The Cardiovascular an Lymphatic Systems

The Circulatory System

• The cardiovascular system consists of the blood vessels and the heart.

• The blood vessels conduct blood in continuous loops.

• The heart is a muscular pump.

• Cardiovascular disease is a major killer in the United States.

• The lymphatic system functions in the circulatory and immune systems.

The Cardiovascular System

• The cardiovascular system is composed of

  • Blood

  • Blood vessels

  • Heart

• Parts of the Cardiovascular System:

  • Veins

    • Carry blood back to the heart.

  • Superior vena cava

    • Carries blood from the upper body back to the heart.

  • Renal vein

    • Carries blood from the kidney to the heart.

  • Radial vein

    • Carries blood from the hand back to the heart.

  • Femoral vein

    • Carries blood from the thigh and inner knee back to the heart.

  • Jugular veins

    • Carry blood from head to the heart.

  • Pulmonary veins

    • Carry oxygenated blood from the lungs to the heart.

  • Inferior vena cava

    • Carries blood from the lower body back to the heart.

  • Iliac vein

    • Carries blood from the pelvic organs and abdominal wall back to the heart.

  • Arteries

    • Carry blood away from heart.

  • Carotid arteries

    • Deliver blood to the head and the brain.

  • Coronary arteries

    • Deliver blood to the heart muscle cells.

  • Iliac artery

    • Delivers blood to pelvic organs and abdominal wall.

  • Aerta

    • Delivers blood to the body tissues.

  • Pulmonary arteries

    • Deliver oxygen-poor blood to the lungs.

  • Renal artery

    • Delivers blood to the kidney.

  • Radial artery

    • Delivers blood to the hand.

  • Femoral artery

    • Delivers blood to thigh and inner knee.

The Blood Vessels Conduct Blood in Continuous Loops

• Blood passes through the following loop of vessels moving away from the heart.

  • Arteries

  • Arterioles

  • Capillaries

  • Venules

  • Veins

• Blood returns to the heart from the veins.

  

Blood Vessels

• The hollow interior of all blood vessels is called the lumen.

• Arteries

  • Thick, muscular vessels that carry blood away from the heart.

  • Are able to withstand high blood pressure.

• The elasticity of the arteries maintains pressure on the blood between heartbeats to keep it flowing through the vessels.

• As the heart pumps blood into the arteries, they expand such that one is able to feel a pulse.

• The pulse rate is the same as the heart rate.

• Vasoconstriction

  • When muscle contracts and the diameter of the lumen narrows, reducing blood flow.

• Vasodilation

  • When muscle relaxes and the diameter of the lumen increases, increasing blood blow.

• Arterioles are the prime controllers of blood pressure.

• Arterioles serve as gatekeepers to the capillary networks keeping them open or closed.

  

• An aneurysm occurs when the wall of an artery is weakened and swells.

• The primary risk is that it will burst, causing blood loss.

• If it does not burst it can form life-threatening clots.

• Capillaries have walls that are one cell thick and connect arterioles and venules.

  

• Capillaries form branching networks that allow for the exchange of materials between the blood and tissues.

• Blood flows more slowly due to the large surface area.

• Provides more time for the exchange of materials.

  

• Capillaries merge to form the smallest kind of vein, a venule.

• Veins

  • Carry blood back to the heart.

  • Serve as reservoirs for blood volume.

• Veins

  • Blood is moved against gravity toward the heart by:

    • Contracting skeletal muscles.

    • Pressure differences caused by the movement of the thoracic cavity during breathing.

    • Valves.

      • Prevent blood flowing backwards.

  

The Heart is a Muscular Pump

• The heart is made of cardiac muscle tissue called myocardium.

  
  

• The interior of the heart is lined by endocardium.

• A fibrous sac, the pericardium, encloses the heart and holds the heart in the center of the thoracic cavity.

• The two halves of the heart are separated by a septum.

• Each half has two chambers.

