2. • OPPORTUNITY IS MISSED BY MOST PEOPLE BECAUSE IT IS DRESSED IN
OVERALLS AND LOOKS LIKE WORK.
• THOMAS A. EDISON
3. • 2 The cardiovascular system
• (a) The structure and function of arteries, capillaries
and veins to include endothelium, central lumen,
connective tissue, elastic fibres, smooth muscle and
valves. The role of vasoconstriction and vasodilation
in controlling blood flow.
6. What is the Cardiovascular system?
• The cardiovascular system, also known
as the circulatory system, is composed
of blood, blood vessels and the heart.
• The heart functions as a pump to
move blood through the blood vessels
of the body.
• A circulatory system is essential for
large, multi-cellular organisms, such as
humans and animals, and provide at
least five major functions that are
necessary for life.
7.
8.
9. The five major functions of the cardiovascular
system are:
• Transporting oxygen and removing
carbon dioxide
• Transporting nutrients and removing
wastes
• Fighting disease
• Transporting hormones
• Regulating body temperature
13. Blood vessels
A layer of cells called the endothelium lines the
central lumen of all blood vessels. It is surrounded by
layers of tissue. These surrounding layers differ in
each type of blood vessel.
The middle of the vessel is called the central lumen.
15. Arteries
• Arteries carry blood away from the heart. The further the blood
travels away from the heart, the lower the blood pressure gets.
• They have an outer layer of connective tissue containing elastic
fibres and a middle layer containing smooth muscle with more elastic
fibres. The elastic walls of the arteries stretch and recoil to
accommodate the surge of blood after each contraction of the
heart.
• The smooth muscle can contract, called vasoconstriction. This
decreases the blood flow. It can also relax, causing vasodilation.
This increases blood flow. Movement of these muscles controls
blood flow.
16. VEINS
• Carry blood towards the
heart
• Endothelium
• Larger lumen than
arteries
• Thinner muscle layer &
few elastic fibres
• Blood at lower pressure
• Fibrous tissue
17. VEINS
• Contain valves
• Prevents backflow of
blood
• Situated between
skeletal muscles
• Muscle compresses vein
when contracted
• Blood “squirted” towards
heart
18. Veins
• Veins have an outer layer of connective tissue
containing elastic fibres but a much thinner
muscular wall than arteries. They contain
valves to prevent back flow of blood as blood
is at a lower pressure in veins than arteries.
19. CAPILLARIES
• Transport blood between
arteries and veins
• Form large networks
(capillary beds)
• Exchange of materials
between blood and cells
• Their walls are only one cell
thick, allowing nutrients and
waste to diffuse through
with ease.
22. • (i) The exchange of materials between tissue fluid and
cells through pressure filtration and the role of lymph
vessels.
• Similarity of tissue fluid and blood plasma with the
exception of plasma proteins.
26. Plasma Tissue fluid
Protein e.g. red blood cells No protein
Oxygen and carbon dioxide Oxygen and carbon dioxide
glucose, amino acids glucose, amino acids
water water
Comparison of contents of plasma and tissue fluid
27. Tissue fluid
• Dissolved substances move out through the
capillary walls by pressure filtration, forming
tissue fluid. Tissue fluid is similar to blood
plasma except it does not contain plasma
proteins e.g. red blood cells. Tissue fluid
surrounds cells and supplies them with glucose,
amino acids, oxygen and other useful
substances. Carbon dioxide and other
metabolic waste (waste produced by chemical
reactions in the cell) diffuse out of the cells
and into the tissue fluid to be excreted.
28. Blood
arriving in
the arteriole
high
pressure
Blood
leaving in
venule
low
pressure
Lymph
vessel
capillary
Respiring cell
Tissue fluid
Some tissue
fluid enters
lymphatic
system
Some plasma
forced out of
capillary
Some tissue fluid
enters capillary
by osmosis
Lymph passes
into lymphatic
system
Summary Tissue Fluid and
Lymphatic System
29. • Case study on disorders of the lymphatic system. Suitable examples
include the effect of kwashiorkor on fluid balance and elephantiasis.
