Questions and Answers
In a working tissue like skeletal muscle, carbon dioxide may accumulate along with an increase in lactic acid. What do carbon dioxide and lactic acid act as?
What does the numerator (upper number) of the blood pressure ratio represent?
systolic pressure
When carbon dioxide accumulates in a tissue, local arterioles will _________, increasing perfusion and decreasing carbon dioxide levels.
dilate
What is the measure of the difference between systolic and diastolic pressures called?
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Increased blood pressure will increase the heart rate.
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Resistance in the blood vessels is primarily controlled by altering what?
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Where does gas exchange occur in both pulmonary and systemic circulation?
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What is the layer of blood vessel wall composed of circularly arranged layers of smooth muscle cells called?
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Decreased plasma protein concentration causes an increase in blood colloid osmotic pressure.
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Which of the following arteries help form the cerebral arterial circle (circle of Willis) in the brain?
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Chemoreceptors in the carotid and aortic bodies do NOT detect what?
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Where are chemoreceptors also located?
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As the cross-sectional area of blood vessels increases, what happens to the velocity of blood flow?
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What is the condition caused by obstruction of lymphatic drainage?
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What drains deoxygenated blood from the heart myocardium into the right atrium?
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Which of the following is NOT a mechanism that assists venous return?
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What anastomosis of arteries within the brain equalizes blood pressure?
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What effect does vasoconstriction have on blood flow and blood pressure?
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What is the main chemical stimulus for cerebral autoregulation?
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Study Notes
Circulatory System and Blood Vessels
- Carbon dioxide and lactic acid act as vasodilators in working skeletal muscle, facilitating increased blood flow.
- Systolic pressure is the upper number in the blood pressure ratio.
- Resistance in blood vessels is mainly controlled by altering vessel radius.
- Capillaries are composed solely of a tunica intima, allowing for efficient gas and nutrient exchange.
- Increased tissue protein concentration can lead to edema by reducing osmotic pressure in capillaries.
- Decreasing plasma protein levels also contribute to edema through lower osmotic pressure effects.
Blood Pressure Dynamics
- Mean arterial pressure is calculated as diastolic pressure plus one-third of the pulse pressure (difference between systolic and diastolic pressures).
- Vasodilation increases blood flow and reduces blood pressure, while vasoconstriction decreases blood flow and elevates blood pressure.
- Upon standing, blood pressure in the veins of the lower limbs increases due to gravitational effects.
Blood Circulation Specifics
- Gas exchange occurs at capillaries in both pulmonary and systemic circulation.
- Blood with low levels of proteins may decrease colloid osmotic pressure, affecting fluid reabsorption.
- In pulmonary circulation, correct anatomical labeling is crucial for understanding flow dynamics.
Neural Regulation
- Baroreceptors, located in the aorta and carotid arteries, monitor blood pressure and relay information to the brain via the vagus and glossopharyngeal nerves.
- The main chemical stimulus for cerebral autoregulation is pH level changes related to blood gas content.
Arteries and Circulation
- The internal carotid arteries contribute to the formation of the cerebral arterial circle (Circle of Willis), ensuring collateral blood flow in case of blockages.
- The coronary sinus drains deoxygenated blood from the heart myocardium into the right atrium.
- The anatomy of arteries, veins, and capillaries is essential in understanding blood circulation and pressure maintenance.
Factors Affecting Vascular Resistance
- Long vessels, dehydration, polycythemia, and angiogenesis increase blood resistance.
- Conversely, shorter vessels, anemia, and increased vessel diameter lower resistance, affecting overall blood flow.
Clinical Considerations
- Central venous pressure must be higher than venule pressure for effective venous return.
- Changes in position, such as moving from lying down to standing, can alter blood volume distribution and pressure in limbs.
Summary of Capillary Dynamics
- Fluid reenters capillaries at the venous end due to higher net filtration pressure compared to the arterial end, highlighting mechanisms of nutrient and waste exchange.
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Test your knowledge in Bio 145 with these flashcards, covering important concepts like vasodilators and blood pressure ratios. This quiz will strengthen your understanding of key biological terms and their definitions, making it a great study aid for students.