  • One smaller and thin-walled atrium.

  • One larger, more muscular ventricle.

  

• The right side of the heart.

  • Contains blood rich in carbon dioxide.

    • Returns from the issues.

    • Flows out to the lungs.

  • The left side of the heart.

    • Contains blood rich in oxygen .

      • Returns from the lungs.

      • Flows out to the tissues.

  

• Valves

  • Atrioventricular (AV) valves

    • Separate the atria from ventricles

  • Semilunar valves

    • Separate the ventricles from the exit vessels.

    • Keep blood from flowing backwards.

    • Give rise to the typical “lub-dup” sounds of the heartbeat.

• The AV valve on the right

  • Called the tricuspid valve

  • Has three flaps

• The AV valve on the left.

  • Called the bicuspid or mitral valve

  • Has two flaps

  

• Pulmonary Circuit

  • The right side of the heart pumps blood to and from the lungs.

• Systemic Circuit

  • The left side of the heart pumps blood to and from the tissues.

  

• The heart muscle is nourished by coronary circulation.

  

• The cardiac cycle

  • Contraction of the atria.

  • Followed by contraction of the ventricles.

  • Followed by a rest when neither chamber is contracting.

• Contraction is called systole.

• Relaxation is called diastole.

  

• The sinoatrial (SA) node

  • Generates an electrical signal that sets the tempo.

  • Called the pacemaker.

• The SA node

  • Causes contraction of the atria and sends a signal to the atrioventricular (AV) node, which relays information to the atrioventricular bundle and out through the Purkinje fibers, causing the ventricles to contract.

  

• A combination of nervous and endocrine signals control the strength and rate of contraction of the heart.

• An electrocardiogram (ECG/EKG)

  • Recording of the electrical events associated with the heartbeat.

  • A powerful diagnostic tool.

    • Abnormal patterns can indicate heart problems.

    

• A typical ECG/EKG consists of three distinguishable deflection waves.

  • P wave

  • QRS wave

  • T wave

  

• Blood pressure

  • Highest (systolic) when the ventricles contract, sending blood into the arteries.

  • Lowest (diastolic) when the heart relaxes between beats.

Cardiovascular Disease Is a Major Killer in the United States

• Sphygmomanometer

  • Measures blood pressure.

  • Can provide early identification of hypertension, or high blood pressure, the silent killer.

    
  

Cardiovascular Disease

• Atheroscloerosis

  • A narrowing of the arteries due to fatty deposits and thickening of the wall.

  • Can lead to heart attack or stroke.

    • When this occurs in the arteries of the heart muscle, it is called coronary artery disease.

  

• Angiography

  • Can show coronary artery blockage, which can then be treated with medicines or surgical operations such as angioplasty or coronary bypass surgery.

  

• Heart muscle dies because an insufficient blood supply during a heart attack (myocardial infarction) and is gradually replaced by scar tissue.

• Scar tissue cannot contract, so part of the heart permanently loses it pumping ability.

  

• Heart failure

  • Condition in which the heart becomes an inefficient pump.

  • Leads to shortness of breath, fatigue, and fluid accumulation.

The Lymphatic System

• Lymphatic system functions.

  • Return interstitial fluid to the blood stream.

  • Transport products of fat digestion.

  • Defend the body against disease causing organisms and abnormal cells.

  

• Elephantiasis

  • A condition in which parasites block the passage of lymphatic fluid returning to blood.

  • Results in massive swelling, darkening, and thickening of the skin in the affected area.

    

• Lymph

  • Interstitial fluid that builds up around the cells.

  • Enters the lymph capillaries, then passes through a series of vessels and is returned to the circulatory system.

  

• Lymph nodes

  • Bean-shaped structures.

  • Filter lymph.

  • Contain macrophages and lymphocytes that actively defend against disease-causing organisms.

  

• Lymphoid organs include

  • Tonsils

  • Thymus gland

  • Spleen

  • Peyer’s patches