Chapter 05 Cardiovascular System - · PDF fileChapter 05 Cardiovascular System. 2 ... 23 How is blood ... What is the hepatic portal system? 5.5 Two Cardiovascular Pathways

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Chapter 05

Cardiovascular

System

2

Cardiovascular System:

Heart and Blood Vessels

3

Points to ponder

• What are the functions of the cardiovascular system?

• What is the anatomy of the heart? Of blood vessels, such as veins and arteries?

• How is the heart beat regulated?

• What is blood pressure?

• What are common cardiovascular diseases and how might you prevent them?

4

5.1 Overview of the Cardiovascular System

Figure 5.1 The cardiovascular system

and homeostasis.

What is the cardiovascular system?Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

O2

tissue cellsRespiratory System

kidneys

food

liver

Urinary SystemDigestive System

metabolic wastes

(urine)

indigestible

food residues (feces)

CO2

Cardiovascular System

• Includes Heart & blood vessels

• Functions:

• Organs that refresh blood:

• What’s involved?

5

External anatomy of the heartleft subclavian artery

left common carotid artery

brachiocephalic artery

superior vena cava

aorta

left pulmonary artery

pulmonary trunk

left pulmonary veins

right pulmonary artery

right pulmonary veins

left atrium

left cardiac vein

right atrium

right coronary artery

left ventricle

right ventricle

left anterior descending

coronary artery

inferior vena cava

apex

Figure 5.3 The arteries and veins associated with

the human heart.

5.3 The Heart is a Double Pump

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Internal anatomy of the heartCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

left subclavian artery



superior vena cava

aorta


pulmonary trunk




semilunar valve

left atrium

right atrium

atrioventricular

(bicuspid) valve

atrioventricular

(tricuspid) valve

chordae tendineae

papillary muscles

right ventricle

septum

left ventricle

inferior vena cava

a.Figure 5.4a The heart is a double pump.


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Figure 42.7

Pulmonary artery

Right

atrium

Pulmonary

Semilunar

valve

Right

ventricle

Left

ventricle

Atrioventricular Valve

• Bicuspid/Mitral

Aortic Semilunar

valve

Left

atrium

Pulmonary

artery

Aorta

Atrioventricular Valve

• Tricuspid

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Visualizing blood flow through the heart

Figure 5.4 The heart is a double pump.


Intercalated disc with gap junctions

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Figure 42.10Artery

Red blood cells

Endothelium

Artery

Smoothmuscle

Connectivetissue

Capillary

Valve

Vein

Vein

Basal lamina

Endothelium

Smoothmuscle

Connectivetissue

100 m

LM

Venule

15

mL

M

Arteriole

Red blood cell

Capillary

Main pathway of

blood in the

body?

10

What are the 2 cardiovascular pathways

in the body?

• Pulmonary circuit

• Systemic circuit

5.5 Two Cardiovascular Pathways

O2

O2CO2

head and armscarotid artery

(also subclavian

artery to arms)

jugular vein

(also subclavian

vein from arms)

CO2

CO2

O2

O2

lungs

pulmonary

artery

superior

vena cava

inferior

vena cava

hepatic

vein

hepatic

portal

vein

renal

vein

iliac vein

CO2

trunk and legs

iliac

artery

renal

artery

intestinal

artery

aorta

pulmonary

vein

liver digestive

tract

kidneys

heart

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Figure 5.10 Overview of the cardiovascular system.

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common

carotid arteryinternal

jugular vein

superior

vena cava

inferior

vena cava

renal artery

abdominal

aorta

mesenteric

vein

common

iliac vein

femoral

artery

great

sphenoid

vein

femoral

vein

common

iliac artery

inferior

mesenteric

artery

renal vein

subclavian

vein

subclavian

artery

external

jugular vein

Figure 5.11 The major arteries

and veins of the systemic circuit.


12Figure 5.2 Structure of a capillary bed.

