Anat 121 Lecture 3 (Integumentary System) PDF

Anat 121 | Gross Anatomy Nasal Skin- s.granulosum and s.lucidum are absent Lecture 3 Dermis INTEGUMENTARY SYSTEM Common Integument Stro...

Anat 121 | Gross Anatomy Nasal Skin- s.granulosum and s.lucidum are absent Lecture 3 Dermis INTEGUMENTARY SYSTEM Common Integument Strong, flexible connective tissue: your “hide” Cells: fibroblast, macrophages, mast cell, WBS’s Protective covering of the body. Fiber types: collagen, elastic, reticular Skin, Hair, Claws, Pads and Mammary Glands. Rich supply of nerve and vessels Skin (Cutis) Critical role in temperature regulation (the vessels) One of the largest organs of the body- 16% BW Continuous with the mucous membranes of the Hypodermis/superfacial fascia respiratory, digestive and urogenital tracts and the mucocutaneous junction. “Hypodermis” (GK)=below the skin “Subcutaneous” (latin)= below the skin Skinn Thickness of the dogs “fasia” latin= band; in anatomy: sheet of connective tissue Thickest- neck region Fatty tissue which stores fat and anchors skin Thinner- over the sternum (areolar tissue and adipose cells) Thinnest-Ventral surface of the abdomen Different patters of accumulation (male/female) Function of the Skin: Skin Color (three skin pigment) Protects the body from invasive microorganisms Melanin: the most important and noxious chemicals Carotene: the carrot and yellow veggies Acts as a sensory organ Hemoglobin: the pink of light skin Site of Vitamin D synthesis Regulates the body temperature Skin Appendages Prevents desiccation and dehydration From Epidermis but sometimes into dermis Layers of the skin: Epidermis, Dermis, ad Hypodermis Hair and Hair follicle Sebaceous (oil) glands, Sudoiferous (sweat) Epidermis glands Most Superficial layer Nails and mammary gland Non-vascular composed of stratified squamous Hair and hair follicles: complex epithelium in varying thickness Derived from epidermis and dermis Dermis Everywhere but palms, soles, nipples, parts of With vessels, nerve, and glands genitalia Hypodermis Function of Hair Fats cell develop and Subcutis or Subcutaneous Warmth tissue Sence light touch of the skin Protection LAYERS OF THE EPIDERMIS (lower to upper) Parts Basement Membrane Stratum Basale Root imbedded in skin Stratum Spinosum-Prickle-cell layer Shaft protecting above the skin surface Stratum Granulosum-Granular layer Make up of hair: Hard Keratin Stratum lucidum-clear layer Three Concentric Layer Stratum corneum-horny layer  Medulla (core) The superciliary vibrissae (located above the Cortex (surrounds medulla) eye), protect a dog’s eyes from dust and dirt in Cuticle (single layer, overlapping) the air. A dog’s vibrissae perceive air currents, providing Guard hairs- longer, harder, smoother, and thicker than information about temperature to a dog’s brain. the softer undercoat of dog. Classification of Hair of Dog Based on Length Hairs acts as an additional layer of insulation “topcoat” also prevent injuries to the dog’s skin. 1. Normal Coat – German Sheered, Wolf, Jackal 2. Short Hair-Boxer Hair (Pili) 3. Long Hair-wire hair, tight curly hair, and flat long hair- Cocker spaniel, poodle 4. Other classification: Straight hair, bristle hair, wavy bristle hair, bristled wavy hair, large wavy hair, fine wine hair. Muscle of the skin Erector Pili Muscle Hair muscle Responsible for the erection of hairs in animals in response to cold, fear or anger (piloerection) Cutaneous Muscle/Cutaneous Trunci Muscle that twitches the skin Glands of Canine Skin Sweat Glands Eccrine sweat glands secrete sweat directly onto Vibrissae/Whiskers-enlarged hairs: tactile receptors the surface of the skin located under the skin. o located over almost the entire body, with higher # in the foot pads Apocrine sweat glands secrete fluid into the sac of hair follicle through which it eventually comes out on the skin o found in armpits, genital area, and around the nipples Sebaceous Glands Responsible of oi secretion Glands of ear canal Purpose of vibrissae or “whiskers” Secretes cerumen Canine whiskers help a dog measure distance in the dark. Air currents, perceived by the Bartholin glans (bitch) vibrissae, allow a dog to obtain an idea about space size and object location in relation to the two in number body. located in the constrictor muscles of the vestibule and secrete mucus most actively at estrus  Each Bartholin gland opens in the lateral wall of the vestibule by a single duct Glands of anal sac Lies in the 4 and 8 o’clock position of the anal canal Together with sebaceous glands lead to formation of a viscous liquid or pasty material with a foul odor Supracaudal Gland, Tail Gland, violet gland Located at the dorsal aspect of the tail for intra-species signalling, scent marking, and contributes to the strong odor of foxes in particular Claws Function: traction, defense, catching prey Parts: Sole, Two Walls, Central Dorsal Ridge Nerve Supply of the Mammary Glands Digital Pads Cran. Thora. MG – 4th, 5th, 6th vent. Cutaneous Toughest region of the canine skin nerves Rough surface of the pads are due to the Caud. Thora. MG – 6th & 7th vent. Cutaneous presence of heavily keratinized conical papillae nerves Abdominal & inguinal MG – inguinal nerve and Mammary Glands the vent. superficial branches of the first 3 Cranial and caudal thoracic mammary glands lumbar nerves Cranial and caudal abdominal mammary glands Inguinal mammary glands Body Supply of the Mammary Glands Arterial supply of the thoracic and abdominal mammary glands – sternal branches of the internal thoracic arteries Arterial supply of the inguinal mammary glands – external pudendal arteries Venous supply- cranial and caudal epigastric veins