The Cardiovascular System

William Harvey (1628) demonstrated that the circulatory system forms a circle so that blood is continuously pumped out of the heart by way of another set of vessels. (i.e. Arteries and Veins)

The Cardiovascular SystemHeart attacks are, perhaps, the number one killer in the USA. In middle

age and older persons, the probability of developing a coronary disease increases with:

1. Smoking

2. Obesity

3. Cholesterol/triglycerides

4. Abnormal ECG

5. Hypertension

The Cardiovascular System

I. Blood Vascular

A. Heart

B. Arteries

C. Capillaries

D. Veins

II. Lymphatic Vascular

A. Lymphatic Capillaries

B. Lymphatic Vessels

Thoracic Duct

Right Lymphatic Duct

Impulse ConductionA-V Node

Junctional fibers (0.01m/s)

Node (0.1m/s)

Transitional (0.4m/sec)

Bundle of His

Branches of bundle of His E Purkinje fibersrate L5 to 4.0 m/sec

AtrionodalNodal

Nodal His

Cardiac Action Potentials

Atrial Myocradial cell

Ventricular Myocradial cell

Pace-maker

1. Resting potential2. Spike (rapid depolarization)3. Plateau (Ca++ perinmeability )4. Repolarization

-90

-90-6040

1

23

4No+

in Coin

K+

set

P

Q S

RT

Electrocardiogram (ECG)

I. Unipolar (V) leads (9 locations)

A. Chest leads (precordial)

V 1- 6 B. Limb leads

VR (right arm) VL (left arm) VF (left foot)

II. Bipolar Limb Leads I. from RA to LA

II. from RA to LL III. from LA to LL

The ECG is the algebraic sum of the electrical events which occur during a heart beat. These signals are transmitted via the body fluids to the body surface where they are recorded by electric amplifiers. The series of pikes and depressions have arbitrarily been labeled

Relationship between Monophasic Action Potential

and Ventricular Activity

Depolarization Repolarization

R

Q

T

S

ECG

Duration Event Ave. Range

PR interval 0.18 0.12-0.20 Atrial Dep. Through AV

QRS duration 0.08 0.006-0.10 Aent. Dep.

QT interval 0.40 0.37-0.43 Vent. Dep + Repol.

ST interval 0.32 Vent. Repolarization

PR segment

QRS Duration

QT interval

ST segment

PR interval

P

Q S

T

R

Pathological Conditions Mean Electrical Axis

(mark changes in current flow)Left Axis Deviation

(hypertrophy of left ventricle) 1. Hypertension

(muscle mass on left side of heart) 2. Aortic Valvular stenosis 3. Aortic Valvular regurgitation 4. Several congenital heart conditionsRight Axis Deviation 1. Hypertrophy of right ventricle

(pulmonary stenosis) 2. Tetralogy of Fallot

(congenital right to left shunt )

I. Correlation of Plasma K+ Level

a. Noraml (plasma K+ 4 - 5.5 mEq/l)

b. Hypokalemia (plasma K+ + 2.5 mEq/l)

c. Hypokalemia (plasma K+ + 2.3 mEq/l)

d. Hyperkalemia (K+ + 7.0)

e. Hyperkalemia (K+ + 8.5

II. Atrial Enlargement

a. “p” pulmonale

b. “p” mitrale

Cardiac Arrhythmias

p tu

tu

Origin of the heartbeat & the electrical activity of the heart

Cardiac Rhythms & Arrhytmias

Cardiovascular Pressures & Sounds

Key (color)Key (color)1. Left ventricular 1. Left ventricular P.P.2. Aortic pressure2. Aortic pressure3. Left atrial p.3. Left atrial p.

Electrocardiogram

Phonocardiogram1. Lub2. Dub3. Rapid ventricular filling4. Atrial contraction

Dicrotic notch

14 2 3

closes opensmitral valve

a c v

aortic valveopens closes

120 -100 -

80 -60 -40 -20 -

0 -

Art

eria

le

cap

ille

ries

Ven

ale

Comparison of Pressures Within the Circulatory System

120

100

80

60

40

20

0

Aor

ta

Lar

ge a

rter

ies

Mai

n a

rter

ial b

ran

ch

Ter

min

al a

rter

ies

Ter

min

al v

ein

s

Mai

n v

enou

s b

ran

ch

Lar

ge v

ein

s

Ven

a ca

va

Systolic Pressure

Diastolic Pressure

Heart Sounds

120-

100-

80-

60-

40-

20-

0

120-

80-

40-

0 0.2 0.4 0.6 0.8

Ventricle

Systole Disstole1

2

34

5

6

Volume (ml)

Pressure (mmHg)

Heart sounds2nd 3rd1st

Time seconds

Heart Murmurs(Bruits - Outside the heart)

Types:

A Innocent (functional)

B pathogenics (non-functional)1. Stenosis - narrowing of valve

2. Regurgitant (insufficient)

3. Prolaspse

C. Congential

2. Patent ductus arteriosis

2. Interventricular septal defect

Heart Murmurs(Bruits - Outside the heart)

Valve Name Abnormality Timing of Murmur

Stenosis Systolic

Regurgitation Diastolic

Stenosis Diastolic

Regurgitation Systolic

Aortic or

Pulmonary

Mitral or

Tricuspid

Rheumatic Vascular lesions cause an autoimmune disease inwhich the heart valves are likely to be damaged .It is caused by a group A streptococcal toxin such as the oneswhich cause sore throat, scarlet fever, or middle ear infection.

