Circulatory System

Circulatory System
Functions of Blood
• Locomotion
• Transport
– Oxygen
– Nutrients
– Solutes
– Metabolic wastes
– Secretions (hormones, etc.)
• Maintain pH and osmotic pressure
• Site of immune response
• Maintain body temperature
Circulatory, Respiratory and Digestive Systems
CIRCULATORY SYSTEM
Various Circulatory System
Various Circulatory System
Flow Through Open and Closed
Circulatory Systems
Closed Circulatory Systems of Vertebrates
Closed Circulatory Systems of Vertebrates
Birds and mamals?

Comparison
Closed Systems Open Systems
High P Low P
High R Low R
High P sustained May sustain high P
Direct blood delivery May have direct delivery
Distribution well regulated Distribution not well
regulated
Rapid return to heart Slow return to heart
Blood Volume and Composition
• 4 - 5 l in volume (human)
• Plasma : 50 - 60 % total volume
– Water 91 - 92 %
– Protein 7 - 8 %
– Solutes 1 - 2 %
– Cellular portion
• Red blood cells 5.4 million/ml
• White blood cells 5,000 - 10,000
• Platelets 250,000 - 300,000
Components Relative Amounts Functions
Plasma Portion (50%–60% of total volume):
1. Water 91%–92% of Solvent
plasma volume
Defense, clotting, lipid
2. Plasma proteins (albumin,
transport, roles in extracellular
globulins, fibrinogens, etc.) 7%–8% fluid volume, etc.
3. Ions, sugars, lipids, amino acids, 1%–2% Roles in extracellular fluid

hormones, vitamins, dissolved volume, pH, etc.
gases
Cellular Portion (40%–50% of total volume):
1. Red blood cells 4,8 – 5,400,000 Oxygen, carbon dioxide
per microliter transport
2. White blood cells:
Neutrophils 3,000–6,750 Phagocytosis during inflammation
Lymphocytes 1,000–2,700 Immune responses
Monocytes 150–720 Phagocytosis in all defense responses
(macrophages) Defense against parasitic worms
Eosinophils 100–360 Secrete substances for inflammatory
Basophils 25–90 Response and for fat removal from
blood
3. Platelets 250,000–300,000 Roles in clotting
The Cellular Components of Blood
Blood Types and
Transfusion
• Agglutination of
incompatible
blood
• Antibodies
Rh Blood Typing
• Presence or absence of Rh markers
• Erythroblastis fetalis
Human Cardiovascular System
• Heart
– Double pump
• 2 circuits
– Pulmonary
– Systemic
Systemic Circuit
for Blood Flow
• Aorta
• Arteries
• Arterioles
• Capillaries
• Venules
• Veins
Distribution of Blood
- Heart Output
Cardiovascular
system
CAROTID ARTERIES
JUGULAR
VEINS
ASCENDING AORTA
SUPERIOR
VENA CAVA PULMONARY ARTERIES
PULMONARY
VEINS CORONARY ARTERIES
HEPATIC BRACHIAL ARTERY
PORTAL VEIN
RENAL RENAL ARTERY
VEIN
INFERIOR ABDOMINAL AORTA
VENA CAVA
ILIAC ILIAC ARTERIES

VEINS
FEMORAL FEMORAL ARTERY

VEIN
Heart Structure
• Thoracic cavity
• Pericardium
• Endothelium
• Coronary
circulation
arch of aorta
superior
vena cava
(from head,
Heart Structure trunk of
upper limbs) pulmonary
arteries
right semilunar
valve (shown left semilunar
closed); to the valve (shown
pulmonary trunk closed); to aorta
right pulmonary left pulmonary

veins (from lungs) veins (from lungs)
left atrium
right atrium
right AV valve left AV valve

(shown open) (shown open)
Right ventricle Left ventricle
(muscles that endothelium

prevent valve and underlying
from everting) connective
tissue
inferior vena cava inner layer of
(from trunk, legs) pericardium
septum (partition
heart’s
between heart's
myocardium apex
two halves)
Cardiac Cycle
• Systole
• Diastole
• Closure/
Opening
of valves
Contraction of ventricles is the force for blood flow

