The structure of the canary's incubation patch

Abstract

The gross morphology, histology and ultrastructure of the canary's incubation patch and the ventral apterium from which it arises are described. The apterium is vascularized by pectoral, external mammary, incubation, and prepubic arteries. It is innervated by cutaneous branches of spinal nerves. It has a surface area of 6 cm . Its epidermis is a stratified squamous epithelium with basal, intermediate, transitional and cornified layers. Cells in the stratum germinativum contain a normal array of organelles, but are characterized by tonofilaments, desmosomes and interdigitating surfaces. Cellular organelles disappear in the stratum transitivum and are replaced by large vacuoles and keratohyalin bands. Nonmyelinated nerve fibers are abundant in the stratum germinativum. The dermis consists of (1) an avascular layer of dense collagen subjacent to the epidermis and containing many nonmyelinated nerves, and (2) an underlying layer of areolar connective tissue containing blood vessels, lamellar corpuscles and nerves. A layer of coarse elastic fibers, reinforced by collagen and smooth muscle, separates the dermis from subcutaneous tissue. In contrast to the ventral apterium, the incubation patch is featherless and visibly hypervascular and edematous. Its epidermis is both hypertrophic and hyperplastic. Large spaces separate cells in the stratum germinativum. The visible hypervascularity is due to hyperemia and increased number and size of blood vessels in the dermis. Visible edema is due to the accumulation of fluid interstitially. Although no histological differences exist among various regions of the ventral apterium, such differences are present in the incubation patch.

Density of arteriovenous anastomoses in some skin areas of the domestic fowl (gallus domesticus)

“…The thoracic skin of birds has received particular attention due to its seasonal development of a brood patch, and several detailed descriptions of the blood vessels exist (Lange, 1928;Selander and Yang, 1966;Jones, 1971;Kern and Coruzzi, 1979). However, the present study appears to be the first to report the presence of AVAs in the thoracic skin.…”

The Use of the VOF‐Model to Study the Wetting of Solid Surfaces

“…A discussion about the different patterns of rivulet liquid flow on a flat plate and the development of liquid flow from drops to a single laminar rivulet and then to a wavy and turbulent rivulet flow was presented by Kern [9,10]. Schmuki and Laso [12] discussed in their work the stability of rivulet flow and the existing regimes of different patterns exhibited by a liquid flowing down an inclined plate.…”

Functional morphology of arteriovenous anastomoses on rat ovary

“…AVAs have been tested in human and many animal organs [3,4,5,6,7]. AVAs have been observed to have thermoregulatory functions in human skin [8,9].…”