chapter 15a
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Chapter 15a. Blood Flow and the Control of Blood Pressure. About this Chapter. The blood vessels Blood pressure Resistance in the arterioles Distribution of blood to the tissues Exchange at the capillaries The lymphatic system Regulation of blood pressure Cardiovascular disease. - PowerPoint PPT PresentationTRANSCRIPT
Chapter 15a
Blood Flow and the Control of Blood
Pressure
About this Chapter
• The blood vessels• Blood pressure• Resistance in the arterioles• Distribution of blood to the tissues• Exchange at the capillaries• The lymphatic system• Regulation of blood pressure• Cardiovascular disease
Figure 15-1
Functional Model of the Cardiovascular SystemElastic arteries
Aorta
Aortic valve
Left heart
Right heart
Lungs
Left ventricle
Right ventricle
Left atrium
Right atrium
Pulmonary veins
Pulmonary arteryPulmonary valve
Tricuspid valve
Capillaries
Mitral valve
Venae cavae
Venules
Arteriole withvariable radius
Exchange ofmaterial withcells
Expandable veins
Blood Vessel Structure
Figure 15-2
Blood Vessel Structure & Function
PLAY Interactive Physiology® Animation: Cardiovascular System: Anatomy Review: Blood Vessel Structure & Function
Metarterioles Regulate Flow into Capillary Beds
• Capillaries lack smooth muscle and elastic tissue reinforcement, which facilitates exchange
Figure 15-3
Collateralarteries
Arteriole wall is smooth muscle.
Metarterioles can act asbypass channels.
Vein
Venule
Capillaries
Arteriovenousbypass
Precapillarysphincters
Smallvenule
Angiogenesis
• New blood vessel development• Necessary for normal development• Wound healing and uterine lining growth• Controlled by cytokines• Stimulate (mitogens): VEGF and FGF• Inhibit: angiostatin and endostatin
• Coronary heart disease • Collateral circulation
Elastic Recoil in Arteries
Figure 15-4a
1
2
3
1
Ventricle contracts.
Aorta and arteries expand andstore pressure in elastic walls.
Semilunar valve opens.
(a) Ventricular contraction
Arterioles
2
3
Elastic Recoil in Arteries
Figure 15-4a, step 1
1
1
Ventricle contracts.
(a) Ventricular contraction
Arterioles
Elastic Recoil in Arteries
Figure 15-4a, steps 1–2
1
21
Ventricle contracts.
Semilunar valve opens.
(a) Ventricular contraction
Arterioles
2
Elastic Recoil in Arteries
Figure 15-4a, steps 1–3
1
2
3
1
Ventricle contracts.
Aorta and arteries expand andstore pressure in elastic walls.
Semilunar valve opens.
(a) Ventricular contraction
Arterioles
2
3
Elastic Recoil in Arteries
Figure 15-4b
1
2
3
1
Isovolumic ventricularrelaxation
Elastic recoil of arteries sendsblood forward into rest ofcirculatory system.
Semilunar valve shuts, preventingflow back into ventricle.
(b) Ventricular relaxation occurs.
2
3
Elastic Recoil in Arteries
Figure 15-4b, step 1
1
1
Isovolumic ventricularrelaxation
(b) Ventricular relaxation occurs.
Elastic Recoil in Arteries
Figure 15-4a, steps 1–2
1
21
Isovolumic ventricularrelaxation
Semilunar valve shuts, preventingflow back into ventricle.
(b) Ventricular relaxation occurs.
2
Elastic Recoil in Arteries
Figure 15-4a, steps 1–3
1
2
3
1
Isovolumic ventricularrelaxation
Elastic recoil of arteries sendsblood forward into rest ofcirculatory system.
Semilunar valve shuts, preventingflow back into ventricle.
(b) Ventricular relaxation occurs.
2
3
Review of Blood Flow
Table 15-1
Pressure Throughout the Systemic Circulation
• Blood pressure is highest in the arteries and decreases continuously as it flows through the circulatory system
Figure 15-5
Blood Pressure
• Pulse Pressure = systolic P – diastolic P• Valves ensure one-way flow in veins• MAP = diastolic P + 1/3(systolic P – diastolic P)
PLAY Interactive Physiology® Animation: Cardiovascular System: Measuring Blood Pressure
Cuff pressure> 120 mm Hg
Stethoscope
Cuff pressurebetween 80 and
120 mm Hg
Cuff pressure< 80 mm Hg
Inflatablecuff
Pressuregauge
(a)
(b)
(c)
Measurement of Arterial Blood Pressure
Figure 15-7
Blood Pressure
• Mean arterial pressure is a function of cardiac output and resistance in the arterioles
Figure 15-8
Elastic arteriesArteriolesLeft ventricle
Mean arterial pressureCardiac output Variable resistance
Mean arterial pressure cardiac output resistance
Blood Pressure
• Blood pressure control includes rapid responses from the cardiovascular system and slower responses by the kidneys
Bloodvolume
Bloodpressure
leads to
triggers
Compensationby
cardiovascularsystem
Vasodilation Cardiac output Excretion of fluid in urineblood volume
Bloodpressureto normal
Compensationby kidneys
Stimulus
Integrating center
Tissue response
Systemic response
Slow responseFast response
KEY
Blood Pressure
Figure 15-9
Factors that Influence Mean Arterial Pressure
Figure 15-10
Factors that Influence Mean Arterial Pressure
PLAY Interactive Physiology® Animation: Cardiovascular System: Factors That Affect Blood Pressure