The complete presentation of the Cardiovascular System for Biology 12

2. 13-3

3. ! Arteries (and arterioles) take blood away from
the heart.
! Artery walls contain smooth muscle that are
able to constrict.
" Regulates blood flow
" Regulates blood pressure
! Arterioles can also constrict to regulate blood
pressure.

5. X Capillaries have walls only one cell thick to
allow exchange of gases and nutrients with
tissue fluid.
X Capillary beds are present in all regions of
the body but not all capillary beds are open
at the same time.
X Contraction of a sphincter muscle closes off
a bed and blood can flow through an
arteriovenous shunt that bypasses the
capillary bed.

7. X Venules drain blood from capillaries, then
join to form veins that take blood to the
heart.
X Veins have much less smooth muscle and
connective tissue than arteries.
X Veins often have valves that prevent the
backward flow of blood when closed.
X Veins carry about 70% of the body’s blood
and act as a reservoir during hemorrhage.

8. X The heart is a cone-shaped, muscular organ
located between the lungs behind the
sternum.
X The heart muscle forms the myocardium, with
tightly interconnect cells of cardiac muscle
tissue.
X The pericardium is the outer membranous
sac with lubricating fluid.

12. X The heart has four chambers: two upper, thin-
walled atria, and two lower, thick-walled
ventricles.
X The septum is a wall dividing the right and left
sides.
X Atrioventricular valves occur between the atria
and ventricles – the tricuspid valve on the right
and the bicuspid valve on the left; both valves
are reinforced by chordae tendinae attached to
muscular projections within the ventricles.

15. X Semilunar valves occur between the ventricles
and the attached arteries
X The aortic semilunar valve lies between the left
ventricle and the aorta
X The pulmonary semilunar valve lies between
the right ventricle and the pulmonary trunk.

17. → anterior and posterior vena cava → right atrium
→ tricuspid valve → right ventricle →
→ pulmonary semilunar valve → pulmonary trunk →
→ pulmonary veins → left atrium →
→ bicuspid valve → left ventricle →
→ aortic semilunar valve → aorta → to the body.

20. X The pumping of the heart sends out blood
under pressure to the arteries.
X Blood pressure is greatest in the aorta; the wall
of the left ventricle is thicker than that of the
right ventricle and pumps blood to the entire
body.
X Blood pressure then decreases as the cross-
sectional area of arteries and then arterioles
increases.

21. X Each heartbeat is called a cardiac cycle.
X When the heart beats, the two atria contract
together, then the two ventricles contract;
then the whole heart relaxes.
X Systole is the contraction of heart chambers;
diastole is their relaxation.
X The heart sounds, lub-dup, are due to the
closing of the atrioventricular valves, followed
by the closing of the semilunar valves.

22. 13-25

23. X The SA (sinoatrial) node, or pacemaker,
initiates the heartbeat and causes the atria to
contract on average every 0.85 seconds.
X The AV (atrioventricular) node conveys the
stimulus and initiates contraction of the
ventricles.
X The signal for the ventricles to contract travels
from the AV node through the atrioventricular
bundle to the smaller Purkinje fibers.

28. X A cardiac control center in the medulla
oblongata speeds up or slows down the
heart rate via the ANS.
X PNS – constant stimulation. Increase
stimulation decreases HR. Decrease stimulation
increases HR.
X SNS – Increased stimulation increases HR.
X Hormones epinephrine and norepinephrine
from the adrenal medulla also stimulate
faster heart rate.

29. X An electrocardiogram (ECG) is a recording of
the electrical changes that occur in the
myocardium during a cardiac cycle.
X Atrial depolarization creates the P wave,
ventricle depolarization creates the QRS
complex, and repolarization of the ventricles
produces the T wave.

30. This diagram
demonstrates the
relationship
between the
cardiac cycle
(ECG) and the
pressure within
the Aorta, L.V., and
L.A.

31. The cardiovascular system includes two circuits:
1) Pulmonary circuit which circulates blood
through the lungs, and
2) Systemic circuit which circulates blood to the
rest of the body.

33. X The pulmonary circuit begins with the
pulmonary trunk from the right ventricle
which branches into two pulmonary arteries
that take oxygen-poor blood to the lungs.
X In the lungs, oxygen diffuses into the blood,
and carbon dioxide diffuses out of the blood
to be expelled by the lungs. (more to come
on this in the next unit)
X Four pulmonary veins return oxygen-rich
blood to the left atrium.

34. X The systemic circuit starts with the aortic
arch. The Aortic Arch begins from the left
ventricle and branches into:
X Brachiocephalic, left common carotid, left
subclavian
X The aorta then branches to arteries going to
each specific organ.
X Generally, an artery divides into arterioles
and capillaries which then lead to venules.

