The Mammalian Circulatory System (Circulation)The Mammalian Circulatory System (Circulation)

The cardiac circulationThe cardiac circulation

The pulmonary circulationThe pulmonary circulation

The systemic circulationThe systemic circulation

The Mammalian Circulatory System (Components)The Mammalian Circulatory System (Components)

Transport vesselsTransport vesselsFluid TissueFluid Tissue

Pumping MechanismPumping Mechanism

Arteries, Veins, arterioles, Arteries, Veins, arterioles, venules & Capillariesvenules & Capillaries

BloodBloodHeartHeart

TransportTransport vesselsvessels

Arteries

• Structure Tunica intima (endothelium)

Tunica media

Tunica adventitia

Tunica intima (endothelium): A single layer of endothelial cells

Ttunica media: Alternating circular smooth muscle fibres and bands of elastic fibres

Tunica adventitia: Mainly connective tissue and few elastic fibres

Veins

• Structure Tunica intima (endothelium)

Tunica media

Tunica adventitia

Transport vesselsTransport vessels

valve

* Veins cannot contract behind the blood to keep it moving * Veins cannot contract behind the blood to keep it moving towards the heart however they are equipped with valves that towards the heart however they are equipped with valves that prevent the blood from flowing backwardprevent the blood from flowing backward

The “muscle pump” helping to return venous blood to the heart

Transport vesselsTransport vessels Capillaries

• Structure

Tunica intima (endothelium): One cell in thickness

BloodBlood

RedRed

ViolencViolenc

ee

CrimeCrime

LifeLife Oxygen

Oxygen

Carbon

Carbon dioxide

dioxide

Haemoglobi

Haemoglobi

nn

AccidentsAccidents

Nutrients

Nutrients Hormone

Hormone

ss

The Transport MediumThe Transport Medium (Blood)(Blood)

PlasmaPlasma

R.B.Cs (Erythrocytes)R.B.Cs (Erythrocytes)

White Blood Cells (leucocytes)White Blood Cells (leucocytes)

55 %55 % 44 %44 % 1%1%

%%%% %%

PlateletsPlatelets

R.B.Cs, White Blood Cells, and Platelets are called the R.B.Cs, White Blood Cells, and Platelets are called the formedformed elements of the elements of the blood.blood.

The Transport MediumThe Transport Medium (Blood)(Blood)

Blood cellsBlood cells

R.B.Cs (Erythrocytes)R.B.Cs (Erythrocytes) White Blood Cells (leukocytes)White Blood Cells (leukocytes)

GranulocytesGranulocytes

BasophilsBasophilsEosinophilsEosinophils

NeutrophilsNeutrophils

AgranulocytesAgranulocytes

LymphocytesLymphocytes MonocytesMonocytes

B - lymphocytesB - lymphocytes T - lymphocytesT - lymphocytes

Oxygen Pick-up and release factorsOxygen Pick-up and release factors

What are the factors that affect oxygen pick-up and release by the respiratory What are the factors that affect oxygen pick-up and release by the respiratory pigment? pigment?

These factors areThese factors are

The concentration of oxygenThe concentration of oxygen The acidity of the surrounding fluidThe acidity of the surrounding fluid

• • The concentration of oxygen is usually measured in kPa.The concentration of oxygen is usually measured in kPa.

• • Since oxygen makes up about 21% of the atmospheric pressure, and the air Since oxygen makes up about 21% of the atmospheric pressure, and the air pressure is 101 kPa at sea level, then oxygen partial pressure in the lungs should pressure is 101 kPa at sea level, then oxygen partial pressure in the lungs should be: 0.21 x 101 kPa = 21.21 kPa be: 0.21 x 101 kPa = 21.21 kPa

• The concentration of oxygen is usually measured in kPa.The concentration of oxygen is usually measured in kPa.

