Comparative+Anatomy+and+Physiology+of+Digestion+in+Vertebrates+-+rachel

// Comparative Anatomy and Physiology of Digestion in Vertebrates //

1. The role of teeth in increasing the surface area of complex food is that they break the food up to increase the surface area so the digestive chemicals can break down more food, faster. 2. __carnivore:__ digestive system is unable to break down the cell walls of plants. The digestive system cannot handle vegetation and they extract all the nutrients from raw meat products.

__Herbivore:__ uses the cellulose in the plant cell wall for nutrients. Grazing herbivores like cows have 4 stomachs that first ingest the food, which goes to the first stomach which then comes back up to the mouth in the form of cud, which the cow chews again and again until it goes through all the stomachs each stomach responsible for adding or breaking down the grass.

__Nectar feeding animals:__ nectar feeding animals have incredibly high metabolic rates which need a nutrient rich source to satisfy their system. That is why they feed on sweet nutrient rich nectar. The nectar feeder’s stomach has two digestive sacs; one is responsible for regular digestion, and another is used to store nectar when you

3. Herbivores have long digestive tracts because it takes a long time to absorb nutrients from the plant material which they eat. They also have a large caecum which helps digestion, along with enzymes, that breakdown the plant material and cellulose. Carnivores have shorter digestive tracts as they can quickly obtain nutrients from the meat they consume. They have a relatively small caecum as their diet only consists of small amounts of plant material. Human digestive systems can best be described as a herbivorous digestive system because of its length and the ability for humans to survive solely on food from a vegetation base.

Fibre Cellulose || Fibre Cellulose- Plant cell walls || Sugars : sucrose, glucose, fructose || ||  ||
 * || ** Mammalian Carnivore ** || ** Mammalian Grazing Herbivore ** || ** Mammalian Nectar Feeder ** ||
 * Examples of animals in this group || Fox, lion, Wolf || Cow, Rabbit, Sheep, horse || Honey Feeder Possum ||
 * Chemicals common in foods ingested by animal || Protein
 * Diagram of digestive system (cut & paste from internet) ||

The cow tears grass from the field and grinds it between the two mouth parts. || delicately constructed and has only a few, minute teeth. The mandible (lower jaw) is reduced to a thin flexible rod and is not suitable for the insertion of strong musculature or deep rooted teeth. The incisors and canines are pointed but the cheek teeth are flattened pegs with rounded tips and do not resemble the normal structure of mammalian teeth. ||
 * Comparison of system parts – teeth || The gr eat canine teeth are spaced so that they can slip between the cervical vertebrae and sever the spinal cord of animals. The shape of the back teeth, which are called carnassals instead of molars, makes them work like a pair of scissors, for cutting pieces of meat. The jaw is not capable of moving side-to-side. The rest of the teeth are conical, and designed for cutting and tearing. || A cows mouth is adapted for grazing, the top part of the mouth is a hard pad and the bottom part a row of flat-topped teeth. Cows have 32 teeth in all, 8 incisors on the bottom part and 6 molars on the top and bottom parts on each side.
 * Comparison of system parts – stomach(s) || As carnivores are meat eaters they can digest they food very easily and gain their nutrients such as protein more easily than herbivores. They only need one stomach to do this. || A cow has only 1 stomach. There are 4 stomach chambers in a cow. As cows only consume fibres-plant cell walls it is harder for them to absorb these nutrients into their system this is why they have 4 stomachs || The stomach serves as a storage pouch for nectar. The oesophagus is line with ||
 * Comparison of system parts – small intestine || Because lions don't have to digest sugars they have the smaller small intestines than most animals because they re bodes aren t designed to absorb sugars. most chemical digestion is done n the small intestine and nutrient absorption. || large proportion of the digestion and absorption of nutrients and water occurs in the small intestine. Enzymes in the small intestine break nutrient molecules down into their building blocks. Carbohydrates are broken down to simple sugars (monosaccharides), fats into fatty acids nucleic acids inton nucleotides and proteins into amino acids. Some of these enzymes are on the surfaces of intestinal cells, while others are secreted into the small intestine, primarily from the liver and pancreas. || Pollen is digested progressively in the small intestine. Experiments to show the passage of pollen through the intestines (remember it is hard to tell the small from the large) indicate that pollen is digested by the time it reaches the rectum. ||
 * Comparison of system parts – Caecum || In lions it controls the flow of liquids from the small intestine to the large intestine. || controls flow of materials between small and large intestine || Honey possums do not have caecum’s ||
 * Comparison of system parts – Large Intestine || Acts as incubator for microbes, turns indigestible material into faeces || undigestible material is passed trough to the large intestines and is turned in faeces || Honey Feeder Possums do not have large intestines. As they only eat sugars they can digest these compounds of glucose very easily and only need one small intestine to absorb the nutrients. ||