Comparing the Anatomy of a Rat to a Toad

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Aim

The aim is to compare the integumentary systems and the digestive systems of a rat to that of a cane toad.

Introduction

The Integumentary system is defined by Adam.com, Inc. as an extensive system compromising of skin, hair, nails along with sweat and sebaceous glands. It also includes specialized nerve receptors which alert us to changes around us such as touch, cold, heat, pain, and pressure. These organs help in the way that they protect internal structures, protects against entry of diseases, temperature regulation and excretion through perspiration (2001). The integumentary system then becomes more specific within the different classes of vertebrates. This is proven when the integumentary system of a rat and a cane toad are compared. A rat is a mammal and therefore has many features common to all mammalian. Cane toads, however, are amphibians and so there are many differences to a rat. A rat’s body has a thick covering of hair which is unique to mammals. This provides insulation, vital for maintaining a constant internal body temperature. A cane toad, being an amphibian, has no hair on its body. There are some similarities in the skin though. Both their skins are made up of two layers, the epidermis and the dermis, though this is a far as parallels go. Augusta State University says that the epidermis of a cane toad is lined with a layer of dead cells (2006). This aids the animal by decreasing the amount of water lost through the skin. The dermis in most amphibians is very rich in capillaries because they breathe through their skin. The blood vessels must be near the skin for effective diffusion between the oxygen in the air to the blood. For the rat, the epidermis is the upper layer and protects the animal from t...

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...The caecum inside the rat was well developed and large compared to the toad. The rat’s caecum was connected to the digestive system between the small and large intestines and extended up to behind the stomach. The toad’s caecum was a lot shorter. The large intestine in both animals was rather similar. The colon was connected to the small intestine and had a much larger diameter but wasn’t as long. In both animals the large intestine was grey in colour though the toad’s colon had a pink tinge. The rectum then joined on to the colon. The rectum was a lot shorter but was even wider in diameter. It was also a darker grey. This grey would be caused by the faeces inside the colon and rectum.

Overall, though the integumentary system of a rat and toad had a great number of differences, the digestive system of both animals had many parallels despite some minor variances.

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