Part 2
The
Circulatory
System
Review from last class
Blood Vessels - Arteries
• Arteries
–
, elastic walls to
withstand
blood pressure
generated during contraction of
– large diameter to reduce resistance
to
– Do not have valves since the heart
give them enough
to
send blood through the
• Arterioles
–
walls and smaller diameter
than arteries therefore cannot
withstand as much
–
blood flow through
some organs by
smooth muscle to reduce blood
flowing into
Blood Vessels - Veins
• Veins
– blood pressure
in
veins
have
thinner, more flexible walls
than arteries &
– blood
too low in
veins to push blood flow
therefore
of skeletal
muscle to squeezes veins
needed to force blood
through
–
are found in veins
that carry blood
the
force of gravity
Blood Vessels - Capillaries
Capillaries
• cannot withstand significant
blood pressure therefore
must reduce
in arteries to lower blood
pressure by having numerous
capillaries
• extensive capillary network
provides large
Capillary Exchange
• Low blood velocity provides more time for diffusion across
capillary walls
• Capillary exchange takes place due to the following forces:
– blood pressure:
pressure higher in blood than tissues,
which drives
from blood plasma into tissue fluid
– osmotic pressure: solute
higher in tissues than blood,
which drives substances from
fluid to
plasma
Capillary Exchange
1.
2.
blood pressure greater than osmotic pressure at arteriole end, which
drives
,
,
,
acids, ions, & hormones from
blood plasma into tissue fluid & then into cells, while larger substances
remain in blood plasma, e.g. red blood cells,
,&
osmotic pressure greater than blood pressure at venule end, which
drives
,
, & some H2O from tissue fluid into blood
The Body
Systemic Circulation
Circuits
• Pulmonary Circulation
– carries deoxygenated blood from
right ventricle to lungs &
oxygenated blood from lungs to
left atrium of heart, i.e. pathways
between heart & lungs
• Systemic Circulation
– carries oxygenated blood from left
ventricle through body &
deoxygenated blood from body to
right atrium of heart, i.e. pathways
between heart & body
NOTE: volume of blood entering/exiting
pulmonary circulation always equal to volume of
blood exiting/entering systemic circulation
Major Arteries
and Veins
•
•
•
•
•
•
•
•
•
•
•
•
Subclavian arteries and veins
Jugular veins
Carotid arteries
Mesenteric arteries
Anterior and posterior vena
cava
Pulmonary veins and arteries
Hepatic vein
Hepatic portal vein
Renal arteries and veins
Iliac arteries and veins
Coronary arteries and veins
aorta
Branches of the aorta
• Subclavian arteries:
–
artery
blood to the left arm
–
artery
blood to right arm, with
a branch to the
• Carotid artery
– Supplies
to the
head and neck
• The
vein
draws
blood from the arms
into the
vena
cava
• The jugular vein draws
blood
from the
and
neck into the superior
Mesenteric
• Mesenteric artery
– Major artery that branches
from the
aorta and supplies the
small intestine, large
, and pancreas
with
blood
• Mesenteric vein
– Carries
blood from the same
organs into the
vena cava
• Hepatic portal vein
– It receives blood from the
stomach,
, large
intestine, pancreas, spleen
and
through the
inferior mesenteric, gastric,
and cystic veins. It carries the
blood received from all these
parts of the body to the
.
– The blood that is brought to
the liver by the hepatic portal
vein is
by the
liver
• Hepatic vein
– Drains cleaned and
blood from
the liver into the inferior vena
cava
Renal
• Renal arteries
– Branch from the
– Supply kidneys with
• Renal veins
– Drain
blood from the kidneys
into the
vena
cava
Iliac
• Iliac arteries
– Branches from the
and carries
blood to the legs and
feet
• Iliac veins
– Drains
blood into the inferior
vena cava
Summary
Lymphatic System
Functions
1. Returns
fluids
from
to
blood, i.e. prevents
in tissues
2. Transports fats from
to
blood
3. Defends body
disease caused by
invaders
• When blood flows through
capillaries, the molecules that
are
out for tissue cells
to absorb are know as
• Interstitial fluid is composed of
acids,
,
fatty acids, coenzymes,
hormones, neurotransmitters,
salts, as well as waste products
from the
• Not all interstitial fluid will be
absorbed by
, and so
lymph capillaries, which
surround blood capillaries,
absorb this fluid, now known as
• lymph capillaries: narrow, thin–walled vessels
that collect
fluid from tissues
• lymph: fluid within lymphatic system, i.e. fluid
that enters through
capillaries
• lymphatic veins: collects
lymph from capillaries
and
fluid to blood
through veins in neck
(right of left
vein)
– contraction of skeletal
muscle moves lymph
therefore require one–way
to move lymph in
one direction, i.e. similar to
veins in
system
• lymph nodes: filters
lymph and produce
white blood
cells that destroy
invaders in
lymph
– located along lymphatic
veins
Fetal Circulation
Features of Fetal Circulation
•
Nutrients and waste are exchanged through
the
–
•
Pulmonary circulation not required because
fetus receives oxygenated blood from
mother
–
•
1.
