Blood Vessels: The Vascular System

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The Cardiovascular System Part 2
Blood Vessels: The Vascular System

Taking blood to the tissues and
back
o Arteries
o Arterioles
o Capillaries
o Venules
o Veins
The Vascular System

Vessels have 3 layers or tunics
Differences Between Blood Vessel Types

Walls of arteries are the ________________

Lumens of veins are ________________


Larger veins have ______________ that prevent backflow of blood
___________________ muscle “milks” blood in veins toward the heart

Walls of capillaries are only ___________________ layer thick to allow for exchanges
between blood and tissue
Movement of Blood Through Vessels

Most _____________ blood is pumped by the heart

____________ use the milking action of muscles to
help move blood
Capillary Exchange

Substances exchanged due to ________________
_____________________
o ____________ and _______________ leave
the blood
o _______________________ and other
wastes leave the cells
Capillary Exchange: Mechanisms

Direct ______________ across plasma membranes

______cytosis or _____cytosis

Some capillaries have _______ (intercellular clefts)
o Plasma membrane not joined by tight
junctions

Fenestrations of some capillaries
o Fenestrations = __________
Diffusion at Capillary Beds
Special Circulations: Hepatic Portal Circulation

Veins of the _______________ portal circulation drain the digestive organs, spleen and
pancreas and deliver this blood to the liver via _________________________________

Liver processes _____________, ________ and ____________ before they enter the
systemic circulation

Some nutrients are removed to be ______________ for later release to the blood

_____________ feed the liver circulation
Special Circulations: Circulation to the Fetus

Lungs and digestive system are ________ functional

All nutrient, excretory and gas exchanges occur through the ________________

Umbilical cord contains ____ blood vessels
o ____ large umbilical __________

Carries nutrients and ________________ the fetus
o ____ smaller umbilical ______________


Carries ____________________ and __________ from fetus to placenta
As blood flows to the fetal heart, most of it ____________ the _____________________
via the ductus venosus and enters the inferior vena cava and is carried to the right atrium

Since _______________________________________, 2 shunts bypass them
o Blood entering right atrium is shunted into the left atrium via _______________
_________________, an opening in the interatrial septum
o Blood that enters the right ventricle is pumped out the pulmonary trunk and
shunted into the ductus arteriosus, which connects it to the aorta

_________________ carries blood to fetal tissues and ultimately back to the placenta via
the umbilical arteries

Shortly after birth, the foramen ovale closes and the ductus arteriosus collapses and is
converted to the ______________________________________________
Developmental Aspects of the Cardiovascular System

A simple “tube heart” develops in the embryo and pumps by the ______________ week

The heart becomes a ____________________________ organ by the end of _________
weeks

Few structural changes occur after the seventh week
Pulse

Pulse – pressure ___________ of blood

Monitored at “_______________________________” where pulse is easily palpated

Resting pulse averages ______________ beats/min
Blood Pressure

Measurements by health professionals are made on the pressure in large arteries
o Systolic – pressure at the peak of ventricular _____________________
o Diastolic – pressure when ventricles ______________

Pressure in blood vessels ___________ as the distance away from the heart ___________
Measuring Arterial Blood Pressure
Comparison of Blood Pressures in Different Vessels
Blood Pressure: Effects of Factors

Neural factors
o Autonomic nervous system adjustments (sympathetic division) cause
____________________________, which ______________________ BP

Renal factors
o Regulation by altering blood _________________

Allowing more water to leave as urine, __________________ BP
 Retaining water ____________________ BP
o _______________ – hormonal control - _______________ BP (vasoconstriction)

Temperature
o Heat has a _____________________________ effect
o Cold has a _____________________________ effect

Chemicals
o Various substances can cause increases or decreases


_______________ BP – epinephrine and nicotine

_______________ BP – alcohol and histamine
Diet
Factors Determining Blood Pressure
Variations in Blood Pressure

Human normal range is variable
o Normal

140–110 mm Hg ________________

80–75 mm Hg ________________
o ______tension (low BP)

________ systolic (below 100 mm HG)

Often associated with long life and an old age free of illness

Chronic hypotension may hint at poor ________________
o _______tension

___________ systolic (above 140 mm HG)

Can be dangerous if it is _____________
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