5.2 The Types of Blood Vessels

Arteries, Capillaries, Veins

a.

v.

v. = vein; a. = artery

valve

blood

flow

blood

flow

connective

tissue

artery

arteriole

capillary bed

arteriovenous

shunt

vein

venule

smooth muscle

endothelium

elastic tissue

precapillary

sphincter

(left): © Ed Reschke; (right): © Biophoto Associates/Photo Researchers

• Arteries

• Arterioles

• Venules

• Veins

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How can you tell the difference

between an artery and vein?Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

arteriovenous

shunt

vein

venule

arteriole

artery

connective

tissue

v.=vein; a.=artery

blood

flow

valve

blood

flow

smooth muscle

endothelium

elastic tissue

precapillary

sphincter

v.

a.

(left): © Ed Reschke

Figure 5.2 Structure of a capillary bed.


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Visualizing the heartbeat

SA node

AV node

branches of

atrioventricular

bundle

Purkinje fibers

a.


Figure 5.6a An electrical signal pathway through the heart.


• Internal control SA Node (pacemaker)

• External control:

• Medulla oblongata – cardiac ctr

• Sympathetic increase HR

• Parasympathetic decrease HR

• Hormones

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What does a normal ECG look like?

SA node

AV node

branches of

atrioventricular

bundle

Purkinje fibers

b. Normal ECG

P

Q

T

S

R

b: © Ed Reschke

Figure 5.6a-b An electrical signal pathway through the heart.


• P wave

• QRS complex

• T wave

Electrical events (heart muscle excitement) lead to mechanical events (contraction)

Electrical event (Pacemaker)

Electrical event (heart muscle excitement)

Mechanical event (heart muscle contraction)

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What is the cardiac cycle?

Figure 5.5 The stages of the cardiac cycle.


bicuspid valveaortic semilunar valvesemilunar

valves close

(“dup”)

superior

vena cavasemilunar

valves

pulmonary

trunk

aorta

right

atrium

right

ventricle

a.

aorta

b.

atrioventricular (AV)

valves close

(“lub”)

d.pulmonary

trunk

c.

right

atrium

inferior

vena cava

left

atrium

left

ventricle

represents

contraction


d: © Biophoto Associates/ Photo Researchers

How often does your heart beat?

• Systolic/diastolic

Heart sounds (lup…dup)?

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The cardiac cycle aka The Beast

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• Systole

• Diastole

• Average: 120/80 mmHg (systolic/diastolic)

• Mean arterial pressure (MAP)

DP + 1/3 Pulse pressure; (PP = SP – DP)


What is blood pressure?

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Cardiac Output

• Amount ejected by a ventricle in 1 minute

• CO = Heart Rate x Stroke Volume• HR = how many times your heart beats/min

• SV = volume of blood ejected/beat (mL/beat)

• Resting values, usually about 4 to 6L/min

• Vigorous exercise

– CO to 21 L/min for fit person

– up to 35 L/min for world class athlete

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Determining Cardiac Output

• End diastolic volume =

• End systolic volume =

• Ejection volume (stroke volume) =

• Ejection fraction = 70ml/120ml = 58%

(normally 60%)

• If heart rate (HR) is 70 beats/minute, what is

cardiac output?

• Cardiac output = HR * stroke volume

= 70 beats/min * 70 ml/beat

= 4900 ml/min 4.9 L/min

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Mean Arterial Pressure

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5.4 Features of the Cardiovascular System

Figure 5.7 Sphygmomanometers measure blood pressure.

How blood pressure is measured

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How is blood pressure categorized?


24

How can you tell the difference

between an artery and vein?Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

arteriovenous

shunt

vein

venule

arteriole

artery

connective

tissue

v.=vein; a.=artery

blood

flow

valve

blood

flow

smooth muscle

endothelium

elastic tissue

precapillary

sphincter

v.

a.

(left): © Ed Reschke

Figure 5.2 Structure of a capillary bed.


25Figure 5.8 Blood velocity and pressure in the blood vessels.


What is important about blood flow?Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Rela

tive

ma

gn

itu

de

total

cross-sectional

area of

vessels

velocity

blood

pressure

arteries arterioles capillaries venules veins

Blood flow (starting from heart)

Pressure greatest

Blood flow slowest

Why???

Pressure minimal,

Flow increased

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If blood pressure is so low in the veins,

why does the blood flow increase?

• They have help.

to heartto heart

a. Contracted skeletal

muscle pushes blood

past open valve.

b. Closed valve prevents

backward flow of blood.


Figure 5.9 The skeletal muscle

pump.