• Since oxygen makes up about 21% of the atmospheric pressure, and the air pressure is 101 kPa at sea level, then oxygen partial pressure in the lungs should pressure is 101 kPa at sea level, then oxygen partial pressure in the lungs should be: 0.21 x 101 kPa = 21.21 kPa be: 0.21 x 101 kPa = 21.21 kPa

TemperatureTemperature

Red Blood CellsRed Blood Cells

• • When oxygenWhen oxygen partial pressure is low, the bond that links oxygen to the haem partial pressure is low, the bond that links oxygen to the haem group weakens, and oxygen will be released easily.group weakens, and oxygen will be released easily.

• • Similarly an increase in the acidity will loosen the bond and lead to the release of Similarly an increase in the acidity will loosen the bond and lead to the release of oxygen.oxygen.

• • The increase in the acidity of the blood results from the increase in the The increase in the acidity of the blood results from the increase in the concentration of carbon dioxideconcentration of carbon dioxide

What is the effect of a low oxygen partial pressure?What is the effect of a low oxygen partial pressure?

•• Another factor that influences the rate at which oxygen dissociates from Another factor that influences the rate at which oxygen dissociates from haemoglobin is the haemoglobin is the temperaturetemperature..

In cooler temperatures, haemoglobin releases oxygen more slowly.In cooler temperatures, haemoglobin releases oxygen more slowly.

* This is no problem for warm-blooded animals, whose body temperature remains * This is no problem for warm-blooded animals, whose body temperature remains constant, however it is an important factor in determining the activity level of constant, however it is an important factor in determining the activity level of cold-blooded animals like amphibians and reptiles.cold-blooded animals like amphibians and reptiles.

What is the significance of the effect of temperature?What is the significance of the effect of temperature?

Carbon dioxide Pick-upCarbon dioxide Pick-up

Who are the players?Who are the players?

RBCsRBCs

About 20% bind to About 20% bind to haemoglobin to form haemoglobin to form carbaminohaemoglobincarbaminohaemoglobin

PlasmaPlasma

About 10% are carried About 10% are carried by the blood plasmaby the blood plasma

Water in the plasma (90%)Water in the plasma (90%)

The rest of the 70% The rest of the 70% combines with water to combines with water to form carbonic acidform carbonic acid

HH22O + COO + CO22 H H22COCO33 H H++ + HCO + HCO33--

The blood plasma buffer systemThe blood plasma buffer system

KHb + HKHb + H++ K K++ + H Hb + H Hb

White Blood CellsWhite Blood Cells

•• In contrast to RBCs , White blood cells are nucleated and colourless, hence the In contrast to RBCs , White blood cells are nucleated and colourless, hence the name “White Blood Cells”name “White Blood Cells”

Why are “White Blood Cells” called so?Why are “White Blood Cells” called so?

• • There are several types of white blood cells, two of the most important disease-There are several types of white blood cells, two of the most important disease-fighting cells are fighting cells are macrophagesmacrophages and and lymphocyteslymphocytes. .

What are the different types of white blood cells?What are the different types of white blood cells?

What is the role of macrophages in fighting disease?What is the role of macrophages in fighting disease?

Macrophages are phagocytic cells that can pass through the walls of capillaries to Macrophages are phagocytic cells that can pass through the walls of capillaries to engulf and digest pathogens.engulf and digest pathogens.

Macrophages are part of the body’s Macrophages are part of the body’s innate immune responseinnate immune response, which is the body’s , which is the body’s generalized response to infection.generalized response to infection.

What is the role of lymphocytes in fighting disease?What is the role of lymphocytes in fighting disease?

• • Lymphocytes are non phagocytic cells that play a role in Lymphocytes are non phagocytic cells that play a role in the body’s the body’s acquired immune responseacquired immune response..

• • This is the response that allows the body to fend against This is the response that allows the body to fend against specific pathogens (Viruses).specific pathogens (Viruses).

