Life Processes- Transportation in Human Beings Flashcards
define blood
Blood is a fluid connective tissue that consists of plasma, blood cells and platelets
define plasma? what is its function
blood consists of a fluid medium in which cells are suspended called plasma. Plasma transports food, carbon-dioxide and nitrogenous wastes in the dissolved form. It also carries salts and hormones.
why do we need a pumping organ
Blood is a fluid connective tissue in which cells are suspended. It transports food, carbon dioxide,nitrogenous wastes, salts and hormones. The red blood cells carry oxygen. Since all organs need oxygen to obtain energy, A pumping organ is required to push blood all around the body, a network of tubes to make sure blood reaches all the tissues and a system to ensure that this network is repaired, if damaged.
describe the heart
The muscular organ which is located near the chest slightly towards the left in the thoracic region.The heart is the main pumping organ of the body.
The human heart is divided into four chambers which are involved in the transportation of oxygenated and deoxygenated blood.
The upper two chambers are called atria whereas the lower two chambers are called as ventricles.
explain the process of movement of blood from body–>heart–>lungs–>heart–>body
De-oxygenated blood comes from the body to the upper
chamber on the right, the right atrium, as it relaxes. As the right atrium
contracts, the corresponding lower chamber, the right ventricle, dilates.
This transfers blood to the right ventricle, which in turn pumps it to the
lungs for oxygenation.Oxygen-rich blood from
the lungs comes to the thin-walled upper
chamber of the heart on the left, the left atrium. The left atrium relaxes
when it is collecting this blood. It then contracts, while the next chamber,
the left ventricle, relaxes, so that the blood is transferred to it. When the
muscular left ventricle contracts in its turn, the blood is pumped out to
the body.
why is the heart divided into 4 chambers
-Because
both oxygen and carbon dioxide have to
be transported by the blood, the heart
has different chambers to prevent the
oxygen-rich blood from mixing with the
blood containing carbon dioxide.
-The separation of the right side and the left side of
the heart is useful to keep oxygenated and deoxygenated blood from mixing. Such separation
allows a highly efficient supply of oxygen to the
body. This is useful in animals that have high
energy needs, such as birds and mammals, which
constantly use energy to maintain their body
temperature.
what about cold blooded animals? do they require as many chambers of their heart?
In animals that do not use energy
for maintaining body temperature, the body temperature depends
on the temperature in the environment. Such
animals, like amphibians or many reptiles have
three-chambered hearts, and tolerate some mixing
of the oxygenated and de-oxygenated blood
streams.
explain the heart structure in fishes
Fishes, on the other hand, have only two
chambers to their hearts, and the blood is pumped
to the gills, is oxygenated there, and passes directly
to the rest of the body. Thus, blood goes only once
through the heart in the fish during one cycle of
passage through the body.
define single circulation
A circulatory system in which the blood travels once through the heart during one complete cycle of the body is called Single Circulation
define double circulation
A circulatory system in which the blood trvales twice through the heart during one complete cycle of the body is called Double Circulation
why is double circulation necessary in human beings?
The double circulation system is necessary in human beings for oxygenated blood to reach all parts of the body and so that the de-oxygenated blood is re-oxygenated in the lungs.
why do ventricles have thick walls
Since ventricles have to pump blood into various
organs, they have thicker muscular walls than the atria do.
why are there valves present in the heart
Valves ensure
that blood does not flow backwards when the atria or ventricles contract.
what are blood vessels?
Blood vessels are the tubes that carry blood throughout the body. There three types of blood vessels; arteries, veins and blood capillaries.
define arteries
Arteries are the vessels which carry blood away from the heart to various
organs of the body.
why do arteries have thick walls?
Since the blood emerges from the heart under high
pressure, the arteries have thick, elastic walls.
define veins
Veins are the vessels which collect blood from the various organs and bring it back to the heart.
why do veins not have thick wals? why do they valves
They do not need
thick walls because the blood is no longer under pressure, instead they
have valves that ensure that the blood flows only in one direction.
how are the oxygenated and deoxygenated blood exchanged?
On reaching an organ or tissue, the artery divides into smaller and
smaller vessels to bring the blood in contact with all the individual cells.
The smallest vessels have walls which are one-cell thick and are called
capillaries. Exchange of material between the blood and surrounding
cells takes place across this thin wall. The capillaries then join together
to form veins that convey the blood away from the organ or tissue.
why should any leakage or damage in the vessels be prevented
leakage would
lead to a loss of pressure which would reduce the efficiency of the pumping system
what is the function of platelets
the blood has platelet cells which circulate
around the body and plug any leaks in the vessels by helping to clot the blood at
these points of injury.
define clotting of blood
Blood Clotting is the process of forming a clot in order to prevent excess loss of blood from the body.
It is a gel-like mass which is formed by the platelets and a fibre-like protein in the blood.
define lymph? how is it formed
Through the pores present in the walls of
capillaries some amount of plasma, proteins and blood cells escape into
intercellular spaces in the tissues to form the tissue fluid or lymph. It is
similar to the plasma of blood but colourless and contains less protein.
what happens to lymph that gets collected in intercellular spaces
Lymph drains into lymphatic capillaries from the intercellular spaces,
which join to form large lymph vessels that finally open into larger veins.
what are the functions oflymph
Lymph carries digested and absorbed fat from intestine and drains excess
fluid from extra cellular space back into the blood.
differentiate between arteries and veins
arteries
- arteries have thick walls
- they do not have valves
- they carry oxygenated blood except the pulmonary artery
- the carry blood from the heart to different organs of the body
- blood flows from the heart to different organs
- the flow of blood is fast, jerky and under high pressure.
veins
- they do not have thick walls
- veins have valves
- they caryy de-oxygenated blood except the pulmonary vein
- they collect blood from different organs of the body and bring it back to the heart
- f low of blood is from the ograns to the heart
- the flow of blood is slow, steady and under low pressure
