chapter 12 cardiovascular physiology-1

7/25/2019 Chapter 12 Cardiovascular Physiology-1

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Chapter 12 Cardiovascular physiology

Section A. Overall design of the circulatory system

1. Three components (Table 12-1) (1) Heart

(2) Blood (Fig.12-1) Formed elements

RBC (hematocrit) WBC

Platelets

B!""# coat Plasma

($) Blood %essels

&rteries 'eins

icrocirc!lation

&rterioles Capillaries

'en!les

Portal %essels

2. Blood circ!lation -#stemic and p!lmonar# circ!lation (Fig.12-2)

(1) #stemic circ!lation

Transports blood to and "rom the bod# *e"t %entricle to right atri!m

(2) P!lmonar# circ!lation

Carries blood to and "rom the l!ngs

Right %entricle to le"t atri!m$. +istrib!tion o" s#stemic blood "lo, in di""erent organs (Fig.12-$)

+istrib!tion o" total blood %ol!me in di""erent parts o" cardio%asc!lar s#stem (Fig.12-)

. Press!re "lo, and resistance F / +P0R (Fig.12-)

F Blood "lo, rate

+P Press!re di""erence R Resistance

R / *h 0p r(Fig.12-3)

h Fl!id %iscosit# * *ength o" the t!be

r inside radi!s o" the t!be

0p constant (1) Blood %iscosit#

Hematocrit is a "actor

Relati%el# constant

(2) *ength o" blood %essels is constant ($) 4nside radi!s o" the blood %essels is resistance determinant

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Section B. The Heart

1. &natom# o" heart

1) *ies near the anterior chest ,all directl# behind the stern!m 2) !rro!nded b# pericardial ca%it# (Pericardi!m)

-T,o membrano!s co%erings pericardi!m and epicardi!m

$) Cardiac m!scle (Fig.12-5m!scles) (1) triated %ol!ntar# m!scle

(2) &erobic metabolism rich in mitochondria and blood %essels

($) 4ntercalated disc cell to cell connection b# desmosome 6!nction () echanicall# chemicall# and electricall# connected b# gap 6!nction

(3) Cond!cting s#stem

Pacema7er cells

Connected b# gap 6!nction (8) &trial natri!retic hormone +ecrease blood press!re thro!gh 9a:e;cretion "rom 7idne#

) Blood s!ppl# to the heart

(1) Coronar# arteries

*e"t and right coronar# arteries Branch "rom the base o" the aorta

The highest blood press!re in the s#stemic circ!it (2) Coronar# sin!s

*arge thin-,alled %ein


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itral %al%e prolapse (c!spids)

(8) *e"t %entricle

>6ects blood into the s#stemic circ!it &ortic semil!nar %al%e bet,een le"t %entricle and aorta

Has a thic7 m!sc!lar ,all to p!sh blood to the bod# s#stem

- 9eed 8 to ? times more press!re than right %entricle Path o" blood "lo, (Fig.12-= Heart circ!lation)

2. Heartbeat coordination

1) e@!ence o" e;citation (Fig.12-1AFig.12-11) (1) inoatrial (&) node

*ocation posterior ,all o" right atri!m cardiac pacema7er

*eads contraction o" both atria

+etermines heart rate (2) &trio%entric!lar (&') node

*ocation "loor o" right atri!m

lo, in action potential propagation -pro%ide complete atrial contraction be"ore

%entric!lar contraction ($) &' b!ndle (B!ndle o" His)

*ocation top o" inter%entric!lar sept!m


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2) i%es o%erall cardiac m!sc!lar electric acti%ities (b!t not speci"ic portion onl#)

$) >lectrocardiogram leads placement (Fig.12-13>intho%enDs triangle)

>ach lead is a set o" positi%e and negati%e electrode (Table 12-2) *ead 4 Right arm(-) and *e"t arm(:)

*ead 44 Right arm(-) and *e"t leg(:)

*ead 444 *e"t arm(-) and *e"t leg(:) ) Paper speed is 23mm0 sec.

Thin %ertical line - A.Asec.

