Gross Anatomy PDF

GROSS ANAT Transcribed by: MANABAT, Leann Topographic terms Hair and hair follicles: Complex INTEGUMENTARY SYSTEM Derived from epidermis and dermis...

GROSS ANAT Transcribed by: MANABAT, Leann Topographic terms Hair and hair follicles: Complex INTEGUMENTARY SYSTEM Derived from epidermis and dermis Everywhere but palms, soles, nipples, parts of genitalia Common integument – Protective covering of the body. – Composed of skin, hair, claws, pads and mammary glands Skin (Cutis) – One of the largest organs of the body – 16% BW Continuous with the mucous membranes of the respiratory, digestive and urogenital tracts at the mucocutaneous junction Skin thickness of dogs: Functions of hair: Thickest – neck region Warmth – less in man than other Thinner - over the sternum mammals Thinnest - ventral surface of the abdomen Sense light touch of the skin Protection – scalp Functions of the skin: Parts Protects the body from invasive microorganisms and Root imbedded in skin noxious chemicals Shaft projecting above skin surface Prevents dessication and hydration Make up of hair – hard keratin Acts as a sensory organ Three concentric layers Regulates temperature change Medulla (core) Secretion of substances Cortex (surrounds medulla) Excretion of substances Cuticle (single layers, overlapping) Site of Vitamin D synthesis Reservoir of fats Guard hairs are typically stiffer, harder, glossier, smoother, Reflects the general health condition of the animal coarser, longer and/or thicker in diameter than the softer Layers of the skin: undercoat of a dog. Epidermis The hair acts as an additional o the most superficial layer layer of insulation, a “topcoat,” if o non-vascular , composed of stratified squamous you will, to protect a dog from epithelium in varying thickness cold weather. It also helps Dermis prevent injuries to the dog’s skin, o Lies immediately underneath the epidermis and, to a large extent, o With vessels, nerves, and glands determines the dog’s appearance because of its unique Hypodermis coloring. o Subcutis or subcutaneous tissue o Fats cells develop Hair (Pili) Denser - dorsal and lateral parts Layers of the Epidermis: Thinner – abdomen, flanks and (Basement membrane) Parts of the hair: Stratum basale o Shaft (scapus pili) Stratum spinosum – prickle- cell layer o Root (radix pili) Stratum granulosum – granular layer Vibrissae – enlarged hairs Stratum lucidum – clear layer Superciliary hairs – enlarged ears, and underside of the tail Stratum corneum – horny layer hairs above the eye Nasal skin – s.granulosum and s.lucidum are absent Vibrissae – enlarged hairs; these are tactile receptors located under Dermis the skin Strong, flexible connective tissue: your “hide” Cells: fibroblasts, macrophages, mast cells, WBCs Fiber types: collagen, elastic, reticular Rich supply of nerves and vessels Critical role in temperature regulation (the vessels) Hypodermis “Hypodermis” (Gk) = below the skin “Subcutaneous” (Latin) = below the skin Also called “superficial fascia” “fascia” (Latin) =band; in anatomy: sheet of connective Purposes of Vibrissae or “whiskers” tissue Canine whiskers help a dog measure distance in the dark. Fatty tissue which stores fat and anchors skin (areolar Air currents, perceived by the vibrissae, allow a dog to tissue and adipose cells) obtain an idea about space size and object location in Different patterns of accumulation (male/female) relation to the body. The superciliary vibrissae (located above the eye), protect Skin color a dog’s eyes from dust and dirt in the air. Three skin pigments: A dog’s vibrissae perceive air currents, providing Melanin: the most important information about temperature to a dog’s brain. Carotene: from carrots and yellow veggies Hemoglobin: the pink of light skin Classification of Haircoat of Dog Based on Length Normal coat Skin appendages: o Ex. Wolf, jackal, GS Derived from epidermis but extend into dermis Short hair Include o Ex. Boxer o Hair and hair follicles Long hair- wire hair, tight curly hair, and flat long hair o Sebaceous (oil) glands o Ex. Cocker spaniel, poodle o Sweat (sudoriferous) glands o Nails o Mammary glands GROSS ANAT Transcribed by: MANABAT, Leann Other classifications of hairs Mammary glands Straight hair Cranial and caudal thoracic Bristle hair mammary glands Wavy bristle hair Cranial and caudal Bristled wavy hair abdominal mammary Large wavy hair glands Fine wavy hair Inguinal mammary glands Muscles of the Skin Erector pili muscle o Hair muscle Blood supply of mammary glands: o Responsible for the Arterial supply of the thoracic and abdominal mammary erection of hairs in glands – sternal branches of the internal thoracic arteries animals in response to Arterial supply of the inguinal mammary glands – external cold, fear or anger pudendal arteries (piloerection) Cutaneous muscle / cutaneous trunci o When contracted tend to move the skin and its associate structures o Muscle that twitches the skin Venous supply – cranial and caudal epigastric veins Glands of the Canine Skin Sweat glands o Eccrine sweat glands secrete sweat directly onto the surface of the skin ▪ located over almost the entire body, with higher # in the foot pads o Apocrine sweat glands secrete fluid into the sac of hair follicle through which it eventually comes out on the skin ▪ found in armpits, genital area, and around the Nerve supply of mammary glands nipples Cran. Thora. MG – 4th, 5th, 6th vent. cutaneous nerves Sebaceous glands Caud. Thora. MG – 6th & 7th vent. cutaneous nerves o Responsible for oily secretion Abdominal & inguinal MG – inguinal nerve and the vent. Glands of ear canal superficial branches of the first 3 lumbar nerves o Secretes cerumen Bartholin glands (bitch)/ Greater vestibular glands o two in number o located in the constrictor muscles of the vestibule and secrete mucus most actively at estrus o Each Bartholin gland opens in the lateral wall of the vestibule by a single duct Glands of anal sac o Lies in the 4 and 8 o’clock position of the anal canal o Together with sebaceous glands lead to formation of a viscous liquid or pasty material with a foul odor Supracaudal gland / tail gland / violet gland o Located at the dorsal aspect of the tail o for intra-species signalling, scent marking, and contributes to the strong odor of foxes in particular Claws Functions: traction, defense, catching prey Parts: o Sole o Two walls o Central dorsal ridge Digital pads Toughest region of the canine skin o Rough surface of the pads are due to the presence of heavily keratinized conical papillae