CH 15
1. about this chapter
- blood vessels
- blood pressure
- resistance in arterioles distribution of blood to the tissues
- regulation of CV function
- exchange at the capillaries
- the lymphatic system
- CV disease
→ vasovagale syncope= flauwvallen; decrease in blood pressure;
→ arteries = pressure reservoir
→ small vessels = arterioles
→ veins = volume reservoir
2. blood vessels
- layers of smooth muscle
- endothelium + elastic connective tissue = tunica intima
2.1 veins: volume reservoir
- more numerous than arteries
- large diameter
- thinner walls; less elastic tissue
- 50% of total blood volume
- lie closer to the surface
- blood drawing (venipuncture)
→ Tourniquet oefent druk uit op de bloedvaten, maar ook op de diepe hoge druk slagaders
worden niet aangetast, alleen de lagedruk aders => bloed verzamelt zich in de aderen,
waardoor er ze worden zichtbaarder
2.2 the microcirculation
- arteries: thick; smooth muscle layer; large amount of elastic connective tissue
- major arteries: go to smaller and smaller arteries; becoming less and less muscular
- arterioles form microcirculation
- arterioles branch into metarterioles
- precapillary sphincters: muscle rings: relaxed: blood flowing into metarteriole into
capillary beds
- pre capillary sphincters: muscle rings: constricted: metarteriole blood bypasses the
capillaries and goes directly to the venous circulation
- from arterioles to capillary to venule
= circulation that takes place on micro niveau (very small)
- microcirculation: exchange (main function)
- ene kant arteriole (komt van aorta; arteries)
- andere kant venule
- ertussen capillary
- linker kant: arteriole: smooth muscle; receive innervation; nerves control
, - van aan het bloedvat tot de capillary: hebben ze aan het vat een pre capillary
sphincter; controls entry blood; no innervation; not controlled nerve system
- metarterioles: connecting arterioles to venules; smooth muscle fibers; geen
innervation; not controlled nerve system
- capillary: net groot genoeg voor RBC en andere cellen erdoor te laten; 4-9mm
diameter; RBc komt bijna tegen wand van capillary: exchange kan snel gebeuren
dan
- wall: endothelial cells (thin); basement membrane; exchange:
* intercellular cleft (adjacent endothelial cells; proteins connecting neighboring cells; 6-7nm
* proces: coated pit in endothelial cells; captioning fluid en vesikels naar andere kant van de
cell en inhoud losgelaten door basal membrane; transcytose; soms heb je veel vesikels
achter elkaar die fuseren en een gang maken voor de inhoud direct en vlot naar de overkant
te brengen (vesicular channel)
- continuous; fenestrated; sinusoidal → capillary
*continuous: average permeability; lungs; skin; brain
*fenestrated: endothelial thin en have fenestrae; increase permeability; around epithelia
*discontinuous/ sinusoidal: most permeable: fenestrae; and large gaps; in bone marrow
- vanule: larger than arterioles; weaker muscle coates; less pressure; contract; mak
veins en than vena cava
3. capillaries: exchange
- plasma and cells exchange materials across thin capillary walls
- capillary density is related to metabolic activity of cells
- capillaries have the thinnest walls
● single layer of flattened endothelial cells
● supported by basal lamina
● continuous or fenestrated
- bone marrow; liver; spleen → typical capillaries but rather sinusoids (5x wider than
capillaries)
- capillaries: smallest vessels in cvs
- primary site of exchange between blood and interstitial fluid
- smooth muscle; elastic or fibrous tissue
- pericytes: tightness of capillary permeability
- more pericytes; less leaky the capillary endothelium
- pericytes secrete factors that influence capillary growth
- loss of pericytes: disease: diabetic retinopathy: blindness
4.angiogenesis
- development of new blood vessels from existing ones
- wound healing; but also tumors
- growth factors such as vascular endothelial growth factor (vegF) and fibroblast
growth factor (FGF) → promotes angiogenesis
● promotie mitoses (cell division)
- inhibition of angiogenesis through angiostatin and endostatin
- aanmaken van nieuwe bloedvaten uit bestaande bloedvaten (probleem in bloedvat;
nieuw takje aangemaakt)
