Composition of blood

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Composition of blood

• General Composition of Blood
• Closer look at white blood cells White Blood
  Cells - Learning Activity

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Blood Vessels

• There are three types of blood vessels
• Arteries
• Veins
• Capillaries
• The Circulatory System is known as a CLOSED
  SYSTEM because the blood is contained within
  either the Heart or Blood Vessels at all times.

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ARTERIES AND ARTERIOLES (SMALL ARTERIES)

• Arteries carry blood AWAY the HEART TO
  CAPILLARIES AND THE REST OF THE BODY
• The Walls of Arteries are generally THICKER than
  those of Veins.
• EXCEPT FOR THE PULMONARY ARTERIES, ALL ARTERIES
  CARRY OXYGEN-RICH BLOOD.

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• Elastic Fibers make up walls
• Tough and Flexible. 
• withstand the high pressure of blood as it is
  pumped from the Heart.
• The force that blood exerts on the walls of blood
  vessels is known as BLOOD PRESSURE.

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The aorta

• The Artery that carries Oxygen-Rich Blood from
  the LEFT VENTRICLE to all parts of the body,
  EXCEPT THE LUNGS, is the AORTA.

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Capillaries

• Thin wall microscopic in size.
• Nutrients, wastes, and hormones are exchanged
• Control of blood flow into capillary beds is done
  by nerve-controlled sphincters

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Capillaries to veins

• Veins carry blood from capillaries to the heart.
• With the exception of the pulmonary veins, blood
  in veins is oxygen-poor
• The veins have valves that prevent back-flow of
  blood.

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Muscle contractioon

• Pressure in veins is low, so veins
• depend on
• nearby muscular
• contractions
• to move blood
• along.

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Together
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• Changes in blood pressure, velocity, and the area
  of the arteries, capillaries, and veins of the
  circulatory system

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• Ventricular contraction propels blood into
  arteries under great pressure.
• As blood gets farther from the heart, the
  pressure likewise decreases

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• Systemic pressure is sensed by receptors in the
  arteries and atria. Nerve messages from these
  sensors communicate conditions to the medulla in
  the brain. Signals from the medulla regulate
  blood pressure.

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The Heart

• What does it really look like

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Anatomy of heart

• Four chambers
• right and left atria
• right and left ventricles

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• Atria act as collecting reservoirs for blood
  returning to the heart
• The two ventricles act as pumps to eject the
  blood to the body.
• Comes with valves to prevent backflow
• Heart Center Online Animated Encyclopedia
  how valves work

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• Medmovie.com - Products and Services Overview

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• What are the four heart valves?
• The tricuspid valve is between the right atrium
  and right ventricle.
• The pulmonary or pulmonic valve is between the
  right ventricle and the pulmonary artery.
• The mitral valve is between the left atrium and
  left ventricle.
• The aortic valve is between the left ventricle
  and the aorta.

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Right side left side

• Blood enters the heart through two large veins,
  the inferior and superior vena cava, emptying
  oxygen-poor blood from the body into the right
  atrium.

• The pulmonary vein empties oxygen-rich blood,
  from the lungs into the left atrium

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Right side Left side

• Atrial contraction blood flows from your right
  atrium into your right ventricle through the open
  tricuspid valve.

• Atrial contraction blood flows from your left
  atrium into your left ventricle through the open
  mitral valve.

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Right side Left side

• When the ventricles are full, the tricuspid valve
  shuts. This prevents blood from flowing backward
  into the atria while the ventricles contract
  (squeeze).

• When the ventricles are full, the mitral valve
  shuts. This prevents blood from flowing backward
  into the atria while the ventricles contract
  (squeeze).

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Right side Left side

• Ventricular contraction blood leaves the heart
  through the pulmonic valve, into the pulmonary
  artery and to the lungs.

• Ventricular contraction blood leaves the heart
  through the aortic valve, into the aorta and to
  the body

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• Blood Flow through the Human Heart
• See Your Blood Flow

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• Oxygen-poor blood (shown in blue) flows from the
  body into the right atrium.

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• Blood flows through the right atrium into the
  right ventricle.

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• The right ventricle pumps the blood to the lungs,
  where the blood releases waste gases and picks up
  oxygen.Through the pulmonary valve

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• The newly oxygen-rich blood returns to the heart
  and enters the left atrium.

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• Blood flows
• through the left
• atrium into the
• left ventricle.
• Mitral valve

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• The left
• ventricle
• pumps the
• oxygen-rich
• blood to all
• parts of the
• body.

