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I. Circulatory System Notes
1. Major Blood vessels
Label the following blood vessels on
the diagram below: 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
2. Route of
Blood Through the Heart and Lungs
-deoxygenated blood returning to the heart from the body enters the right atrium
(auricle) of the heart through 2 large veins. The Posterior (inferior) vena cava
(brings blood back from the body) and the Anterior (superior) vena cava (brings
blood back from the head).
-this blood first travels to the right ventricle through an atrioventricular
valve (A-V valve) and is then sent to the lungs to be reoxygenated. It first
travels through a semilunar valve which separates the right ventricle and the
pulmonary artery. The circulation of blood between the lungs and heart is called
the pulmonary circuit.
-oxygenated blood returning from the lungs enters the left atrium of the heart
through the pulmonary vein, travels through another A-V valve into the left
ventricle and leaves the heart to enter the body through another semilunar valve
which separates the left ventricle and the aorta. The Chordae Tendinae prevent
the valves from inverting (turning inside out) when they shut. The blood will
now circulate through the body and back into the heart again through the vena
cavas. This circulation of blood through the body to meet the needs of the
tissues is called the systemic circuit.
Be able to label the chambers, blood
vessels, septa, chordae tendinae, and valves in the 2 diagrams of the heart
below
W = posterior vena cava X =
anterior vena cava Y = Aorta Z = pulmonary artery
3. Control of the Heartbeat
-the heart is controlled by a pacemaker called the Sino-atrial node (S-A node)
.(it is found in wall of the right atrium where the vena cavas enter.) It sends
a nerve impulse that causes the atria to contract. The impulse is carried to the
atrioventricular node (A-V node) (located in the base of the right atrium.) The
A-V node delays the ventricle beat until the atrial beat is complete and then
sends the impulse to the purkinje fibers which cause the ventricles to contract.
In this way the atria beat finishes before the ventricle beat begins. When the
heart is in a relaxed state it is called diastole and in a contracted state it
is called systole.
4. Factors Which
Regulated Blood Pressure
i. Arteries and veins - Since the arteries are closer to the
heart, blood pressure is higher in the arteries than in the veins. The elastic
structure of the arteries and the subsequent expansion and contraction
contribute to increased blood pressure.
ii. ADH - This hormone is released from the posterior pituitary
when the osmotic pressure (amount of solute or salt is high. The blood is
concentrated...) of the body fluids or blood is high. This causes the collecting
duct and distal tubule of the kidney to reabsorb water increasing the volume of
body fluids to dilute the blood, therefore increasing blood pressure.
iii. Angiotensin - The juxtaglomerular apparatus senses a drop in
blood pressure and releases rennin. Rennin catalyzes the conversion of
Angiotensinogen to Angiotensin. Angiotensin stimulates the release of
Aldosterone from the Adrenal Cortex which causes the kidney to reabsorb sodium
into the blood. The reabsorption of sodium increases the osmotic pressure of the
blood (makes the blood more concentrated) and causes water to move by osmosis
back into the blood from the body tissues. ADH is also secreted which causes
further reabsorption of water. Reabsorption of water increases the blood
volume, which increases blood pressure.
iv. Carotid arteries and
stretch receptors l - increased blood pressure will cause the pressure
receptors in the carotids to send a signal to the medulla of the brain. The
medulla will either, slow the heart rate down, which decreases the amount of
blood pumped into the system, which reduces the volume of fluid, causing a
reduction in blood pressure, or it will cause the blood vessels to dilate (get
bigger in diameter) also reducing the pressure.
v. Nervous system -
i. Sympathetic system
(adrenalin) will increase heart rate, which increases amount of blood pumped and
increases pressure. It also constricts the lumen (size of the diameter) of the
arteries increasing blood pressure.
ii. Parasympathetic system
(acetylcholine) will decrease the heart rate and amount of blood pumped reducing
the pressure. It also dilates the lumen of the arteries decreasing blood
pressure
5. Nervous Control of the Heart
i. Sympathetic system - increases the rate and strength of the heart
beat and constricts the lumen of the arteries increasing blood pressure.
ii. Parasympathetic system - decreases the rate and weakens the strength
of the heart beat and dilates the lumen of the arteries decreasing blood
pressure
6. Structure of the Blood
vessels
i. Arteries - are blood vessels that carry blood away from the
heart. They are composed of three layers. (1) an outer layer of connective
tissue, containing elastic fibers which give the arteries their characteristic
elasticity; (2) a middle layer of smooth muscle which can regulate the size of
the arterial lumen (opening); and (3) an inner layer of connective tissue lined
with endothelial cells. Arterioles are smaller versions of arteries
ii. Veins - are blood vessels that carry blood towards the heart.
