Circulation of Blood
CARDIAC CYCLE
Sequence of events
which take pace during completion of one heart beat is called “Cardiac Cycle”
PHASES
(I) DIASTOLE
It is resting
period of heart chambers.
II) SYSTOLE
During which
heart’s chambers contract. In cardiac cycle, blood is circulated in whole body.
TYPES OF
CIRCULATION
PULMONARY CIRCULATION
In pulmonary
circulation following events take place.
RT. ATRIAL SYSTOL
First the blood
from whole systems of body, except lungs enter in right Atrium through superior
and Inferior vena cavae into the right atrium by atiral systole, blood comes
into right ventricle from right atrium via Tricuspid valve.
RT. VENTRICLE SYSTOLE
After coming of
blood into the Rt. Ventricle, it goes to the lungs via pulmonary trunk by
ventricular systole, for oxygenation of blood by passing through pulmonary
valve.
SYSTEMIC CIRCULATION
In systemic
circulation, following events take place.
LEFT ATRIAL SYSTOLE
When oxygenated
blood comes into left atrium, then left atrial sytole causes blood to enter
left ventricle through bicuspid valve
LEFT VENTRICULAR SYSTOLE
When blood reaches
here it sends into aorta through aortic valve to provide blood to body systems.
CARDIAC OUTPUT
The blood volume
pump per minute by left ventricle into the systemic circulation
HEART BEAT
The contraction of
heart chambers are known heart beat which are regular, rhythmic.
Ventricular systole is LUB
Ventricular systole is LUB
Ventricular
diastole is DUB
TIME FOR HEART BEAT
0.8 sec is time for
one heart beat.
CONDUCTING SYSTEM OF HEART
It consists of
1.AV-NODE
2.SA-NODE
3)AV-BUNDLE
4) PURKINJI FIBERS.
2.SA-NODE
3)AV-BUNDLE
4) PURKINJI FIBERS.
1. SA-NODE
SA NODE found near
upper end of superior vena cava in RT. atrium
PARTS
1. Specialized cardiac Muscles.
1. Specialized cardiac Muscles.
2. Autonomic Nerve
endings.
FUNCTIONS
It Initiates the contraction of heart chambers through impulses & also transmit to AV node.
It Initiates the contraction of heart chambers through impulses & also transmit to AV node.
2. AV- NODE
It is found in
lower end of RT. Atrium. Structurally it is smilar to SA-NODE
FUNCTION
It transmit nerve impulses to ventricles for contraction rhythmically.
It transmit nerve impulses to ventricles for contraction rhythmically.
3. AV-BUNDLE
AV BUNDLE are the
fibers originate from AV node. The bundle divided into Right AV bundle, Left AV
bundle
FUNCTION
It transmit nerve impulses to ventricles.
It transmit nerve impulses to ventricles.
4. PURKINJI FIBERS
AV bundles red
divided into small fibres which penetrate the ventricle wall also known as purkinji
fibers / Bundle of His small thin fibers.
LEUKEMIA
DEFINATION
“The malignant disorder of increase number of abnormal leucocytes in blood.”
“The malignant disorder of increase number of abnormal leucocytes in blood.”
CAUSE
The cause of leukemia is unknown.
The cause of leukemia is unknown.
FACTORS
Factors associated with leukemia are
Factors associated with leukemia are
§ Ionizing Radiation
§ Cytotoxic drugs.
§ Retroviruses.
§ Genetic
EFFECTS OF DISEASE
§ In result of leukemia, normal leucocytes counts become less.
§ This is progressive, and fatal condition which leads to
heamorrhage or infection
THALASSEMIA
DEFINITION
“Genetically impaired globin chains formation leads to impaired or defected formation of hemoglobin.”
“Genetically impaired globin chains formation leads to impaired or defected formation of hemoglobin.”
GENETIC DISEASE
Thalassemia is a
genetic disorder, it may be
1. Hetrozygous
/Mild thalassemia:
2. Homozygous.
TYPE
BETA – Thalassemia
BETA – Thalassemia
α – Thalassemia
BETA-THALASSEMIA
When globin chain is impaired or defected. It is most common one.
When globin chain is impaired or defected. It is most common one.
ALPHA-THALASSEMIA
when α-thalassemia globin chain of (HB) hemoglobin is defected.
when α-thalassemia globin chain of (HB) hemoglobin is defected.
KINDS OF THALASSEMIA
THALASSEMIA MINOR
When thalassemia is
of heterozygous type with mild anemia.
THALASSEMIA MAJOR
When thalassemia is
of homozygous type with profound hypochromic anemia. It is more common in
children & results with enlargement of kidney.
