Biology pluck dissection

The Newstead College Biology 2 class investigated the respiratory and circulatory systems on 26 June, with the help of a pig pluck. A pluck refers to the heart, lungs, liver, trachea, oesophagus and tongue of a pig, typically removed during butchering. This provides a unique opportunity for students to see how body systems are arranged, as well as the wide variety of body tissue (connective, muscular, and epithelial) in each organ.

If you're interested in knowing what we did, keep reading! 

Starting with the mouth (and a very large tongue), they followed the trachea (or breathing tube) down to the lungs. The trachea is lined with cartilage (the same hard tissue in your nose tip, and ears) rings that keep our airways open regardless of our head position.

Sitting just behind the trachea is the oesophagus (the food tube). It travels into your stomach, propelling food along its smooth muscle walls using peristalsis (wave-like muscle contractions). 

High up on the trachea is the larynx (voice box), which contains vocal cords. The shape and arrangement of these determine your voice, just like they determine a pig's oink, or a sheep's baaa. 

Lower down the trachea, the tube branches into two primary bronchi that travel down into the lungs. As these bronchi travel further and further they go through repeated bifurcation (splitting into two). This is how the large trachea becomes tiny tubes that carry air into the terminal lung sacs, called alveoli. 

We, mammals, have so many air sacks in our lungs that they are light and soft, even floating on water!

Students also looked into the hearts, cutting them open and viewing the four chambers and valves that open and close between each. They traced the journey of blood through our hearts. 

Each lub-dub sound of the heart is due to the opening and closing of valves as blood is pumped between chambers. The diagram below shows the movement of blood through the heart. 

When lub (1st heart sound) is heard, it is as the pulmonary and aortic valves open, pushing blood to the lungs, and the body. When dub (2nd heart sound) is heard, it is as the tricuspid and mitral valves open, pushing blood from the atriums into the ventricles. 

Do you notice how thick the muscle on the left side of the heart is? That's because the pumping of the left side pushes blood around your whole body! 

I hope you enjoyed learning what we are exploring, and happy heartbeats to you all! 

Kaija, Teacher