Cardiovascular System: Heart and Blood Vessels

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Chapter 5

• Cardiovascular System Heart and Blood Vessels

( heart / vessel system )
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Outline

• Overview of the Cardiovascular System
• The Types of Blood Vessels
• The Heart Is a Double Pump
• Features of the Cardiovascular System
• Two Cardiovascular Pathways
• Exchange at the Capillaries
• Cardiovascular Disorders
• Lymphatic System

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Overview of the Cardiovascular System

• The entire purpose of circulation of blood
  through the body is exchange of materials
• that all cells must have to survive!
• Involves the interaction b/w the Cardiovascular,
  Respiratory, Digestive, and Urinary Systems.
• The Lymphatic System assists the Cardiovascular
  System in this exchange process.

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Functions of the Cardiovascular System

• Contractions of the heart generates blood
  pressure, which moves blood through blood
  vessels.
• Blood vessels transport blood, which moves from
  the heart into arteries, capillaries, and veins,
  before returning to the heart.
• Exchanges at the capillaries (smallest vessels)
  refreshes blood and then tissue fluid
  (interstitial fluid).
• The heart and blood vessels regulate blood flow,
  according to the needs of the body.

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The Types of Blood Vessels

• In humans, the right side of the heart pumps
  blood to the lungs, and the left side pumps blood
  to the tissues.
• Three types of blood vessels.
• Arteries.
• Capillaries.
• Veins.

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The Arteries

• Arteries carry blood away from the heart to the
  capillaries.
• Arterioles are small arteries visible to the
  naked eye.
• The greater the number of dilated vessels, the
  lower the blood pressure.

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The Capillaries

• Capillaries permit exchange of material with
  tissues.
• Arterioles branch into capillaries.
• Capillary beds are present in all regions of
  the body.
• Relative constancy of tissue fluid is dependent
  upon capillary exchange.

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Capillary Bed Anatomy
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The Veins

• Veins return blood from the capillaries to the
  heart.
• Venules are small veins that drain blood from the
  capillaries and then join to form a vein.
• Veins often have valves to prevent backward blood
  flow.

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Blood Vessels
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The Heart Is a Double Pump

• Major portion of the heart, myocardium, consists
  largely of cardiac muscle.
• Humans have a four chambered heart.
• Two artria (auricles) and two ventricles.
• Septum separates heart into halves.
• Heart has four valves.
• Atrioventricular (AV) valves between atria and
  ventricles.
• Semilunar valves between ventricles and attached
  vessels.

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External Heart Anatomy
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Heart Anatomy Links
http//info.med.yale.edu/intmed/cardio/imaging/ h
ttp//info.med.yale.edu/intmed/cardio/imaging/anat
omy/heart_anatomy/index.html
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Passage of Blood through the Heart

• Oxygen-poor blood never mixes with oxygen-rich
  blood the heart is a double-pump (right and
  left).
• Blood must go through the lungs to pass from
  right side to left side of the heart.
• Right ventricle sends blood through lungs
  (pulmonary circuit).
• Left ventricle sends blood throughout the body
  (systemic circuit).
• Concept Map of Heart?

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The Heartbeat Is Controlled

• Each heartbeat is referred to as a cardiac cycle.
• Takes a total of 0.85 seconds / cycle on the
  average when at rest. . . . .
• Thats 70 X/minute, range 60-80 beats/ minute.
• Systole - Contraction of heart muscle.
• Diastole - Relaxation of heart muscle.
• Video clip of The Cardiac Cycle and Production
  of Heart Sounds

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Cardiac Cycle Stages
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Extrinsic Control of Heartbeat

• Cardiac control center in the medulla oblongata
  (within the brain stem at the base of the
  brain) can alter the beat of the heart by way of
  the autonomic system.
• Parasympathetic system.
• Sympathetic system.
• Hormones epinephrine and norepinephrine are
  released by the adrenal medulla and also
  stimulate the heart.

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Intrinsic Control of Heartbeat

• Video clip (38).
• Intrinsic conduction system is composed of four
  major regions.
• Sinoatrial (SA) node.
• Also known as the pacemaker.
• Atrioventricular (AV) node.
• Atrioventricular (AV) bundle.
• Also known as the bundle of His
• Purkinje fibers.

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The Electrocardiogram

• An electric heart picture (ECG or EKG) is a
  recording of electrical changes that occur in the
  myocardium during a cardiac cycle.
• Electrocardiograph?
• SA node triggers an impulse, and atrial fibers
  produce electrical charge (P wave).
• QRS complex signals ventricles are about to
  contract, and electrical changes produce T wave.

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Conduction System of the Heart
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Features of the Cardiovascular System

• Rhythmic expansion and recoil of an arterial wall
  can be felt as a pulse in an artery close to the
  bodys surface.
• Blood pressure is the pressure of blood against
  the wall of a blood vessel.
• Highest pressure, systolic pressure, is reached
  when blood ejects from the heart.
• Lowest pressure, diastolic pressure is reached
  when the ventricles are relaxing.
• Blood pressure is SP/DP.

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Blood Flow in Capillaries and Veins

• Slow movement of blood through capillaries allows
  time for exchange of substances between the blood
  and surrounding tissues.
• Venous return is dependent on three factors.
• Skeletal muscle contraction.
• Presence of valves in veins.
• Respiratory movements.

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Two Cardiovascular Pathways

• Cardiovascular system includes two circuits.
• Pulmonary circuit circulates blood through the
  lungs.
• Pulmonary arteries take oxygen-poor blood to the
  lungs, and pulmonary veins return oxygen-rich
  blood to the heart.
• Systemic circuit takes blood from the left
  ventricle to the body and then back to the right
  atrium.
• Coronary arteries serve heart muscle.