>%er# "i"th hea%ier line -A.2sec. 3) Heart beat and ,a%es (Fig.12-1 Tracer= cond!ct)

(1) P ,a%e +epolariEation o" the atrial ,alls -atrial s#stole

(2) IR comple; 'entric!lar depolariEation and atrial repolariEation -%entric!lar s#stole

and atrial diastole &trial repolariEation is mas7ed b# IR comple;

($) T ,a%e 'entric!lar repolariEation -%entric!lar diastole

*ength o" time d!ring and bet,een the ,a%es indicates the e""icienc# o" cond!ction

8) 4nterpretation o" electrocardiogram (Fig. 12-18) P ,a%e atrial disorders -"l!tter "ibrillation

IR ,a%e %entric!lar disorders P-R inter%al & node - &' node bloc7

T segment in"arctionJ

. Cardiac m!scle contraction imilar to s7eletal m!scle contraction ,ith some di""erences

e@!ence o" cardiac m!scle contraction (Fig. 12-1?)

4mp!lse to sarcolemma


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-&ortic and p!lmonar# %al%e closed

-&trial contraction (at the end o" diastole)

$) P!lmonar# circ!lation press!re (Fig.12-21) $) !mmar# o" cardiac c#cle (Fig.12-2A)

) tro7e %ol!me

tro7e %ol!me / >nd-diastolic %ol!me - >nd-s#stolic %ol!me tro7e %ol!mes o" right and le"t %entricle are the same

8. Heart so!nds

*!b so!nd -Clos!re o" the &' %al%e at the onset o" s#stole

-o"t and lo, pitched

+!p so!nd

-Clos!re o" the aortic and p!lmonar# %al%es at the onset o" diastole Heart m!rm!rs (Fig.12-22)

-tenosis (narro,ed %al%es)

-4ns!""icienc# (lea7# %al%es) Prolapsed mitral %al%e

-eptal de"ect Hole in the inter%entric!lar sept!m?. Cardiac o!tp!t

1) Cardiac o!tp!t (C+'

' tro7e %ol!me >+' >nd-diastolic %ol!me

9ormal 3A to ?AL !nder resting condition

(2) #mpathetic inp!t

Higher norepinephrine ca!ses higher %entric!lar contractilit# (Fig.12-2?)

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tim!lation ca!ses increased stro7e %ol!me (Fig.12-28)

tim!lation increases a%ailabilit# o" Ca::

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C. Reacti%e h#peremia

-onitored b# obstr!ction o" arterioles

+. Response to in6!r# (2) >;trinsic controls

&. #mpathetic ner%es

-9orepinephrine %asoconstriction B. Paras#mpathetic ner%es

-9o inner%ation

C. 9oncholinergic nonadrenergic a!tonomic ne!rons -9itric o;ide %asodilator

+. Hormones

->pinephrine (Fig.12-$3)

b -adrenergic receptor M %asodilation a -adrenergic receptor M%asoconstriction

-&ngiotensin 44 (7idne#) %asoconstriction

-&+H %asoconstriction

!mmar# o" controlling "actors (Fig.12-$8= Fig.12-31) ($) &rteriolar control in speci"ic organs (Table 12-3ab)

$) Capillaries (1) 'elocit# o" capillar# blood "lo, (Fig.12-$5)

(2) o%ement across capillar# ,all

tr!ct!re o" capillar# (Fig.12-$?) Thro!gh intercell!lar cle"t and "!sed-%esicle channels

icrocirc!lation (Fig.12-$)

>;oc#tosis and endoc#tosis "or larger molec!les

+i""!sion across capillar# ,all (Fig.12-A) B!l7 "lo, across capillar# ,all (Fig.12-1)

-Filtration o" protein-"ree plasma to interstitial "l!id

($) Factors determining "l!id mo%ement across capillaries (Fig.12-2) Capillar# h#drostatic press!re

4nterstitial "l!id h#drostatic press!re


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-Contraction o" smooth m!scle at l#mph %essels

-7eletal m!scle contraction

-Respirator# mo%ement

Section . !egulation of systemic arterial pressure

-#stemic arterial press!re (Fig.12-31) ean s#stemic arterial press!re / Cardiac o!tp!t K Total peripheral resistance

Blood %ol!me and arterial press!re (Fig.12-32) 1) Baroreceptor re"le;es

onitor changes in blood press!re

Baroreceptor action potential and mean arterial press!re (Fig.12-3) &rterial press!re control thro!gh baroreceptor (Fig.12-33)

Blood press!re compensation b# arterial baroreceptor re"le; (Fig.12-38)

(1) &rterial baroreceptors (Fig.12-3$) Carotid sin!s baroreceptors (nec7)

&ortic arch baroreceptor

(2) ed!llar# cardio%asc!lar center 4n med!lla oblongata

Recei%es inp!t thro!gh baroreceptors

4nner%ated into s#mpathetic and paras#mpathetic ne!rons to heart and %essels

($)

chapter 12 cardiovascular physiology-1

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