Circulatory SystemCirculatory System

Circulatory System IntroCirculatory System IntroThe Circulatory or cardiovascular system The Circulatory or cardiovascular system

consists of:consists of:• The HeartThe Heart• The BloodThe Blood• Blood VesselsBlood Vessels

Together with the lymphatic system, the Together with the lymphatic system, the circulatory system:circulatory system:

• Delivers oxygen and nutrients to cellsDelivers oxygen and nutrients to cells• Removes waste from cellsRemoves waste from cells• Maintains the balance of water in the bodyMaintains the balance of water in the body

Animation of the HeartAnimation of the Heart

BloodBlood• A Specialised type of connective tissueA Specialised type of connective tissue

• It is a thick liquid with a metallic tasteIt is a thick liquid with a metallic taste

• Blood accounts for about 8% of our total Blood accounts for about 8% of our total body weightbody weight

• Blood volume in a healthy adult:Blood volume in a healthy adult:

Male = 5-6LMale = 5-6L Female = 4-5LFemale = 4-5L

Functions of BloodFunctions of BloodBlood performs a number of specialised Blood performs a number of specialised

functions:functions:• Transports nutrients, oxygen, carbon dioxide, Transports nutrients, oxygen, carbon dioxide,

waste products and hormones to cells and waste products and hormones to cells and organs around the body.organs around the body.

• Protects us from bleeding to death, via Protects us from bleeding to death, via clotting, and from disease, by destroying clotting, and from disease, by destroying invasive microorganisms and toxic invasive microorganisms and toxic substances.substances.

• Acts as a regulator of temperature (vessels Acts as a regulator of temperature (vessels constrict to conserve or dilate to release heat constrict to conserve or dilate to release heat to the surface for cooling), the water content to the surface for cooling), the water content in cells and body pH.in cells and body pH.

Composition of BloodComposition of Blood1.1. Solid component (Blood Cells)Solid component (Blood Cells)• 45% of total blood volume.45% of total blood volume.• Red blood cells (erythrocytes), white blood Red blood cells (erythrocytes), white blood

cells (leukocytes), or platelets cells (leukocytes), or platelets (thrombocytes).(thrombocytes).

2.2. Liquid component (Blood Plasma)Liquid component (Blood Plasma)• 55% of total blood volume.55% of total blood volume.• Composed of 91.5% water and 8.5% of Composed of 91.5% water and 8.5% of

nutrients, waste products, proteins, enzymes nutrients, waste products, proteins, enzymes and hormones.and hormones.

• Straw coloured or yellowy solution.Straw coloured or yellowy solution.• Nutrients from the small intestine is Nutrients from the small intestine is

absorbed into the plasma and transported absorbed into the plasma and transported around the body.around the body.

Red Blood CellsRed Blood CellsBi-concave discsBi-concave discs

Contains an oxygen-carrying pigment Contains an oxygen-carrying pigment called Haemoglobin (Hb). This gives called Haemoglobin (Hb). This gives blood its red colour.blood its red colour.

Oxygen (OOxygen (O22) is carried by Hb and ) is carried by Hb and transported from the lungs to all cells. transported from the lungs to all cells. This reaction forms oxyhaemoglobin This reaction forms oxyhaemoglobin (aided by iron molecules).(aided by iron molecules).

Carbon Dioxide(COCarbon Dioxide(CO22) is also transported ) is also transported this way. Formation is called this way. Formation is called carbaminohaemoglobin.carbaminohaemoglobin.

Red Blood CellsRed Blood Cells

Red Blood Cell shapeRed Blood Cell shape

Red Blood Cell cut in halfRed Blood Cell cut in half

Red Blood Cells as they Red Blood Cells as they appear in a blood clotappear in a blood clot

Red Blood CellsRed Blood CellsLife Cycle is approximately 120 days Life Cycle is approximately 120 days and they are replaced at the rate of 2 and they are replaced at the rate of 2 million per second. They are destroyed million per second. They are destroyed in the spleen.in the spleen.

They are reproduced in red bone They are reproduced in red bone marrow from stem cells.marrow from stem cells.

Red Blood Cells function is to transport Red Blood Cells function is to transport OO22 and CO and CO22 around the body. around the body.

PlateletsPlateletsSmall colour-less bodies that usually Small colour-less bodies that usually appear as irregular spindles or discs appear as irregular spindles or discs that are much smaller than RBC & WBC.that are much smaller than RBC & WBC.

Produced in red Produced in red

bone marrow.bone marrow.

Life cycle is approximately 5 to 9 days.Life cycle is approximately 5 to 9 days.

Platelets are involved in the process of Platelets are involved in the process of clotting and they help to repair slightly clotting and they help to repair slightly damaged blood vessels.damaged blood vessels.

White Blood CellsWhite Blood CellsSlightly larger than red blood cells.Slightly larger than red blood cells.

Classified according to the presence of Classified according to the presence of absence of granules in their cytoplasm.absence of granules in their cytoplasm.

Life cycle is from a few hours to a few Life cycle is from a few hours to a few days.days.

Produced in bone marrow and lymph Produced in bone marrow and lymph tissue.tissue.

