blood and Circultion Flashcards
what is the circulat5ory system
The transporting system of the body, consisting of the heart, blood, blood vessels, lymph lymph vessels
what are the functions of blood
Transporting oxygen and nutrient to all cells of the body
Transporting carbon dioxide and wastes away from the cells
Transporting chemical messengers (hormones) to cells
Maintaining the pH of body fluids
Distributing heat and maintaining body temps
Maintaining water content and ion concentration of the body fluid
Protecting against disease causing micro-organisms
Preventing blood loss through clotting when vessels are damaged
what is blood
Blood is made up of a plasma and formed elements.
what is plasma
Plasma 55% of the blood volume. It is the fluid part of the blood in which the cells (formed elements) are suspended in.
what are formed elements?
Formed elements are any cell or cell like structure in the blood. They make up 45% of the blood volume.
what do the formed elements consist of ?
The formed elements that are suspended in the blood plasma are red blood cells (erythrocytes), white blood cells (leucocytes) and platelets (thrombocytes).
what is plasma made of?
91% of plasma is water, with the rest made up of dissolved substances include nutrients such as amino acids, glucose lipids, ions such as Na+, K+, Ca2+, Cl-, HCO3-, gases such as O2 and CO2, hormones, proteins and wastes such as urea.
what are red blood cells erythrocytes?
Contains haemoglobin, no nucleus (to allow more room for haemoglobin).
They are biconcave disks, thinner in the middle than at the edges.
Haemoglobin is the pigment in red blood cells, involved in the transport of oxygen and some carbon dioxide through the body. When combined with oxygen, haemoglobin is red. Giving the erythrocytes their red colour.
They live for 120 days
They are produced in the bone marrow and destroyed in the liver and spleen.
what are white blood cells leucocytes ?
Contains nucleus but no haemoglobin.
They are larger and fewer in number than red blood cells.
Leucocytes can remove dead or injured cells and invading micro organisms.
They can live for a few minutes during infection to years when infection is not present.
There are 2 different types of leucocytes.
Granulocytes, which have a granular cytoplasm with a lobed nucleus.
Monocytes or lymphocytes have a spherical nucleus and an agranular cytoplasm.
what are platelets thrombocytes?
very small cell fragment of cytoplasm enclosed in a membrane,
it lacks a nucleus.
They are about ⅓ the size of an erythrocyte.
Formed in the red bone marrow
Lasts for 7 days
Important for normal blood clotting
how is oxygen trasnsported?
Oxygen is not very soluble in water (nonpolar), so only about
3% of oxygen is carried in solution in the blood plasma. The other
97% is carried in combination of haemoglobin molecules in red blood cells
Oxygen combines with haemoglobin to form oxyhaemoglobin
Hb+o2 -> Hbo2
when does oxygen combine with haemoglobin and when does it break down to its individual components?
Oxygen combines with haemoglobin in situations where the oxygen levels are relatively high. This occurs in capillaries in the lungs where oxygen diffuses into the blood from the air in the air sacs
Oxyhemoglobin breaks down to haemoglobin and oxygen in situations where the concentration of oxygen is relatively low.
what is oxygenated blood/
blood with proportions of oxyhaemoglobin. (lots of oxygen). It is bright red, arteries are bright red (except for pulmonary artery going to lung)
what is deoxygenated blood?
blood with only haemoglobin and no oxygen, it is dark red or purple, veins are dark red or purple (except for pulmonary vein to lungs)
why are red blood cells suited to their function of transportq
It contains haemoglobin which able to combine with oxygen.
The presence of haemoglobin in red blood cells increases the oxygen carrying capacity of the blood by about 60 - 70 x.
Has no nucleus, so more haemoglobin molecules can fit in the cell.
Shaped like biconcave disks, the biconcave centre increases the surface area for the transport of oxygen and the thick edges gives a large volume that allows room for the haemoglobin molecules.
how is co2 transported?
8% of CO2 is dissolved in the plasma and carried in solution.
Other 22% combines with the globin part of haemoglobin molecule to form carbaminohaemoglobin.
The remainder
70% is carried in plasma as bicarbonate ions, HCO3-
describe the transportation fo co2
Alveoli air sacs are surrounded by a dense network of capillaries
In the blood in these capillaries, Co2 dissolved in the plasma diffuses out of the blood into the air in the alveolus.
The carbaminohaemoglobin breaks down and the co2 molecules released diffuse into the alveolus.
Hydrogen and bicarbonate ions recombine to form carbonic acid which breaks down under enzyme action into water and carbon dioxide. The carbon dioxide diffuses into the alveolus.
what are arteries
blood vessels that carry blood away from the heart
what are veins
blood vessels that carry blood towards the heart
what is a capillary
Capillary is a microscopic blood vessel which links arterioles and venules.
what is circulatioh
Circulation is the movement of blood through the heart and blood vessels
what is the heart
The heart is a hollow muscular organ that pumps blood.
Located slightly to the left of chest
Roughly conical in shape and is the size of closed human fist.
Membrane called the pericardium that surrounds the heart. It holds the heart in place but allows the heart to move as it beats. prevents the heart from over stretching.
how are nutrients and wastes transported?
dissolving in the blood plasma, glucose, vitamins, amino acids, fatty acids and glycerol.
Inorganic nutrients are transported by ions.
organic wastes that are transported in solution to the blood plasma include uric acid, urea and creatine.
what does the pulmonary trunk do
divides into two arteries that carry deoxygenated blood to the lungs to be oxygenated.
superior vena cava
major vein carrying blood bringing blood to the heart form the head and upper body
right atrium
receiving chamber of deoxygenated blood that has been through the capillaries of the body
inferior vena cava
major vein bringing blood to the heart form the lower body and legs