The circulatory system carries blood to and from all the cells of our body. It brings cells nourishment and other important molecules, and takes away their.

The circulatory system carries blood to and from all the cells of our body. • It brings cells nourishment and

other important molecules, and takes away their wastes.

The circulatory System is comprised:*Blood*Blood vessels *Heart

• Is a fluid tissue.• Is red and viscous.• Blood constituents: is made up

of: Plasma and the Blood cells.

• On average our body contains 5.6 L for males and 4.5 L for females, of blood but we can lose up to 1 L before it becomes life threatening.

Plasma• Plasma is clear yellow fluid and makes up

55% of our blood volume.

• Plasma contains 90% water and 10% dissolved substances such as :– Nutrients: Ex. Glucose– Hormones: Ex. Testosterone– Antibodies: Proteins that can destroy bacteria– Other Proteins: that help in the coagulation of

blood.– Waste Products: Carbon dioxide, urea

• Its function is to transport these dissolved substances throughout the body.

Blood Cells (Formed Elements)• Makes up 45% of blood volume• Three basic kinds of blood cells :

– Red blood cells – White blood cells. – Platelets.

• about 5 billion / mL• Red, biconcave disks • Made in bone marrow• No nucleus, few organelles• Contain the protein hemoglobin (contains

iron) to transport oxygen(O2) to body cells. • As Hemoglobin takes in oxygen it turns

from a wine colour to bright red.• Transports CO2, goes from bright red to

wine colour.

• Part of the immune system • 4-11 million (5 types)• Provides immunity to defend against

invaders such as bacteria and viruses. • made in the bone marrow and can be

stored in the lymph nodes until needed

• Some can travel outside of the normal blood stream, in the lymphatic system to track down sites of infections.

Platelets – 150-400 million– Irregular shaped– Come from large cells in bone marrow– Transparent cells– Function in blood-clotting process.

Blood Types.• There are 8 different blood types in humans, based on the

ABO-Rh system.• A+, A-, B+, B-, AB+, AB-, O+, O-• Blood type is determined by the kind of antigen present on

the surface of the red blood cells of a person.• An antigen is a protein or carbohydrate that acts as a label,

to signal the body to recognize foreign substances that enter the body.

Antigens and Antibodies.• There are 3 basic antigens that can be found

on the surface of red blood cells :– Antigen A– Antigen B– Antigen Rh

• There are also 3 basic antibodies corresponding to these antigens :– Anti- A, B, and Rh, each react to their particular

antigen and cause the blood to clump together.

Antigens and Antibodies.• A person with antigen A and the Rh factor

on their RBC’s is said to be of type A+ .• This also means that their plasma will

contain the antibodies against the B antigen, but not against A or Rh.

• A person with antigens A,B and Rh has no antibodies against these in their plasma. They are said to be AB + blood.

• A person with no antigens (type O -) will have all the antibodies in their plasma. (A, B, Rh )

Blood Transfusions.• The injection of blood into a person.• Donor: person giving blood for the purpose of a transfusion.• Recipient: person who receives blood from a transfusion.

• Donor’s blood cannot contain any antigens that the recipient’s blood doesn’t have.

• O- is a universal donor because it has no antigen for the antibodies to react to.

• AB+ is the universal receiver• Blood Compatibility: one person can receive blood from

another person.

• The blood vessels act as a closed circuit for transportation.

• Circulation due to pressure supplied by the heart.

• Three types:– Arteries “red”– Veins “blue”– Capillaries “both”

The Cardiovascular System•Comprised of blood, blood vessels and the heart.

• Contain blood that is being sent away from the heart to body parts.

• transport blood high in Oxygen and low in Carbon Dioxide

• Exception: pulmonary artery• Arteries are largest blood vessels.• thick walled and under high pressure,

which is why we can feel a pulse every time the heart beats.

• Largest: Aorta→ main lead from heart.

• Arteries branch into arterioles (small arteries) which branch into capillaries.

Arteries

• These are the smallest blood vessels

• Narrow and are single-cell thick allowing for gas exchange, both at the lungs and at the cells.

• connect the arteries to the veins.• Exchange site for nutrients and

cellular waste.• Nutrients and gas pass from

capillaries to extracellular fluid to cells.

• Waste travels the reverse path.

Capillaries

• Capillaries lead into venules (small veins) that lead into veins that carry blood towards the heart with the aid of one-way valves and muscle contractions.

• Mainly transporting CO2

• Exception: pulmonary vein• thinner walls than arteries • No pulse and are under low blood pressure• Largest: Vena Cava (superior & inferior)

leading towards heart.

Veins

*In a normal vein, the valves close to prevent backward flow of blood.

*In a varicose vein, the flaps cannot close because the vein is abnormally widened, blood can flow in the wrong direction.

Varicose veins

Blood Flow

• Oxygenated blood flows from heart arteries arterioles capillaries (gas exchange) deoxygenated blood (CO2) venules veins heart.