35. X Upper Body and Head – branch from Aortic Arch
X Subclavian – blood to the arms
X Carotid – blood to the head
X Lower Body – all branch from the Aorta
X Hepatic – blood to the liver
X Iliac – blood to the legs
X Renal – blood to the kidneys
X Mesenteric – blood to the GI tract

36. 13-39

37. X Blood flow to the Heart
X Coronary arteries serve the heart muscle.
X Part of the systemic system.
X Easily clogged
X The hepatic portal system
X Blood flow between the GI tract and the liver
X Rich in nutrients, but low in oxygen
X Allows the liver to regulate levels of certain
substances in the blood before entering the rest of
the body.

38. X Blood pressure due to the pumping of the
heart accounts for the flow of blood in the
arteries.
X Systolic pressure is high when the heart
expels the blood.
X Diastolic pressure occurs when the heart
ventricles are relaxing.
X Both pressures decrease with distance from
the left ventricle because blood enters more
and more arterioles and arteries.

39. ! Mean Arterial Pressure (MAP) is the average
blood pressure in an individual.
! Normal Range – 70-110 mmHg
! A minimum of 60 mmHg is required to sustain
organ function in the body

41. X Blood moves slowly in capillaries because of
the large x-sectional area.
X This allows time for substances to be
exchanged between the blood and tissues.

42. 1) Skeletal muscle
contraction:
Compression of
veins causes
blood to move
forward past a
valve that then
prevents it from
returning
backward.

43. 2. Valves: bicuspid valves within valves stop
backflow within veins.

44. 3. Respiratory Movements: Inspiration increases
venous return (contraction of diaphragm) and
expiration decreases return.

45. X Varicose veins develop when the valves of
veins become weak.
X Hemorrhoids (piles) are due to varicose veins
in the rectum.
X Phlebitis is inflammation of a vein and can
lead to a blood clot and possible death if the
clot is dislodged and is carried to a pulmonary
vessel.

47. X Blood separates into two main parts: plasma
and formed elements.
X Plasma accounts for 55% and formed
elements 45% of blood volume.
X Plasma contains mostly water (90–92%) and
plasma proteins (7–8%), but it also contains
nutrients and wastes.
X Albumin is a large group of plasma proteins
that transport various biologically active
molecules and helps regulate blood pressure.

49. ! Red blood cells (erythrocytes or RBC’s) are made
in the red bone marrow of the skull, ribs, vertebrae,
and the ends of long bones.
! Between 4-6 million RBC’s per mm3 of whole
blood exist.
! Hemoglobin (pigment) contains heme, an complex
iron-containing group that transports oxygen
! CO more readily bonds to hemoglobin and may
cause suffocation
! RBC’s have a 120 day lifespan and are dismantled
in the Liver and Spleen.

51. ! RBC’s lack a nucleus.
! Iron from RBC dismantle is reused.
! Lack of enough hemoglobin results in anemia.
! The kidneys produce the hormone
erythropoietin (EPO) to increase blood cell
production when oxygen levels are low.
! EPO is used as a performance enhancing drug
in endurance events.

52. ! White blood cells (leukocytes) have nuclei, are
fewer in number than RBCs, with 5,000 –
10,000 cells per mm3, and defend against
disease.
! Leukocytes are divided into granular and
agranular based on appearance.
! Granular leukocytes (neutrophils, eosinophils,
and basophils) contain enzymes and proteins
that defend the body against microbes.

53. ! The agranular leukocytes (monocytes and
lymphocytes) have a spherical or kidney-shaped
nucleus.
! Monocytes can differentiate into macrophages
that phagocytize microbes and stimulate other
cells to defend the body.
! Lymphocytes are involved in immunity.
! An excessive number of white blood cells may
indicate an infection or leukemia; HIV infection
drastically reduces the number of lymphocytes.

55. ! Red bone marrow produces large cells called
megakaryocytes that fragment into platelets at
a rate of 200 billion per day; blood contains
150,000–300,000 platelets per mm3.
! Twelve clotting factors in the blood help
platelets form blood clots.
! The liver produces fibrinogen and prothrombin,
two plasma proteins involved in the clotting
process.

56. ! Injured tissues release a clotting factor called
prothrombin activator, which converts
prothrombin into thrombin.
! Thrombin, in turn, acts as an enzyme and
converts fibrinogen into insoluble threads of
fibrin.
! These conversions require the presence of
calcium ions (Ca2+).
! Trapped red blood cells make a clot appear red.

58. ! Hemophilia is an inherited clotting disorder
due to a deficiency in a clotting factor.
! Bumps and falls cause bleeding in the joins;
cartilage degeneration and re-absorption of
bone can follow.
! The most frequent cause of death is bleeding
into the brain with accompanying neurological
damage.

