Cardiovascular System:

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Chapter 5

• Cardiovascular System
• Heart and Blood Vessels

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Points to Ponder

• What are the functions of the cardiovascular
  system?
• What is the anatomy of the heart and blood
  vessels (veins and arteries)?
• How is the heart beat regulated?
• What is blood pressure?
• What are common cardiovascular diseases and how
  might you prevent them?

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What is the cardiovascular system?
5.1 Overview of the cardiovascular system

• Includes the heart and blood vessels
• Brings nutrients to cells and helps get rid of
  wastes
• Blood is refreshed in the lung, kidneys,
  intestine, and liver
• Lymphatic vessels help this system by collecting
  excess fluid surrounding tissues and returning it
  to the cardiovascular system

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What are the function of the cardiovascular
system?
5.1 Overview of the cardiovascular system

• Generate blood pressure
• Transport blood
• Exchange of nutrients and wastes at the
  capillaries
• Regulate blood flow as needed

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What is the main pathway of blood in the body?
5.2 The types of blood vessels

• Heart arteries arterioles capillaries -
  venules veins back to the heart

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Arteries and arterioles
5.2 The types of blood vessels

• Carry blood away from the heart
• Their walls have 3 layers
• Thin inner epithelium
• Thick smooth muscle layer
• Outer connective tissue
• Arterioles are small arteries that regulate blood
  pressure

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Capillaries
5.2 The types of blood vessels and 5.6 Exchange
at the capillaries

• Microscopic vessels between arterioles and
  venules
• Made of one layer of epithelial tissue
• Form beds of vessels where exchange with body
  cells occurs
• Combined large surface area

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Exchange at the capillary beds is primarily a
result of osmotic and blood pressure
5.6 Exchange at the capillaries
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Veins and venules
5.2 The types of blood vessels

• Venules are small veins that receive blood from
  the capillaries
• Venule and vein walls have 3 layers
• Thin inner epithelium
• Thick smooth muscle layer
• Outer connective tissue
• Veins carry blood toward the heart
• Veins that carry blood against gravity have
  valves to keep blood flowing toward the heart

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How can you tell the difference between an artery
and vein?
5.2 The types of blood vessels
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Anatomy of the heart
5.3 The heart is a double pump

• A large, muscular organ consisting of mostly
  cardiac tissue called the myocardium
• It is surrounded by a sac called the pericardium
• Consists of two sides, right and left, separated
  by a septum
• Consists of 4 chambers 2 atria and 2 ventricles
• 2 sets of valves semilunar valves and
  atrioventricular valves (AV valves)
• The valves give the resulting lub and dup
  sound of the heart

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External anatomy of the heart
5.3 The heart is a double pump
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Internal anatomy of the heart
5.3 The heart is a double pump
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What are the two cardiovascular pathways in the
body?
5.5 Two cardiovascular pathways

• Pulmonary circuit the right side of the body
  that brings blood from the body to the heart and
  the lungs
• Systemic circuit the left side of the heart that
  brings blood to the entire body to deliver
  nutrients and rid it of wastes

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The Heart

• Passage of Blood Through the Heart
• 1. Superior and Inferior vena cava (O2-poor)
• 2. Right Atrium
• 3. Tricuspid Valve
• 4. Right Ventricle
• 5. Pulmonary SL valve
• 6. Pulmonary Arteries
• 7. Lungs

• 8. 4 Pulmonary veins (O2-rich)
• 9. Left Atrium.
• 10. Mitral valve (bicuspid Valve)
• 11, Left Ventricle.
• 12. Aortic SL valve
• 13. Aorta
• 14. ALL body tissues.

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Visualizing blood flow through the heart
5.3 The heart is a double pump
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How do the structure of the vessels and heart
match their functions?
5.3 The heart is a double pump

• The left ventricle is much more muscular than the
  right ventricle because it must pump blood to the
  entire body
• The arteries are more muscular than veins to
  withstand the higher pressure exerted on them
• The veins have a thinner wall and a larger center
  to store blood

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How does the heartbeat occur?
5.3 The heart is a double pump

• During systole the atria contract together
  followed by the ventricles contracting together
• This is followed by diastole, a rest phase, when
  the chambers relax
• This cardiac cycle, heartbeat, on average occurs
  70 times/minute

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What is the cardiac cycle?
5.3 The heart is a double pump
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How is the heartbeat controlled?
5.3 The heart is a double pump

• Internal control
• The SA node in the right atrium initiates the
  heartbeat and causes the atria to contract
• This impulse reaches the AV node, also in the
  right atrium, to send a signal down the AV bundle
  and Purkinje fibers that causes ventricular
  contraction
• These impulses travel between gap junctions at
  intercalated disks
• External control
• heartbeat is also controlled by a cardiac center
  in the brain and hormones such as epinephrine and
  norepinephrine

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Visualizing the heartbeat
5.3 The heart is a double pump
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What is an electrocardiogram (ECG)?
5.3 The heart is a double pump

• A record of the electrical changes in the heart
  muscle during a cardiac cycle
• The atria produce an electrical current when
  stimulated by the SA node called the P wave
• The contraction of the ventricles is the QRS
  complex
• The recovery of the ventricles is called the T
  wave
• Looking at these electrical changes allows
  doctors to detect abnormalities

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How does a normal and abnormal ECG compare?
5.3 The heart is a double pump
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5.4 Features of the Cardiovascular System

• Pulsealternating
• expansion and recoil
• of an arterial wall.
• (ALWAYS taken in
• systemic artery)

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What is blood pressure?
5.4 Features of the cardiovascular system

• The pressure against a blood vessel wall, usually
  measured in an artery in the arm
• The highest pressure is during blood ejection
  from the heart called the systolic pressure
• The lowest pressure is the diastolic pressure
  when the ventricles relax
• High end of normal blood pressure is recorded at
  about 120/80 mmHg (systolic/diastolic)
• Reminder this is controlled by the arterioles

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How is blood pressure categorized?
5.4 Features of the cardiovascular system
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What is important about blood flow?
5.4 Features of the cardiovascular system

• Blood flow is under the highest pressure in the
  arteries but remember the thick, muscular walls
• Blood flow is slower in the capillaries which is
  important to allow time for exchange between
  cells
• Blood pressure is minimal in the veins and
  venules but blood flow increases

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If blood pressure is so low in the veins why does
the blood flow increase?
5.4 Features of the cardiovascular system

• They have help
• 1. Skeletal muscle contraction
• 2. Breathing
• 3. Valves

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The hearts blood supply Coronary circulation
5.5 Two cardiovascular pathways

• There are small coronary arteries that supply the
  heart that are separate from the systemic and
  pulmonary pathways of the body

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Disorders

• Thromboembolisma clot that has been carried in
  the bloodstream but is now stationary.
• Thrombus stationary clot
• Embolus clot moving in the blood
• Bradycardia -heart beats too slow
• Tachycardia -heart beats too fast
• Heart murmur -valves of heart do not close
  completely

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Heart Problems

• Congestive heart failure
• More blood enters the heart than leaves.
• The left ventricle does not pump blood
  effectively
• Blood backs up causing edema in tissues and lungs
• Pulmonary edema -can cause right heart to fail

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5.6 Cardiovascular Disorders

• Disorders of the Blood Vessels cont.
• Heart attack (MI)occurs when a part of the heart
  muscle dies due to lack of O2.
• Aneurysmweak spot in a blood vessel where it
  balloons out and may rupture.
• Angina pectorischest pain or radiating pain in
  the left arm.
• Varicose veinsdevelop when the valves of the
  veins become weak and ineffective (also occur in
  the rectumhemorrhoids)
• Phlebitisinflammation of a vein and blood clots
  may form.
• t-PA (tissue plasminogen activator) is being used
  to dissolve blood clots.

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Why should we care about cardiovascular disease?
5.7 Cardiovascular disorders

• Cardiovascular disease (CVD) is the most common
  cause of death in the western world

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Disorders
5.7 Cardiovascular disorders

• Hypertension/high blood pressure
• Atherosclerosis
• Stroke
• Heart attack
• Aneurysm

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Hypertension
5.7 Cardiovascular disorders

• High blood pressure results when blood moves
  through vessels at a rate higher than normal
  often due to arterial plaque
• 140/90 mmHg is considered hypertension
• A silent killer because there are few symptoms
• Can lead to a heart attack, stroke or kidney
  failure

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Atherosclerosis
5.7 Cardiovascular disorders

• A build up of plaque in blood vessels
• Plaque that is stationary is called a thrombus
  and an embolus when it detaches and can move to
  distant sites
• Associated with a stroke, heart attack, and
  aneurysm

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Stroke
5.7 Cardiovascular disorders

• Also known as a cerebrovascular accident (CVA)
• Usually occurs when a cranial artery is blocked
  or bursts
• Part of the brain dies dues to lack of oxygen
• Symptoms may occur including numbness of hands or
  face, difficulty speaking, and inability to see
  in one eye

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Heart attack
5.7 Cardiovascular disorders

• Also known as a myocardial infarction (MI)
• Part of the heart dies due to lack of oxygen
• Can begin with angina pectoris, a pain that
  radiates down the left arm due to a blockage of a
  coronary artery

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Aneurysm
5.7 Cardiovascular disorders

• A ballooning of a blood vessel
• Atherosclerosis and hypertension can weaken a
  vessel and cause ballooning
• The most commonly affected is the abdominal
  artery or the arteries leading to the brain

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How are disorders of the blood vessels treated?
5.7 Cardiovascular disorders

• Dissolving blood clots
• t-PA is a drug that dissolves clots
• Treating clogged arteries
• Bypass surgery usually a vein from the leg is
  taken and used to bypass a clogged artery
• Stents wire mesh cylinder inserted into a
  clogged artery to hold it open
• Angioplasty a tube with a balloon is inserted
  into the clogged area and the balloon is then
  inflated to open the vessel
• A stent and angioplasty may be used in
  combination

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Disorders of the heart and its treatment
5.7 Cardiovascular disorders

• Disorders
• Heart failure is when the heart no longer pumps
  properly
• Treatments
• Left ventricular assist device(LVAD)
• Heart transplant either natural or artificial

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Health Focus The dos and donts for prevention
of cardiovascular disease?
5.7 Cardiovascular disorders

• Do not smoke
• Do not abuse drugs
• Keep your weight down to decrease chances of
  hypertension and Type II diabetes
• Eat a healthy diet
• Low in saturated and trans fats
• Low in cholesterol
• Know your blood cholesterol
• Exercise

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Discussion Questions

• Page 98 Reading You will have test questions
  from this page.
• Page 103-104 questions 1, 15-25, 27-31