•• There are two types of lymphocytes: T lymphocytes There are two types of lymphocytes: T lymphocytes which mature in the thymus gland, and B lymphocytes which mature in the thymus gland, and B lymphocytes which arise from the bone marrowwhich arise from the bone marrow

Types of lymphocytesTypes of lymphocytes

T lymphocytesT lymphocytes B lymphocytesB lymphocytes

Helper T cellsHelper T cells

Bind to the antigenBind to the antigen

Cytotoxic T cellsCytotoxic T cells

The reaction triggers the The reaction triggers the multiplication of multiplication of T cellsT cells

These cells persist for a long These cells persist for a long time after an infection has time after an infection has resolved resolved and can respond and can respond quickly following a second quickly following a second exposure to the same antigen exposure to the same antigen

Memory B cellsMemory B cells

destroy virally destroy virally infected cells and infected cells and tumor cells tumor cells

Plasma B cellsPlasma B cells

Produce antibodies at a Produce antibodies at a rate of 2000 per secondrate of 2000 per second

What are the types of lymphocytes?What are the types of lymphocytes?

Antibodies are antigen Antibodies are antigen specific they have constant specific they have constant regions and variable regions and variable regions, these variable regions, these variable regions act like a (lock) for regions act like a (lock) for the antigens (key) to bind.the antigens (key) to bind.

Variable regionsVariable regions

Constant regionConstant region

PlateletsPlatelets

What are platelets?What are platelets?

Platelets are Platelets are fragments of cellsfragments of cells that were created when larger cells in that were created when larger cells in the bone marrow broke apart, each platelet lasts about a week to 10 the bone marrow broke apart, each platelet lasts about a week to 10 days.days.

What is the main function of platelets?What is the main function of platelets?

The important role of blood platelets is The important role of blood platelets is blood clottingblood clotting, therefore , therefore preventing the body from excessive blood loss.preventing the body from excessive blood loss.

What are the steps of blood clotting?What are the steps of blood clotting?

Substances released Substances released by a broken blood by a broken blood vessel attract platelets vessel attract platelets to the site of the to the site of the broken vesselbroken vessel

Platelets collect Platelets collect and rupture and rupture releasing releasing chemicalschemicals

Chemicals from the Chemicals from the platelets + clotting platelets + clotting agents from the agents from the plasma produce the plasma produce the enzyme enzyme thromboplastinthromboplastin

Thromboplastin + Prothrombin + CaThromboplastin + Prothrombin + Ca++ ThrombinThrombin

ThrombinThrombin + Fibrinogen + Fibrinogen FibrinFibrin

* * FibrinFibrin is an insoluble material that forms a mesh of strands around the area of is an insoluble material that forms a mesh of strands around the area of injury, trapping blood cells and forming the clot.injury, trapping blood cells and forming the clot.

Blood PlasmaBlood Plasma

Composition of plasmaComposition of plasma

WaterWater

92 %92 %

Blood proteinsBlood proteins - - Fibrinogen - Fibrinogen - Serum albumin - Serum albumin - Serum globulinSerum globulin

7 %7 %

Organic substancesOrganic substances e.g. Ureae.g. Urea

Inorganic ionsInorganic ions - Calcium - Calcium - Chlorine - Chlorine - Magnesium - Magnesium - Potassium - Potassium - Sodium - Sodium - Bicarbonates - Bicarbonates - Carbonates - Carbonates - Phosphates - Phosphates

0.14 %0.14 % 0.93 %0.93 %

Blood PlasmaBlood Plasma

When the fibrinogen and other clotting agents are removed from the blood, the When the fibrinogen and other clotting agents are removed from the blood, the straw coloured liquid that remains is called serum.straw coloured liquid that remains is called serum.

What is serum?What is serum?

Serum contains hormones, electrolytes, enzymes, antibodies and waste materials. Serum contains hormones, electrolytes, enzymes, antibodies and waste materials.

What is the composition of serum?What is the composition of serum?

What is anti sera?What is anti sera?

Serum from an immune animal or a person to a particular disease can be injected Serum from an immune animal or a person to a particular disease can be injected into a patient to provide temporary immunity from the disease.into a patient to provide temporary immunity from the disease.

Blood GroupsBlood Groups

Blood Type Protein markers Serum antibodies

A A anti-B

B B anti-A

O neither anti-A and anti-B

AB both A and B neither

Blood Types Determine Blood Compatibility

Rhesus factor and blood compatibility Rhesus factor and blood compatibility

People who carry the Rh protein are called Rh – positive, while People who carry the Rh protein are called Rh – positive, while people without the protein are called Rh – negative.people without the protein are called Rh – negative.

