The circulatory system consists of the heart, blood, and blood vessels. The heart pumps blood through two circuits - the pulmonary circuit, which pumps blood to the lungs to receive oxygen and remove carbon dioxide, and the systemic circuit, which pumps oxygenated blood to the rest of the body. Blood flows from the heart through arteries, then to capillaries where gas exchange occurs, then through veins back to the heart. The circulatory system transports oxygen, nutrients, hormones and waste products throughout the body.

1. Human Movement
Basic Anatomy and
Physiology
The Circulatory System
http://www.youtube.com/watch?v=mu2BLnI-afI

2. CIRCULATORY SYSTEM
The circulatory or cardiovascular system consists of
•The Heart
•The Blood
•Blood vessels
Together with the Lymphatic System, the Circulatory
System:
•Delivers oxygen and nutrients to cells
•Removes waste from cells
•Maintains the balance of water in the body.
WEBSITE:
The Heart: An online Exploration
http://www.sin.fi.ed/biosci/biosci.html

3. BLOOD
A specialised type of connective tissue
It is a thick liquid with a metallic taste
Blood accounts for about 8% of our total body weight
Blood volume in a healthy adult:
Male 5 – 6 L Female 4 – 5 L
Functions:
Blood performs a number of specialised functions:
Transports nutrients, oxygen, carbon dioxide, waste products and
hormones to cells and organs around the body
Protects us from bleeding to death, via clotting, and from disease, by
destroying invasive micro-organisms and toxic substances
Acts as a regulator of temperature (vessels constrict to conserve heat or
dilate to release heat to the surface for cooling), the water content in cells
and body pH.

4. Composition of blood:
1. Solid component (Blood cells)
 45% of total volume
 Red blood cells (erythrocytes), white blood cells
(leukocytes), or platelets (thrombocytes)
2. Liquid Component (Blood plasma)
 55% of total blood volume
 Composed of 91.5% water and 8.5% of nutrients, waste
products, proteins, enzymes and hormones
 Straw coloured or yellowy solution
 Nutrients from the small intestine is absorbed into the
plasma and transported around the body

5. RED BLOOD CELLS
Contains an oxygen carrying pigment called Haemoglobin (Hb).
This gives blood its red colour.
Oxygen (O2) is carried by Hb and transported from the lungs to all
cells. This reaction forms oxyhaemoglobin (aided by iron molecules)
Carbon dioxide (CO2) is also transported this way. Formation is
called carbaminohemoglobin
Life cycle is approximately 120 days and they are replaced at the rate
of 2 million per second
They are produced in red bone marrow from stem cells
Red blood cells function is to transport O2 and CO2 around the
body

6. PLATELETS
Small colour-less bodies that usually appear as
irregular spindles or discs that are much smaller than
RBC and WBC
Produced in red bone marrow
Life cycle is approximately 5 to 9 days
Platelets are involved in the process of clotting and
they help to repair slightly damaged blood vessels

7. WHITE BLOOD CELLS
Slightly larger than red blood cells
Classified according to the presence or absence of granules in
their cytoplasm
Life cycle is from a few hours to a few days
Produced in bone marrow and lymph tissue
They move to areas of infection or disease to engulf invading
bodies (puss is the accumulation of WBC)

8. BLOOD VESSELS
HEART → ARTERIES → ARTERIOLES →
CAPILLARIES → VENULES → VEINS → HEART.

9. ARTERIE
S
Carry blood away from the heart to tissues
Thick elastic walls as blood is pumped through them at high pressure in surges
Three layers
- endothelium lining
- involuntary muscle
- tough fibrous tissue
Surges are called heart beats
Pressure decreases as distance from the heart increases. Blood passes through
small vessels called arterioles

10. VEIN
S
Carry blood from tissues back to the heart
Thinner walls and less elastic as pressure decreases as the blood gets closer to
the heart
The contraction and relaxation of muscles assists the blood to stream back
steadily to the heart
Valves prevent the blood from flowing back the wrong way against a force of
gravity. After standing for a long time, legs can feel heavy and swollen. Blood pools
in the lower legs because of gravity and lack of movement. Once moving, the
muscles squeeze the blood up through the veins toward the heart.
Gravity affects blood flow – blood above the heart flows easily

11. CAPILLARIES
A very small network of vessels
One cell wide
Lie between arterioles and venules, connecting both systems
Semipermeable membrane where O2, CO2 and nutrients are
exchanged between the blood and the cells of the body
Feeds muscles, joints, tissues and organs in clusters

12. THE HEART
Involuntary cardiac muscle
Pericardium is a triple layered bag that surrounds, anchors and protects the heart
Four hollow chambers
- 2 atria
- 2 ventricles
Atria act as receiving chambers for blood returning to the heart. Small and thin as
they only pump next door
Ventricles are large as they propel the blood from the heart into circulation around
the body
Dense connective tissue called valves, prevent the back flow of blood into the
chambers by opening and shutting when the heart contracts and relaxes. Tricuspid
and Bicuspid valves
Heart contracts and squeezes blood into arteries – systole
Heart relaxes and fills with blood – diastole

15. Pulmonary Artery has deoxygenated blood travelling in
it. Other arteries have oxygenated blood. Being an
artery it still travels away from the heart
Pulmonary veins have oxygenated blood. Other veins
have deoxygenated blood.

16. ANATOMY OF THE HEART
ATRIUM: the receiving chamber of the heart
VENTRICLE: the propulsion chamber of the heart
SEPTUM: separates the two ventricles and the two atrium
VENA CAVA: returns blood from the systemic system to the right atrium
PULMONARY ARTERY: carries blood from the right ventricle to the lungs via
the circulatory system
PULMONARY VEIN: carries blood from the lungs to the left atrium
AORTA: carries blood from the left ventricle to the systemic circuit
around the body
MYOCARDIUM WALLS: have different thicknesses depending on the pressure
they are under eg atrium walls are thinner because it is
easier to push blood into the ventricles
ATRIOVENTRICULAR VALVES: these are forced shut as the ventricle pressure
increases, preventing back flow of blood into the atria when
the ventricles are pumping – they are bicuspid and tricuspid
SEMILUNAR VALVES: prevent blood returning to the ventricles after they have
completed contracting
SINUATRIAL VALVE: is the pacemaker. It controls
contractions and is found in the right atria.

17. PULMONARY AND SYSTEMIC CIRCULATION
The heart is actually a double pump that serves two circulations.
Two types of blood circuits are created:
Pulmonary circuit – circulates blood from the right side of the heart to
the lungs and then back to the heart.
Systemic circuit – pumps blood from the left side of the heart out to all
body tissues and then back to the right side.
PULMONARY CIRCUIT
Deoxygenated blood from the body enters the right atrium via 3 veins,
superior vena cava, inferior vena cava and coronary sinus. From here the
blood flows into the right ventricle, which pumps it to the lungs via the left
and right pulmonary arteries. In the lungs CO2 is released and O2 is picked
up.
SYSTEMIC CIRCUIT
Oxygenated blood then enters the left atrium via 4 pulmonary veins. The
blood flows into the left ventricle, from where it is
pumped up through the aorta and out to the upper and lower
body via a number of arteries.

18. The cycle
Oxygen-poor blood from the body collects in the right atrium,
which contracts, filling up the right ventricle
Right ventricle contracts and pushes blood to the lungs
In the lungs, blood loses carbon dioxide and picks up oxygen
Oxygen-rich blood returns to the left atrium, which contracts, filling up the left
ventricle
Powerful contractions of the left ventricle, expels oxygen-rich blood in the aorta,
from where artery branches distribute blood throughout the body.
In the muscles and body organs, blood releases oxygen and nutrients, and
absorb food and water from the intestines. Liver processes nutrients, and
together with kidneys, purifies the blood
Oxygen-poor blood returns to the heart through the veins.
Another cycle begins.