1. about this chapter
- blood vessels
- blood pressure
- resistance in arterioles distribution of blood to the tissues
- regulation of CV function
- exchange at the capillaries
- the lymphatic system
- CV disease
→ vasovagale syncope= flauwvallen; decrease in blood pressure;
→ arteries = pressure reservoir
→ small vessels = arterioles
→ veins = volume reservoir
2. blood vessels
- layers of smooth muscle
- endothelium + elastic connective tissue = tunica intima
2.1 veins: volume reservoir
- more numerous than arteries
- large diameter
- thinner walls; less elastic tissue
- 50% of total blood volume
- lie closer to the surface
- blood drawing (venipuncture)
→ Tourniquet oefent druk uit op de bloedvaten, maar ook op de diepe hoge druk slagaders
worden niet aangetast, alleen de lagedruk aders => bloed verzamelt zich in de aderen,
waardoor er ze worden zichtbaarder
2.2 the microcirculation
- arteries: thick; smooth muscle layer; large amount of elastic connective tissue
- major arteries: go to smaller and smaller arteries; becoming less and less muscular
- arterioles form microcirculation
- arterioles branch into metarterioles
- precapillary sphincters: muscle rings: relaxed: blood flowing into metarteriole into
capillary beds
- pre capillary sphincters: muscle rings: constricted: metarteriole blood bypasses the
capillaries and goes directly to the venous circulation
- from arterioles to capillary to venule
= circulation that takes place on micro niveau (very small)
- microcirculation: exchange (main function)
- ene kant arteriole (komt van aorta; arteries)
- andere kant venule
- ertussen capillary
- linker kant: arteriole: smooth muscle; receive innervation; nerves control
, - van aan het bloedvat tot de capillary: hebben ze aan het vat een pre capillary
sphincter; controls entry blood; no innervation; not controlled nerve system
- metarterioles: connecting arterioles to venules; smooth muscle fibers; geen
innervation; not controlled nerve system
- capillary: net groot genoeg voor RBC en andere cellen erdoor te laten; 4-9mm
diameter; RBc komt bijna tegen wand van capillary: exchange kan snel gebeuren
dan
- wall: endothelial cells (thin); basement membrane; exchange:
* intercellular cleft (adjacent endothelial cells; proteins connecting neighboring cells; 6-7nm
* proces: coated pit in endothelial cells; captioning fluid en vesikels naar andere kant van de
cell en inhoud losgelaten door basal membrane; transcytose; soms heb je veel vesikels
achter elkaar die fuseren en een gang maken voor de inhoud direct en vlot naar de overkant
te brengen (vesicular channel)
- continuous; fenestrated; sinusoidal → capillary
*continuous: average permeability; lungs; skin; brain
*fenestrated: endothelial thin en have fenestrae; increase permeability; around epithelia
*discontinuous/ sinusoidal: most permeable: fenestrae; and large gaps; in bone marrow
- vanule: larger than arterioles; weaker muscle coates; less pressure; contract; mak
veins en than vena cava
3. capillaries: exchange
- plasma and cells exchange materials across thin capillary walls
- capillary density is related to metabolic activity of cells
- capillaries have the thinnest walls
● single layer of flattened endothelial cells
● supported by basal lamina
● continuous or fenestrated
- bone marrow; liver; spleen → typical capillaries but rather sinusoids (5x wider than
capillaries)
- capillaries: smallest vessels in cvs
- primary site of exchange between blood and interstitial fluid
- smooth muscle; elastic or fibrous tissue
- pericytes: tightness of capillary permeability
- more pericytes; less leaky the capillary endothelium
- pericytes secrete factors that influence capillary growth
- loss of pericytes: disease: diabetic retinopathy: blindness
4.angiogenesis
- development of new blood vessels from existing ones
- wound healing; but also tumors
- growth factors such as vascular endothelial growth factor (vegF) and fibroblast
growth factor (FGF) → promotes angiogenesis
● promotie mitoses (cell division)
- inhibition of angiogenesis through angiostatin and endostatin
- aanmaken van nieuwe bloedvaten uit bestaande bloedvaten (probleem in bloedvat;
nieuw takje aangemaakt)