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Exchange at the Capillaries

• Pumping of heart sends blood out via arteries to
  the capillaries where exchange takes place
  through capillary walls. Blood returns via veins.
• Arterial blood contains more oxygen and nutrients
  than venous blood.
• Venous blood contains more wastes, including
  carbon dioxide, than arterial blood.

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Blood Capillaries

• Processes at work during capillary exchange.
• Blood pressure.
• Diffusion (movement from a region of many
  molecules to a region of fewer molecules).
• Osmotic pressure.

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Arterial End of Capillary

• When arterial blood enters tissue capillaries
• Bright red due to high oxygen levels.
• Rich in dissolved nutrients.
• Blood pressure is higher than osmotic pressure,
  therefore. . . .
• Water and nutrients exit capillary.
• Oxygen exits capillary due to diffusion.

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Midsection of Capillary

• The mechanism of exchange is the process of
  diffusion.
• The oxygen and nutrients move from a high
  concentration in the blood to the tissue fluid
  where cells take it up and use it constantly.
• The carbon dioxide and wastes move from a high
  concentration in the tissue fluid where cells are
  constantly producing and releasing it to the
  blood where there is little.

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Venous End of Capillary

• Blood pressure is reduced because capillaries
  have a greater cross-section compared to blood
  vessels that enter and leave capillaries.
• No reduction of osmotic pressure, therefore. . .
  . .
• Water tends to enter capillary carrying wastes
  with it (but not all that originally left!).
• Carbon dioxide enters the blood because of
  diffusion.

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Capillary Exchange
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Lymphatic Capillaries

• Lymphatic vessels are one-way system that carry
  lymph.
• Valves prevent backflow.
• Lymphatic capillaries absorb excess fluid (water)
  at blood capillaries and return it to the plasma
  before the blood reenters the heart.
• If the excess fluid is not properly absorbed,
  what do we call the condition?
• Edema.

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Lymphatic Capillaries
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Cardiovascular Disorders

• Cardiovascular disease (CVD)
• - the 1 killer in the U.S. !
• - runner-up is cancer !
• Hypertension
• - the silent killer.
• - High blood pressure.
• - affects 20 of Americans!
• risk factors?

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• Atherosclerosis - Accumulation of plaque in
  arterial linings or fatty arteries.
• - means artery, to harden or
• - Hardening of the arteries.
• -Cholesterol plaques
• -Prevention?
• - Thrombus vs. embolus?
• - Stroke Portion of brain dies due to
  lack of oxygen.
• - Aneurysm Ballooning of a blood vessel.

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• Heart attack is when . . .
• a portion of the heart muscle dies due to a lack
  of oxygen.
• Angina pectoralis ?
• nitroglycerin !
• Myocardial infarction ?
• muscle heart disruption or heart attack.

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Dilated and Inflamed Veins

• Varicose veins Where most likely found ?
• Hemorrhoids (piles) ?
• are varicose veins in the rectum external vs.
  internal
• Phlebitis?
• are inflammation in the veins
• Could lead to blood clots (thrombi) and emboli
  which could lead to possible death.

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Medical Treatment for Blood Clots

• Dissolve clot using t-PA biotechnology drug.
• Coronary Bypass.
• Attach other blood vessels to heart and bypass
  clogged areas.
• Angioplasty.
• Thread tube into artery to the region of plaque,
  where a balloon attached to the tube is inflated,
  forcing the vessel open.
• Stents or chemicals may be needed.

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Coronary Bypass
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Angioplasty
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Medical Treatment for Congestive Heart Failure

• What is congestive heart failure ?
• What are some approaches to treat it ?
• 1) Wrap back muscle around heart and stimulate
  with a pacemaker.
• 2) Heart Transplants.
• Tissue match, rejection ?
• 3) Artificial Hearts (TAH) !!!

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HEALTH FOCUSPrevention of Cardiovascular Disease

• The Donts
• Smoking
• Drug Abuse
• Weight Gain
• The Dos
• Healthy Diet
• Exercise

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Lymphatic System

• Lymphatic system consists of lymphatic vessels
  and lymphatic organs.
• Three functions contribute to homeostasis.
• Lymphatic capillaries take up excess tissue
  fluid, and return it to bloodstream.
• Lacteals receive lipoproteins and transport them
  to bloodstream.
• Lymphatic system helps defend body against
  disease.

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Lymphatic Organs

• Now in Ch. 7, Immunity
• We will summarize some basics about it here.
• Lymph nodes filter lymph because macrophages
  phagocytize (phagocytosis eat, cell) debris
  or pathogens and activate lymphocytes.
• Spleen cleanses blood with macrophages.
• Filters debris, pathogens, and worn-out red blood
  cells.

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Lymph Node
Afferent at
Efferent - exit
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BIOETHICAL FOCUSPaying for an Unhealthy Lifestyle

• Would you support charging higher insurance
  premiums or taxes on people who do not practice a
  healthy lifestyle?
• Do you support the use of public money for
  prevention programs targeted toward unhealthy
  people, if there is the possibility of saving
  money in the future?
• Since the public does subsidize health care that
  disproportionately benefits the less healthy, do
  you believe that financial interests trump
  personal freedom in this matter? Why or why not?

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Review

• Overview of the Cardiovascular System
• The Types of Blood Vessels
• The Heart Is a Double Pump
• Features of the Cardiovascular System
• Two Cardiovascular Pathways
• Exchange at the Capillaries
• Cardiovascular Disorders
• Lymphatic System

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