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Coronary circulationCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

left subclavian artery



superior vena cava

aorta


pulmonary trunk




semilunar valve

left atrium

right atrium

atrioventricular

(bicuspid) valve

atrioventricular

(tricuspid) valve

chordae tendineae

papillary muscles

right ventricle

septum

left ventricle

inferior vena cava

a.Figure 5.4a The heart is a double pump.


Coronary sinus

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Coronary circulationleft subclavian artery



superior vena cava

aorta


pulmonary trunk




left atrium

left cardiac vein

right atrium

right coronary artery

left ventricle

right ventricle

left anterior descending

coronary artery

inferior vena cava

apex

Figure 5.3 The arteries and veins associated with

the human heart.


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What is the hepatic portal system?


• Portal system capillary to capillary

• Hepatic portal btn intestines & liver

• Amino acids

• Glucose

• “cleanses” blood from GI tract

• Returns blood via inferior vena cava

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Exchange at the capillary beds is primarily a

result of osmotic and blood pressure

5.6 Exchange at the Capillaries


from heart

Arterial End

Blood pressure is higher

than osmotic pressure.

Net pressure out.

water

oxygen amino

acids

Tissue Fluid

glucosecarbon

dioxide

wastes

arteriolesmooth

muscle fiberblood pressure

osmotic pressure

plasma

protein

Venous End

Osmotic pressure is higher

than blood pressure.

Net pressure in.

venule

to heart

salt

water

Figure 5.12 The movement of solutes in a capillary bed.

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Exchange at the capillaries

Figure 5.13 Interaction of lymphatic and capillary beds.

5.6 Exchange at the Capillaries


venule

Lymphatic duct with lymph subclavian veins

blood

capillary

lymphatic

capillary

tissue

cells

arteriole

Precapillary sphincter

32

Cardiovascular disease (CVD)Disorders of:

heart (cardio) and blood vessels (vascular)

5.7 Cardiovascular Disorders

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Cardiovascular disease (CVD)

Risk Factors

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Disorders of the blood vessels

• Hypertension/high blood pressure

• Atherosclerosis

• Stroke

• Heart attack

• Aneurysm


35

Hypertension• Often due to arterial plaque.

• 140/90 mmHg is considered hypertension.

• Silent killer few symptoms

• It can lead to a heart attack, stroke, or kidney failure


36

Hypertension

37Figure 5B Coronary arteries and plaque.


Atherosclerosis

coronary artery ulceration

lumen of vessel

atherosclerotic

plaquecholesterol

crystals

fat


© Biophoto Associates/Photo Researchers

• Build up of plaque

• Thrombus

• Embolus dislodged thrombus

• Associated with stroke, heart attacks and aneurysms

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Treatments for Atherosclerotic

Plaque in Coronary Arteries

• Bypass surgery

• Stents: wire mesh cylinder inserted

• Angioplasty: a tube with a balloon inflated

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Stroke• Stroke aka cerebrovascular accident (CVA)

• Cranial artery is blocked or bursts

• Part of the brain dies

• Symptoms may include:• numbness of hands or face

• difficulty speaking

• inability to see in one eye


Sudden burst

40

Aneurysm• Blood vessel balloons (weaken walls)

• Atherosclerosis and hypertension

• Most commonly affected

– abdominal artery or the arteries leading to the brain.


41

Heart attack• Heart attack or myocardial infarction (MI)

• Angina pectoris:


42

How are disorders of the blood

vessels treated?

• Dissolving blood clotst-PA (tissue plasmogen activator)

drug that dissolves clots


43

Disorders of the heart and its treatment

• Disorders

Congestive heart failure

• Treatments

Left ventricular assist device (LVAD)

Heart transplant either natural or artificial


44Figure 5.15 An artificial heart.


Disorders of the heart and its treatmentCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

replacement

heart

photograph of

artificial heart

wireless

energy-

transfer

system

rechargeable

internal

battery

external

battery

pack

internal

controller

external

wireless

driver

(right): Courtesy SynCardia Systems, Inc.

45

Cardiovascular Disease Prevention


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Chapter 05 Cardiovascular System - · PDF fileChapter 05 Cardiovascular System. 2 ... 23 How is blood ... What is the hepatic portal system? 5.5 Two Cardiovascular Pathways