The walls of veins are thinner and the lumens larger than those of arteries. The
same three layers are present but the outer layer has fewer elastic fibers and
the middle layer of smooth muscle is much thinner. The walls of the veins are
therefore much less rigid and easily change shape when the muscles press against
them. Veins also have valves which prevent backflow and maintain the direction
of blood flow to the heart. Venules are smaller versions of veins. Look
a the diagram of a vein shown below. Notice the valve. Blood flows in the
direction the valve is pointing
iii. Capillaries - are blood vessels that connect the arteries and
veins. (1) They are thin walled, (one endothelial cell layer thick) which
permits rapid diffusion of substances through the capillary membrane. (2)They
are extensively branched, which increases the cross sectional area of the
capillary system, which causes the blood to slow down allowing more time for the
exchange process to occur. (3) They have a very small diameter which provides
friction which increases the resistance of flow. This causes the blood pressure
to drop in the capillaries which allows easier passage of materials between the
tissues and the blood.
7. Fetal and Adult Circulation
Since the fetal lungs do not function to exchange gases, and oxygentated
blood is obtained from the mother, there are some significant differences in the
circulatory system of adults and the fetus. The following structures (In order
from the mother to the fetus) are present in the fetus but not in the adult:
i. The venous duct - This structure connects the umbilical veins,
that lead from the placenta, with the vena cava of the fetus. Oxygen diffuses
across the placenta into the blood of the umbilical veins, the blood then
travels through the venous duct, into the vena cava, and mixes with the fetus'
deoxygentated blood.
ii. The oval opening - it is an opening between the right and left
atria, that allows blood from both sides of the heart to mix. Normally
deoxgenated blood enters the right atrium via the anterior or posterior vena
cava but since the fetus receives oxygentated blood from the mother, the right
atrium contains mixed blood. There is no need for the blood to go to the lungs
to be oxygenated therefore the oval opening allows blood to enter the pulmonary
circulation directly.
iii. The arterial duct - Blood leaving the right ventricle
normally goes through the the pulmonary artery to the lungs.The arterial duct is
a connection between the pulmonary artery and the aorta so blood can bypass the
non-functioning fetal lungs.
iv. The Umbilical arteries and veins - These vessels carry wastes
and oxygen to and from the placenta. The arteries carry wastes and CO2 to the
placenta the veins carry oxygen from the placenta
Identify the parts
listed above in the diagram of the fetus below
II.
Blood and Lymph system
1. Major components of blood -made up of the following things:
a. Plasma - Blood cells are suspended in the plasma. Plasma
makes up 55% of the blood. Made up mostly of water (90%) it carries a number of
important things like:
i. Fibrinogen - plasma proteins made in the liver involved in
blood clotting
ii. Gammaglobulins - plasma proteins made in the liver involved in
fighting infections (immunoglobulins = antibodies)
iii. Albumin -plasma proteins that maintain the high
osmotic potential of the plasma preventing loss of fluid from the bloodstream to
the tissues
iv. Angiotensinogen - Involved in reabsorption of sodium and
control of blood volume and blood pressure
v. Nutrients -(glucose, fats and amino acids)
vi. Gases - oxygen and carbon dioxide
vii. Miscellaneous substances - various ions, hormones, and
waste materials (eg. urea and ammonia.)
b.) Blood cells - make up 45% of the blood and consists of the
following:
i. Red blood cells - Red blood cells, also called erythrocytes,
transport oxygen. They are biconcave, (See diagram in text), live for 120 days
and are produced in the red bone marrow of adults at the rate of about 1.5
million per second. As the blood cells mature they extrude their entire cell
contents. (all the cell organelles) and use the increased area to carry
hemoglobin. (hemoglobin carries oxygen in red blood cells).
