Kinesiology 2230 Past Lecture Notes PDF

Kinesiology 2230, November 7 Putting the vascular in cardiovascular - We must transport the oxygen from the alveoli into the blood stream so that it can makes its way to the muscle - Gas exchange occurs twice (alveoli-\>blood) and (blood-\>muscle) Cardiovascular system - Comprised of:...

Kinesiology 2230, November 7 Putting the vascular in cardiovascular - We must transport the oxygen from the alveoli into the blood stream so that it can makes its way to the muscle - Gas exchange occurs twice (alveoli-\>blood) and (blood-\>muscle) Cardiovascular system - Comprised of: - blood vessels (venous vs. arterial sides) as well as capillaries - Arteries -\> arterioles -\> capillaries -\> venioles -\> veins - Capillaries are very small to optimize SA and slow blood down - Blood Blood - Average adult has 4-5L of blood - Comprised of: - 55% Plasma (water, proteins) - 45% Blood cells (mostly RBCs (99%), some WBCs (1%)) - **Hematocrit:** proportion by volume of RBCs in the blood - Quantifies how effective the blood is to do its job - The greater the hematocrit (more RMCs), the better oxygen carrying capacity Red blood cells - No nucleus (can't reproduce on their own) - Serves one function until it dies - Lifespan of 4 months - Replaced regularly via **hematopoiesis** - Formation of RBCs within bone marrow of big bones - Hemoglobin - Iron containing protein in the blood - Involved in the transport of oxygen in RBCs - 4 iron molecules per hemoglobin, attracts 4 oxygen molecules - 250 hemoglobin per RBC Oxygen transportation - Can be dissolved into the fluid portion of the blood (2% of O~2~) - Can combine with hemoglobin in RBCs (98% of O~2~) - Both are necessary for function oof oxygen delivery - Dissolved oxygen in the blood establishes the PO~2~ that is exerted on the RBC's. Facilitates the binding and unbinding of oxygen to hemoblogobin Gas exchange - Transport of gas from one compartment to another - Usually from air in the alveoli exchanging gas with the blood and the blood exchanging gas with the muscles - Focus with metabolism is the exchange of oxygen and CO~2~ - Getting O~2~ into the muscle and CO~2~ out - Exchange rates depend largely on the partial pressure of the gas in both compartments Partial pressure - Partial pressure of a certain gas - Each gas exerts a pressure proportional to its abundance - The sum of each gas' partial pressure gives the total pressure - The greater the differential in PP across a membrane, the larger the driving force for more diffusion to occur - If PPs are even in different compartments, there is no net diffusion - Less gas = lower partial pressure = less gas exchange - More gas = greater partial pressure = more gas exchange - Can be calculated if we know the overall air pressure and proportion of gas in the air - Ex: PO~2~ = total pressure x 0.2093 Partial pressure cascade - As we get deeper into the tissue the PO~2~ drops - Ambient air has higher PO~2~ than alveoli which has higher PO~2~ than arteries which has a higher PO~2~ than capillaries which has higher PO~2~ than myoglobin/mitochondria External gas exchange - Between alveoli/lungs into blood vessels - O~2~ diffuses from alveoli into arterial ends of pulmonary capillaries and CO~2~ diffuses into alveoli - Diffusion results in equalization of PP between venous ends of pulmonary capillaries and alveoli - PO~2~ tends to drop between venous end of capillaries and pulmonary veins (V~A~-Q mismatch) Internal gas exchange - O~2~ diffuses out of arterial ends of capillaries into tissues and CO~2~ diffuses into capillaries - Diffusion results in equalization of PP between venous ends of tissue capillaries and tissue - The gradient drives diffusion and impacts the delivery of oxygen and CO~2~ \\ Oxyhemoglobin Dissociation curve - O~2~ hemoglobin saturation: Proportion of hemoglobin in the blood that is saturated (has 4 O~2~ (max)) with oxygen - As more oxygen dissolves in the blood, it increases the PO~2~ which allows more O~2~ to bind to hemoglobin - Oxygen needs to be able to attach to hemoglobin but it also needs to be able to detach - Loading portion: Saturation stays quite even with large changes in PO~2~: Oxygen loading - Unloading portion: Saturation changes quickly with even small changes in PO~2~: Enables oxygen unloading to tissues - Oxygen has to bind to hemoglobin to be delivered but once it reaches the destination is also must be able to unbind Curve shifting - Right shift (Bohr shift): Reduces how much oxygen can bind to hemoglobin - Increase unloading of oxygen (lower affinity) - Occurs with lower pH or higher temperature - (If H^+^ accumulates due to exercise) - Allows the body to improve its ability of aerobic metabolism in response to increase anaerobic activity - Left shift: Makes oxygen more likely to bind to hemoglobin - Decrease unloading of oxygen (higher affinity) - VO~2~max decreases as altitude increases - 5-10% drop in VO~2~max for every 1000m increase in elevation - Any athletes that play in conditions with less oxygen must be aware Blood flow (Q) - Is the total volume of blood pumped through a vessel each minute (L/min) - Main difference is the partial pressure between arteries/arterioles and venioles/veins - Blood coming from the heart has much higher pressure than it does after gas exchange once blood is dropped off - Veins contain valves which allow the blood to flow in on direction - As we go from small arteries to smaller arteries to arterioles and capillaries, the velocity of blood flow is decreased to promote gas exchange - Capillaries are also very small/thin to increase SA - MAP: Arterial pressure -- venous pressure - TPR: Total peripheral resistance **Arterial blood pressure** - When the heart contracts, blood pressure gets very high, when it relaxes, pressure gets very low - The farther the blood travels from the heart, the more the pressure will drop - Systolic pressure (SBP): - Highest pressure in artery (during systole) - When blood pressure is reported, this is the top number (\~110 to 120mmHg at rest) - Diastolic pressure (DBP): - Lowest pressure in the artery (during diastole) - When blood pressure is reported, this is the bottom number (\~70 to 80mmHg at rest) - Mean arterial pressure (MAP): - Average pressure exerted on the arterial vessel walls over an entire cardiac cycle - MAP \~ 2/3 of DBP + 1/3 of SBP Venous blood pressure - Central venous pressure (CVP): - Blood pressure taken in right atrium - Reflects amount of blood returning to the heart - Very low pressure (ranges from 0-8mmHg) Total peripheral resistance - The resistance to cardiac output that is offered by the systemic vasculature - Dependant on: - Blood viscosity (doesn't change much) - Vessel length (doesn't change) - **Vessel radius** (can be modified and is the biggest contributing factor) - Arterioles are driving factor - Vasoconstriction increases resistance (radius decreases) - Vasodilation decreases resistance (radius increases) - Arterioles contain strong muscular walls of smooth muscle - These can either constrict or dilate - Biggest contributors in blood flow are highlighted yellow Exercise - There is an Increase in blood pressure with forceful cardiac contractions - As we dilate arterioles we get a decrease in resistance but will have more blood flow Effective functioning of the cardiovascular system depends on: - Gas exchange of oxygen into blood - Transport of oxygen to working muscles - Gas exchange of oxygen out of blood and into the muscle