••

•• Unlike the A and B antibodies, the anti – Rh antibody is not always Unlike the A and B antibodies, the anti – Rh antibody is not always present in the blood, it is manufactured by the body only after the present in the blood, it is manufactured by the body only after the exposure to the Rh protein marker.exposure to the Rh protein marker.

This becomes a problem when an Rh-positive father and an Rh-This becomes a problem when an Rh-positive father and an Rh-negative mother conceive a child who is Rh-positive, and red blood negative mother conceive a child who is Rh-positive, and red blood cells leak across the placenta into the mother’s circulatory system cells leak across the placenta into the mother’s circulatory system initiating an immune response and the production of anti-Rh initiating an immune response and the production of anti-Rh antibodies, this will destroy all the foetus red blood cells and put all antibodies, this will destroy all the foetus red blood cells and put all the subsequent pregnancies at risk. the subsequent pregnancies at risk.

This is overcome by giving the mother anti-Rh antibodies midway This is overcome by giving the mother anti-Rh antibodies midway through her first pregnancy or through her first pregnancy or no later than 72 hoursno later than 72 hours after giving after giving birth. This will result in the destruction of any of the baby’s red birth. This will result in the destruction of any of the baby’s red blood cells that have crossed the placenta before the mother’s blood cells that have crossed the placenta before the mother’s immune system starts producing antibodies.immune system starts producing antibodies.

Rh factor and the possible pregnancy complications:Rh factor and the possible pregnancy complications:

The Cardiac CirculationThe Cardiac Circulation

The Heart

How is the control of the heartbeat? How is the control of the heartbeat?

The regulation of the heartbeat comes from within the The regulation of the heartbeat comes from within the heart itself, the impulse that triggers the heartbeat heart itself, the impulse that triggers the heartbeat originates from a specialized muscle tissue in the wall of originates from a specialized muscle tissue in the wall of the right atrium, stimulating the muscle fibres to contract the right atrium, stimulating the muscle fibres to contract and relax rhythmically, this tissue is called the and relax rhythmically, this tissue is called the sinoatrial sinoatrial node (S-A) node.node (S-A) node.

The The sinoatrial nodesinoatrial node is more commonly known as the is more commonly known as the pacemakerpacemaker..

What is the atrioventricular node (A-V node) ? What is the atrioventricular node (A-V node) ?

As the atria contract the impulse reaches another node As the atria contract the impulse reaches another node called the called the atrioventricularatrioventricular node (A-V node)node (A-V node), , this node is this node is located near the atria on the partition between the two located near the atria on the partition between the two ventricles, it transmits the electrical impulse all over the ventricles, it transmits the electrical impulse all over the walls of the ventricles to start their contraction. walls of the ventricles to start their contraction.

The electrical signals can be measured using a device called The electrical signals can be measured using a device called the the electrocardiogram (ECG)electrocardiogram (ECG), the tracing produced is called , the tracing produced is called the the electrocardiographelectrocardiograph..

• SA node: cardiac pacemaker

• AV node: relay impulse

• AV bundle and Purkinje fibers: carry impulse to ventricles

Cardiac Conduction

• Three formationsThree formations

– P wave:P wave: impulse across atria impulse across atria

– QRS complex:QRS complex: spread of impulse down septum, spread of impulse down septum, around ventricles in Purkinje fibersaround ventricles in Purkinje fibers

– T wave:T wave: end of electrical activity in ventricles end of electrical activity in ventricles

Electrocardiograms (ECG)

Electrocardiograms (ECG)

Irregularly irregular, no set pattern

Regular pattern

Chemical regulation of the heart rateChemical regulation of the heart rate

Increasing the heart rateIncreasing the heart rate Decreasing the heart rateDecreasing the heart rate

COCO2 2 increasesincreases

Receptors in the blood vessel Receptors in the blood vessel transmit the information to the transmit the information to the medulla oblongatamedulla oblongata

Medulla oblongata sends impulses to Medulla oblongata sends impulses to release release noradrenalinenoradrenaline that makes the that makes the node fire rapidly.node fire rapidly.