REMEDY
The only remedy is transfusion of blood at regular intervals.
The only remedy is transfusion of blood at regular intervals.
CVD CARDIOVASCULAR
DISEASE
Diseases of heart,
blood vessels and blood circulation are generally term as CVD.
ATHEROSCLEROSIS
The disease of
arterial wall with lose of elasticity, thickness of inner wall causing
narrowing of lumen, results in impairing of blood flow.
ATHEROMATOUS
PLAQUES
The narrowing is due
to formation of fatty lesions called atheromatous plaque in inner lining of
arteries.
COMPONENTS OF PLAQUE
These plaques
consist of
§ LDL-LOW DENSITY LIPO PROTEINS
§ DECAYING MUSCLES CELLS
§ FIBROUS TISSUE
§ PLATELETES
§ CLUMP OF BLOOD
CAUSES
Smoking, Hypertension, Obesity, Diabetes (Severe), family history of arterial disease
Smoking, Hypertension, Obesity, Diabetes (Severe), family history of arterial disease
EFFECTS
Atherosclerosis produces no symptoms until the damage to artery is so severe that it restricts blood flow.
Atherosclerosis produces no symptoms until the damage to artery is so severe that it restricts blood flow.
ANGINA PECTORIS
If blood flow to
heart muscles is restricted causes (cell damage) necrosis called angina
pectoris. Pain in chest, arm, or jaws usually during exercise.
THROMBUS FORMATION
The formation of
blood clot with in the intact blood vessel initiated by atheromatous plaque.
REASON FOR THROMBUS FORMATION
Due to formation
athromatous plaque loss of elasticity, intact blood vessel get destroyed, blood
from vessel wall comes out & later change to blood clot and blocks the
lumen of small arteries.
RESULT OF THROMBUS FORMATION
Initially thrombus
block the lumen partially result in decrease blood flow to organs & leading
to impairment of physiology of organs. Later on, thrombus blocks the lumen
completely so due to complete loss of blood supply, cells damage occur.
CORONARY THROMBOSIS
Type of thrombosis
when narrowing of lumen occurs in coronary blood vessels due to formation of
clot.
EFFECT
Occulsion of coronary atery causes myocardial infarction and heart attack.
Occulsion of coronary atery causes myocardial infarction and heart attack.
HEAMORRHAGE
The escaping of
blood from intact blood vessels.
STROKE
Most dangerous type
of heamorrhage is that of brain which results in paralysis or strokes.
HAEMATOMA
The accumalation of
blood in interstitial spaces known as haematoma.
This will lead to edema.
This will lead to edema.
STROKE
DEFINITION
The damage to the part of brain caused by, restriction in blood supply or leakage of blood outside the vessels.
The damage to the part of brain caused by, restriction in blood supply or leakage of blood outside the vessels.
CHARACTERISTICS
Impairment of sensation, movement & function controlled by damage part of brain.
Impairment of sensation, movement & function controlled by damage part of brain.
CAUSES
§ Hypertension
§ Atherosclerosis
HEMIPLEGIA
Damage to any, one
cerebral hemisphere can cause weakness or paralyses of one side of body called
hemiplegia
PRECAUTIONARY MEASURES
Blood pressure
should be with in normal range through proper diet. Salt should be used in less
quantities exercise should be the regular habit. Smoking must be avoided.
Person life should be free of worries.
BLOOD VESSELS
DEFINITION
“The closed vessels or tubes through which transporting medium or blood circulate with in body called “blood vessels”.
“The closed vessels or tubes through which transporting medium or blood circulate with in body called “blood vessels”.
TYPES OF BLOOD VESSELS
1. Arteries.
2. Capillaries.
3. Veins.
ARTERIES
DEFINITION
Thick walled blood vessels which carry blood from heart to the organs of body.
Thick walled blood vessels which carry blood from heart to the organs of body.
LAYERS
It consists of three layers.
It consists of three layers.
1. Tunica Externa/
Adventitia
2. Tunica Media
3. Tunica Intima
1-TUNICA EXTERNA
It is thin but
tough layer, having abundant amount of collagen fibers. It is outer most layer.
2-TUNICA MEDIA
The middle layer
has smooth muscle fibers & elastin fibers. It is the thickest layer.
3-TUNICA INTIMA
It consists of
squamous endothelium.
LUMEN
Thick walled vessels & having smaller lumen than that of veins except arteries of brain & related to cranium having large lumen.
Thick walled vessels & having smaller lumen than that of veins except arteries of brain & related to cranium having large lumen.
SEMILUNAR VALVES
They are not
present in arteries.
BRANCHES – DIVISIONS
Aorta divides into
large arteries, large arteries into smaller arteries, smaller arteries into
arterioles, then they give rise to capillary.
