Vascular biology II Flashcards
(24 cards)
What are the three types of capillaries?
- Continuous
- Fenestrated
- Sinusoidal
What type of junctional complexes do continuous capillaries have?
Tight junctions (complete or incomplete)
What are the main characteristics of continuous capillaries?
- Tight junctions
- Lack pores or fenestrae
- Numerous pinocytotic vesicles
- Well-developed basal lamina
Where are continuous capillaries found?
- Brain
- Muscle
- Connective tissue
- Exocrine glands
What are the characteristics of fenestrated capillaries?
- Fenestrae / pores
- Pores closed by thin diaphragm
- Continuous basal lamina
Where are fenestrated capillaries found?
Areas of rapid exchange:
- Kidney, nonglomerular
- Endocrine glands
- Intestines
- Kidney, glomerulus - diaphragms absent
What are the characteristics of sinusoidal capillaries?
- Discontinuous endothelial lining - large openings
- Discontinuous or absent basal lamina
- Macrophages present
Where are sinusoidal capillaries found?
Areas of rapid exchange where cells can be exchanged:
- Red bone marrow
- Liver
- Spleen
- Adrenal cortex
Which veins possess longitudinal bundles of smooth muscle in the adventitia?
IVC, SVC, brachiocephalic, renal, iliac
Vasculogenesis: definition
De novo vessel formation
De novo vessel formation
Vasculogenesis
Angiogenesis: definition
Growth from pre-existing EC-derived channels
Growth from pre-existing EC-derived channels
Angiogenesis
Arteriogenesis: definition
Formation of arteries, arterioles and collateral vessel remodeling
Formation of arteries, arterioles and collateral vessel remodeling
Arteriogenesis
Neovascularization: definition
Overarching term to include vasculogenesis, angiogenesis, and arteriogenesis
Overarching term to include vasculogenesis, angiogenesis, and arteriogenesis
Neovascularization
Vascular remodeling: definition
Vascular response to alterations in the environment
Vascular response to alterations in the environment
Vascular remodeling
What are the two mechanisms of blood vessel formation?
- From endothelial precursor cells
2. From pre-existing vessels
Where do EPCs reside?
Red bone marrow of adults and non-bone marrow niches
What are the functions of the EPC mechanism for vessel formation?
- Replace lost endothelial cells
- Re-endothelialization of vascular implants
- Neovascularization of ischemic organs, wounds, and tumors
What are the steps for vessel formation from pre-existing vessels?
- Vasodilation (via NO) and increased permeability (via VEGF)
- Proteolytic degradation of basal lamina (via MMPs)
- Loss of intercellular junctions (via plasminogen activator)
- Migration and proliferation of endothelial cells (via VEGF, ANG-2)
- Endothelial cells mature into endothelial capillary tube
- Elaboration of basal lamina (via FGF) and recruitment of periendothelial cells
What protein do tumor endothelial cells express?
Tumor endothelial marker 8 (TEM8)