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• McGraw-Hill Online Learning Center TestltBLURTgt
• Heart Diagram - Human Heart Drawing

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• Our Hearts Contract or Beat about once every
  second of every day of our lives. 
• The heart beats more than 2.5 million times in an
  average life span. 
• The only time the Heart gets a Rest is Between
  Beats.

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• The Heart is Enclosed in a Protective Membrane
  Sac called the PERICARDIUM.  The Pericardium
  surrounds the heart and secretes a fluid that
  Reduces Friction as the heart beats.

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• Anatomy of the Human Heart - Texas Heart
  Institute Heart Information Center

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Cardiac Cycle 3 stages

• Atrial Systole (pronounced sis-toe-lay). The SAN
  contracts and transmits electrical impulses
  throughout the atria, which both contract,
  pumping blood into the ventricles. The ventricles
  are electrically insulated from the atria, so
  they do not contract at this time.

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• 2. The ventricles contract shortly after the
  atria, from the bottom up, squeezing blood
  upwards into the arteries.
• The blood can't go into the atria because of the
  atrioventricular valves, which are forced shut
  with a loud "lub".

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• 3. Diastole. The atria and the ventricles relax,
  while the atria fill with blood. The semilunar
  valves in the arteries close as the arterial
  blood pushes against them, making a "dup" sound.

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• http//academic.kellogg.edu/herbrandsonc/bio201_Mc
  Kinley/f22-11_cardiac_cycle_c.jpg
• You need to be able to discuss the events of the
  cardiac cycle.

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The cardiac cycle

• The cardiac cycle consists of two parts
• systole (contraction of the heart muscle)
• diastole (relaxation of the heart muscle). Atria
  contract while ventricles relax.
• Cardiac Cycle Animation and Diagram - Cardiac
  Physiology Animation by Anatimation

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The cardiac cycle
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• Watch The Cardiac Cycle ( scroll down)

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Ventricular Systole

• ventricles contract
• ventricular contraction regulated by AV node
• semilunar valves (to aorta pulmonary arteries)
  open
• atrioventricular valves close ("lub")

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Ventricular Diastole

• ventricles relax, atria contract
• atrial contraction regulated by SA node
  (pacemaker)
• semilunar valves close ("dupp")
• atrioventricular valves open

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Regulation of heart beat

• Impulse ( action potential ) originate from the
  sinoatrial node (SA node) near the right atrium
• The signal spreads to the atrioventricular node
  (AV node).
• Signals carried from the AV node, slightly
  delayed, through bundle of His fibers and
  Purkinjie fibers cause the ventricles to contract
  simultaneously.

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Pacemaker/ the beat
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• Howstuffworks "How Your Heart Works"
• The Cardiac Cycle scroll down

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The players
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Heart beat control

• Heart Rate Control- The nervous system control of
  the heart rate is within the medulla oblongata of
  the brainstem.

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Adjustments to the inherent heart rate and
strength.

• A. Medulla of the lower brain sends speeding or
  slowing signals to the heart via the sympathetic
  or parasympathetic nervous system respectively.
• 1. Sympathetic nervous system - most of the
  nerves coming to the heart from the medulla
  terminate at the SA node. When stimulated they
  release norepinephrine (noradrenalin) from the
  nerve endings causing the cells to fire faster
  than their normal rate

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• 2. Parasympathetic nerves (vagus nerve) follow
  the same scenario with the exceptions that
  acetylcholine is released which decreases the
  heart rate

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• medulla will send out these signals according to
  information it receives from many sources via
  nerves
• 1. Carotid bodies and aortic bodies detecting
  oxygen levels.
• 2. Carbon dioxide-pH detectors located in the
  medulla itself which is indirectly sensing the
  CO2-pH levels in the blood around the brain.

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What Causes Hardening Of The Arteries?

• Blood vessels lose a certain amount of elasticity
  with aging.
• A build up of fatty deposits (plaque) occurs in
  the blood vessel lining.
• Loss of vessel elasticity is termed
  arteriosclerosis, while fatty deposit build-up is
  termed atherosclerosis.
• The process is thought to begin early in life.
• Causative factors
• Cigarette smoking.
• High blood pressure
• Diabetes
• Obesity

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• Atherosclerosis, Hardening of the Arteries
• 1. Lumen (Opening)2. Plaque3. Artery Wall

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• Howstuffworks "How Heart Disease Works