The Blood System (6.2)
SECTION LINKS: |
Notes and Review:The Blood System Notes (SL and HL) |
William Harvey and BLood Circulation
In 1628, William Harvey discovered and demonstrated the unidirectional circulation of blood.
What did Harvey discover and predict?
|
Blood Composition
What is in your blood?
Blood Plasma is the watery fluid in which all other parts are suspended. It contains about contains 90% water.
|
Arteries, Veins, and Capillaries
Contrary to popular belief, the difference between arteries and veins has nothing to do with oxygen. Arteries carry blood AWAY from the heart and Veins carry blood TO the heart.
Capillaries occur in between the arteries and veins where most of the exchange of nutrients is done, to provide for the cells. |
ArteriesMove blood at high pressure from the heart (ventricles) to the tissues of the body
|
|
Artery Walls and Blood Pressure
Artery walls have muscle and elastic fibers. The lumen (the area where the blood flows) is surrounded by multiple layers of muscle, cells, and elastic fibers. Three of these layers of wall are:
|
|
The thick walls of the arteries assist to maintain blood pressure between pump cycles. This pumping forsm what we know as "Blood Pressure."
Blood Pressure is reported as Systolic over Diastolic
|
Vein Valves
Valves in the veins ensure circulation moves in a single direction and prevents backflow. This is important because we do not want unoxygenated blood to flow in the opposite direction back to the heart to be recirculated.
|
Double Circulation
Mammalian organisms use a system called Double Circulation. This means that there are two seperate circulation systems. One circulates blood from the heart to and from the lungs. The other circulates blood from the heart to the rest of the body/ organs and back.
|
Heart Structure And Blood Flow
The heart:
Blood flow direction:
|
Heart Diagram Quiz
Click on the yellow "Start" button. Then type in the names of the structures indicated. If correct, it will turn green. Try to get them all right without looking!
Blood Flow ORder Quiz
Click on the yellow "Start" button. Then move the words around so that you put them in the correct order. Begin with the vena cava! Try to get them all in the right order without looking!
Atherosclerosis
|
Atherosclerosis is the development of fatty issue (called atheroma) in the arterial wall adjacent to endothelium lining of an artery or vein wall.
How it works?
|
The Sinoatrial Node
Heartbeat is initiated by a group of specialized muscle cells in right atrium called the sinoatrial node. Heart contracts WITHOUT stimulation from motor neurons, which is unique to the heart. As a result it is called myogenic, meaning contraction is generated in muscle itself.
|
The Cardiac Cycle
The cardiac cycle looks at how the heart pumps blood. This can be measured in various ways, most commonly through an Electrocardiodiagram (or EKG) and through pressure in the heart.
|
|
|
Basic flow of heart movement:
|
REgulating Heart Rate and Epinephrine (aka adrenalin)
Heart Rate is regulated as a homeostatic response due to pH of the blood (measured by CO2) and pressure within the arteries. Heart rate can be increased or decreased by impulses brought to heart through two nerves (Sympathetic and Vagus nerves) from medulla of brain.
|
Epinephrine is a hormone nicknamed "Fight or Flight" (also known as adrenaline).
This is the drug found in epipens used to combat allergic reaction by increasing heart rate and blood flow and preventing the arteries from closing. |