• The heart is the pump of the circulatory (cardiovascular) system.• ~size of fist, located in thoracic cage between lungs.

• It is composed of 4 chambers; the left and right atria and left and right ventricles.

• The left and right sides of the heart are separated by a septum.

• The left atrium receives O2 blood from lungs via pulmonary vein and pumps it down into left ventricle. The ventricle pumps into the Aorta.

• The right atrium receives CO2 blood from vena cavas and pumps it down into right ventricle. The ventricle pumps blood to lungs via pulmonary artery.

Chambers of the heart.

• control the flow of blood, making sure that it flows in only one direction.

• found in the heart and in the veins, especially those of the legs, where they help to return the blood back up to the heart.

• Valves between the atria and ventricles are called atrioventricular valves.

• Atrioventricular valves: tricuspid valve (right side), mitral valve (left side)

Septum

Circulation• Pulmonary circulation: blood

circulation between the right side of the heart and the lungs.

• Rich in CO2 passes through right ventricle pulmonary artery pulmonary arterioles pulmonary capillaries of the lungs pulmonary venules pulmonary vein left atrium.

• Gas exchange between capillaries and alveoli.

• Blood rich in O2 returns via pulmonary vein towards left side of heart.

• Is a shorter route.

Pulmonary Circulation

Systemic Circulation• Blood circulation between the left side

of the heart and the rest of the body (both upper and lower regions).

• Blood is rich in O2 as it leaves the left ventricle and enters aorta.

• Leads to smaller arteries and arterioles to capillaries

• Drops off O2, nutrients and other substances, picks up CO2 and other waste.

• Blood returns to heart via the superior and inferior vena cava.

• Is a longer route.

• Diastolic pressure : Is the pressure inside of the arteries after the contraction, when the heart muscle relaxes the atria refills with blood (diastole).

• Systolic pressure : Is the pressure inside the arteries at the moment of the muscular contraction of the heart’s ventricles (systole).

• The tool used to measure blood pressure is called a : Sphygmomanometer.

• Optimal blood pressure in an adult at rest is 120/80 mmHg, in which 120 describes systolic pressure and 80 describes diastolic pressure.

• Your pulse is a wave of high pressure that can be felt at the arteries following the contraction of the ventricles of the heart. (Systolic pressure)

• The average pulse for a human at rest is around 75 beats / minute.

• The maximum amount of times your heart can beat in a minute is calculated by: 220 – age.

• High blood pressure/Hypertension: condition that can lead to cardiovascular disease.

• Constricted arteries decreases blood flow, causes excessive pressure against vessel walls. The heart works harder to pump blood through the narrowed arteries.

• If the condition persists, damage to the heart and blood vessels is likely, increases risk for stroke, heart attack, and kidney or heart failure.

• Hypertension is defined as blood pressure greater than or equal to 140/90 mm HG at rest.

FYI

• Is a system of thin tubes that runs parallel to the circulatory system. • It is the go-between for the circulatory system and cells. •The exchange of substances, ex: nutrients, occurs between the extracellular/interstitial fluid.• Extracellular fluid: clear liquid surrounds cells, contains water, white blood cells and other substances from plasma.

Blood (in capillaries)

Lymphatic Vessels• These tubes are called lymphatic vessels.• The lymphatic vessels branch through all parts of the body

carrying a colourless liquid called lymph (extracellular fluid).

• Muscle contractions move the lymph through the vessels and the large vessels contain valves to keep the flow in the right direction.

• Water constantly leaks out of plasma into extracellular fluid, this fluid becomes lymph.

• Lymph contains a high number of lymphocytes (white blood cells), cellular waste and water.

• Lymph is eventually returned to the circulatory system via the veins.

Lymph nodes/glands

• Along the lymph vessels are small bean-shaped lymph nodes or glands: they act as filters of the blood and lymph to fight off infections.

• High concentration of white blood cells.

• White blood cells leave capillaries through a process called diapedesis. They do this by altering their shape to pass through the pores.

• Foreign invaders usually make their way into extracellular fluid, lymph or blood.

3) Fighting infection• Makes special white blood cells (lymphocytes) that produce

antibodies • Lymphocytes consume invaders through phagocytosis. • Phagocytosis: white blood cells ingest and destroy

microorganisms.• Antibodies recognize antigens of specific invaders.

• Can neutralize invader and/or mark for destruction.• Antigens are substances recognized as foreign by the body

triggering production of antibodies. • White blood cells are immunizing: can remember how to

produce a particular antibody.

• Spleen→  acts a filter for lymph fluid: destroys any microorganisms and worn out red blood cells. Aids in production of red blood cells.  • Thymus → produces white blood cells.    • Tonsils → protects entrance of oral and nasal cavity from bacteria and viruses.  

The Lymphatic System also includes:

The lymphatic system does three main jobs in the body:

1) Drains fluid back into the bloodstream from the tissues

2) Filters lymph through spleen 3) Fights infections