DIGESTIVE SYSTEM OF BIRDS The digestive system of the bird includes the beak, mouth, pharynx, oesophagus, crop, proventriculus, gizzard, intestine, caecum, rectum and anus (cloaca).
The digestive system of birds is highly specialized to allow them to fly. Birds have a number of adaptations that make their digestive system more efficient and lightweight, including:
- Beak: Birds do not have teeth, so they use their beaks to break down food before they eat it. The shape of a bird’s beak is adapted to its diet. For example, seed-eating birds have short, stout beaks, while insect-eating birds have long, slender beaks.
- Crop: The crop is a pouch located in the oesophagus of birds. It stores food temporarily and allows birds to eat quickly and then fly away to digest their food in a safe place.
- Proventriculus: The proventriculus is the first part of the stomach in birds. It secretes acid and digestive enzymes to start the process of breaking down food.
- Gizzard: The gizzard is the second part of the stomach in birds. It is a muscular organ that contains small stones and grit. The gizzard grinds up food into smaller pieces, which are then easier to digest.
- Small intestine: The small intestine is the longest part of the digestive system in birds. It is responsible for absorbing nutrients from food.
- Large intestine: The large intestine is shorter than the small intestine and is responsible for absorbing water from food and storing waste products.
- Ceca: The ceca are two pouches located at the junction of the small and large intestines in birds. They contain bacteria that help to digest plant material.
- Cloaca: The cloaca is a single opening that serves as the urinary, reproductive, and digestive outlet in birds.
Birds have a very fast digestive system. It takes about 2-4 hours for food to travel from the mouth to the cloaca. This allows birds to eat quickly and then fly away to digest their food in a safe place.
The digestive system of birds is a complex and fascinating system that is adapted to their unique lifestyle. It allows birds to eat a variety of foods and digest them quickly and efficiently.
The bird has no teeth but the food such as fruits, grains etc. is picked up by the beak. The food then moves from the mouth through the oesophagus to the crop which is the key function of the digestive system of birds.
The food is stored temporarily in the crop where it is moistened and fermented by some bacteria. From the crop, the food now passes on to the proventriculus where digestive enzymes are secreted on the food.
The proventriculus is often regarded as glandular stomach because it has glands which secret digestive enzymes, e.g. pepsin and amylase on the food.
From the proventriculus, the food moves to the gizzard where the actual grinding of the food takes place. (The gizzard is often regarded or called glandular stomach) with the aid of small stones or grit, the food is grinded by the gizzard.
From the gizzard, the food now moves to the duodenum and the intestine where further digestion and absorption of food take place.
The undigested food particles are moved through the caeca to the rectum and finally to the anus (cloaca) where the faeces and urine are removed from the body at the same time.
It should be noted that birds just like other herbivores have a relatively long alimentary canal to provide a large surface area for the digestion and absorption of food.
Similarities and Differences Between the digestive system – ALIMENTARY canals of a Bird and That of a Grasshopper
SIMILARITIES
1. Both have narrow esophagus
2. Crop is present in both organisms
3. Muscular gizzard is present in both
4. There is the presence of caecum in both
5. Mid-gut is present in both organisms
DIFFERENCES
BIRD
1. There is the presence of a tongue in the mouth
2. Mouth is modified into beak
3. There is the presence of duodenum
4. It has a long alimentary canal
5. The hind gut ends in cloaca
6. Malphighian tubules are absent
7. There is the presence of the pancreas
grasshopper digestive system
1. Tongue is absent
2. Mouth is modified into mandible and maxillae for chewing and grinding
3. Duodenum is not present
4. It has a relatively short alimentary canal
5. Hind gut ends in the anus distinct from the reproductive tract
6. Malphighian tubules are attached to the alimentary canal.
7. Pancreas is absent
Alimentary Canal and Digestion of Food in Man
The alimentary canal of man includes: the mouth, oesophagus, stomach, duodenum, small intestine or ileum, caecum, appendix, large intestine or colon, rectum and anus. read more of these here
The description and importance of the parts of the digestive system are as follows:
1. Mouth: the alimentary canal of man starts from the mouth. The mouth contains the teeth, salivary gland and tongue
2. The teeth: (i) the teeth are used to cut, grind or chew food into tiny particles. (ii) they expose large area of food for the action of enzyme
