circulatory system my notes

1. The Circulatorysystem
The Circulatorysystem is one of the important organ system in Human
bodyconsists of Heart and great vessels that circulates blood and
nutrients, oxygen/carbon dioxide and hormones to various cells in the
body.
Consists of,
Heart
Blood vessels (Arteries, Veins, Capillaries)
Blood consists of plasma, RBC, WBC, and platelets.
HEART is a muscular organ located in the chest at mediastinum between
the lungs behind the sternum and above the diaphragm. It pumps
oxygenated blood to the various parts of the bodyand deoxygenated
blood to the lungs.
The heart wall has three layers (Outer epicardium, Middle myocardium,
& Inner endocardium) Heart is enclosed by a sac called pericardium with
pericardial fluid.
In the human heart there are four chambers,
1. Right and Left atrium
2. Right and Left ventricle.
There are four valves present in the human Heart,
1. Aortic valve - Between left ventricle and Aorta.
2. Pulmonary valve - Between right ventricle and pulmonary artery.
3. Bicuspid valve / mitral valve - Between left atrium and left
ventricle.
4. Tricuspid valve - Between right atrium and right ventricle.
The heart valves are attached to the ventricular walls via the chordea
tendineae they are attached to the papillary muscles so that the cusps are
held in position.
The pericardium is double walled sac covering the heart and greater

2. vessels. Contain pericardial fluid.
Pulmonary circulation and Systemic circulation
The pulmonary circulation is the circulation of the blood between heart
and lungs for purification of blood. The oxygen less blood from the
Superior and Inferior vena cava enters into the right atrium of the heart
and flows through the tricuspid valve into the right ventricle; from their
blood is pumped to the lungs through pulmonary artery.
Gas exchange happens in the lungs at alveoli. The carbon dioxide is
moved from blood capillaries to lungs and oxygen is moved from lungs to
blood capillaries.
Four pulmonary vein returns the oxygen rich blood to the left atrium of
heart.
The systemic circulation is the circulation of the blood to all parts of the
bodyfrom the heart. Systemic circulation is the portion of the
cardiovascular system which transports oxygenated blood away from the
heart through the aorta from the left ventricle.
Coronary Circulation: Supplying blood to heart muscles by Right and
Left Coronary arteries. The vessels that remove the deoxygenated blood
from the heart muscle are known as cardiac veins.
Branches of the coronary circulation,
FromAorta
1. Right coronary artery (RCA)
AV node artery
Right marginal artery
Posterior descending artery
Posterio-lateral artery

3. 2. Left coronary artery / Left main coronary artery (LMCA)
Left circumflex artery (LCX)
Obtuse marginal artery
Left anterior descending artery (LAD)
Diagonal artery
The Aorta is the largest artery in the human bodyarises from the left
ventricle of the heart. The aorta distributes oxygenated blood to all parts
of the bodythrough the systemic circulation.
The venae cava are large veins that return deoxygenated blood from the
bodyinto the heart. The superior vena cava and the inferior vena cava,
both empty into the right atrium.
ARTERIES: Carry oxygen-rich blood away from the heart. Arteries
branch into small passages called arterioles and then into the capillaries
CAPILLARIES: Are the smallest and thinnest of the blood vessels in the
body. Capillaries carry blood very close to the cells of the tissues of the
bodyin order to exchange gases, nutrients, and waste products
VEINS: Carry oxygen-poor blood back to the heart. Capillaries merge
into Venules – Veins - Vena cava.
The arteries possessstronger and thicker walls than the veins, three layers
are, 1. Tunica intima 2. Tunica media 3. Tunica
externa
Electrical System of the heart
The heart has the ability to create its own electrical impulses for
continues involuntary functioning.

4. Impulses travel in the following order,
1. The sino-atrial (SA) node
2. The atrio-ventricular (AV) node
3. The bundle of His
4. The LT & RT bundle branches
5. The Purkinje fibres
BLOOD: The human bodycontains about 4 to 5 liters of blood. Blood is
made up of RBC, WBC, platelets and plasma.
RBC (RED BLOOD CELLS) / ERYTHROCYTES
— Erythrocytes transport oxygen in the blood through the red pigment
hemoglobin
WBC (WHITE BLOOD CELLS) / LEUKOCYTES
— Important functions in the body’s immune system.
— Neutrophils, eosinophils, basophils, lymphocytes and monocytes
PLATELETS / Thrombocytes
— Responsible for the clotting of blood.
— Platelets normally remain inactive in the blood until they reach
damaged tissue or leak out of the blood vessels through a wound.
PLASMA
— Liquid portion of the blood that makes up about 55% of the blood’s
volume.
— Around 90% of plasma is made of water.
BLOOD PRESSURE: Refers to the pressure in large arteries of the

5. systemic circulation,
— SYSTOLIC - Ventricles contracts
— DIASTOLIC - Ventricles relaxes
Normal BP: 120 / 80 mmHg
Pulse rate - 72 beat per min
RBC – 4 to 6 million cells per micro liter of blood
WBC – 4000 to 11000 per micro liter of blood
Platelet – 150,000 to 450,000 cells per micro liter of blood
Common Disease of Circulatory System:
1. Aortic aneurysm - is a bulge in a section of the aorta.
2. Coronary artery disease (CAD) – is a disease in which a waxy
substancecalled plaque builds up inside the coronary arteries.
3. Deep vein thrombosis - A blood clot in a deep vein, usually in the legs.
4. Rheumatic Heart disease – Permanent damage to heart valves is caused
by rheumatic fever.
5. Atherosclerosis – Is a disease of the arterial vessels, in which the walls
of the blood vessels became thickened and hardened by plaques.
6. Hypertension – Is a condition in which the arteries have persistently
elevated blood pressure.
7. Hypercholesterolemia – Is the presence of high levels of cholesterol in
the blood.
8. Myocardial Infarction - is the irreversible death (necrosis) of heart
muscle secondaryto prolonged lack of blood (oxygen) supply.
MEDICAL TERMS:
1. Heart - Cardio
2. Vessels - Angio / Vasculo / Vaso
3. Artery - Arterio
4. Veins - Phlebo
5. Blood - Hemato

6. 6. RBC - Erythrocytes
7. WBC - Leukocytes
8. Platelet - Thrombocytes
MEDICAL ABBREVIATIONS:
1. ABI - Ankle-brachial index
2. ABG - Arterial blood gas
3. ASHD - Arteriosclerotic heart disease
4. BP - Blood pressure
5. CABG - Coronary artery bypass graft
6. CAD - Coronary artery disease
7. CHF - Congestive heart failure
8. CPR - Cardiopulmonary resuscitation
9. CVP - Central venous pressure
10. DVT - Deep vein thrombosis
11. ECG – Electrocardiogram
12. ESR - Erythrocyte sedimentation rate
13. FHT - Fetal heart tones
14. HB – Hemoglobin
15. HDL - High-density lipoprotein
16. HTN – Hypertension
17. ICA - Internal carotid artery
18. LAD - Left anterior descending
19. LCA - Left coronary artery
20. LDL - Low-density lipoprotein
21. LVH - Left ventricular hypertrophy
22. MI - Mitral insufficiency; myocardial infarction
23. PICC - Peripherally inserted central catheter
24. PTCA- Percutaneous transluminal coronary angioplasty

7. 25. RVH - Right ventricular hypertrophy
26. SVT - Supraventricular tachycardia
27. WBC - White blood cell