(a) What is lymph ? State two major functions of lymph.
(b) What is meant by saying that the blood pressure of a person is 120/80 ?
(a)(i) Lymph is a light yellow liquid which is unidirectional in it's flow.It's cellular part consists of only leukocytes and no blood platelets. It's non cellular part consists of water (94%) and the non-cellular part is composed of solids consisting of proteins, fats, carbohydrates, enzymes and antibodies (6%).
(ii) The two main functions of the lymph are as follows
(1) It drains away excess tissue fluid and metabolites , returns proteins to the blood from tissue spaces in addition to absorbing fats from the intestines through the lacteals.
(2) Lymphocytes and monocytes of the lymph function to defend the body by removing bacteria from the tissues, along with the lymph nodes. The antibodies it produces help to localise the infection and prevent it from spreading to the entire body for e.g.the tonsils.
(b) Blood pressure is the pressure which the blood flowing through the arteries exert on their walls. There are two limits of this pressure - the upper limit called the systolic pressure .It is with this pressure of 120mm of mercury that the oxygenated blood is pumped into the artery through ventricular contraction of the heart.
The lower limit called the diastolic pressure is the one that is felt in the arteries consequent to ventricular relaxation , when blood flows from the upper chambers into it.It is measured as 80mm of mercury.