59. ! A stem cell is capable of dividing into new
cells that differentiate into particular cell
types.
! Bone marrow is multipotent, able to
continually give rise to particular types of
blood cells.
! The skin and brain also have stem cells, and
mesenchymal stem cells give rise to
connective tissues including heart muscle.

61. ! At the arteriole end of a capillary. Water moves
out of the blood due to the force of blood
pressure.
! At the venule end, water moves into the blood
due to osmotic pressure of the blood.
! Substances that leave the blood contribute to
tissue fluid, the fluid between the body’s cells.
! In the midsection of the capillary, nutrients
diffuse out and wastes diffuse into the blood.

62. ! Plasma proteins remain in the blood stream
and create a concentration gradient for
osmosis to occur.
! Excess tissue fluid is returned to the blood
stream as lymph in lymphatic vessels.

65. ! Cardiovascular disease (CVD) is the leading
cause of death in Western countries.
! Modern research efforts have improved
diagnosis, treatment, and prevention.
! Major cardiovascular disorders include
atherosclerosis, stroke, heart attack, aneurysm,
and hypertension.

66. ! Atherosclerosis is due to a build-up of fatty
material (plaque), mainly cholesterol, under the
inner lining of arteries.
! The plaque can cause a thrombus (blood clot)
to form.
! The thrombus can dislodge as an embolus and
lead to thromboembolism.

68. Top sample shows the beginnings of lipid build-up.

70. ! A cerebrovascular accident, or stroke, results
when an embolus lodges in a cerebral blood
vessel or a cerebral blood vessel bursts; a
portion of the brain dies due to lack of oxygen.
! A myocardial infarction, or heart attack, occurs
when a portion of heart muscle dies due to lack
of oxygen.

71. ! Partial blockage of a coronary artery causes
angina pectoris, or chest pain.
! An aneurysm is a ballooning of a blood vessel,
usually in the abdominal aorta or arteries
leading to the brain.
! Death results if the aneurysm is in a large
vessel and the vessel bursts.
! Atherosclerosis and hypertension weaken blood
vessels over time, increasing the risk of
aneurysm.

72. Minor lipid build-up just beginning.

73. X-sectional view shows the complexity of lipid build-up.

76. ! A coronary bypass operation involves removing
a segment of another blood vessel and
replacing a clogged coronary artery.
! It may be possible to replace this surgery with
gene therapy that stimulates new blood vessels
to grow where the heart needs more blood flow.

78. ! Angioplasty uses a long tube threaded through
an arm or leg vessel to the point where the
coronary artery is blocked; inflating the tube
forces the vessel open.
! Small metal stents are expanded inside the
artery to keep it open.
! New procedure uses this idea to increase blood
flow to brain in MS patients. Controversial.

80. ! Medical treatments for dissolving blood clots
include use of t-PA (tissue plasminogen
activator) that converts plasminogen into
plasmin, an enzyme that dissolves blood clots,
but can cause brain bleeding.
! Aspirin reduces the stickiness of platelets and
reduces clot formation and lowers the risk of
heart attack.
! High doses of Aspirin can increase the risk of
internal bleeding in contact sport participants.

81. ! Heart transplants are routinely performed but
immunosuppressive drugs must be taken
thereafter.
! There is a shortage of human organ donors.
! Work is currently underway to improve self-
contained artificial hearts, and muscle cell
transplants may someday be useful.

82. ! About 20% of Americans suffer from
hypertension (high blood pressure).
! Hypertension is present when systolic pressure
is 140 or greater or diastolic pressure is 90 or
greater; diastolic pressure is emphasized when
medical treatment is considered.
! A genetic predisposition for hypertension
occurs in those who have a gene that codes for
angiotensinogen, a powerful vasoconstrictor.

83. 13-88
Specialized vessels deliver blood from heart to
capillaries, where exchange of substances takes
place; another series of vessels delivers blood
from capillaries back to heart.
The human heart is a double pump: the right side
pumps blood to the lungs, and the left side
pumps blood to the rest of body.

84. 13-89
Pulmonary arteries transport blood low in
oxygen to lungs; pulmonary veins return blood
high in oxygen to the heart.
Systemic circulation transports blood from the
left ventricle of the heart to the body and then
returns it to the right atrium of the heart.
Blood is composed of cells and a fluid
containing proteins and various other
molecules and ions.

85. 13-90
Blood clotting is a series of reactions; a clot
forms when fibrin threads entrap red blood
cells.
Nutrients pass from blood and tissue fluid
across capillary walls to cells; wastes move the
opposite direction.
The cardiovascular system is efficient but it is
still subject to degenerative disorders.