Lab practice - Dissection of a heart

Today we have continued with the dissection of the heart in order to find out similarities and differences between the right and left ventricle, the right and left atrium and the aortic and pulmonic valves.

Working on the recognition of lab instruments

Today we have been playing a game to search for specific lab instruments at the lab.

Did you know that volumetric pippetes are more accurate than graduated pippetes?

Lab Practice – Observing the heart - Are ventricles different?

The circulation of the blood in humans is double and complete.

Objective     

To check if there are anatomical differences in the heart between its right side and its left side. 

Hypothesis

If there are two different circulatory systems, maybe there are anatomical differences in the heart.

Do you think there will be any differences? Choose a hypothesis and justify it.  

                                   

                        A) The left ventricle will be thicker and more resilient.

                        B) The right ventricle will be thicker and more resilient.

                        C) There is not significant anatomical difference.

Materials

 

      tweezers, scalpel, hand needle,scissors, dissecting tray and probe

Procedure – Part 1

To do this practice, each group has brought a real heart to the laboratory. Some have come with a lamb's heart; others have come with a pig heart. Both of them are very similar to the human heart, so somehow we could say that we have done a dissection of... "our own heart"!

First, we have observed the external shape of the heart and its relationship with the lungs. Some volunteers have investigated the ventilation capacity of the lungs of the poor lamb, or pig. Very daring!

We have learned to distinguish between the front and rear areas of the heart. Then, we have identified the right side of the heart and the left side, and the corresponding chambers (atria and ventricles).

 

On its surface, you can clearly see the coronary arteries and veins, which are responsible for nurturing and maintaining this vital organ healthy and running.

The task of identifying the veins that carry blood to the heart has been a little more complicated. The arteries that leave the ventricles, which are responsible for pumping blood to all the body's cells, have been easier to identify than veins. But in the end we managed to recognize all the major veins and heart-related arteries.

 

Then, we proceeded to dissect the heart to better understand its internal structure. 

First we have opened it through the pulmonary artery, and so we have seen the right side of the heart (right atrium and right ventricle) and the valves that let the blood through the heart (tricuspid valve) and then through the pulmonary artery to the lungs. These heart valves allow blood to pass only in one direction, preventing the fluid from returning back. 

Subsequently, we have opened the left side of the heart with scissors cutting through the aorta. We have seen the valve between the left atrium and left ventricle (mitral valve) quite well. We have also seen the flap valves, which are just where the aorta connects to the ventricle.

Definitely, the internal structure of the heart is a real show! 

And we have found that, among the three hypothesis we had set ourselves at the beginning, the right one is the first: the left ventricle is thicker and stronger than the right. That is because the left side of the heart is responsible for pumping blood throughout the body, through greater or general circuit, while the right side of the heart is only responsible for operating the pulmonary circuit.

 

Some snippets from our Oral Presentations about the Heart and the Circulatory System

Today we have been working on the oral presentations about the heart and the circulatory system. You can find some snippets from the presentations below. 

In these presentations, students explained concepts bilingually in English and Catalan with the visual support from posters and PowerPoint presentations which were monolingual (only in English).

Blood and the circulatory system (Biology 3 ESO-D)

Blood and the circulatory system

Be careful with your health

Observing human blood and blood vessels

Human blood appears to be a red liquid to the naked eye, but under a microscope we can see that it contains four distinct elements: plasma, red blood cells, white blood cells and platelets.

                       

  

                         

We have learning also what are the differences between arteries and veins based on the observations under the optical microscope and the main characteristics of the capillaries in organs like the lungs or kidneys.

   

Thermal Equilibrium

Today we have been working with a lab practice to check the concept of thermal equilibrium.

Did you know that thermal equilibrium obeys the zeroth law of thermodynamics?