At arteriole level, small sphincters are present which are known as PRE-CAPILLARY SPHINCTER.
At arteriole level, small sphincters are present which are known as PRE-CAPILLARY SPHINCTER.
SPHINCTER
FUNCTION
They are for regulating the diastolic pressure.
They are for regulating the diastolic pressure.
CHARACTERSTICS
§ Arteries are elastic so during systolic pressure, they do not rupture
and dilate.
§ During ceasement/ stopage of systolic pressure of heart,
arteries contract & supply even flow of blood.
§ The arteries carry oxygenated blood except pulmonary arteries.
VEINS
DEFINITION
The thin walled blood vessels that drian blood from body parts/organs into heart called veins.
The thin walled blood vessels that drian blood from body parts/organs into heart called veins.
LAYERS
Tunica Externa
Tunica Media
Tunica Intima
1. TUNICA EXTERNA
Thickest layer in
veins. It contains collagen, elastin and smooth muscles cells.
2. TUNICA MEDIA
Not thicker as that
of arteries. Elastic tissues and small smooth muscle.
3. TUNICA INTIMA
Contains
endothelial cells layer.
LUMEN
It has large lumen and thin wall.
It has large lumen and thin wall.
SEMILUNAR VALVES
They are present in
veins to prevent back flow of blood in the influence of gravity.
TRIBUTARIES
Veninules -> small veins -> large veins -> vena cava.
Veninules -> small veins -> large veins -> vena cava.
BLOOD PRESSURE
In veins blood
pressure is low and are non pulsatile.
CHARACTERISTICS
The blood flows slowly and smoothly in veins. Veins are superficial and collapse when empty.
The blood flows slowly and smoothly in veins. Veins are superficial and collapse when empty.
CAPILARIES
The intimate
microscopic closed channels of both arterial & veinous interconnected
network is called capillaries.
DIAMETER
Capillaries are extremely narrow in diameter of about 7-10 μ.
Capillaries are extremely narrow in diameter of about 7-10 μ.
LAYERS
Capillaries are thin walled vessels & contains single layer of endothelium which offers small resistance in transport of material across the capillary wall.
Capillaries are thin walled vessels & contains single layer of endothelium which offers small resistance in transport of material across the capillary wall.
FUNCTION
Through diffusion and active transport of oxygen is transported to tissues & CO2 to capillaries. Nitrogenous waste is filtered through the capillaries into excretory tubules.
Through diffusion and active transport of oxygen is transported to tissues & CO2 to capillaries. Nitrogenous waste is filtered through the capillaries into excretory tubules.
BLUE BABIES
(CYANOSIS)
Blue baby is a
layman terminology. In medical science it is known as cyanosis.
DEFINITION
The term cyanosis” means the blueish discolouration of the skin & mucous membrane due to excessive cone of reduced (deoxygenated haemoglobin) in the blood & it appears when reduced Hb conc in capillaries is more than 5 gm/dl of blood. The reduced Hb has an intense dark blue purple colour that is transmitted through the skin.
The term cyanosis” means the blueish discolouration of the skin & mucous membrane due to excessive cone of reduced (deoxygenated haemoglobin) in the blood & it appears when reduced Hb conc in capillaries is more than 5 gm/dl of blood. The reduced Hb has an intense dark blue purple colour that is transmitted through the skin.
MOST COMMON CAUSE OF CYANOSIS
Although there are
various other causes of cyanosis but the most common cause is CONGENITAL
CYANOTIC HEART DISEASE.
BASIC CAUSE OF CYANOSIS
In congenital heart
diseases, there is an abnormal connection b/w right and left side of heart,
which permits the large amount of unoxygenated venous blood to bypass the
pulmonary capillaries & dilute the oxygenated blood in systemic arteries
i.e RIGHT TO LEFT SHUNT, which results in cyanosis.
SOME EXAMPLES OF CONGENITAL HEART DISEASES
§ Some congenital heart diseases which are responsible for the
abnormal connection between right and left sides of heart are as follows.
§ ATRIAL SEPTUM DEFECT (ASD)
§ VENTRICULAR SETPUM DEFECT (VSD)
§ PERSISTANT DUCTUS ARTEROSUS
§ In all these conditions, blood begins to flow from the aorta
(left side) into pulmonary arteries (right side) & the people donot show
cyanosis until late in life when heart fails or lungs become congested.
TETRALOGY OF FALLOT (RIGHT –TO-LEFT SHUNT)
It is the most
common cause of cyanosis or blue baby in which aorta originates from right
ventricles rather than left & receives deoxygenated blood.
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