Digestion seminar – Dissection!

This week in anatomy and physiology we learnt about the digestive system. Types of digestive systems include monogastric, hind-gut fermenters and ruminants.

The monogastric digestive system is a simple one stomached system. It is found in animals capable of eating meat and not a lot of planet matter for example: dogs, cats an pigs.

Monogastric systems are also found in animals that do eat a lot of plant matter however these are referred to as ‘hind-gut fermenters. For example: horses. Their one stomached chamber doesn’t possess enzymes strong enough to breakdown the plant matter they consume which is why their caecum appears much larger than that of a basic monogastric. The caecum contains bacteria, fungi and protozoa which can break down the bonds of plant matter.

Ruminants ferment plant matter in the fore-gut which is why they’re often referred to as ‘fore-gut fermenters’. Examples of ruminants include: goats, sheep and cows. They have four stomach chambers: the rumen, reticulum, omasum and the abomasum (also referred to as the ‘true stomach’). Fermentation within a ruminant system happens within the first stomach chamber: the rumen. The rumen partly digests food with aid of bacteria. Large food particles accumulate in the reticulum to form a bolus for regurgitation and cudding. In the omasum, food is grinded and nutrients are absorbed into the bloodstream. In the abomasum other nutrients are absorbed and micro-organisms are killed.

Continuing on from the morning lecture, our seminar involved the dissection of a sheep and pigs digestive systems in the labs. We were able to visibly see the difference between a monogastric (pig) and ruminant (sheep) digestive system. Our tutor Laura dissected through the ruminants four stomach chambers to show us how each one differs visually from one another. We were able to see that the rumen had lots of tightly packed papillae which act like ‘villi’ by increasing surface area for the absorption of nutrients. The reticulum had a honey comb appearing structure to it which traps large food particles for ‘cudding’. Like the rumen, the omasum had papillae but much less of them.

The dissection was very interesting and has really helped me to better visualise how the digestive system works.