Heart & Circulation1.Blood

Blood cells become packed at the bottom of the tube when whole blood is centrifuged, leaving the fluid at the top of the tube. Red blood cells are the most abundant of the blood cells -- white cells & platelets float ?? Only a thin, light-colored “buffy coat” at the interface between the packed red blood cells and the plasma.

Blood volume 80-85 ml/kg body weightBlood osmoiality 280-296 mOsmBlood pH 7.35-7.45Enzymes:Creatine Female: 10-79 U/L phosphokinase (CPK) Male : 17-148 U/L Lactic Dehydrogenase 45-90 U/L(LDH)Phosphate (acid) Female: 0.01-0.56

Sigma U/ml Male: 0.13-0.63 Sigma

Measurement Normal RangeRepresentative normal plasma values

Hematology Values:Hematocrit Female: 37%-48% Male: 45%-52%Hemoglobin Female: 12-15 g/100ml Male: 13-18 g/100mlRed blood cell count 4.2-5.9 million/mm3White blood cell count 4,300-10,880/mm3

Hormones Testosterone Male: 300-1,100ng/100mlAdrenocorticotropic (ACTH) 15-70 pg/mlGrowth hormone Children: over 10ag/ml Adult male: below 5 mg/mlInsulin 6-26 * U/ml (fasting)

Measurement Normal RangeRepresentative normal plasma values

IonsBicarbonate 24-30mmol/lCalcium 2.1-2. 6mmol/lChloride 100-106mmol/lPotassium 3.5-5.0mmol/lSodium 135-145mmol/1

Measurement Normal RangeRepresentative normal plasma values

Measurement Normal RangeRepresentative normal plasma values

Organic Molecules (other)Cholesterol 120-220mg/100mlGlucose 70-110mg/100ml (fasting)Lactic acid 0.6-1.6mmol/lProtein (total) 6.0-8.4g/100mlTriglyceride 40-150mg/100mlUrea nitrogen 8-25mg/100mlUric acid 3-7 mg/100ml

Hemostasis

Mechanisms

1. Vascular Spasms (vasoconstricitions)

2. Formation of Platelet Plug

3. Blood Coagulation

Table 13.4 Plasma Clotting Factors

* Require Vitamin K

+ Antihemophilic factors

*

*

* +

+* +

Table 13.5 Some acquired and inherited defects in the clotting mechanism

Extrinsic pathway

Common pathway

Intrinsic pathway

Extrinsic pathway

Activator:tissue thromboplastin

VII VII activated

VII complex(VII, tissue

thromboplastin,calcium,

phospholipids)Common pathway

Common pathway

Intrinsic pathwayActivators:

collagen,gas, and others

XII XII activated

XI XI activated

IX IX activated

VIII complex(VIII, (X activated,

calcium, phospholipids)

Common pathway

Fibrinogen FibrinFibrin

polymerXIII

V complex (V, X activated, calcium, phospolipids

Prothrombin Thrombin

X X activated

Extrinsic pathway

Intrinsic pathway

Prevention of Blood ClottingA. In-Vivo

1. Endothelial Surface Factors (Prostocyclin)

2. Heparin: A conjugated polysaccharide produced by mast cells (basophils)

3. Coumarin(Warfarin) & Phenindione: orally administered; blocks the synthesis of Vit.-K dependent clotting factors

4. Aspirin

Prevention of Blood ClottingB. In-Vitro

1. Removal of Ca++

a. Oxalates

b. Citrates

c. Chelating agents (EDTA)

2. Inhibition of vitamin-K

Dicumarol (coumarin) 3. Aspirin

Inhibits platelet aggregation

EDTA A chelate of

ethylenediamine tetraacetate with a divalent metal cation (Me2+). The shaded portion represents the plane of the coordination bonds

Me 2+

O

O

O

O

O

O

OO

C

C

C

C

CH2

CH2

CH2

CH2

CH2

CH2

N

N

Causes for Excessive Bleeding

1. Vitamin-K Deficiency

Factors II, VII, IX & X

2. Hemophilia

Factors VII (75%), IX (15%), & XI (5-10%)

3. Thrombocyopenia

Intrinsic Pathway Extrinsic Pathway

ContactActivation

ActivatedPlatelets

ActivatedPlatelets

Vessel DamageVessel Damage

Exposed CollagenSubendothelial CellsExposed to Blood

Tissue FactorXII

XI

IX IX

X

V

X

Prothrobin

VIII

VII

VIIaXIIa

XIa

Ixa

XIIIa

Xa

Va

Thrombin