Increased heart rate means Increased heart rate means increased blood pressure increased blood pressure

Receptors in the blood vessels sense the Receptors in the blood vessels sense the increase in the blood pressure and increase in the blood pressure and transmit the information to the medulla transmit the information to the medulla oblongata oblongata

Medulla oblongata sends impulses to Medulla oblongata sends impulses to release release acetylcholineacetylcholine that makes the that makes the node fire slowly.node fire slowly.

The cardiac output and the fitnessThe cardiac output and the fitness

The cardiac output:The cardiac output: is the amount of blood pumped by the heartis the amount of blood pumped by the heart in one minute.in one minute.

The more the oxygen delivered to the bodyThe more the oxygen delivered to the body

The more the cardiac outputThe more the cardiac output

The more the fitnessThe more the fitness

What is the cardiac output?What is the cardiac output?

What is the stroke volume?What is the stroke volume?

The stroke volume:The stroke volume: is the amount of blood forced out of is the amount of blood forced out of the heart with each heart beat.the heart with each heart beat.

Cardiac output = stroke volume x heart rateCardiac output = stroke volume x heart rate

* The average person has a stroke volume of about 70 ml and a * The average person has a stroke volume of about 70 ml and a resting heart rate of about 70 beats per minute.resting heart rate of about 70 beats per minute.

The stroke volume and the fitnessThe stroke volume and the fitness

The more the stroke volume The more the stroke volume

The more the fitnessThe more the fitness

The heart rate and the fitnessThe heart rate and the fitness

The lower the heart rate at rest The lower the heart rate at rest

The more the fitnessThe more the fitness

The lower heart rate is an indication to the higher stroke The lower heart rate is an indication to the higher stroke volume, in elite athletes the heart rate at rest could reach volume, in elite athletes the heart rate at rest could reach 30 beats per minute, with a maximum cardiac output of 4 30 beats per minute, with a maximum cardiac output of 4 litres per minute.litres per minute.

How?How?

Heart Defects

• Abnormal sound of blood flow in aAbnormal sound of blood flow in a narrow or incompetent valvenarrow or incompetent valve

• Can be from a “hole in the heart”Can be from a “hole in the heart” between the atria or ventriclesbetween the atria or ventricles

• Heart murmursHeart murmurs

• Mitral valve prolapseMitral valve prolapse

• The flaps of the mitral valves close unevenlyThe flaps of the mitral valves close unevenly

CauseCause

CauseCause

Coronary artery by-pass grafting (CABG)Coronary artery by-pass grafting (CABG)

• Smoking: Don’t • Blood lipids: monitor cholesterol levels• Exercise: regular and moderate• Blood pressure: treat hypertension• Weight: being overweight increases risk

of heart attack and stroke• Stress: avoid chronic stress

Reducing the Risk of Cardiovascular DiseaseReducing the Risk of Cardiovascular Disease

Copyright © 2001 Benjamin Cummings, an imprint of Addison Wesley Longman, Inc.

Cardiac Anatomy Quiz

Blood Pressure:Blood Pressure:• Is the force exerted by the blood on the walls of blood vessels• The instrument used to measure the blood pressure is the

mercury sphygmomanometer in conjunction with the stethoscope

• There are many factors that affect the blood pressure:• The diet: Excess salt raised the blood pressure, as the increased

levels of Na+ ions in the blood will result in the retention of more water and increase the volume of the blood

• Waste products: like CO2 and lactic acid result in the vasodilatation of arterioles, which increases the blood flow and lowers the blood pressure

• Some disease conditions: cholesterol deposits narrow blood vessels and result in raising the blood pressure

Sphygmomanometer Stethoscope

• Autonomic Nervous control of blood PressureAutonomic Nervous control of blood Pressure::

Autonomic Nervous System

Sympathetic n.s. Parasympathetic n.s

• Increases the blood pressure• Increases the heart rate • Increases the respiratory rate

• Autonomic Nervous regulation of the blood pressure:Autonomic Nervous regulation of the blood pressure:

