VANA 102 Avian External Anatomy & Integument PDF

# VANA 102 - External Anatomy and Integumentary System of Avian ## External Anatomy of Avian * Understanding avian external anatomy is fundamental to appreciating the diversity and adaptations of birds. ### Importance of Studying Avian Anatomy: 1. **Adaptations for Survival:** Birds exhibit uni...

# VANA 102 - External Anatomy and Integumentary System of Avian ## External Anatomy of Avian * Understanding avian external anatomy is fundamental to appreciating the diversity and adaptations of birds. ### Importance of Studying Avian Anatomy: 1. **Adaptations for Survival:** Birds exhibit unique external features adapted to various environments, such as streamlined bodies for flight, specialized beaks for feeding, and colorful plumage for communication. 2. **Biodiversity and Evolution:** Studying external anatomy helps understand evolutionary pathways, revealing how birds diverged from their ancestors and adapted to occupy diverse ecological niches. ### Applications in Key Fields: 1. **Veterinary Medicine:** * Recognizing healthy anatomical structures is vital for diagnosing diseases or injuries in domestic and wild birds. * Provides a foundation for avian surgery, health assessment, and rehabilitation. 2. **Biology:** * External anatomy is a basis for understanding bird physiology, behavior, and ecology. * Helps classify species based on morphological characteristics. 3. **Ornithology:** * Supports fieldwork to identify species by their external features. * Enhances conservation efforts by linking morphology to habitat needs and threats. ## General Body Regions ### Head: * It contains the beak, eyes, comb (larger in roosters), wattles, and ear openings. * Sensory perception, thermoregulation, and social signaling. * Feeding. ### Neck: * Connects the head to the trunk and is flexible. * Facilitates movement for feeding and vigilance. ### Trunk: * The central body part, housing major organs. * Provides attachment points for wings and legs, and supports flight muscles. ### Wings: * Covered in primary and secondary feathers. * Essential for flight, balance, and display in mating rituals. ### Tail: * Roosters have longer, more decorative tail feathers; hens have simpler tails. * Steering during flight and display purposes. ### Legs and Feet: * Equipped with scales and claws for walking, perching, or scratching. * Locomotion, foraging, and defense. ## SKIN /INTEGUMENT (Integumentum commune) * The skin produces and bears the feathers which are the characteristic of the birds. * The skin is thin and the plumage protects it from mechanical injury. * Highly movable because of its well-developed subcutis. ### Layers of the Skin: * **Epidermis:** * Stratum corneum - covering of integument derivatives * Stratum germinativum * Stratum transitivum * Stratum intermedium - thickest part * Stratum basale * **Dermis:** * Stratum superficiale * Stratum profundum - mm. pennarum * Stratum compactum * Stratum laxum - apterial muscle * **Subcutis** ### Muscle of the Skin: * **"True cutaneous muscle"** - mm. pennarum * **“False cutaneous muscle"** - the feather-bearing region of skin ### Color of the Skin: * Gray and black color is caused by melanophores migrating into the epidermis. * Yellow or red coloration (beak and feet) is caused by lipochromes (carotenoids) ### Other characteristics of the Skin: * **Brood patches:** * less dense feather but highly vascularized on the breast part * They transfer body heat to the incubating eggs. * Supplied by cutaneous artery (a. incubatoria - branch of subclavian artery) * **Sweat glands:** * Absent * **Sebaceous gland** * **Gland ceruminosae** - located in the outer ear * **Preen gland/ Uropygial gland/ oil gland** ## Head Anatomy of Birds * The head of a bird is a highly specialized structure that houses sensory organs, feeding tools, and features for thermoregulation and display. ### Comb: * It is a fleshy, vascular structure located on the top of the heads of birds * In fowl both sexes have comb * The single comb has these parts: * Base * Body * Points ### Wattles: * Pendant, double fold of skin and each lamella. * Suspended in jugal area ### Ear lobe: * At the caudal end of the malar region. * Sinus capillaries control the color * Firbomucoid layer is absent. ### Cere: * Lies at the base of the beak as a soft tissue covered by a membranous corneum. ### Beak: * AKA: "Bill" * Horny covering of the upper and lower beaks are “Rhamphothecae” * Dorsal midline contour of the upper membrane "Culmen" ### Tomia: * are the sharp edges of a bird's beak (or bill), critical for gripping, cutting, or processing food. ## Feathers: * In domestic birds, the contour feathers grow in tracks (pterylae), while the neighboring bald patches (apteria) only have down feathers or none. This arrangement is known as pterylosis. ### Plumage: * Enable the bird to fly * Regulate temperature * During late embryonic life, chicks are covered with "natal of nestling down” ### Types of Feathers: * **Contour Feathers:** Outer feathers that cover the body and define its shape. Found on the head, body, wings, and tail. * **Remiges (Flight Feathers):** Large, stiff feathers responsible for flight. Attached to the wing. * **Primary Remiges:** Outer wing feathers, attached to the "hand" bones, responsible for propulsion. * **Secondary Remiges:** Inner wing feathers, attached to the ulna, providing lift. * **Tertiary Feathers:** Closest to the body, aiding in airflow. * **Rectrices (Tail Feathers):** Stiff feathers on the tail. Attached to the pygostyle. * **Coverts:** Small feathers overlaying and protecting the bases of larger feathers. Found on wings and tail. * **Wing Coverts:** Cover the primary and secondary remiges. * **Tail Coverts:** Cover the base of the rectrices. * **Semiplumes:** Feathers with a mix of downy and contour characteristics. Beneath contour feathers, especially around the body. * **Down Feathers:** Soft, fluffy feathers without a central rachis or with reduced barbs. Found under contour feathers, more abundant in chicks. * **Filoplumes:** Hair-like feathers with a few barbs at the tip. LNear contour feathers, especially around the wings and tail. * **Bristle Feathers:** Stiff, hair-like feathers with little to no barbs. Around the eyes, nostrils, and occasionally the toes. ## Legs and feet (Scales and claws): * **Scutes-** General term - Dorsal and plantar surface * **Scutellae-** intermediate size - lateral * **Reticulae** - small size - ventral surface of toe ## Legs and feet (Scales and claws): * **Cancellate:** present in toes webs of aquatic birds. ## Spur * A spur is a sharp, bony outgrowth or projection covered in keratin, commonly found on the legs of certain bird species. * It is typically associated with male birds and serves various roles, particularly defense, competition, and display. * Tarsometatarsus. * Bone will support it until about 6months.