Chapter 19:

Cardiovascular System:

Blood Vessels

Étienne-Jules Marey – french physiologist born in 1830 credited with the invention of the sphymanograph (which has evolved into the sphymanometer (blood pressure cuff) used today.

Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn

Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.

Figure 19.1: Generalized structure of arteries, veins, and capillaries, p. 715.

(a)

(b)

Tunica intima• Endothelium• Subendothelial layer

Tunica media

Tunica externa

Artery VeinLumen Lumen

Internal elasticlamina

External elasticlamina

Valve

Artery Vein

Endothelial cells

Capillarynetwork

Capillary

Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn

Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.

Figure 19.2: Overview of vascular components and blood distribution, p. 717.

Pulmonary bloodvessels 12%

Capillaries 5%

Systemic arteriesand arterioles 15% Systemic veins

and venules 60%

Lymphaticcapillary

Precapillarysphincter

Metarteriole

Terminalarteriole

Arterioles(resistancevessels)

Arteriovenousanastomosis

Postcapillaryvenule

Sinusoid

Capillaries(exchangevessels)

Thoroughfarechannel

Venoussystem

Largeveins

Largelymphaticvessels

Smallveins

Arterialsystem

Lymphnode

Lymphaticsystem

Muscular arteries(distributingvessels)

Elastic arteries(conductingvessels)

Heart

Heart 8%

(a)

(b)

Cap

aci

tan

ce v

ess

els

Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn

Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.

Figure 19.4: Anatomy of a capillary bed, p. 721.

Precapillary sphincters

Terminalarteriole

Sphincters open

Postcapillaryvenule

Metarteriole

Vascular shunt

Truecapillaries

Terminalarteriole

Sphincters closed

Postcapillaryvenule

Thoroughfarechannel

(a)

(b)

Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn

Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.

Figure 19.5: Blood pressure in various blood vessels of the systemic circulation, p. 725.

Systolic pressure

Mean pressure

Diastolic pressure

Blo

od

pre

ssu

re (

mm

Hg

)

0

20

40

60

80

100

120

Ao

rta

Art

erie

s

Art

erio

les

Cap

illar

ies

Ven

ule

s

Vei

ns

Ven

ae c

avae

Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn

Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.

Figure 19.3: Capillary structure, p. 720.

Pericyte

Red blood cell in lumen

IntercellularcleftEndothelialcell

Endothelialnucleus

Tight junction

Basementmembrane

Pinocytoticvesicles

Pericyte

Red blood cell in lumen

Intercellularcleft

Fenestra-tions (pores)

Endothelialcell

Endothelialnucleus

Basement membraneTight junction

Pinocytoticvesicles

Nucleus of endothelial cell

Pericyte

Red blood cell in lumen

Endothelialcell

Large intercellularcleft

Tight junctionIncompletebasementmembrane

(a) (b)

(c)

Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn

Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.

Figure 19.6: The muscular pump, p. 726.

Valve (open)

Contracted skeletalmuscle

Valve (closed)

Vein

Direction ofblood flow

Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn

Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.

Figure 19.8a: Baroreceptor reflexes that help maintain blood pressure homeostasis, p. 728.

Stimulus:Rising bloodpressure

Homeostasis: Blood pressure in normal range

Baroreceptorsin carotidsinuses andaortic archstimulated

Arterialblood pressurerises abovenormal range

Impulse traveling alongafferent nerves frombaroreceptors:Stimulate cardio-inhibitory center(and inhibit cardio-acceleratory center)

Rate of vasomotorimpulses allowsvasodilation( vessel diameter)

Sympatheticimpulses toheart( HR and contractility)

R

CO

CO and Rreturn bloodpressure tohomeostaticrange

Inhibitvasomotor center

Imbalance

Imbalance

Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn

Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.

Figure 19.8b: Baroreceptor reflexes that help maintain blood pressure homeostasis, p. 728.

Vasomotorfibersstimulatevasoconstriction

Stimulatevasomotorcenter

CO and Rreturn bloodpressure toHomeostaticrange

Peripheralresistance (R)

Cardiacoutput(CO) Sympathetic

impulses to heart( HR and contractility)

Impulses frombaroreceptors:Stimulate cardio-acceleratory center(and inhibit cardio-inhibitory center)

Stimulus:Decliningblood pressure

Arterial blood pressurefalls below normal range

Baroreceptors incarotid sinusesand aortic archinhibited

Homeostasis: Blood pressure in normal range

Imbalance

Imbalance

Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn

Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.

Figure 19.11: Body sites where the pulse is most easily palpated, p. 732.

Common carotid artery

Brachial artery

Radial artery

Femoral artery

Popliteal artery

Posterior tibial artery

Dorsalis pedis artery

Temporal artery

Facial artery

Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn

Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.

Figure 19.18a: Pulmonary circulation, p. 744.

R. pulmonaryartery

Pulmonarycapillariesof theR. lung

Pulmonarycapillariesof theL. lung

L. pulmonaryartery

R. pulmonary veins

Pulmonarytrunk

Tosystemiccirculation

RA LA

LVRV

L. pulmonaryveins

Fromsystemiccirculation

(a)

Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn

Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.

Figure 19.18b: Pulmonary circulation, p. 744.

Left pulmonaryartery

Air-filledalveolusof lung

Pulmonarycapillary

Two lobar arteriesto left lung

CO2

O2

Gas exchange

Right pulmonaryarteryThree lobararteries to right lung

Pulmonaryveins

Rightatrium

Aortic arch

Pulmonary trunk

Rightventricle

Leftventricle

PulmonaryveinsLeft atrium

(b)