20. SYSTEMIC CIRCUIT
This circuit has 4 major areas:
1.Coronary Circulation
Coronary arteries feed the cardiac muscle
2.Portal Circulation
Blood from the stomach and intestine returns through the liver and
then to the heart
3.Muscle circulation
Circulation to the muscles
4.Skin Circulation
Circulation to the skin
Hot weather → Blood vessels dilate
Cold weather → Blood vessels constrict

21. HEART RATE
Number of beats per minute
Resting heart rate is best taken when you first wake
up in the morning. It is a good indicator of the
efficiency and strength of the heart
Heart rate increases due to fear, excitement,
exercise, food ingestion, illness, smoking, drugs,
body position, age and temperature changes
Pulse is the pressure wave of blood continuing along
the arteries
Measurement of pulse is best taken from
the radial or carotid site. Take if for 6, 10,
15, 20 or 30 seconds and then multiply by
10, 6, 4, 3 or 2 respectively, to calculate
your heart rate over a minute.

22. HEART SOUNDS
2 sounds that accompany blood movement
Blood moves in spurts rather than a constant flow
1st spurt, caused by the ventricular contraction
(systole) this increases the pressure in the ventricles
The AV (tricuspid and bicuspid) valves shut quickly
due to this pressure and this sharp closure makes the
1st sound
2nd sound occurs as the ventricle relaxes (diastole),
the atria fills and the semilunar valves shut quickly

23. HEART DISORDERS
Abnormal heart rate: a regular heart rate lower than 60 and higher
than 100 is abnormal.
Heart block: SA node fails to send impulses which tell the heart to
contract. Ventricles contract at their own rate slower than the atria.
Arteriosclerosis: Hardening and narrowing of coronary arteries. If
an artery blocks then myocardial infarction occurs (heart attack)
Myocardial Infarction: blood flow is interrupted to heart muscle.
This tissue dies. Complete rest is needed. If a large area is starved
of oxygen, death will occur
Heart muscle can become infected
Valves of the heart can become ineffective
Cardiomyopathy – virus of the heart causing
heart to enlarge and harden making it ineffective.
Death will result if the heart is not transplanted.

24. HEART RATE CONTROL
HR is controlled by the involuntary (autonomous) nervous system
Sympathetic System – heart beats faster
Parasympathetic System – returns heart to normal
Electrical impulses from these systems stimulate the atria to contract
together. The impulses travel to the ventricles, which contract 0.1
seconds after the atria. The rate at which the sinoatrial node
(pacemaker) sends impulses determines heart rate.

25. Blood flow through the body:
Use your text, notes and knowledge to arrange the following
body processes into the correct order (no.1 and No. 12 are
already done)
1. Deoxygenated blood to the right atrium
2. Right ventricle
3. Deoxygenated blood to the lungs
4. Oxygenated blood from the lungs
5. Left atrium
6. Left ventricle
7. To body via aorta, arteries and arterioles
8. To capillaries
9. To tissues, organs and muscles
10.To capillaries
11.To veins
12.Deoxygenated blood back to the right atrium

26. BLOOD PRESSURE
Blood pressure is the pressure of the blood in the arteries as the heart
pumps it around the body.
Hence it is the arteries that are mainly at risk of damage from high blood
pressure.
Blood flow and blood pressure surge each time the heart contracts. The
peak pressure is called the systolic pressure.
The pressure falls as the heart relaxes to fill. This lower pressure is called
the diastolic pressure.
Blood pressure in each individual varies the whole time according to
numerous influences such as posture (whether you are lying or
standing), emotion, pain and sleep.
For example – blood pressure may be higher the first time that you visit a
new doctor. Readings tend to become lower as the patient relaxes with
subsequent visits.
The WHO (World Health Organisation) defines the following
“Normal adult blood pressure is arbitrarily defined as a systolic
pressure equal to or less than 140mmHg together with a diastolic
equal to or below 90 mmHg. Hypertension in adults is arbitrarily
defined as a systolic pressure equal to or greater than 160 mmHg
and/or diastolic pressure equal to or greater than 95 mmHg.”

