Chapter 15 ~ Blood Flow and Blood Pressure Control (PDF)

**[Chapter 15 \~ Blood flow and the Control of Blood Pressure]** 1. Explain what creates blood pressure and how blood pressure changes as blood flows through the systemic circulation. Ventricular contraction causes blood pressure - Blood pressure decreases as blood flows through the system...

**[Chapter 15 \~ Blood flow and the Control of Blood Pressure]** 1. Explain what creates blood pressure and how blood pressure changes as blood flows through the systemic circulation. Ventricular contraction causes blood pressure - Blood pressure decreases as blood flows through the systemic circuit **Flow through a tube is directly proportional to the pressure gradient** - **Higher pressure = higher flow** - **Fluid flow depends on pressure gradient... NOT the absolute pressure** Force -- exerted by fluid on its container Hydrostatic pressure -- force fluid exerts on walls **Pulse Pressure** -- measure of strength of pressure produced in ventricular pressure Pulse pressure = systolic pressure -- diastolic pressure \*If flow into arteries exceeds flow out, then arterial blood volume increases and MAP increases \*If flow out of arteries exceeds flow in, then arterial blood volume decreases and MAP decreases 2. Explain the relationship between blood flow, pressure gradients, and the resistance of the system to flow. Use Poiseuille's law to explain the factors that influence resistance. **Flow ∞ Pressure/Resistance** - Factors affecting resistance: radius of blood vessels, length of blood vessels, viscosity of blood - Velocity of flow depends on cross-sectional area of vessels - Smaller radius = Increased resistance A close up of a text Description automatically generated **\*\*\*changing radius = most drastic change!** 3. Explain the contributions of cardiac output and peripheral resistance to blood pressure. Cardiac output = flow out of left ventricle MAP ∞ CO x PR Mean arterial pressure (MAP) = diastolic pressure + 1/3(pulse pressure) Pulse pressure = systolic pressure -- diastolic pressure  A diagram of blood flow Description automatically generated 4. Calculate mean arterial pressure. MAP = primary driving force for blood flow MAP ∞ CO x PR **Mean arterial pressure (MAP) = diastolic pressure + 1/3(pulse pressure)** Pulse pressure = systolic pressure -- diastolic pressure 5. Define myogenic autoregulation and explain its role in altering local blood flow. **This might be an area that should be reviewed.** **Myogenic autoregulation** = how arterioles regulate their own blood volume - Occurs independent of brain! - Regulates LOCAL blood flow - Arterioles = main site of variable resistance - Vascular smooth muscle regulates its own state of contraction - Stretched vascular smooth muscle has mechanically gated Ca2+ channels that contract to resist stretching - RESPONSE TO STRETCH TO MAINTAIN STABLE FLOW 6. Explain how the body can use local and long-distance signaling to direct blood flow to or away from specific organs or tissues. **Keep in mind the distinctions between local & long-distance.** **Blood distributions vary according to the metabolic needs of tissues** - Governed by local control mechanisms & Homeostatic reflexes - Possible because arterioles are arranged in parallel - Cerebral blood flow remains relatively constant - Coronary blood flow parallels the work of the heart **\*Local control** = immediate changes based on local metabolic needs \- Myogenic autoregulation \- Hyperemia (high activity in SKM) \- Paracrine signaling -- local signaling molecules regulate resistance blood flow \***Long distance control** = integrates needs of entire organism prioritizing homeostasis through critical organs \- Neural control \~ tonic control (sympathetic nervous system: vasodilation & vasoconstriction) \- Hormonal control \~ epinephrine & angiotensin 2 \- Systemic adjustments in MAP  7. Describe in detail the steps of the baroreceptor reflex, including the stimulus, sensor, input pathway, integrating center(s), output pathways, target(s), **cellular response(s**), tissue response(s), and systemic response(s). Include all chemical signal molecules and their receptors as well as any feedback loops. Baroreceptor pathway = controls blood pressure - Located in carotid arteries and aorta - Changes in stretch = change frequency of action potential to the brainstem **Change in blood pressure (STIMULUS) Carotid and aortic baroreceptors (SENSOR) Sensory neuron (AFFERENT PATHWAY) Medullary Cardiovascular control center (INTEGRATING CENTER) sympathetic & parasympathetic neurons (OUTPUT SIGNAL)** - Sympathetic output affects NE release on alpha & B1 receptors - Alpha receptor TARGETS: arteriolar smooth muscle - TISSUE RESPONSE: Vasodilation/Vasoconstriction - THIS AFFECTS PERIPHERAL RESISTANCE - B1 receptor TARGETS: SA node and Ventricular myocardium - Ventricular myocardium TISSUE RESPONSE = affects force of contraction - FORCE OF CONTRACTION AFFECTS CARDIAC OUTPUT - SA Node TISSUE RESPONSE = affects Heart rate - HR AFFECTS CARDIAC OUTPUT - Parasympathetic output affects Ach on muscarinic receptor - Muscarinic receptor TARGETS: SA node - TISSUE RESPONSE: increase/decrease Heart rate - HR AFFECTS CARDIAC OUTPUT SYSTEMIC RESPONSE = Change in blood pressure Negative feedback = change in blood pressure - Acts on the baroreceptors in carotid and aorta (SENSOR) \*\*\*know sympathetic uses alpha receptors Targets: arterioles, veins, SA node, contractile cells Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings  A diagram of a heart Description automatically generated 8. Explain the forces that influence capillary filtration and absorption. **Bulk flow** = mass movement of fluid between blood and interstitial fluid - Net pressure = Hydrostatic pressure -- Colloid osmotic pressure **Filtration** = fluid movement out of capillaries - Caused by **HYDROSTATIC PRESSURE** **Absorption** = fluid movement into capillaries - Caused by **COLLOID OSMOTIC PRESSURE** - Influenced by proteins \*\*\*positive Net = filtration \*\*\*Negative net = absorption