High blood High blood pressurepressure

The blood pressure receptors in The blood pressure receptors in The Aorta and the carotid arteries The Aorta and the carotid arteries Will detect the high pressure and Will detect the high pressure and

signal the medulla oblongatasignal the medulla oblongata

The Medulla Oblongata will stop The Medulla Oblongata will stop the action of the Sympatheticthe action of the Sympathetic

Nervous System and stimulate Nervous System and stimulate the action of the Parasympatheticthe action of the Parasympathetic

Nervous SystemNervous System

Lower the Lower the Blood pressureBlood pressure

• Capillary Fluid Exchange

Arterial SideArterial Side Venous SideVenous Side

35 mm Hg35 mm Hg 15 mm Hg15 mm Hg

Blood PressureBlood Pressure

Osmotic PressureOsmotic Pressure

25 mm Hg25 mm Hg

Tissue CellsTissue Cells Tissue CellsTissue Cells

WaterWater W

ater

Wat

er

The Lymphatic SystemThe Lymphatic System

• The lymphatic system is the system responsible for:The lymphatic system is the system responsible for:

1.1. Returning lymph (with its content of the plasma proteins that Returning lymph (with its content of the plasma proteins that have leaked to the tissues) back to the blood circulation have leaked to the tissues) back to the blood circulation through the through the Thoracic ductThoracic duct that pours its contents into the right that pours its contents into the right atrium. This prevents a high osmotic pressure in the tissues, atrium. This prevents a high osmotic pressure in the tissues, which if happens will result in tissue swelling.which if happens will result in tissue swelling.

2.2. Defence through the production of lymphocytes and the Defence through the production of lymphocytes and the filtration of blood and lymph.filtration of blood and lymph.

• The Lymphatic System has its own vessels, which join the The Lymphatic System has its own vessels, which join the circulatory system when the thoracic duct pours its contents in circulatory system when the thoracic duct pours its contents in the right atrium.the right atrium.

The lymphatic system The lymphatic system in relation to the in relation to the

circulatory systemcirculatory system

The Lymphatic SystemThe Lymphatic System

Lymph Lymph vessels Lymph organsLymph Lymph vessels Lymph organs

1. Lymph: 1. Lymph: is a clear, watery fluid, sometimes faintly yellow, lymph is a clear, watery fluid, sometimes faintly yellow, lymph removes certain proteins from the tissues as well as bacteria, the removes certain proteins from the tissues as well as bacteria, the bacteria will be filtered by the lymph nodes while the proteins bacteria will be filtered by the lymph nodes while the proteins will return back to the blood when the lymph is poured through will return back to the blood when the lymph is poured through the thoracic duct into the right atrium and mixes with the bloodthe thoracic duct into the right atrium and mixes with the blood

2. Lymph vessels: 2. Lymph vessels: A net work of vessels that have a dead end A net work of vessels that have a dead end beginnings, these vessels merge until they finally form the beginnings, these vessels merge until they finally form the thoracic duct that opens in the right atrium of the heart, and this thoracic duct that opens in the right atrium of the heart, and this is where lymph mixes with the bloodis where lymph mixes with the blood

3. Lymph organs 3. Lymph organs

Primary Lymph organs Secondary Lymph organsPrimary Lymph organs Secondary Lymph organs

1. Red bone marrow 1. The Spleen1. Red bone marrow 1. The Spleen2. Thymus gland 2. The lymph nodes2. Thymus gland 2. The lymph nodes

Red bone marrow: Red bone marrow: Is the site for manufacturing both Is the site for manufacturing both types of lymphocytes (B-lymphocytes and T-lymphocytes)types of lymphocytes (B-lymphocytes and T-lymphocytes)

Thymus gland: Thymus gland: Is the site where the maturation of the Is the site where the maturation of the T-lymphocytes take placeT-lymphocytes take place

The spleen: The spleen: has the following functions:has the following functions:1. Acts as a reservoir for the storage of blood, and in case of 1. Acts as a reservoir for the storage of blood, and in case of

emergency it can contract and push more blood to the emergency it can contract and push more blood to the circulation.circulation.

2. Is an organ designed to filter blood2. Is an organ designed to filter blood3. Is involved in the production of lymphocytes3. Is involved in the production of lymphocytes