30. Lymphatic system
• Excess tissue fluid is absorbed by lymphatic
vessels which are found around cells in each
tissue, forming lymph fluid. The lymph fluid
eventually returns to the blood.
31. • (b) The structure and function of the heart.
• (i) Cardiac function and cardiac output.
• Definition of cardiac output and its calculation.
33. Heart Rate (HR)
• Number of times heart beats in one minute
• Normal values around 72bpm
• Normal range is between 60-90
34. Stroke Volume (SV)
• Volume of blood ejected by each ventricle during
contraction
• The heart pumps the same volume of blood through
the ventricles during each beat.
• ~ 70ml
35. Cardiac Output
Cardiac Output is the volume of blood pumped by
each ventricle per minute and is the function of
two factors:
• Heart rate (beats per minute)
• Stroke volume (the volume of blood ejected by
each ventricle during each contraction)
CO = HR x SV
37. Cardiac output
• Heart rate (HR) = number of beats of the heart
per minute (bpm)
• Stroke volume (SV) = volume of blood ejected by
each ventricle during contraction (ml).
The left and right ventricles pump the same
volume of blood through their arteries each time.
• Cardiac output (CO) measures the volume of
blood pumped out by each ventricle per minute.
To calculate this:
CO = HR x SV
39. Pulmonary and Systemic Circuits
• Systemic Circuit
• Left side of heart
• Pumps oxygenated blood to body
via arteries
• Returns deoxygenated blood to
right heart via veins
• Pulmonary Circuit
• Right side of heart
• Pumps deoxygenated blood to
lungs via pulmonary arteries
• Returns oxygenated blood to left
heart via pulmonary veins
40.
41. • The opening and closing of the AV and SL
valves are responsible for the heart sounds
which can be heard with a stethoscope.
42. • (ii) The cardiac cycle to include the functions atrial
systole, ventricular systole, diastole. Effect of pressure
changes on atrio-ventricular (AV) and semi lunar (SL)
valves.
44. Cardiac Cycle
• Systole
• Contractile phase of heart
• Electrical and mechanical changes
• E.g. blood pressure changes
• E.g. blood volume changes
• Diastole
• Relaxation phase of heart
• Takes twice as long as systole
• E.g. resting HR = 60
• Systole = 0.3 s
• Diastole = 0.6 s
45. Cardiac cycle
• The cardiac cycle consists of three stages:
1. Atrial systole
2. Ventricular systole
3. Diastole
46. Cardiac cycle
1. Atrial systole
Pressure in the atria builds up as muscles of the atria walls contract,
forcing blood through the AV valves into the ventricles. AV valves open, SL
valves shut.
2. Ventricular systole
Pressure in the ventricles build up as muscles of the ventricle walls
contract, forcing blood through the SL valves into the arteries. SL valves
open, AV valves shut.
3. Diastole
Pressure decreases in both atria and ventricles as muscles relax.
Blood flows back into the atria and starts to flow into the ventricles. The
higher pressure in the arteries closes the SL valves. AV valves open, SL
valves shut.
47. Autonomic Nervous System Control of Heart Rate
• Sympathetic control
• Stimulates “fight or flight”
response
• Speeds up heart rate and stroke
volume
• Sympathetic tone > 100 bpm
• Parasympathetic control
• Connected to vagus nerves
• Slows down heart rate
• Parasympathetic tone 60 – 100
bpm
48.
49. Pure Science Specials - Of Hearts and Minds
• https://www.youtube.com/watch?v=Xwx5fbElMfk
• 50 mins
50. • (iii) The structure and function of cardiac conducting
system including nervous and hormonal control.
• Control of contraction and timing by cells of the sino-
atrial node (SAN) and atrio-ventricular node (AVN).
Interpretation of electrocardiograms (ECG).
• The medulla regulates the rate of the SAN through the
antagonistic action of the autonomic nervous system
(ANS). Sympathetic accelerator nerves release
adrenaline (epinephrine) and slowing parasympathetic
nerves release acetylcholine.
52. Electrical activity of the heart
• http://www.youtube.com/watch?v=v3b-YhZmQu8&feature=related
53. Cardiac conducting system
• The heart beat is regulated by both nervous
and hormonal control.
