the transport system ib topic 6.2. the transport system mammals have a closed circulation blood…
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Features of the circulatory system Advantages in mammalian circulation: Simultaneous high pressure delivery of oxygenated blood to all regions of the body Oxygenated blood reaches respiring tissuesTRANSCRIPT
The Transport SystemIB topic 6.2
The transport system Mammals have a closed circulation
Blood is pumped by the heart and circulated in a continuous system of arteries, veins, and capillaries
Under pressure The heart has four chambers The heart is divided into right and left sides
Blood flows from the right side of the heart to the lungs, then back to the left side of the heart
From here, it is pumped around the rest of the body and back to the right side of the heart
Blood passes twice through the heart in every single circulation of the body (double circulation)
Features of the circulatory system Advantages in mammalian circulation:
Simultaneous high pressure delivery of oxygenated blood to all regions of the body
Oxygenated blood reaches respiring tissues
Blood Blood is tissue Consists of:
Liquid medium called plasma Erythrocytes (RBC)
Involved in transport of respiratory gases (O2, CO2) Leucocytes (WBC)
Combat infection Lymphocytes
Form antibodies Phagocytes
Ingest bacteria or cell fragments Platelets
Blood clotting mechanism
Blood break-down Blood is:
55% plasma Plasma is:
90% water 10% dissolved substances (proteins, salts, lipids)
45% cells RBC, WBC, platelets
Blood transports … Nutrients Oxygen Carbon dioxide Hormones Antibodies Urea Heat
The plumbing of the circulation system There are three types of vessels:
Arteries: carry blood away from the heart Veins: carry blood back to the heart Capillaries: fine networks linking arteries and veins
Both arteries and veins have strong, elastic walls Arteries are very much thicker and stronger Strength: collagen Elastic: smooth muscle fibers
Capillaries Endothelium (inner layer) Branch No cell is far from a capillary
Why the differences? Blood leaving the heart is under high
pressure Thick arteries
By the time blood reaches the capillaries , the pressure has decreased greatly Thinner capillaries and veins Also, low pressure may mean backflow, which
is why veins have valves Valves are opened by blood pressure from
behind
Differences Capillary – site of exchange
Artery – carries blood away from heart under high pressure
Vein – carries blood back to heart under low pressure
Outer Layer (collagen)
Absent Present Present
Middle Layer (elastic fibers and involuntary muscle fibers)
Absent Thick layer Thin layer
Inner layer (or endothelium)
Present Present Present
Valves Absent Absent Present
The arrangement of arteries and veins The right side
Pumps deoxygenated blood to the lungs Arteries, veins, capillaries = pulmonary
circulation The left side
Pumps oxygenated blood to the rest of the body
Arteries, veins, capillaries = systemic circulation
Aorta (artery)
Process The branching sequence of circulation: Aorta artery arteriole capillary
venule vein vena cava Vena cava carries blood back to the heart
The Heart About the size of a
clenched fist
The heart as a pumpDivided into 4 chambers
Upper: thin walled atria (atrium = singular) Receive blood into the heart
Lower: thick walled ventricles The left is much thicker than the right The volumes are identical Pump blood out of the heart
You should know the flow of blood
The heart as a pump Coronary arteries supply the walls of the
heart with oxygenated blood Valves prevent backflow
Atrio-ventricular valves prevent backflow from ventricles to atria
Right side: tricuspid valve Left side: bicuspid or mitral valve
Tendons are attached to prevent folding back Semi-lunar valves separates the ventricles
from pulmonary artery (right side) and aorta (left side)
Animations http://www.nhlbi.nih.gov/health/health-
topics/topics/hhw/contraction.html Penn health cardiology and cardiac
surgery http://www.pennhealth.com/health_info/an
imationplayer/