Blood Vessels/Pressure Flashcards
(28 cards)
Types of Vessels
Arteries -> Arterioles
Arterioles -> Capillaries
Capillaries -> Venules
Venules -> Veins
Layers of Vessels
Tunica Intima
Tunica Media
Tunica Externa
Which vessels have valves?
Veins-to prevent backflow
Tunica Intima
- Endothelial Cells
- Nitric Oxide causes contraction
Connected by Basement Membrane to connective tissue
What is Tunica Media made of?
Smooth Muscle
Gap Junctions
Elastin fibres
Thickest Layer
What is Tunica Externa made of?
Collagen and Elastin
Capillaries (vasa vasorum= vessels of vessel)
Functions of Arteries
Take blood away from heart
Distribution
Elastic tissue
Arterial compliance is ?
Ability of arterial wall to distend and increase volume with increased pressure
Windkessel’s effect of arteries?
Large arteries store a portion of the stroke volume with each systole and discharge that volume with diastole.
- Arteries contain more blood in systole than diastole.
- Decreases with age
What is Myogenic Theory in Arterioles
-Reflex response to changes in blood pressure.
-Contraction due to increased tension
-Relaxation due to decreased tension
What is Metabolic theory?
If decrease in arteriole perfusion, there is decreased stretching of the smooth muscle results in relaxation of the smooth muscles and dilation of the arteriole.
What is Atherosclerosis?
- Inflammatory response
-Thickening of the Tunica Intima causing narrowing of lumen
-Infection, Trauma, Hypertension
What is an aneurysm?
- Bulge in blood vessel wall caused by weakness.
- Blood pressure causes area of weakness to expand like balloon.
Difference of Veins to Arteries
-Thin Walled -Larger lumen
-Contain valves to prevent backflow
-2/3 of blood supply
What is Preload?
-Initial stretching of the myocytes prior to contraction.
-Ventricular filling
-Preparation to eject
What is Afterload
Force/Load against which the heart has to contract to eject the blood.
What is Central Venous Pressure?
- Pressure within Right Atrium by IVC and SVC
- Reflects amount of blood returning to heart and ability of the heart to pump the blood back to arterial system
What can cause decrease in Central Venous Pressure? (CVP)
Reduce blood volume via loss of fluid or haemorrhage
What can cause increase in Central Venous Pressure? (CVP)
Increased fluid retention by kidneys
What are Varicose Veins
-Swollen enlarged veins caused by incompetent vein valves.
-Lumpy, Bulging
-Aching and uncomfortable
What is DVT?
Thrombus formation within deep veins
Embolus is small piece of thrombus that breaks off and travels in blood
-Leg pain and swelling
Difference in O2 transportations
Systemic Arteries— High o2
Pulm. Arteries—- Low o2
Systemic Veins– low o2
Pulm. Veins–High o2
What is the Capillary Bed?
Network of capillaries that join arterial to venous systems
Controlled by precapillary sphincters
What is Oedema?
Build up fluid within the Interstitial space
Leg Swelling
Cause-
Inadequate lymph drainage
Decreased Absorption Increased Filtration
