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Phys2 Lect 1
Question | Answer |
---|---|
Key functions of CV system | 1.Move nutrients & Gases. 2.Major Temperature regulator. 3.Remove metabolic waste and deliver it to the kidneys. |
Only two places in the body where short distance diffusion occurs? What distribution method is used elsewhere throughout the body? | 1.Lungs (alveoli). 2.Capillaries. **Bulk flow is used everywhere else, driven by the pressure generated by systole. |
Since the R and L sides of the heart are two different pumps, how much BL does each side pump out? | THE SAME AMOUNT (usually 5L/min). |
What happens when the R side of the heart's output is less than the L side's? | BL will accumulate in the periphery, backing up is tissues b/c more is being pumped out into the systemic circulation. |
What happens when the L side of the heart's output is less than the R side's? | BL will accumulate in the lungs, leading to vascular congestion in the lungs: PULMONARY EDEMA. |
Is the L ventricle thicker than the R? | YES, 2X |
Why is it functionally advantageous to have two seperate pumps? | CONSERVES ENERGY. It allows there to be a low pressure pump (pulmonary:deoxy 20mmHg) and a high pressure pump (systemic:oxy 100mmHg) |
How can VSD lead to cyanosis in a Patient? What kind of hypertension can this cause? | B/c the oxygenated BL in the L ventricle will move from high to low pressue back into the R ventricle, taking away from the O2 being pumped into systemic circulation. **PULMONARY HYPERTENSION due to Inc volume leaving the R ventricle. |
What is the only organ thats circulation is not in parallel with the heart? What type of circulation does it get? | LIVER. **It gets SERIES flow instead of parallel flow b/c it gets BL after it has traveled through the stomach, pancreas, and intestines. |
What is responsible for vasoconstriction? | Alpha1 Adrenergic receptors |
What is responsible for controlling vascular smooth muscle tone locally? Systemically? | LOCAL: 1.Metabolic Factors (O2, Lactate). 2.Paracrine Factors (effects pre-capillary sphincters). SYSTEMIC: 1.SNS Hormones. |
Explain the hearts resting O2 consumption compared to its % of cardiac output recieved | Heart muscle has 100% O2 extraction from the BL. Therefore it is the MOST efficient but has NO RESERVE extraction capabilities during increased demand (ex: exercise). |
What is the only way for the Heart to increase it's O2 consumption during situations like exercise? | INCREASE BL FLOW. **If there is any coronary artery blockage, it will greatly decrease this and cause patholoy. |
BL flow at rest to the Liver? | It recieves 1/4 the CO from the heart (avg: 1.25L/min). Its O2 consumption at rest is slightly higher. |
What two organs have poor O2 extraction and therefore consumption at rest? | 1.Kidney. 2.Skin. **They recieve a higher % of CO with a lower O2 consumption. |
Mean Arterial Pressure | Diastolic + [1/3 X Pulse Pressure]. **Pulse pressure: Systolic - Diastolic. |
What does Systolic BP represent? | The PEAK arterial pressure generated from the ventricular contraction. |
What does diastolic BP represent? | The end diastolic/ minimum pressure generated while the ventricles relax. |
How does the Arterial:Venous pressure difference change when a person stands up? | IT STAYS THE SAME! the overall pressure in a particular area may Inc (Legs:+90) or Dec (Brain:-38) compared to the heart, but the A:V pressure difference doesn't change. |
When looking at the the equation: Pt = Pin - Pout, what happens to vessels physiologically when Pout exceeds Pin? | The vessel will collapse. **This can occur in cardiac arrest. CPR keeps Pin higher. |
What is Vessel Compliance? | Change in V/Change in Pt. It represents how stretchable the vessel is. **The change in volume in response to pressure decreases with age due to dec elasticity (EXERCISE CAN HELP!!) |
What type of vessel has the highest compliance? | VEINS!! much higher than arteries. **Change in 1mmHg can change volume 20-30%. |
What is the major role of veins? | STORE VOLUME. They hold up to 75% of the BL at a given time. **They can store more due to thin walls and dec elastic fibers. |
What is responsible for maintaining diastolic BP of 80mmHg when the ventrical relaxes? | Elastic Recoil. It is the energy stored in the arteries when they expand during systole. **Therefore low diastolic pressure can be pathologic. |