27. FACTORS AFFECTING SYSTOLIC BLOOD
PRESSURE
Short term factors include –
Smoking – increases blood pressure, as the capillaries
constrict or reduce in size when the nicotine is present which
increases the resistance to blood flew. This effect lasts for about
20 minutes
Exercise – increases BP and HR (heart rate)
Fright, stress or anxiety – increases BP
Body position – affects BP due to the pull of gravity. Standing
increases BP while lying down decreases BP.
Long term factors include:
Diet – high intake of fat and salt can lead to a permanent
increase in BP into the unhealthy range. Fatty deposits narrow
the artery walls and lead to a loss of elasticity in artery walls
Stress – can cause high BP due to an imbalance in hormone
levels
Exercise – regular exercise can lead to a decrease in
blood pressure when at rest, if blood pressure has been
high

28. THE HEART
Stroke Volume (SV) – the volume of blood ejected into the aorta by
one ventricle during contraction (systole)
Cardiac Output (Q) – the total volume of blood pumped from a
ventricle per minute
Q = HR x SV
Blood pressure (BP) – it is the pressure exerted in systemic arteries by
the contraction and relaxation of the ventricles. Blood flows along a
pressure gradient from areas of higher pressure to areas of lower pressure.
BP is expressed in terms of mm of Mercury (mmHg)
Systole contraction ie 120 (Normal +/- 10)
Diastole relaxation 80 mmHg
*BP can depend on sex, age,
exercise and condition of
the cardiovascular system.

29. THE EFFECTS OF EXERCISE ON THE
HEART
During exercise, your heart rate will increase quite
rapidly in proportion to the increase in workload
intensity until a maximum point, where it levels off.
This point is called your maximum heart rate – HR
max.
To determine HR max:
220 – age = HR max
Heart rate is seen to rise with
work intensity, as anyone knows
after climbing a long flight of
stairs. But unlike cardiac output
and VO2
, the relationship between
heart rate and absolute work
intensity is variable across
individuals; like your grandmother
(Black line) and the marathon
runner (Black line).

30. For training purposes it is often recommended that people
exercise at certain percentages of their HR
•Long distance runners would tire quickly if working at
100% of HR max, therefore they train at lower
intensities of 75 – 85%.

31. CARDIAC ADAPTATIONS TO EXERCISE
Cardiac Output – increases linearly with increases in intensity up to exhaustion
SV – increases due to more blood returning to the heart. Maximal SV occurs during
sub-maximal work.
HR – increases as intensity increases up to a maximum
Systolic BP – increases linearly with increased exercise intensity due to an increase
in Q.
Blood Flow – increased blood flow to working muscles and skin, 80 – 85% →
muscles.
Blood Plasma Volume – decreases especially in hot weather due to increased
sweating.
Other Adaptations:
Increase in arteriovenous O2 difference
Increase in blood acidity (more lactic acid)
Decrease in muscle glycogen
Increase in coronary blood flow
*Over time with training, the heart undergoes other physiological changes:
- it becomes stronger and in some cases slightly larger
- resting heart rate will decrease

32. Immediate (Acute) Effects Area Long-Term (Chronic) Effects
HR increases
CO increases
SV increases
Increases coronary circulation
Maximum HR may be reached
Heart Resting HR decreases
SV increases at test and exercise
Increases blood supply to the heart muscle
at rest and work
Increased size of left ventricle
Maximum HR remains the same
Increased BP on artery walls
Capillaries and veins dilate to allow
increased blood flow
One way valves in veins help return blood
to the heart
Arteries
Capillaries
Veins
Elasticity of artery walls is maintained
Reduced build up of fatty deposits in
arteries
Decreased risk of high BP and CV disease
Increased capillary supply to heart and
skeletal muscles
Increased speed of blood flow
Increased temperature of muscles
Oxygen levels in venous blood decreases
as the body uses more oxygen for exercise
Blood is redistributed from the internal
organs to the working muscles
Blood Increased blood volume
Increased haemoglobin’ count
Increased oxygen carrying ability
SUMMARY OF THE EFFECTS OF EXERCISE