A: If I visit a doctor, I would ask the following questions about sphygmomanometer.
1. what is the name of this instrument?
2. why are you wrapping the cloth/cuff tightly on the upper arm of the patient?
3. what is the normal blood pressure of a human being?
4. why is the pump used? 5. why is the dial used?
6. what is the use of the valve? 7. how is stethoscope useful in determining the systole and diastole?
(Practice preparing different types of questions in relation to each concept discussed in the lesson. The questions should be thought provoking.)
Q: Anand observed a mammalian heart while his teacher demonstrated the experiment. He noted the observations in his lab record. Did you observe a mammalian heart in your classroom activity or by going out to observe in a butcher's shop? What was your experience? Explain. (4 Marks)
A: Yes. I went to a butcher's shop to observe a mammalian heart. I observed a sheep's heart. I brought it to school and asked our teacher to explain. She has demonstrated an experiment. I am writing my observations below.
Aim: Observation of the internal structure of the mammalian heart.
Material required: Since the structure of all the mammalian hearts is similar, we take the sheep's or goat's for our observation. For this we need the following materials.
Freshly collected specimen of heart of sheep / goat from the butcher.
Soda straws, Sharp and long blade / scalpel, Tray and a jug of water.
Dissection scissors and forceps.
Procedure: We washed the heart thoroughly so that blood is completely drained from the chambers .
We took the soda straws and inserted them into the stumps of the blood vessels.
We observed the arrangement of blood vessels on the wall of the heart.
We placed the heart in the tray in such a way that a large arch like tube faces upwards.
We observed it to be the ventral side.
Then we took a sharp blade/scalpel and opened the heart in such a way that the chambers are exposed.
Observations: We observed the thickness of the wall of the heart, number of chambers, size of the chambers and the differences between the chambers, connection of chambers with each other.
We observed white coloured structures in the lower part of the heart, noted down the size and shape and to which parts they are attached.
Inference: The heart is covered by two layers of membranes.
The heart is divided into four parts by grooves.
Two upper parts are called atria, and the lower ones are called ventricles.
The two atria and the two ventricles are separated from each other by muscular partitions called septa. The openings between atria and ventricles are guarded by valves.
After careful examination we can observe valves in the pulmonary artery and aorta as well.
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