leukocyte along endothelium of blood vessel
- activation of an integrin on the leukocyte
- integrin can bind to its ligand on the endothelium. This is firm arrest
- Diapedesis = movement of the leukocyte through the endothelial layer
