The Cardiovascular System

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The Cardiovascular System
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Tasks of the CV System

• Carry oxygen from the lungs to body cells.
• Carrying carbon dioxide, a waste gas, from your
  cells back to the lungs to be exhaled.
• Delivering other waste products to the kidneys
  for removal from the body.

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Tasks of the CV System

• Absorbing nutrients from food and delivering
  nutrients to body cells.
• Helping white blood cells fight disease by
  attacking infectious organisms (pathogens).

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The Heart

• The heart is the muscle that makes the
  cardiovascular system work.
• It consists of a special type of muscle called
  myocardium.
• It is composed of 4 chambers
• The 2 upper chambers are the atria
• The 2 lower chambers are the ventricles

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The Heart

• A wall of tissue called the septum separates the
  4 chambers of the heart.
• One way valves at the exits of each heart chamber
  guarantee that blood can flow in only one
  direction.

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The Heart

• A small area of the right atrium serves as a
  natural pacemaker, controlling the rate at which
  the heart beats.
• Electrical impulses stimulate the atria to
  contract, forcing blood into the ventricles.
• These electrical impulses travel through the
  heart to an area between the 2 ventricles.
• There they stimulate the muscles of the
  ventricles to contract, pumping blood out of the
  heart

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Blood

• Blood is the fluid that delivers oxygen,
  hormones, and nutrients to the body cells and
  carries away waste that the cells produce.
• Blood is produced in the bone marrow of long
  bones.

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Blood

• Plasma
• The fluid in which other parts of the blood are
  suspended.
• It makes up 55 of the total blood volume.
• Its mainly water (92), but also contains
  nutrients, proteins, salts, and hormones.

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Blood

• Red Blood Cells
• The cells that transport oxygen and carbon
  dioxide molecules.
• Makes up about 40 of normal blood
• Each red blood cell contains hemoglobin, a
  protein in the blood which
• Contains iron that binds with oxygen and carbon
  dioxide molecules
• Gives the blood its red color

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Blood

• White Blood Cells
• The cells that protect the body against
  infection.
• Some white blood cells
• Surround and ingest the organisms which cause
  disease.
• Form antibodies that provide immunity against a
  second attack from a specific disease
• Fight allergic reactions

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Blood

• Platelets
• The cells in the blood that cause blood clots to
  form.
• When the wall of a blood vessel tears, they
  collect at the tear and release a chemical which
  causes the blood to produce small fibers (fibrin)
  which trap the platelets along with red and white
  blood cells.
• The mass of fibrin, platelets, and red and white
  blood cells plug the injury and forms a clot
  which dries to form a scab.

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Blood Vessels

• Blood is distributed throughout the body through
  a network of vessels.
• There are more than 60,000 miles of blood vessels
  in your body.
• The blood vessels are divided into
• Arteries
• Capillaries
• Veins

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Blood Vessels

• Arteries
• Blood vessels that carry oxygenated blood away
  from the heart.
• They branch into progressively smaller vessels
  called arterioles which deliver blood to the
  capillaries.
• The arteries thick walls enable it to withstand
  the high blood pressure it is subjected to every
  time the heart beats.

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Blood Vessels

• The artery walls are composed of three layers
• A tough, fibrous outer layer
• A thick muscular middle layer
• An inner layer of smooth epithelial cells

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Blood Vessels

• The muscular wall of the artery helps the heart
  pump the blood by contracting when the heart
  relaxes.
• Since it keeps pace with the heart, we can
  measure heart rate by counting the contractions
  of the artery (pulse)

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Blood Vessels

• Capillaries
• The small blood vessels that carry blood from the
  arterioles to the venules which empty into veins.
• Some capillaries are 50 times thinner than a
  strand of hair.

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Blood Vessels

• It is through the thin capillary walls that
  oxygen and nutrients pass from the blood to body
  cells, and waste products move from cells into
  the blood.

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Blood Vessels

• Capillaries near the skins surface dilate (open)
  or constrict (close) to help regulate the bodys
  temperature.

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Blood Vessels

• Veins
• The blood vessels that return deoxygenated blood
  to the heart.
• The walls of the veins are thinner than those of
  the arteries, so blood is visible through the
  skin on some parts of your body.
• The blood appears blue because your skin refracts
  light.

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Blood Vessels

• Many veins have valves, that along with muscle
  contractions from surrounding muscles, help
  prevent the backflow of blood as its pumped back
  to the heart.

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Circulation of Blood

• Pulmonary Circulation
• The movement of blood from the heart, to the
  lungs, and back to the heart again.
• Deoxygenated blood enters the right atrium
  through the vena cava.
• The right atrium contracts, pushing the blood
  into the right ventricle.
• The right ventricle contracts, pushing the blood
  into the pulmonary artery.
• The pulmonary artery takes the blood to the lung

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Circulation of Blood

1. In the lung, deoxygenated blood is exchanged for
   oxygenated blood
2. The pulmonary vein takes the oxygenated blood to
   the left atrium.
3. The left atrium contracts, pushing the blood into
   the left ventricle.
4. The left ventricle contracts, pushing the blood
   into the aorta.

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Circulation of Blood

• Systemic Circulation
• The movement of blood to and from the heart.
• It delivers oxygen and nutrients to the tissues
  of the body and the movement of deoxygenated
  blood and waste products to the heart.