2.
3.
Fetus receives O2 and nutrients from mother
through
, while CO2 and
waste from fetus removed by mother through
Fetus does not use its lungs for gas exchange
Structures required to bypass pulmonary
circuit:
: connects right and left
atria, which reduces blood flow into right
ventricle
: connects pulmonary
trunk to aorta, which reduces blood flow
into pulmonary arteries
: connects umbilical vein
at liver to posterior vena cava, which
reduces blood flow through liver
By the End of this Section you should
be able to:
• identify and give functions (including where blood is coming from
and going to, as applicable) for each of the following:
– left and right atria
– left and right ventricles
– coronary arteries and veins
– anterior and posterior vena cava
– aorta
– pulmonary arteries and veins
– pulmonary trunk
– atrioventricular valves
– chordae tendineae
– semi-lunar valves
– septum
• recognize heart structures using both internal and external diagram
views
• describe the location and functions of the
sinoatrial (SA) node, atrioventricular (AV) node,
and Purkinje fibres
• describe how the autonomic nervous system
increases and decreases heart rate and blood
pressure
• differentiate between systolic and diastolic
pressures
• describe hypertension and hypotension and their
causes
•
identify and give the function (including where the vessel is carrying blood from
and where it is carrying blood to) of each of the following:
– subclavian arteries and veins
– jugular veins
– carotid arteries
– mesenteric arteries
– anterior and posterior vena cava
– pulmonary veins and arteries
– hepatic vein
– hepatic portal vein
– renal arteries and veins
– iliac arteries and veins
– coronary arteries and veins
– aorta
•
describe and differentiate among the five types of blood vessels with reference to
characteristics such as
– structure and thickness of vessel walls
– presence of valves
– direction of blood flow (toward or away from the heart)
• differentiate between pulmonary and systemic circulation
with respect to oxygenation or deoxygenation of blood in
the vessels involved
• demonstrate a knowledge of the path of a blood cell from
the aorta through the body and back to the left ventricle
• relate blood pressure and blood velocity to the total crosssectional area of the five types of blood vessels
• describe capillary-tissue fluid exchange
• identify and describe differences in structure and
circulation between fetal and adult systems, with reference
to umbilical vein and arteries, oval opening, venous duct,
arterial duct
• describe the shape, function, and origin of red
blood cells, white blood cells, and platelets
• list the major components of plasma
• explain the roles of antigens and antibodies
describe the functions of the lymphatic
system
• identify and give functions of lymph
capillaries, veins, and nodes
Mandatory Vocabulary
anterior vena cava, antibody, antigen, aorta, arterial duct
atrioventricular valve, autonomic nervous system, atrioventricular (AV)
node, blood, blood pressure, blood velocity, blood vessel, capillarytissue fluid exchange, carotid artery, chordae tendineae, coronary
artery, coronary vein, diastolic pressure, fetal circulation, heart rate,
hepatic portal vein, hepatic vein, hypertension, hypotension, iliac
artery, iliac vein, jugular vein, left atrium, left ventricle, lymph
capillaries, lymph node, lymphatic system, lymphatic veins, mesenteric
artery, oval opening, plasma, platelets, posterior vena cava, pulmonary
arteries, pulmonary circulation, pulmonary trunk, pulmonary veins,
Purkinje fibres, red blood cell, renal artery, renal vein, right atrium,
right ventricle, sinoatrial (SA) node, semi-lunar valve, septum,
subclavian artery, subclavian vein, systemic circulation, systolic
pressure, total cross-sectional area, umbilical artery, umbilical vein,
valve, veins, venous duct, vessel wall, white blood cell