Why is a transport system needed by the body?
A multicellular organism needs a way to bring nutrients, oxygen, hormones, etc. to all parts of the body, in very close proximity to each cell of the body. The circulatory
system provides a network of tubes and pump to do this.
What are the parts of this transport system?
The heart (right atrium > tricuspid
valve > right ventricle > pulmonary valve > lungs > mitral valve > left atrium > left
ventricle > aortic valve > body), Arteries, Arterioles, Capillaries, Venules, and Veins
Why is a heart needed?
It is the pump which pushes blood through the vessels.
What are the functions served by the circulatory system?
Transport of oxygen to the body's tissues.
Assists the immune system in fighting infections (blood transports wbc's and anti-
bodies to poison control centers like the liver, lymph glands, and lungs where
bacteria and viruses are sorted and disposed of or rendered safe).
Supplying the body with essential nutrients (via capillaries through their thin
flattened cell walls).
Clotting to seal wounds (vessel walls contract when cut to try to lessen the blood
loss, thrombocytes (platelet's) release chemicals that stimulate further contraction
of the ruptured vessel, then the platelet's become sticky and weave the wound
shut with the helps of protein collagen (threads of fibrin) = scab).
Carrying waste products (like carbon dioxide) away via hemoglobin in the red
Carrying hormones to target organs (dissolved in blood from the endocrine
Regulate body temperature: Thermoregulation (changing the pattern of the flow
of blood when necessary).
Sends blood to assist in digestion (more blood to wherever it's taking place,
diverted to intestines).
What can the heart do to change the flow of blood?
The heart change in rate and/or in stroke volume.
What keeps the blood moving in only one direction?
The circulatory system has one-way-valves in the heart and the veins.
Which body system is the first to develop in the embryo?
The circulatory system, after only eight weeks the heart in the fetus has most of its
adult components. About 30 days after fertilization, there is a working blood transport
How long does it take for the trip of blood around the body?
It takes somewhat less than one minute.
What is the pathway of blood around the body?
Main route: vena cava > right atrium > tricuspid valve > right ventricle >
pulmonary valve > pulmonary arteries > lungs > pulmonary veins > left
atrium > bicuspid valve > left ventricle > aortic valve > aorta > arteries to the body > arterioles leading to capillaries > venules > veins leading to the inferior and superior vena cava again
What are the components of the two circulatory systems (pulmonary and
Pulmonary Circuit: The components of this system are the right side of the heart,
pulmonary arteries and veins, and the lungs.
Systemic Circuit: The components are the left side of the heart, aorta, blood pumping
all around the body (arteries, arterioles, capillaries, venules, veins, vena cava)
What helps the heart muscle to contract in a coordinated way?
The Sinoatrial Node (SA Node) or the anatomical pacemaker. Its actions are linked
to the body's nervous system so that everything is working together. Followed by the
AV-node, the bundle of His, and the purkinje fibers which ensure that the ventricles
contract after the atria and that the contraction begins at the apex (bottom) of the heart
and moves up.
How is systole different from diastole?
Systole: is the higher blood pressure when the heart is contracted. The higher pressure
is measurable in the arteries with the sphygmomanometer.
Diastole: is the lower blood pressure when the heart is relaxed.
The normal range is variable. There is no one fixed pressure for all individuals.
What is the role of the brain in setting the rate of the heart?
The pacemaker regions are connected to the nervous system to ensure that strength,
speed, and capacity of the heart's pumping matches the body's varying needs. As
when you walk up some stairs, your heart rate increases because you need more blood
to your muscles (which need glucose and oxygen), and more blood to the lungs to
pick up oxygen and get rid of carbon dioxide more quickly.
How does heart muscle itself get the oxygen and food it needs?
To sustain its activities, the heart, like any other organ, must have a constant blood
supply. This requirement is met by a special vascular system (the cardiac circuit) that
encircles the heart and reaches deep into its walls, providing the coronary circulation.
The most important coronary arteries are the left coronary artery and the right coronary artery, which arise from the base of the aorta. -Grolier encylclopedia
What are the components of whole blood?
Plasma dissolved materials: 4%
White Blood Cells and Platelets: 1%
Red Blood Cells: 45%
Distinguish between the three types of cellular components in the blood and describe how each helps to provide special functions?
Red blood cells carry oxygen with the red pigment protein hemoglobin.
White blood cells (of several types) form parts of the immune system to help fight
against pathogens and control cancer.
Platelets initiate the clotting reaction to help heal wounds.
How do both cellular and protein parts of blood help in blood clotting when a a
An injury exposes collagen fibers from torn blood vessels. The platelets in the bloodstream react to this by getting 'sticky' and adhere to the torn vessels, helping to
reduce the flow of blood. They also release chemical clotting factors that react with proteins already in the bloodstream. This begin a series of chemical reactions that eventually forms fibers of a protein (fibrin) that trap blood cells and stop the flow of