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Questions and Answers
What is the primary location of the major drop in blood pressure due to smooth muscle contraction?
What is the primary location of the major drop in blood pressure due to smooth muscle contraction?
What is the approximate blood pressure in the capillary beds?
What is the approximate blood pressure in the capillary beds?
What is the primary mechanism by which skeletal muscles help maintain systemic blood pressure?
What is the primary mechanism by which skeletal muscles help maintain systemic blood pressure?
What is the term for the resistance that vessels offer to the flow of blood?
What is the term for the resistance that vessels offer to the flow of blood?
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What is the effect of increased viscosity on peripheral resistance?
What is the effect of increased viscosity on peripheral resistance?
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Which hormone is released in response to stress and affects blood pressure?
Which hormone is released in response to stress and affects blood pressure?
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What is the term for the mechanisms that regulate systemic blood pressure from within certain organs?
What is the term for the mechanisms that regulate systemic blood pressure from within certain organs?
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What is the effect of increased heart rate and force on blood pressure?
What is the effect of increased heart rate and force on blood pressure?
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What is the primary mechanism by which the respiratory pump helps maintain systemic blood pressure?
What is the primary mechanism by which the respiratory pump helps maintain systemic blood pressure?
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What is the purpose of the venous valves in the maintenance of systemic blood pressure?
What is the purpose of the venous valves in the maintenance of systemic blood pressure?
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Study Notes
Cardiovascular System
- When venous return increases, cardiac muscle fibers stretch, and ventricles pump more forcefully (Starling's law)
- The kidneys play a crucial role in regulating blood pressure through the renin-angiotensin mechanism
- The cardiovascular center is located in the medulla and helps regulate heart rate, stroke volume, blood pressure, and blood flow to specific tissues
Nervous Mechanisms
- The autonomic nervous system, including sympathetic and parasympathetic nerves, regulates heart rate, cardiac output, and blood pressure
- Vasomotor nerves (sympathetic nerves) contract smooth muscle in arterioles, increasing vascular resistance and blood pressure
- Vasomotor nerves also contract smooth muscle in veins, moving blood towards the heart and increasing blood pressure
Arteries
- Arteries carry blood away from the heart and have three layers: external, middle, and inner
- The inner layer, the tunica intima, is in contact with blood and produces nitric oxide, a vasodilator
Arterioles and Veins
- Arterioles are smaller arteries that branch into capillaries
- Veins carry blood back to the heart and have the same three tissue layers as arteries
- The inner layer of veins has smooth endothelium and valves to prevent backflow
Capillaries
- Capillaries carry blood from arterioles to venules and have walls only one cell thick
- Precapillary sphincters regulate blood flow into capillary networks
- Capillaries are the sites of exchange of materials between blood and tissue fluid through diffusion and filtration
Circulatory Routes
- Two main circulatory routes: systemic and pulmonary
- Systemic circulation: oxygenated blood travels from the heart throughout the body, deoxygenating as it goes
- Pulmonary circulation: carries blood from the right side of the heart to the lungs to get oxygen and eliminate CO2
- Hepatic portal circulation: portal vein transports blood from GI organs to the liver
Fetal Circulation
- Specialized for exchange of materials with maternal blood and bypass of lungs
- Umbilical arteries and vein connect to the placenta
Blood Pressure
- Blood pressure is the force blood exerts against blood vessel walls
- Systolic pressure occurs when the left ventricle contracts, and diastolic pressure occurs when it relaxes
- Normal blood pressure range: 90-120 mmHg systolic, 60-80 mmHg diastolic
- Hypertension: consistently higher than normal blood pressure, and hypotension: consistently lower than normal
Maintenance of Systemic Blood Pressure
- Venous return: two mechanisms (skeletal muscle contractions and respiratory pump) help return blood to the heart
- Heart rate and force, peripheral resistance, and elasticity of large arteries all contribute to maintaining systemic blood pressure
Regulation of Blood Pressure
- Intrinsic mechanisms: heart, kidneys, and blood vessels regulate blood pressure internally
- Nervous mechanisms: autonomic nervous system and vasomotor nerves regulate blood pressure through nervous signals
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Description
This quiz covers the mechanisms that regulate cardiovascular function, including Starling's law and the renin-angiotensin mechanism.