• Nervous control:
• Cells of the sino atrial node (SAN), also known
as the pacemaker, in the right atrium set the
pace at which cardiac cells contract without
conscious thought. They are called
autorhythmic.
• The SAN generates an electrical impulse which
spreads throughout the atria, causing atrial
systole. The impulse reaches the AVN which
then carries the impulse across the ventricles,
causing ventricular systole.
54. • The autonomic nervous system (ANS) consists
of 2 antagonistic (opposing) branches
• Sympathetic nerve
• Parasympathetic nerve
57. The medulla region in the brain regulates the rate of
the SAN through the Autonomic Nervous System
(ANS). It contains two branches which work in
Antagonistic (opposing) ways.
Sympathetic accelerator nerves release
adrenaline (epinephrine) which increases heart rate.
Slowing parasympathetic nerves release
acetylcholine which decreases heart rate.
59. Hormonal Regulation of the Heart
• Under certain circumstances
e.g. stress or exercise the
sympathetic nervous system
causes the adrenal glands to
produce adrenaline which
travels in the blood to act on
the SAN, which generates
impulses at a higher rate,
increasing heart rate
60. Hormonal Regulation of the Heart
• Under certain circumstances
e.g. stress or exercise the
sympathetic nervous system
causes the adrenal glands to
produce adrenaline which
travels in the blood to act on
the SAN, which generates
impulses at a higher rate,
increasing heart rate
61. • Hormonal control:
• Under circumstances such as stress and exercise, the
sympathetic nervous system causes the adrenal glands to
produce the hormone adrenaline which acts on the SAN to
increase heart rate.
62. Electrical Activity of the Heart
• Contraction of heart depends on electrical stimulation of myocardium
• Impulse is initiated on right atrium and spreads throughout the heart
• May be recorded on an ECG
63.
64. Electrocardiogram
• Records electrical activity of the heart
• P wave
• Atrial depolarization
• QRS complex
• Ventricular depolarization
• T wave
• Ventricular repolarization
65.
66. Diagnostic use of the ECG
• ECG abnormalities may indicate coronary heart disease
• ST-segment depression may indicate myocardial ischemia
67.
68. • The impulses generated by the SAN creates
currents that can be detected by an
electrocardiogram (ECG).
• P wave – atrial systole
• QRS waves – ventricular systole
• S wave - diastole
69. ABNORMAL ECG’S
• Atrial flutter
• Rapid contraction of the atria
• Atria contract 3 times for every
ventricular contraction
71. ABNORMAL ECG’S
• Ventricular fibrillation
• Unco-ordinated electrical activity
• Pumping cannot take place
• Fatal if not corrected
• Defibrillation
72. • (iv) Blood pressure changes, in response to cardiac
cycle, and its measurement.
• Blood pressure changes in the aorta during the
cardiac cycle. Measurement of blood pressure using a
sphygmomanometer. A typical reading for a young
adult is 120/70 mmHg. Hypertension is a major risk
factor for many diseases including coronary heart
disease.
73. Arterial Blood Pressure
• Expressed as systolic/diastolic
• Normal – 120/80 mmHg
• High – 140/90 mmHg
• Systolic pressure (top number)
• Pressure generated during ventricular contraction
• Diastolic pressure
• Pressure during cardiac relaxation
74. Blood Pressure
• Pulse Pressure (PP)
• Difference between systolic and diastolic
• PP = systolic - diastolic
• Mean Arterial Pressure (MAP)
• Average pressure in arteries
• MAP = diastolic + 1/3 (systolic – diastolic)
79. Blood pressure
• Blood pressure changes in the aorta during the cardiac
cycle. It can be measured using a sphygmomanometer.
80. • An inflatable cuff stops blood flow and deflates gradually.
The blood starts to flow (detected by a pulse) at systolic
pressure. The blood flows freely through the artery (and a
pulse is not detected) at diastolic pressure.
• A typical reading for a young adult is 120/70 mmHg.
81. High blood pressure, known as hypertension, is a
major risk factor for many diseases including
coronary heart disease.
