Mammalian Circulatory System

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Mammalian Circulatory System
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Circulatory Systems

• There are both open and closed systems.
• Insects have an open circulatory system (blood
  leaves the heart and flows freely throughout the
  body)
• Mammals have a closed system (blood is at all
  times contained within a series of vessels)
• In the 17th century William Harvey established
  that we have a cyclic system (blood flows in one
  direction)

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Circulatory Cycles

• There are 3 primary circulatory cycles
• Cardiac Cycle the route of blood within the
  heart
• Pulmonary Cycle the route of blood between the
  heart and lungs
• Systemic Cycle the route of blood between the
  heart and the body

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Three key aspects of a closed system

• Vessels to transport blood
• A pump (heart)- to move blood throughout the body
• A transport medium a specialized fluid tissue
  to carry vital elements

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Why do we need a transportation system?

• What does our transportation system have to do
  with maintaining homeostasis?

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Blood Vessels

• Many of the names of vessels comes from the Latin
  or Greek names.
• Remember interest in the body has been since the
  dawn of time!!!

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How blood is transported

• Arteries
• Carry blood away from the heart
• Rigid/Elastic to take blood under high pressure
  (from heart)
• Capillaries
• Very thin narrow where diffusion of gases and
  materials occurs
• opens and closes to regulate blood flow (e.g.
  stress, eating, etc...)
• Veins
• Loosen to expand more (controlled by smooth
  muscles)
• Store great quantities of blood

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Keeping Blood Moving

• Veins posses one-way valves that keep blood
  moving in one direction.
• Muscle contractions squeeze the veins to force
  blood that can be under negative pressure to move
  towards the heart.

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• Varicose Veins prolonged periods of standing
  without leg contractions can increase the risk of
  developing faulty valves

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Another Look at Blood Vessels
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Important ones to note

• Aorta main artery from heart.
• Mesenteric digestive system
• Renal Kidney
• Iliac Hip/Pelvic
• Hepatic Liver
• Inferior Vena Cava blood to heart from lower
• Superior Vena Cava blood to heart from upper
• Carotid Artery neck vessel to brain.
• Jugular vein neck vessel from brain
• Pulmonary Lung
• Cardiac - Heart

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The Heart
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The Heart

• Located within the thoracic cavity positioned
  more on the left side of the body
• The heart is protected by fat and a pericardium.
  (a bilayer tissue filled with fluid)

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How Blood Circulates The Heart
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The Heart

• Contraction of ventricles
• Larger of heart chambers
• Takes blood in from the atria
• Pumps blood out to the lungs/body
• Contraction of atria
• Smaller chambers
• Takes blood in from lungs/body
• Pumps blood into the ventricles
• Coordinated beating of atria then ventricles

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Cardiac Cycle

• Right Atria receives de-oxygenated blood Returned
  from the body. Pumps it to
• Right ventricle - receives blood from R. atria
  and pumps it out to the lungs for oxygen.
• Tricuspid valve prevents back flow from ventricle
  to atria. (Atrioventricular valve)

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Cardiac Cycle cont.

• Left Atria receives oxygenated blood from the
  Lungs and pumps it to
• Left ventricle which then pumps it out to the
  body (Leaving the heart).
• Bicuspid valve prevents back flow from ventricle
  to atria.
• Semi-lunar valves prevent backflow between both
  ventricles and their arteries

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Coordination of the Beating

• The Heart cells naturally beat without conscious
  control.
• Specialized cells in the right atria called the
  SA Node (pacemaker) send an electric impulse to
  neighboring cells stimulating them to contract.
• The atria beat top-down.
• The ventricles beat bottom- up
• Cardiac Cycle

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• Without coordination of the electric signal,
  the heart cells would all beat randomly
  (fibrillation)
• These nerve impulses are detectable using an
  electrocardiogram (ECG) See Fig 9.19 pg 317
• Drug overdoses, electric shock, or other damage
  can trigger random fibrillations. This would need
  ro be corrected by providing a strong electrical
  current directly to the heart. AKA
  De-fibrillation.

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Heart Regulators, Fitness and Disease
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Regulation

• At rest the S-A node fires about 70 beats/min.
• During activity, stress or fear, CO2 builds up
  in the body becoming carbonic acid.
• Sensory receptors transmit this to the medulla
  oblongata (brain) and stimulate the release of
  noradrenaline
• Noradrenaline is a stimulant that causes the
  heart to beat faster.

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Cool Down

• Once the stress is gone the heart is still
  pumping. ? heart rate ? blood pressure.
• This pressure on the arteries triggers sensory
  receptors within the artery wall to send a signal
  to the medulla to release acetylcholine.
• Acetylcholine slows heart rate back to normal
  levels

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Cardiac Output and Fitness

• Cardiac Output is the amount of blood pumped by
  the heart in a time given time period. It
  provides a measure of blood pumped amount of
  oxygen delivered to body.
• CO stroke volume x heart rateStroke volume -
  amount of blood pumped out of the heart per beat.
• AVG (S.V. 70 ml) x ( H.R. 70 b/m) 4900
  ml/min. 5 L in body

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Ailments and Diseases

• Poor fitness decreases the distensibility
  (stretchiness) of the ventricles. (? Stoke vol.)
• Septum defect - heart chamber between the
  ventricles fails to close at birth causing
  Blue-babies. (low oxygen)

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• Heart Murmur - one or more heart valves does not
  open/close restricting the smooth flow of blood
  in the heart.