A diagram and an electron
micrograph of red blood cells
 
ii. White blood cells - white blood cells defend the body against
viruses, bacteria, and other foreign invaders. They do this by engulfing
invaders or by producing antibodies. There are 6000 to 9000 white blood cells
per cc. of blood. Notice that the white blood cells in the diagram have nuclei
There are two different kinds of
white cells:
Neutrophils - make up 60-70% of the white cells, produced in the
red bone marrow, arrive at the site of an injury, first, are very active in
phagocytosis and play a role in wound healing.
Lymphocytes - two kinds of lymphocytes. B cells are produced in
the lymph nodes and are involve in antibody synthesis. T cells originate in the
thymus and are involved in rejection of foreign tissue (organ transplants) and
other immune responses.
iii. Platelets - look like plates, are colorless, round or
biconcave, are smaller than red blood cells, play important roles in blood
clotting and are produced in the bone marrow.
2. Lymph system - Fluid is forced out of the capillaries by blood
pressure. Some of the fluid is returned to the capillaries by osmosis the rest
is collected and returned by the lymph system. This system is similar to the
venous system (the vessels are thin walled and have valves) except the vessels
end blindly in the tissues. Right lymphatic duct empties into the right
subclavian vein and the thoracic duct empties into the left subclavian vein.
Lacteals are blind ends of lymph vessels. As the lymph system circulates it
passes through lymph nodes. These nodes are found in clusters in the groin,
armpits, and neck. They have 2 functions; they manufacture B cells, and remove
foreign particles from the lymph. The lymph nodes also contain leukocytes to
attack bacteria and foreign invaders.
b. Organs of the lymph system -
i. Spleen - manufactures lymphocytes, takes out defective or
damaged red blood cells, removes iron from the hemoglobin and recycles it to the
bone marrow.
ii.Thymus - produces T cell type lymphocytes.
3. Capillary Fluid Exchange-
Exchange of materials at the tissue capillaries
a. Arteriole side of capillary bed - blood pressure higher
than osmotic pressure
-blood from arterioles enters capillary beds of various tissues. The blood is
carrying oxygen (on the hemoglobin of Red Blood Cells) and nutrients like amino
acids and glucose in the plasma.
-on the arteriole side of the capillary bed the blood pressure is higher than
the osmotic pressure.
-the higher blood pressure pushes fluid containing oxygen, water and nutrients
(amino acids and glucose) into the tissues.
-as the blood flows into the capillary bed it slows down. This provides time for
the fluid containing oxygen and nutrients to be pushed out of the capillaries by
blood pressure and for the nutrients and oxygen to diffuse into the tissue
cells.
-Large molecules like red blood cells and plasma proteins, cannot cross into the
tissues. This fluid in the tissues or tissue fluid has all the components of
plasma except for proteins.
b. Midsection of capillary bed
- diffusion of material into the cells
-Materials move into the cell by diffusion eg: high concentrations in tissue
fluid move to low concentrations in the cell and vice versa. For example:
- Oxygen diffuses into the cell from the tissue fluid, cell respiration uses the
oxygen and produces carbon dioxide and water which diffuse out of the tissues,
into the tissue fluid and eventually into the capillary bed.
- Amino acids diffuse into the cell and are broken down producing amino groups.
These amino groups are converted into ammonia which also diffuses out of the
cell, into the tissue fluid and then into a capillary bed.
c. Venule side of capillary bed - blood pressure lower than
osmotic pressure
-blood pressure is much reduce and is lower than osmotic pressure. As a result
osmotic pressure (The force that causes the flow from a high concentration to a
low concentration) fluid is forced back into the capillary.
