Lecture 5: Vascular Conditions Flashcards
What is the conduit system?
The Conduit System Transports Soluble Antigens from the Afferent Lymph to Resident Dendritic Cells in the T Cell Area of the Lymph Nodes
Whats the lumen of a blood vessel?
Space in the middle of a vessel- where blood flows through
What is the three main layers of a blood vessel?
1) tunica intima
2) tunica media
3) tunica externa/adventitia
What is the tunica intima made from?
Innerlayer of endothelium &
Internal elastic membrane (supportive connective tissue)
What is the tunica media made from?
Middle layer composed mostly of smooth muscle and elastic fibres
What is the tunica externa/adventitia made from?
Outer layer of connective tissue
What are distinguishable features of arteries?
Thick tunica media & externa layers
High pressure vessels
Carry blood from the heart
What are distinguishable features of capillaries?
Tunica intima ONLY
Allows gas, nutrient and waste exchange
Are permeable
What are distinguishable features of veins?
Carry blood to HEART
Thin tunica media & externa
Contains valves
Low pressure vessels
What are the two main factors that influence BP
CO and TPR (Total peripheral resistance)
BP = CO x TPR
What is CO influenced by?
CO is the amount of blood out of a ventricle each minute (mL/min). Its influenced by stroke volume and heart rate.
CO = SV x HR
Stroke volume is the volume of blood pumped out of a ventricle with each beat and heart rate is the number of beats per minute of the ventricles
What is TPR and what is it influenced by? (3)
TPR is all of the resistance (friction) that blood will encounter as it flows through the entire vascular circuit.
TRP is influenced by three main things-
1) Blood viscosity
2) The length of the blood vessels
3) The diameter of blood vessels (blood vessel diameter is the most significant factor affecting TPR.)
What would the body do to increase low BP?
Release of ADH and increased water absorption
Increased HR
Increased sympathetic activity
Vasoconstriction
Increased heart contractility
Release of aldosterone and increased sodium reabsorption
What would the body do to decrease high BP?
Increased urinary excretion
Decreased HR
Vasodilation
Increased parasympathetic activity
Release of ANP
What helps the blood flow through the venous system get back to the heart?
Respiratory pump
Muscular (skeletal) pumps
Sympathetic nervous system
Renin-angiotensin aldosterone system (RAAS)- (is the system of hormones, proteins, enzymes and reactions that regulate your blood pressure and blood volume on a long-term basis)
How does the extrinsic mechanism respiratory pump help the blood get back to the heart?
The process ofbreathing alternatelyincreases and decreases abdominal pressure-thereby increasing the pressure against blood vessels in the abdomen, squeezing them andforcing blood in the veins to move towards the heart.
How does the extrinsic mechanism sympathetic nervous system help the blood get back to the heart?
Sympathetic innervation of the tunica media of the veins stimulates vasoconstriction, reducing the diameter of the veins, and therefore increasing vascular resistance, and consequently blood pressure- facilitating an increase in the pressure gradient to better drive blood back towards the atria.
How does the extrinsic mechanism muscular (skeletal) pumps help the blood get back to the heart?
When skeletal muscles contract, they also squeeze nearby blood vessels helping to force blood to flow through the veins.This is particularly important in the veins of the lower limbs.
How does the extrinsic mechanism Renin-angiotensin aldosterone system (RAAS) help the blood get back to the heart?
Angiotensin II, a chemical released as part of this system, also stimulates vasoconstriction to increase vascular resistance and therefore blood pressure to help blood return to the heart.
Whats blood stasis?
Blood pooling, or decreased/ no flow
What is Arteriosclerosis?
Is a type of vascular disease where the blood vessels carrying oxygen away from the heart (arteries) become damaged from factors such as high cholesterol, high blood pressure, diabetes and certain genetic influences.
Arteriosclerosis is the thickening and hardening of the walls of arteries. This occurs due to the migration of smooth muscle cells and collagen fibres into the tunica intima with subsequent mineral deposition. Progressively this narrowsthe lumen of the artery.
Arteriosclerosis occurs as part of the normal aging process, but may also occur in association with hypertension, decreased tissue perfusion, weakening and/or other damage of arterial walls.
What is atherosclerosis?
Atherosclerosis is the most common type of arteriosclerosis and occurs when intra-arterial fat and fibrin deposits form within the vessel wall which subsequently harden over time. Atherosclerotic plaques can form as a result of inflammation due to endothelial damage and the accumulation of LDL cholesterol within the tunica intima.