Slides in this set
All organisms need to transport substance around the body for important life
processes. Small organisms transport substances around the body by
Diffusion would take too long in large organisms, therefore, a heart and
circulation is needed.
There are 4 different types of circulatory systems-Open, Closed, Single and
In an open circulatory system blood travels in large open spaces. A simple
heart pumps blood to the cavities surrounding the organs. Diffusion takes
place. The heart relaxes. Blood is drawn back to the heart.
In a closed circulatory system, blood travels in narrow channels=High blood
pressure. However, this is more efficient and fast.
Fishes have single circulatory systems as the heart has 2 chambers.
Birds and mammals have a double circulatory system as the heart has 4
Blood tranports substances around the body. For example:
C02 and 02- as part of the respiratory system
Amino acids and glucose-metabloites
Blood is mainly made of plasma which transports these substances easily
as it is made of water.
Water is an ideal transport substance.
·It is a polar molecule (attracts 0H sugars and NH2 amino acids)
·It has an unevenly distributed charge
·It is a cohesion molecule…read more
Blood travels through vessels-3 main types of blood vessels are: Arteries,
Arteries: Veins: Capillaries:
·Carry blood AWAY ·Carry blood to the From arteries to
from the heart heart veins through
· Have a thick wall to ·Have thin walls
withstand pressure They have close
·Are less elastic than contact with cells
·Have thick elastic arteries which allows gas
fibres to stretch and ·Large lumen=low exchange
recoil blood pressure Thin wall-single
·Have a small lumen layer of cells
·No valves blood except the No valves
blood except the ·Have valves to
pulmonary artery! prevent backflow!.…read more
How does blood flow around the body=Cardiac Cycle
Atrial Systole- Blood enters the atria, SA node sends an electrical impulse
causing the atria to contract. When the pressure in the atria is more than the
pressure in the ventricles the semi lunar valves open.
Ventricular Systole- AV node sends an electrical impulse causing the
ventricles to contract. When the pressure in the ventricle is higher than that
of the atria- the atrio-ventricular valves close=LUB (first sound). When the
pressure in the ventricles is higher than the arteries the semi-lunar valves
open and blood flows into the arteries.
Diastole- The heart relaxes and once the pressure in the arteries is higher
than the ventricles, the semi lunar valves close DUB (the second sound).
Blood from the right ventricle=pulmonary artery (pulmonary system)
Blood from the left ventricle=aorta (systematic system)
Then the cycle starts again -0.8 seconds! An electrocardiogram measures
heart beat!…read more
Basics- Arthrosclerosis leads to Cardiovascular disease (disease of the heart and
Endothelium damages This causes an They then accumulate
by: inflammatory response deposits from the
· toxins form cigar whereby the WBC blood such as
(moncytes and T cels) cholesterol=Artheroma
go through the lining
·High salt diet into the artery wall.
·High Bp They turn into foam
A plaque also forms as
fibrous tissue and
(causes high BP) and
A blood clot forms because of injury=to prevent blood loss, to prevent
bacteria entering the body.
How does a blood clot form...
Release Platelets stick to
Thromboplastin collagen of wall
Ca2 and Vit Platelets stick to each
Fibrinogen Fibrin…read more