Tricuspid valve with a faulty valve door.
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The Lymphatic SystemThe Other Transport System

• The Lymphatic system is the network of glands and
  vessels throughout the body that transports a
  near colourless fluid called Lymph.
• This vascular system (not found in all animals)
  helps in immunity and maintaining osmotic
  balance.
• It is transported throughout the body using
  muscle contractions and one-way valves, like
  blood in veins.

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Works with Cardiovascular System

• Some plasma that escapes the capillaries to bath
  the body cells does not re-enter the capillaries.
  This fluid is absorbed into the lymphatic system
  and returned to the cardiovascular system through
  ducts near the heart.

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Immunity support

• The Lymphatic system also aids in transporting
  white blood cells that guard the body against
  infection.
• Lymphocytes (White Blood Cells) originate in the
  lymph nodes of the body. (Think swollen lumps in
  your throat when you are sick)

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Blood Pressure

• Blood Pressure is described using two parts
• Systolic Pressure- is the highest pressure
  reached during a ventricular contraction.
• Diastolic Pressure- is the lowest pressure
  reached just before the next ventricular
  contraction.
• Blood Pressure is recorded in mmHg (mm Mercury).
  Normal range equals 120/80 mmHg.

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Hypertension

• Hypertension is a chronically elevated high blood
  pressure. It can be associated with a number of
  health problems.
• Any condition that increases the volume of blood
  or the rate of blood flow can lead to
  hypertension
• Ex. High salt intake, high cholesterol, diet,
  age, fitness.
• http//health.howstuffworks.com/adam-200079.htm
• http//www.healthcentral.com/high-blood-pressure/i
  ntroduction-47-115.html

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Arteriosclerosis Atherosclerosis
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Clots, Stroke, and Heart Attacks
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Angioplasty

• A procedure used to open the artery lumen by
  compressing or removing a plaque deposit.

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Coronary Bypass

• Coronary blockages can lead to major heart
  problems. The muscles of the heart need a
  constant supply of oxygen. During a bypass
  vessels are removed from another part of the body
  and are used to bypass the blockage.

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• READ Pages 322-328
• Do 1, 2, 3 4

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BloodTransport Medium

• Function of Blood
• Composition of Blood
• Blood Types

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Function of Blood

• Transport of
• Oxygen
• Carbon Dioxide
• Nutrients
• Wastes
• Immunity

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Composition Of Blood

• Blood is a collection of cells specialized to
  perform a particular task. Therefore its
  considered a tissue.
• 55 Plasma
• - 45 Cells and Cell Parts

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Plasma

• composed of
• clear golden fluid and water
• dissolved substances
• proteins (Fibrinogen Globulin's)
• Has several functions
• Transports small molecules and ions
• contains Fibrinogen involved in blood clotting
• contains antibodies (globulin's) that are
  involved in disease fighting

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Blood Cells and Cell Parts

• 3 Cellular components to blood
• Red Blood Cells
• White Blood Cells
• Blood Platelets

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• Plasma
• Glucose, hormones, etc. suspended in a viscous
  goo
• White Blood Cells(leukocytes)
• Protect the cells from infection/invasion

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• Platelets
• Clot the blood to prevent it from spilling out
  when a rupture of the fluid conduit occurs
• Red Blood Cells(erythrocytes)
• Transport O2
• 99 of all blood cells

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Red Blood Cells

• Also called Erythrocytes 5 million/ml
• Main function is to carry Oxygen
• Structure
• Mature cells have no nucleus and are disk shaped
  (to ? surface area ? size)
• Cytoplasm contains a molecule called Hemoglobin
• a iron containing molecule to carry oxygen
• every R.B.C contains gt 200 mil. hemoglobin
  molecules

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White Blood Cells

• also called Leucocytes
• Function protect the body from infection
• There are Two main types of W.B.C. s
• macrophages
• move out of the capillary and digest foreign
  materials by phagocytosis
• Lymphocytes
• specialized antibodies that fight infection

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Platelets

• Cell fragments
• 250 million per cubic centimeter
• Function Trigger the Blood Clotting Process

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Blood Clotting

• Broken or damaged blood vessels release
  platelets.
• Ruptured Platelets release chemicals that react
  with plasma proteins to make thromboplastin.
• Thromboplastin reacts with prothrombrin to
  produce thrombrin (needs calcium)
• Thrombrin causes fibrinogen molecules to join
  together to form strands called Fibrin
• Many strands of Fibrin form a mesh or clot that
  stops the bleeding

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Blood Clot
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Blood Clotting
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Review of Blood Components
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Blood Problems

• Anemia - occurs when there is a shortage of
  hemoglobin ib blood
• Leukemia - Cancer of the white blood cells
• A.I.D.S - the H.I.V. virus attacks and destroys
  an important type of WBC
• Sickle Cell Disease - abnormal hemoglobin causes
  RBC s to have irregular shape

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The END