-this bring additional amounts of waste materials (carbon dioxide and ammonia)
Circulatory System Quiz Questions
1. What is the name of the heart chamber that:
a. receives blood returning from the
body b. receives blood returning from the lungs
c. pumps blood to the body d. pumps blood to the
lungs
3. What is the name of the blood
vessel that carries blood from the:
a. body to the Right atrium b.
head to the Right atrium c. Right Ventricle to the lungs
d. Left Ventricle to the body e.
lungs to the Left atrium f. intestines to Inferior Vena Cava
g. aorta to the kidneys
h. kidneys to Posterior Vena Cava i. aorta to the arms
j. aorta to the
head k. arms to the Anterior Vena Cava l. head to Anterio
Vena Cava
m. intestines to
liver n. liver to Inferior Vena Cava o. from
aorta to legs
p. aorta to heart muscle
q. legs to posterior Vena Cava r. heart muscle back to heart
s. aorta to the intestines
4. What is the definition of: a. systole? b. diastole?
5. What is the name of the valve between the atria and ventricles
6. What is the name of the valve between the heart chambers and blood vessels
7. What is the definition of a. systemic circulatory system b.
pulmonary circulatory system
8. What is the definition of a. artery b. vein c.
arteriole d. venule e. capillary
9. Name any 4 structures that found in the circulatory system of a fetus but not
in the adult and describe their function.
10. What is the name of the vessels that provide oxygen to heart tissue
11. What is the name of the vessels that carry blood intestines to the liver
12. Be able to identify the parts of the heart from a diagram
13. What is the name of the tissue that lines the inside of a blood vessel
14. The general name for vessels that carry blood away heart
15. What chemical causes blood vessels to constrict
16. What is the name of the structure that divides into the right and left
pulmonary arteries
17. What is the function of the Chordae tendinae
18. What structure controls the beating of the a. atria b. ventricles
19. What is the function of the Purkinje fibers
III.
Blood Quiz Questions
1. What is the function of platelets
2. What is the function of neutrophils
3. What is the function of red blood cells (RBC)
4. Name two kinds of lymphocytes and their functions
5. Name the 3 kinds of plasma proteins and their functions
6. What is another name for red blood cell
7. Where are red blood cells produced
8. Name two locations where are lymphocytes produced
9. Where are neutrophils produced
10. What is the function of lymph nodes
11. Where are red blood cells produced
12. Name the function and the shape of the following blood cells: a. red blood
cells. b. lymphocytes c. neutrophils d. eosinophils e. basophils
f. monocytes
13. Name two organs of the lymph system and their functions
14. What is the definition of antigens and antibodies.
15. What does an antibody do to an antigen
16. Name 3 components of plasma and describe their functions
17. Name the substances which make up blood
18. What shape do platelets have
IV. Circulatory System Subjective Questions
1. A person receives a severe cut in a traffic accident and is losing
blood quickly. Outline all the things that would occur in the body to compensate
for the the drop in blood presssure.
2. Name any two factors which
regulate blood pressure and describe how they function to accomplish this.
3. Explain how the following would respond to an decrease in blood pressure.
a. The autonomic nervous system
b. Aldosterone concentration in the
blood
c. Antidiuretic hormone (ADH)
4. Outline the role each of the
following plays in maintaining the heartbeat:
a.) the sinoatrial node
b.) the atrioventricular node
5. List 3 functions of the lymph
system
6. Describe the difference between
hypertension and hypotension
7. Starting at the vena cava and
ending at the aorta, name all the structures, vessels and heart chambers, in
order, that deoxygenated blood would contact as it travels through the heart on
its way to be reoxygenated, and once it has been oxygenated, the path through
the heart again on its way back into the body.
(1 mark for order, 1/2 mark per structure, 6 marks total)
VENA CAVA, __________, __________, __________, __________, __________, LUNGS
__________, __________, __________, __________, __________, AORTA
8. Explain how each of the following makes the fetal circulatory system
different from the adult circulatory system.
a.) oval opening
b.) venous duct
c.) arterial duct
d.) umbilical arteries and veins
9. Choose any two structures found in the fetal circulation but not in the adult
circulation and explain the functions of these structures.
10. List 2 functions of lymph nodes
11. Relate the structure of arteries
and veins to their functions:
a. Arteries
b. Veins
12. List any two characteristics of
the:
a. pulmonary system
b. systemic system
V. BLOOD SUBJECTIVE QUESTIONS
1. Relate the components of blood to their functions
2. What structure filters out foreign particles in the lymph
3. Describe capillary-tissue fluid exchange
4. Describe the conditions that facilitate the exchange of materials between the
capillaries and the tissues
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