The Cardiac Cycle
The rhythmic contraction (systole) and relaxation (diastole) of the ventricles is called the cardiac
cycle. The graphical representation below shows pressure and volume changes during the cardiac
cycle for the left-ventricle only.
Measuring Blood Pressure
Blood pressure in the major artery of the arm can be measured with a device called a
sphygmomanometer, which combines an inflatable cuff and a pressure gauge. A
stethoscope is also used to detect sounds created by the blood vessels in response
to changes in pressure during the cardiac cycle.
Cardiac Conducting System
The Heartbeat
Structure of Blood Vessels
Blood Pressure
• Rate of Flow
– Pressure gradient
– Resistance
• Contraction of Ventricle
• Flow
– High pressure area to low pressure area
Control of Flow
• Nervous and Endocrine
• Blood vessel diameter
– Vasodilation
– Vasoconstriction
• Baroreceptors
– Carotid arteries and aortic arch
• Medulla oblongata
• Chemoreceptors
• Kidneys (long-term)
Capillary Function
• Diffusion
• Fluid pressure
• Concentration gradients
• Interstitial fluid
– Net capillary movement
Capillary Types
a. Continuous (fat, muscle,

nervous system) b. Fenestrated
(intestinal villi,
endocrine glands,
kidney glomeruli)
c. Discontinuous (liver,
spleen, bone marrow)
Bulk Flow in a Capillary Bed
Comparison between area, velocity and pressure
in the vessels
Starling’s Forces
Starling’s model explains

how blood volume is
maintained in the
capillary beds.
(a) When blood pressure
is greater than the
colloidal osmotic
pressure, water leaves
the capillary; when blood
pressure falls below this
osmotic pressure, water
returns to the capillary.
(b) The balance of these
two forces changes over
the capillary bed as
blood pressure falls.
Correction to Starling’s model
• During strenuous exercise, the blood pressure in the arterioles

serving the muscles rises substantially, yet edema does not
occur. In birds, the blood pressure in arterioles is much higher
than in mammals, and the colloidal osmotic pressure is lower.
If edema is not a chronic problem in exercising muscles and
in birds, what is missing from Starling’s model?
– CO2 dan HCO3-
The EXPLANATION
When a person is at rest, the increasing HCO3– concentration can
cause the osmotic pressure of the blood at the venous end to
be 30 mm Hg higher than at the arterial end, and during
strenuous exercise this difference can be hundreds of mm Hg.
Thus it appears that CO2 and HCO3– are the major factors that
pull water back into the capillaries, not colloidal osmotic
pressure.
Flowing back
Venous Pressure
• Veins
– Large diameter
– Low resistance
– Valves
– Blood Reservoir
• 50 - 60% or
total blood
volume
Clotting
Control and Regulation of Circulation
The circulatory
system is controlled
and regulated by
neuronal and
hormonal
mechanisms at both
the local and
systemic levels.
Regulating blood pressure and volume
(and maintaining Na+, K+, H+ levels in the blood)
Cardiovascular Disorders
Coronary bypass
• Hypertension
• Atherosclerosis
• Thrombus
• Embolus
• Angina pectoris
Electrocardiogram
• Arrythmias : a
problem with the rate
or rhythm of the
heartbeat
– Bradycardia
– Tachycardia
– Ventricular
fibrillation
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Circulatory System

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Circulatory System

Birds and mamals?

3. Ions, sugars, lipids, amino acids, 1%–2% Roles in extracellular fluid

ILIAC ILIAC ARTERIES

FEMORAL FEMORAL ARTERY

right pulmonary left pulmonary

right AV valve left AV valve

Right ventricle Left ventricle

(muscles that endothelium

Contraction of ventricles is the force for blood flow

a. Continuous (fat, muscle,

Starling’s model explains

• During strenuous exercise, the blood pressure in the arterioles

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