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Circulation of Blood

• Coronary Circulation
• The movement of blood through the tissues of the
  heart.
• Serious heart damage may occur if the heart
  tissue does not receive a normal supply of food
  and oxygen.

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Blood Pressure

• Blood pressure is a measurement of the amount of
  force that the blood places on the walls of blood
  vessels, particularly large arteries, as it is
  pumped through the body.

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Blood Pressure

• Systolic Pressure the maximum pressure as your
  heart contracts to push blood into your arteries.
• Diastolic Pressure the pressure at its lowest
  point where your heart is relaxed.

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Blood Pressure

• A healthy persons blood pressure will vary
  within the normal range of 120/80.
• Blood pressure above 140/90 is considered high
  and places a strain on the heart and can lead to
  cardiovascular disease.

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Blood Types

• There are two distinct chemical molecules, called
  antigens, present on the surface of red blood
  cells.
• Blood type is determined by the presence or
  absence of these antigens.
• Type A A antigen present
• Type B B antigen present
• Type AB Both antigens present
• Type O Neither antigen present

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Blood Types

• If two different blood types are mixed together,
  the blood cells may clump together in the blood
  vessels, causing a potentially fatal situation.
• It is important that blood types be matched
  before blood transfusions take place.
• In an emergency, type O blood can be given
  because it is most likely to be accepted by all
  blood types. However, there is still a risk.

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Rh Factor

• Most blood also contains a certain protein called
  the Rh factor.
• If your blood contains this protein, you are
  referred to as Rh positive.
• Blood that doesnt contain this protein is called
  Rh negative.

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Rh Factor and Pregnancy
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Care Problems of the CV System

• Follow a well-balanced diet low in saturated
  fats, cholesterol, and salt
• Maintain a healthy weight to reduce stress on the
  heart, blood vessels and lymph vessels
• Participate in regular aerobic exercise at least
  30 minutes three or four times per day

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Care Problems of the CV System

• Avoid the use of tobacco products and exposure to
  secondhand smoke.
• Avoid illegal drugs, including stimulants,
  marijuana, and ecstasy.

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Problems of theCardiovascular System
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Congenital Heart Defects

• Congenital is any condition that is present at
  birth.
• One common type is a septal defect, in which a
  hole in the septum allows oxygenated blood to mix
  with deoxygenated blood and affects the pumping
  efficiency of the heart.

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Congenital Heart Defects

• Other defects include valves which may not
  function properly, or the aorta may be abnormally
  narrow, reducing the amount of blood flowing to
  the body.

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Congenital Heart Defects

• In many cases the cause of a congenital defect is
  unknown, but the use of alcohol and other drugs,
  or certain infections during pregnancy may be
  associated with heart defects in newborns. It may
  also be hereditary.
• Most defects require medication and possibly
  surgery to repair the affected portion of the
  heart.

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Cardiovascular Disease

• A group of diseases that include hypertension,
  heart disease, and stroke.
• It is the number one killer of both men and women
  among all racial and ethnic groups in the U.S.,
  killing about 95,000 Americans each year.
• Many of these diseases are associated with
  lifestyle behaviors.

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Heart Murmur

• Abnormal sounds that are made as blood flows
  through the heart.
• It can be caused by a defective valve that is too
  narrow causing blood to be pushed through the
  restricted opening with more force than normal,
  or a valve that doesnt close properly allowing
  blood to leak back through it.
• Most murmurs are slight and disappear without
  treatment, while others may require surgery

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Varicose Veins

• Varicose veins form if the valves in veins do not
  close tightly enough to prevent backflow of
  blood, causing the veins to become large and
  painful.
• They most commonly occur in the legs.
• Weakened valves can be the result of a congenital
  defect, or natural aging.

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Varicose Veins

• Physical activity helps prevent varicose veins.
• Treatment includes
• reducing standing time
• Exercise
• Elevating legs when sleeping
• In extreme cases, surgery to remove the affected
  vein.

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Anemia

• A condition in which the ability of the blood to
  carry oxygen is reduced.
• It can result from low numbers of red blood cells
  or from low concentrations of hemoglobin in the
  blood.
• The most common cause is iron deficiency, which
  can be avoided by eating foods high in iron.
• Taking an iron supplement may also be recommended.

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Anemia

• Sickle cell anemia is a special form of anemia
  where the red blood cells are sickle shaped. They
  are stiff and sticky and tend to clump and block
  blood flow in the blood vessels of the limbs and
  organs, causing pain.

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Leukemia

• A form of cancer in which any one of the
  different types of white blood cells is produced
  excessively and abnormally.
• The abnormal white blood cells cannot function
  properly, making the patient very susceptible to
  infection

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Leukemia

• The uncontrolled production of white blood cells
  can hinder production of red blood cells and
  platelets resulting in infection, severe anemia,
  or uncontrolled bleeding.

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Leukemia

• Treatment options include
• Chemotherapy
• Radiation therapy
• Bone marrow transplants

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Hemophilia

• An inherited disorder in which the blood does not
  clot properly.
• Certain proteins, called clotting factors, are
  not present.
• This may cause uncontrolled bleeding that can
  occur spontaneously, or as the result of injury.

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Hemophilia

• Bleeding may take place internally in muscles,
  tissues of the digestive or urinary tract, and
  the joints.
• It may also occur externally as the result of
  injury or surgery.

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Hemophilia

• Treatment includes injections that introduce the
  missing clotting factors into the blood, which
  are extracted from blood donated by healthy
  individuals.