82. Causes of High Blood Pressure
• Age
• Race
• Heredity
• Diet
• Stress
• Inactivity
83. • Blood group antigens are actually sugars attached to the red blood
cell.
• Antigens are “built” onto the red cell.
• Individuals inherit a gene which codes for specific sugar(s) to be
added to the red cell.
• The type of sugar added determines the blood group.
Blood groups:
ABO blood grouping
84. • Individual’s will form immune antibodies to ABO blood group antigens
they do not possess.
• Substances are present in nature which are so similar to blood group
antigens which result in the constant production of antibodies to
blood group antigens they do not possess.
• Critical for understanding compatibility between ABO blood groups
Landsteiner’s Rule
85. • Immunizations are frequently done to protect us from disease.
• Hepatitis B immunization.
• Actual bits of hepatitis virus injected.
• Body recognizes as foreign and produces an immune antibody.
• Subsequent exposure to real Hepatitis B virus will result in destruction of the virus by
immune antibodies.
• ABO antibodies are immune and will result in destroying incompatible
cells which may result in the death of the recipient.
Antibody clinical significance
86. • Blood group antigens are “codominant”, if the gene is inherited, it will
be expressed.
• Some aberrant genotypes do occur but due to the rarity will not be
discussed.
• Understanding of basic inheritance important.
Inheritance
87. • Two genes inherited, one from each parent.
• Individual who is A or B may be homozygous or heterozygous for the
antigen.
• Heterozygous: AO or BO
• Homozygous: AA or BB
• Phenotype is the actual expression of the genotype, ie, group A
• Genotype are the actual inherited genes which can only be
determined by family studies, ie, AO.
Genetics
89. Group O
• Approximately 45% of the
population is group O.
• No A or B antigens present, think of
as “0” antigens present.
• These individuals form potent anti-
A and anti-B antibodies which
circulate in the blood plasma at all
times.
90. Group A
• Approximately 40% of the
population is group A.
• No B antigens present.
• These individuals form potent
anti-B antibodies which
circulate in the blood plasma
at all times.
91. Group B
• Approximately 11% of the
population is group B.
• No A antigens present.
• These individuals form potent
anti-A antibodies which circulate
in the blood plasma at all times.
92. Group AB
• Approximately 4% of the
population is group AB.
• Both A and B antigens present.
• These individuals possess no
ABO antibodies.
93. Hemolysis
• If an individual is transfused with an incompatible blood group
destruction of the red blood cells will occur.
• This may result in the death of the recipient.
94. Rh (D) Antigen
• Of next importance is the Rh type.
• Term “Rh” is a misnomer.
• Rh is a blood group system with many antigens, one of which is D.
• Re-education of public is difficult.
• Rh refers to the presence or absence of the D antigen on the red
blood cell.
95. Rh (D) Antigen (continued)
• Unlike the ABO blood group system, individuals who lack the D antigen
do not naturally make it.
• Production of antibody to D requires exposure to the antigen.
• The D antigen is very immunogenic, ie, individuals exposed to it will very
likely make an antibody to it.
• For this reason all individuals are typed for D, if negative must receive Rh
(D) negative blood.
96. Rh (D) Antigen (continued)
• The most important patient population to consider is females of child-
bearing age.
• If immunized to Rh (D) antigen the antibody can cross the placenta and
destroy Rh (D) positive fetal cells resulting in death.
• This is why Rh negative women are given Rhogam after birth of Rh
positive baby.
97. Blood Transfusions
• A blood transfusion is a procedure in which blood
is given to a patient through an intravenous (IV)
line in one of the blood vessels. Blood transfusions
are done to replace blood lost during surgery or a
serious injury. A transfusion also may be done if a
person’s body can't make blood properly because
of an illness.
• Who can give you blood?
• People with TYPE O blood are called Universal
Donors, because they can give blood to any blood
type.
• People with TYPE AB blood are called Universal
Recipients, because they can receive any blood
type.
• Rh + Can receive + or -
• Rh - Can only receive -
98. • Universal donor
• O negative
• Universal recipient
• AB positive
Blood donors and recipients
Universal Donor
Universal Recipient
