Gastric Juices, Bird Digestion, and the end of Anatomy 1… (Day 94)

Snowy white owl bird digestion

Today waking up and thinking that it was my last Anatomy credit this semester was pretty weird. It feels like only yesterday that I arrived here in Slovakia yet I am now supposed to know all the different bones, parts of bones, muscles, joints and ligaments. Before Anatomy though I had to get through Physiology.

Today was my turn to present a short seminar to my group, and I had selected to this on the physiology of digestion in birds. Now birds are different to mammals in that their bones are hollow and their red blood cells are different and have a nucleus. In terms of digestion they have an extremely high metabolism, a different structure of digestive tract, and no teeth. This means that the average bird needs to eat 80% of its body weight each day just to maintain its bodyweight.

Snowy white owl bird digestion

The digestive tract for birds starts at the beak, which is adapated in shape and size to the birds environment and the type of food that the bird eats. Birds do not have teeth, though evolutionarily it is believed that they once did (this is backed up by research into their genetics). The next difference is that they have a widening of the eosophagus called the crop which allows birds to store food for later to eat themself or for their young. This also in some species such as pigeons is the milk glands and produces milk for their young.

The stomach organ within birds is called the ventriculus or gizzard and is split into two parts; the pro-ventriculus which is at the front is a chamber where acid is used to break down food, and then the ventriculus or gizzard is two strong muscles which break down food mechanically by grinding (as birds cannot chew). They then have small intestines where most of the absorption takes place, before two chambers at the join between the small and large intestines called the cecum (pl. ceca) where fermentation takes place.

Fermentation is the process by which plant matter is broken down as most animals struggle to break down the cellulose in the cell walls. Within birds this is done by microbiological fermentation where bacteria in the ceca excretes enzymes which can then break down these walls. The large intestine then reabsorbs the water content as this passes through before it is then excreted through the vent. In birds the large intestine is relatively short, however the actual length differs between different species of birds.

The physiology practical was looking at how gastric juice breaks down food, and we used boiiled egg to exam its breakdown in different solutions and under different temperatures.

This afternoon we had our final anatomy session for the Anatomy 1 module, as we had a bank holiday on one of the sessions todays exam was two credit tests combined into one as the joints and ligaments are actually normally taught seperately. There was however no practical other than the test. Todays test went really well with me being on the ball and getting every question correct, seems I can now say I know all the joints and ligaments which is a scary thought. Next semester is Anatomy 2 where we start looking at the organs, blood vessels and brain…