Lecture 14 Vascular Network PDF

Lecture 14 What is the vascular network? - Transports blood and nutrients the body What are the three networks with the vascular network? - Arteries - Veins - Capillaries What do arteries do? - Transport oxygenated blood away from the heart What do veins do? - Transport deoxygenate...

Lecture 14 What is the vascular network? - Transports blood and nutrients the body What are the three networks with the vascular network? - Arteries - Veins - Capillaries What do arteries do? - Transport oxygenated blood away from the heart What do veins do? - Transport deoxygenated blood back towards the heart What do capillaries do? - It is the site of exchange and diffusion - Exchange nutrients and by products from metabolism like lactate What are the characteristics of arteries? - Thicker wall - More smooth muscle - More ability to regulate vascular tone - Allow to dilate and constrict What are the characteristics of veins? - Thinner wall - Less smooth muscle - Less ability to regulate vascular tone - Have a one way valve, to keep blood moving in one direction - Stores blood that comes back from capillaries - It can expand to store blood - When contracting muscles the blood will move up, when relaxing the blood will move down to the valve What are varicose veins? - Non-functioning veins - The flow will back up What is the distribution of the vascular network? - Aorta - Conduit arteries - Feed arteries - Arterioles - Capillaries - Venules - Veins - Vena cava What are arterioles and what do they do? - Site of resistance - Regulation of blood pressure and blood flow - Housed within the organ itself - Small change in size can make a big difference What are the different layers of a blood vessel? - Intima (inner) - Media - Adventia (outer) What is the intima made up of and what blood vessels have it? - Endothelium cells - Veins - Arteries - Capillaries What is the media made up of and what blood vessels have it? - Vascular smooth muscle - Arteries (have more) - Veins What is the adventitia made up of and what blood vessels have it? - Connective tissue - Arteries - Veins Why do capillaries not have a media or adventitia? - They can’t expand - It would be harder for diffusion to go through many different layers What does the intima do for blood vessels? - Release a substance to contract to dilate vessels - They can sense things going on and self regulate - They regulate vascular tone, atherosclerosis and angiogenesis - Synthesis and release of nitric oxide What is nitric oxide? - Production of more blood flow - Relaxes the blood vessels What does the media do for blood vessels? - Regulation of blood flow by contracting or relaxing the vessels with smooth muscle - Elastin sheets allow it to stretch and get bigger What does the adventitia do for blood vessels? - Nerves run through it - Serves as a structural integrity to keep its shape What happens to muscle blood flow when exercising?  - Large increase in blood flow since it needs more oxygen - Modest increase of blood pressure - Large decrease in resistance, all of the arterioles in the working skeletal muscle are dilating in that region What happens to visceral blood flow when exercising? - Modest decrease in blood flow since we want more oxygen to go to the working skeletal muscle and not the organs - Modest increase of blood pressure - Large increase of resistance, all the arterioles that are feeding the organs constrict to go to the working skeletal muscle How does blood flow go up in skeletal muscle but down in visceral organs during exercise? - Functional sympatholysis What is functional sympatholysis? - A release of metabolites and nitric oxide in response to exercise override sympathetic outflow and cause skeletal muscle arterioles to dilate - Shear stress of RBC moving through arterioles that are housed within the skeletal muscle itself to override the sympathetic outflow only within the working skeletal muscle and bind to vascular smooth muscle and causes it to relax - Overriding of the SNS in the active skeletal muscle to allow more blood flow How does endurance exercise training impact the vascular system? - Causes athlete arteries What are athlete arteries? - Increased skeletal muscle blood flow - Increased diameter of conduit arteries and arterioles - Decreased wall thickness - No change in vascular function What happens to arteries after one week of endurance training and their functional adaptations? - They increase - Due to hypertrophy, they are getting larger for more blood flow What happens to arteries after 16 weeks of endurance training and their functional adaptations? - There is no change in function because they get larger in size and don’t dilate as much since they are bigger What are the structural changes to vasculature? - After a week the tube gets bigger - After 16 weeks the tube gets even bigger - It gets bigger so it doesn’t have to dilate every time the person exercise to have greater blood flow Equations Fick equation (oxygen consumption) - VO2 = CO x a-vO2 diff Cardiac output - CO = HR x SV MAP (mean arterial pressure) - DBP + 0.33 (SBP -DBP) Resistance - TPR = (Length x viscosity) / Radius4 Blood pressure - BP = CO x TPR Blood flow - Q = Δ Pressure / Resistance Trained vs. Untrained Equation Rest Submax Max VO2 = = ↑ CO = = ↑ a-vO2 diff = = ↑ HR ↓ ↓ = SV ↑ ↑ ↑ What is the difference between an endurance trained person and a sedentary person with VO2? - Both start the same - A trained person can work longer due to having a higher capacity What is the difference between an endurance trained person and a sedentary person with cardiac output? - Start the same - A trained person is able to go longer, can put more blood longer What is the difference between an endurance trained person and a sedentary person with a-vO2 diff? - Trained person can last longer - Have a greater capillary network - Have a smaller distance for the blood to diffuse What is the difference between an endurance trained person and a sedentary person with max heart rate? - Stays the same due to max heart rate being 220-age What is the difference between an endurance trained person and a sedentary person with stroke volume? - A sedentary person can only reach 40% then plateau - The time for filling up the heart decreases - At 40% of VO2 they can’t increase the amount of blood being ejected - The blood rate is too high - Heart rate will increase - A trained person doesn’t plateau, they keep increase - Have to have a higher stroke volume to accommodate the lower heart rate What happens to blood pressure when increasing exercise? - SBP will increase - DBP will stay at a constant rate What happens to mean arterial blood pressure when exercising? - Will increase What happens to the arterial and venous blood to increase a-vO2 diff? - Venous blood will stay the same - Arterial blood will decrease since it is taking out oxygen from the blood What happens to venous oxygen contact with aerobic exercise? - Decreases - There is less oxygen since there are more capillaries - The venous content stays the same as a sedentary person, they are just able to pull off more oxygen making the venous levels go down What happens to arterial oxygen contact with aerobic exercise? - No change - You can’t increase something that is already at 100%