Quantitative and distributive study of the fungiform papillae in the cat tongue in microvascular cast specimens

Cats use hollow papillae to wick saliva into fur

The cat tongue is covered in sharp, rear-facing spines called papillae, the precise function of which is a mystery. In this combined experimental and theoretical study, we use high-speed film, grooming force measurements, and computed tomography (CT) scanning to elucidate the mechanism by which papillae are used to groom fur. We examine the tongues of six species of cats from domestic cat to lion, spanning 30-fold in body weight. The papillae of these cats each feature a hollow cavity at the tip that spontaneously wicks saliva from the mouth and then releases it onto hairs. The unique shape of the cat's papillae may inspire ways to clean complex hairy surfaces. We demonstrate one such application with the tongue-inspired grooming (TIGR) brush, which incorporates 3D-printed cat papillae into a silicone substrate. The TIGR brush experiences lower grooming forces than a normal hairbrush and is easier to clean.

Functional angioarchitectural comparison of the fungiform papillae of rat, rabbit, cat in scanning electron microscopic specimens

The aim of this study was to compare the functional angioarchitectural fungiform papillae (FuP) of three kinds of mammalia, rat, rabbit and cat, with microvascular cast specimens (MVCS) utilizing the corrosive resin cast method in scanning electron microscopy (SEM). FuP distributed geometrically on the dorsal surface of the tongues of the three mammals with different eating habits were of various kinds of form based on their functional and microvascular structure. The basic form of the capillary loop of FuP in the three mammals consisted of the ascending and descending branches of the capillary bed. The basic form of the loop microstructure in rat FuP was a cylindrical or bamboo-basket-like loop structure. In the rabbit, FuPs consisted of a carnation-like structure and in the cat FuP consisted of a half oval fishnet ball-like structure. It can be said conclusively that from this detailed investigation of the intracapillary microvascular architecture of the three mammals, FuP are effective as a sensory organ receiving the taste of foods and liquids by the expansion of the surface area in various functional and microvascular formations in the rat (cylindrical or bamboo-basket-like loop structure), rabbit (carnation-like) and cat (half oval fishnet-ball-like) respectively.

Angioarchitectural form, functional distributive pattern and classification of the fungiform papillae on the crossbred Japanese cat tongue anterodorsal surface in scanning electron microscopic specimens

The purpose of this study was to undertake a three-dimensional comparative observation of the angioarchitectural form, functional distributive pattern, and to classify the fungiform papillae (FuP) found sporadically and geometrically on the oblique lines of the filiform papillae (FiP) on the entire dorsal surface of the crossbred Japanese cat foretongue in microvascular cast specimens (MVCS). By means of the corrosive resin casting technique, the MVCS of the FuP of the cat tongue were prepared and examined in detail under the scanning electron microscope (SEM). With regard to the arrangement of FiPs and FuPs on the frontal half of the antero-dorsal surface of the cat foretongue, FiP types I-V and FuP types I-IV are arranged a A form with the point in the direction of the apex and in an oblique line running from the antero-central portion to both postero-peripheral portions. In the rear half of the antero-dorsal surface of the foretongue, FiP types I-V and types FuP I-IV are arranged in a V form with the point in the direction of the radix and in an oblique line running from both antero-peripheral portions to the postero-median portion or towards the pharynx on the anterior centro-dorsal surface of the cat foretongue. With the FuP arranged in the medial zone (M) and peripheral zone (P) running from the central to the apical parts, both the peripheral parts and the pharyngeal can be classified into four types (FuP types I-IV) according to the shape and size of the main process (MP), the number of the accessory processes (AP) and the regional position of the lozenge arrangement. FuP Types I-III consisted of a MP containing a large half oval, network-like process, and the AP contained a bundle of spine-like processes arranged radially in a circle at the anterior basal margin of the MP. The FuP Type IV was made up of only one MP. In the central zone (C) of a lozenge part arranged in the A and V forms, there was no FuP as a taste organ. It was assumed that in the lozenge arrangement of the A and V forms, except for the C zone, FuPs could be classified into four types (FuP types I-IV) from the frontal portion of the antero-dorsal surface toward the pharynx on the foretongue, and would play an assistant functional role in receiving the sense of taste of foods and liquids.