They move to areas of infection or They move to areas of infection or disease to engulf invading bodies (puss disease to engulf invading bodies (puss is the accumulation of WBC).is the accumulation of WBC).

White Blood CellsWhite Blood Cells

See overhead or handout for See overhead or handout for diagramdiagram

PhagocytosisPhagocytosis

See overhead or handout for See overhead or handout for diagram diagram

Blood VesselsBlood Vessels

Heart > Arteries > Arterioles > Capillaries > Heart > Arteries > Arterioles > Capillaries > Venules > Veins > HeartVenules > Veins > Heart

ArteriesArteries

• Carry blood away from the heart to tissuesCarry blood away from the heart to tissues• Thick elastic walls as blood is pumped Thick elastic walls as blood is pumped

through them at high pressure in surges.through them at high pressure in surges.

ArteriesArteries• Three layers – endothelium liningThree layers – endothelium lining

- involuntary muscle- involuntary muscle

- tough fibrous tissue- tough fibrous tissue

• Surges are called heartbeatsSurges are called heartbeats

• Pressure decreases as distance from Pressure decreases as distance from the heart increases. Blood passes the heart increases. Blood passes through small vessels called through small vessels called arterioles.arterioles.

VeinsVeinsCarry blood from tissues to Carry blood from tissues to the heartthe heart

Thinner walls and less elastic Thinner walls and less elastic as pressures decreases the as pressures decreases the blood gets closer to the heart.blood gets closer to the heart.

The contraction and relaxation of the The contraction and relaxation of the muscles assists the blood to stream back muscles assists the blood to stream back steadily to the heart.steadily to the heart.

Gravity affects blood flow – blood above the Gravity affects blood flow – blood above the heart flows easily.heart flows easily.

VeinsVeins

Valves prevent the blood from Valves prevent the blood from flowing back the wrong way against flowing back the wrong way against the force of gravity. After standing the force of gravity. After standing for a long time, legs can feel heavy for a long time, legs can feel heavy and swollen. Blood pools in the lower and swollen. Blood pools in the lower legs because of gravity and lack of legs because of gravity and lack of movement. Once moving, the movement. Once moving, the mucsles squeeze the blood up mucsles squeeze the blood up through the veins towards the heart.through the veins towards the heart.

CapillariesCapillaries

A very small network A very small network of vessels.of vessels.

One cell wideOne cell wide

Lie between arterioles and venules, Lie between arterioles and venules, connecting both systemsconnecting both systems

CapillariesCapillaries

Arterioles branch off Arterioles branch off arteries and venules arteries and venules branch off veins. They branch off veins. They meet in the middle to form meet in the middle to form capillaries.capillaries.

Semipermeable membrane where O2, CO2 Semipermeable membrane where O2, CO2 and nutrients are exchanged between the and nutrients are exchanged between the blood and cells of the body.blood and cells of the body.

Feeds muscles, joints, tissues and organs Feeds muscles, joints, tissues and organs in clusters.in clusters.

Blood VesselsBlood Vessels

Circulatory SystemCirculatory System

See overhead or handout for diagram See overhead or handout for diagram of vital blood vessels of the body.of vital blood vessels of the body.

HeartHeartInvoluntary muscle.Involuntary muscle.

Pericardium is a triple layered bag Pericardium is a triple layered bag that surrounds, anchors and protects that surrounds, anchors and protects the heart.the heart.

Four hollow chambers - 2 AtriaFour hollow chambers - 2 Atria - 2 - 2

VentriclesVentricles

Atria act as receiving chambers for Atria act as receiving chambers for blood returning to the heart. Small blood returning to the heart. Small and thin as they only pump next and thin as they only pump next door.door.

HeartHeart

Ventricles are large as they propel the Ventricles are large as they propel the from the heart into circulation around from the heart into circulation around the body.the body.

Dense connective tissue called valves, Dense connective tissue called valves, prevent the back flow of blood into the prevent the back flow of blood into the chambers by opening and shutting chambers by opening and shutting when the heart contracts and relaxes. when the heart contracts and relaxes. Tricuspid and Bicuspid valves.Tricuspid and Bicuspid valves.

Heart contracts and squeezes blood Heart contracts and squeezes blood into arteries – systole.into arteries – systole.

HeartHeartHeart relaxes and fills with blood – Heart relaxes and fills with blood – diastole.diastole.

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

Pulmonary vein has oxygenated blood. Pulmonary vein has oxygenated blood. Other veins have deoxygenated blood. Other veins have deoxygenated blood.

HeartHeart

HeartHeart

See overhead for a greater zoom into See overhead for a greater zoom into the heartthe heart

Anatomy of the HeartAnatomy of the HeartAtrium:Atrium:

Ventricle:Ventricle:

Septum:Septum:

Vena Cava:Vena Cava:

Pulmonary Artery:Pulmonary Artery:

Pulmonary Vein:Pulmonary Vein:

Anatomy of the HeartAnatomy of the HeartAtrioventricular Valves:Atrioventricular Valves:

Semilunar Valves:Semilunar Valves:

Sinuatrial Valves:Sinuatrial Valves:

Papillary Valves:Papillary Valves:

Myocardium Walls:Myocardium Walls:

Aorta:Aorta: