Functional Model of the Cardiovascular System

Figure 15-1

Figure 15-2

Blood Vessel Structure

Figure 15-3

MIcrocirculation

Capillaries lack smooth muscle and elastic tissue reinforcement which facilitates exchange

Figure 15-4a, step 1

Elastic Recoil in Arteries(a) Ventricular contraction

Ventricle contracts.

Arterioles

1

1

Figure 15-4a, steps 1–2

Elastic Recoil in Arteries(a) Ventricular contraction

Ventricle contracts. Semilunar valve opens.

Arterioles

1

1 2

2

Figure 15-4a, steps 1–3

Elastic Recoil in Arteries(a) Ventricular contraction

Ventricle contracts.

Aorta and arteries expand and store pressure in elastic walls.

Semilunar valve opens.

Arterioles

1

1 2

2

3

3

Figure 15-4b, step 1

Elastic Recoil in Arteries(b) Ventricular relaxation

Isovolumic ventricularrelaxation occurs.

1

1

Figure 15-4b, steps 1–2

Elastic Recoil in Arteries(b) Ventricular relaxation

Isovolumic ventricularrelaxation occurs.

Semilunar valve shuts, preventing flow back into ventricle.

1

2

21

Figure 15-4b, steps 1–3

Elastic Recoil in Arteries(b) Ventricular relaxation

Isovolumic ventricularrelaxation occurs.

Elastic recoil of arteries sends blood forward into rest of circulatory system.

Semilunar valve shuts, preventing flow back into ventricle.

1

2

3

3

21

Review of Blood Flow

Figure 15-5

Pressure throughout the Systemic Circulation

Blood pressure is highest in the arteries and decreases continuously as it flows through the circulatory system

Blood Pressure

Pulse Pressure = systolic P – diastolic P

Valves ensure one-way flow in veins

MAP = diastolic P + 1/3(systolic P – diastolic P)

Figure 15-7

Measurement of Arterial Blood Pressure

Figure 15-8

Blood Pressure

Mean arterial pressure is a function of cardiac output and resistance in the arterioles

Figure 15-9

Blood Pressure

Blood pressure control involves both the cardiovascular system and the renal system

Figure 15-10

Factors that Influence Mean Arterial Pressure

Arteriolar Resistance

Sympathetic reflexes

Local control of arteriolar resistance

Hormones

Arteriolar Resistance

Arteriolar Resistance

Myogenic autoregulation

Paracrines Active hyperemia

Sympathetic control SNS: norepinephrine

Adrenal medulla: epinephrine

Hyperemia

Figure 15-11a

Figure 15-12

Norepinephrine

Tonic control of arteriolar diameter

Figure 15-13

Distribution of Blood

Distribution of blood in the body at rest

Figure 15-14a

Blood Flow

Blood flow through individual blood vessels is determined by vessel’s resistance to flow

Figure 15-14b

Blood Flow

Blood flow through individual blood vessels is determined by vessel’s resistance to flow

Flow 1/resistance

Figure 15-18a

Fluid Exchange at a Capillary

Hydrostatic pressure and osmotic pressure regulate bulk flow

Animation: Cardiovascular System: Autoregulation and Capillary DynamicsPLAY

Figure 15-21

Medullary cardiovascular

control center

Carotid and aorticbaroreceptors

Change in blood

pressure

Parasympatheticneurons

Sympatheticneurons

Veins

Arterioles

Ventricles

SA node

Integrating center

Stimulus

Efferent pathway

Effector

Sensor/receptor

KEY

Blood Pressure

Components of the baroreceptor reflex

Figure 15-22

The baroreceptor reflex: the response to increased blood pressure

Figure 15-23

The baroreceptor reflex: the response to orthostatic hypotension

Figure 15-25

Hypertension

The relationship between blood pressure and the risk of developing cardiovascular disease

Essential hypertension has no clear cause other than hereditary

Hypertension

Carotid and aortic baroreceptors adapt

Risk factor for atherosclerosis

Heart muscle hypertrophies Pulmonary edema

Congestive heart failure

Treatment Calcium channel blockers, diuretics, beta-blocking

drugs, and ACE inhibitors