Transcript The Circulatory System

The Circulatory System
Vertebrates have
Closed circulatory systems
• A system that uses a continuous series of
vessels of different sizes to deliver blood to
body cells and return it to the heart
• The human closed circulatory system is
sometimes called the cardiovascular system.
• What is an open circulatory system?
Vertebrates have
Closed circulatory systems
• Multicellular animals do not have most of
their cells in contact with the external
environment and so have developed
circulatory systems to transport nutrients,
oxygen, carbon dioxide and metabolic
wastes.
Components of the circulatory system:
1. blood:
2. heart:
3. blood vessels:
1. Blood
Human Blood Cells
The Components of Blood
• Plasma
– liquid component of blood
• accounts for about ____ of total blood volume.
Plasma consists of ____water and ____ dissolved
materials that include:
– acts as a buffer, maintaining pH near 7.4.
The Components of Blood
Red blood cells (erythrocytes)
• are flattened, doubly concave cells and lack a
nucleus
• carry oxygen ___________________
• small (7 µm in diameter): _________________
• _____ million hemoglobin molecules per cell.
• Humans have a total of ________ (about 1/3 of all
the cells in the body)
The Components of Blood
Red blood cells cont.
• Red blood cells are continuously manufactured in
_________________________________________
________________
• Life-span of an erythrocyte is only ________,
after which they are destroyed in ______ and
__________.
– Iron from hemoglobin is recovered and reused by
red marrow. The liver degrades the heme units and
secretes them as pigment in the bile, responsible for
the colour of feces. Each second 2 million red blood
cells are produced to replace those taken out of
circulation.
The Components of Blood
White blood cells, (_________)
• larger than rbc’s but occupy less than ____ of
the blood volume, have a _________, but lack
__________.
• They function in the _______ ________
response.
• made from _________ in _________.
The Components of Blood
White blood cells, (leukocytes)
There are Five types of leukocytes
1. ___________: enter the tissue fluid by
squeezing through capillary walls and
___________ foreign substances.
2. ___________: release white blood cell growth
factors, causing a population increase for white
blood cells.
The Components of Blood
White blood cells, (leukocytes)
3. ____________: fight infection.
4. __________: attack cells containing _______.
5. __________: produce __________. Antigenantibody complexes are phagocytized by a
macrophage
The Components of Blood
Platelets
• Platelets carry chemicals essential to blood
clotting.
• Platelets survive for _______ before being
removed by the liver and spleen.
• There are ________ to ________ platelets in each
________ of blood.
• Platelets stick and adhere to tears in blood vessels;
they also release ________ _________. A
hemophiliac's blood cannot clot.
Red Blood Cells, Platelets and T-lymphocyte
(erythocytes = red; platelets = yellow; T-lymphocyte = light green)