CGIER 8 - CVS 3 Flashcards
Describe plasma.
Plasma is the liquid component of blood, in which the red blood cells, white blood cells, and platelets are suspended.
It constitutes more than half of the blood’s volume and consists mostly of water containing dissolved salts (electrolytes) and proteins.
Describe red blood cells by giving its amount, protein, and function.
Red blood cells (also called erythrocytes) make up about 40% of the blood’s volume.
Red blood cells contain haemoglobin, is a protein that gives blood its red color and enables it to carry oxygen from the lungs and deliver it to the tissues of the body.
Describe white blood cells by giving its amount and function
White blood cells (also called leukocytes) are fewer in number than red blood cells, with a ratio of about 1 white blood cell to every 660 red blood cells.
White blood cells are responsible primarily for defending the body against infection.
Describe platelets by giving its amount and function.
Platelets (also called thrombocytes) are cell-like particles smaller than red or white blood cells. Platelets are fewer in number than red blood cells, with a ratio of about 1 platelet to every 20 red blood cells.
Platelets help in the clotting process by gathering at a bleeding site and clumping together to form a plug that helps seal the blood vessel.
What is the haematocrit ratio and how is it measured?
Haematocrit Ratio is defined as the ratio of red blood cell (rbc) volume to the total blood volume, i.e. % rbc volume.
Measuring the ratio of the volume of red blood cells to the total volume of blood is typically performed by centrifugation.
Haematocrit varies from tissue to tissue and also with body condition, and is important because this determines the…
effective viscosity of the blood.
Blood represents ~ 7% of the total body mass, e.g. a 70 kg male has about 5 litres of blood.
Since the heat pumps about 80 ml of blood per contraction, it takes approximately _________ for an average blood cell to make one full cycle of the body.
1 minute
There are four stages to blood circulation, list them in detail.
1- In the diastole phase, the heart relaxes between beats. Blood moves into the heart. Both atriums are filled rapidly.
2- When the atriums contract, the systole (pumping) phase begins, blood pushes to ventricles via mitral and tricuspid valves.
3- The contraction of the ventricles forces the blood through semilunar valves into the pulmonary artery which leads to lungs, and through aorta to the rest of the body.
4- When the heart relaxes, the semilunar valves close, blood fills the atrium, beginning the cycle again.
Pumps can be classified to two categories:
Vacuum pumps, designed to reduces the pressure.
Forced pumps, designed to increases pressure such as circulating pumps like heart
The 2-synchronous pumps work on a basis similar to…
Boyle’s Law, which states that for a gas at constant temperature,
Pressure x Volume = Constant
(i.e. PV = constant).
Boyles law: Pressure is inversely proportional to volume.
In the heart chambers, as the chambers expand volume _____ and consequently the pressure ______.
increases, decreases (drawing blood into the chamber).
As the heart contracts, the volume ______, and the pressure ______.
decreases, increases (forcing blood out of the chamber)
The study of fluid in motion is called…
fluid dynamics
What is the streamline (or laminar flow)?
is a flow, that each particle of the fluid follow a smooth path called streamline , and these paths do not cross each other.
ex: flows in a smooth walled, straight section of clean blood vessel.
Streamline (or laminar) flow results in a…
minimum loss of energy in the flow, and is ‘silent’,
i.e. cannot be heard with a stethoscope placed over an artery.
