Hair, Footpads, Nails, Claws and Hoofs,Horns- C. Martonos.pdf

Dr. Cristian Martonos Previous lecturer: Dr. Cristian Dezdrobitu 1 Students should: Define the common integument Describe the role of the skin Describe the types of the hair (what is it, development of hair) Describe the footpads (where they have the best development) Define the nails, claws and hoo...

Dr. Cristian Martonos Previous lecturer: Dr. Cristian Dezdrobitu 1 Students should: Define the common integument Describe the role of the skin Describe the types of the hair (what is it, development of hair) Describe the footpads (where they have the best development) Define the nails, claws and hoofs (differences in species) Define the horns (the importance of the cornual process and frontal sinus) 2 Term COMMON INTEGUMENT = ordinary skin with its covering of hair and variety of skin glands as well as more specialized parts such as claws, hoofs, and horns. https://www.huffingtonpost.com/2013/08/23/sheep-study-rams-big-horns-ewedie_n_3799591.html https://www.myvmc.com/anatomy/human-skin/ https://hinative.com/en-US/questions/923026 3 https://blog.easycareinc.com/its-not-just-bare-feet/ Role: covers the body and protects it against injury temperature control enables the animal to respond to various external stimuli https://www.pinterest.com/pin/426505027183253602/ https://socratic.org/questions/what-layer-of-skin-contains-the-blood4 vessels-and-nerves Layers: Epidermis (out) Dermis (in) 1, Epidermis; 2, dermis; 3, subcutis; 4, sebaceous gland; 5, arrector pili muscle; 6, sweat gland; 7, hair follicle; 8, arterial networks. DYCE, SACK AND WENSING’S TEXTBOOK OF VETERINARY ANATOMY, FIFTH EDITION ISBN: 9780323442640 Rests on a looser connective tissue named: subcutis, hypodermis or superficial fascia. 5 Diagnostic of the class Thick haircoat is spread over the body (most species) except about the mouth and other openings and on the surfaces of the feet https://blazepress.com/2014/11/27-animals-better-hair/ Domestic pig: the covering is sparse 6 Only three types of hair need be distinguished:  straight, rather stiff guard hairs provide a “topcoat”;  fine, wavy wool hairs provide an “undercoat”;  stout tactile hairs of restricted distribution are associated with touch receptors. (A) Guard hair with thick medulla. (B) Guard hair with thick cortex and thin medulla. (C) Wool hair; the cortex is absent. 1, Cuticle; 2, cortex; 3, medulla. 7 DYCE, SACK AND WENSING’S TEXTBOOK OF VETERINARY ANATOMY, FIFTH EDITION ISBN: 9780323442640 Responsible for the colour is:  Melanin  Pigment : produced in a specialized group of cells known as melanocytes.  Also colours the skin FYI - Absence of melanin: Albinism  “congenital absence of any pigmentation or coloration in a person, animal or plant, resulting in white hair, feathers, scales and skin and pink eyes in mammals, birds, reptiles, amphibians and fish and other small invertebrates as well." 9 https://medical-dictionary.thefreedictionary.com/albinism Guard hairs  Lie close against the skin and sweep uniformly in broad tracts;  Giving the coat a smooth appearance disturbed only by the whorls, crests;  It promotes the runoff of rain, preventing the chilling that would occur if water were allowed to penetrate the pile to reach the skin;  Occasionally, animals are born with a disturbed coat pattern, which may seriously impair their ability to withstand severe weather;  Each hair grows from a tiny pit or follicle to protrude above the surface of the skin. 11 Guard hairs  The follicle develops from an ectodermal bud;  The distal end of the bud forms a bulbous enlargement, which is then indented by a mesenchymal (dermal) papilla to form a primitive hair follicle. DYCE, SACK AND WENSING’S TEXTBOOK OF VETERINARY ANATOMY, FIFTH EDITION ISBN: 9780323442640 Development of hair and associated sebaceous and sweat glands, schematic. (A) Ectodermal bud growing into mesenchyme. (B) Differentiation of the bud; indications of glands appear. (C) Hair follicle with accessory structures. 1, Primitive hair follicle; 2, dermal papilla; 3, bud of sweat gland; 4, bud of sebaceous gland; 5, bulb (hair matrix) of hair; 6, hair follicle; 7, root of hair; 8, arrector pili muscle; 9, sebaceous gland; 10, sweat gland. In the adult, many glands open independently, not into hair follicles. 12 Guard hairs  Local variations in the form and development of guard hairs:   stiff, sparsely scattered bristles of pigs the coarse hair of the mane and tail of horses 13 https://en.wikipedia.org/wiki/Mane_(horse) http://www.cpr.org/classical/blog/10-facts-about-horsehair-string-player-s-bow Guard hairs  Local variations in the form and development of guard hairs:  the long tail hairs of cattle  the fetlock tufts of horses  the feathering of the tail and limbs of certain breeds of dogs http://www.kbia.org/post/heres-short-story-cow-tails https://www.alamy.com/stock-photo/fetlock.html 14 https://www.chewy.com/petcentral/behavior-breeds-6short-legged-dog-breeds/ The Local variations of the guard hair: hormone-dependent evident in the human species Lives: Hairs have restricted lives and are discarded sooner or later. Although hair shedding in humans is a continuous process involving only a few hairs at a time, most other species, especially wild species, shed many hairs at a time in a seasonal fashion. 15 Domesticated animals shedding:  Show a recurrent pattern with peaks in the spring and fall; spring shedding lasts about 5 weeks in dogs  More obvious in animals not regularly groomed to remove dead hair  Cats also molt most heavily in spring, with less substantial loss through the summer and fall followed by attaining of prime condition in winter 16 Wool hairs      Provide the soft undercoat Thin Wavy Shorter and more numerous than the guard hair Concealed between the guard hair 17 Wool hairs In many species, including mature dogs and cats, several hairs share a single follicle opening The central (primary) hair is longest and of the guard type The surrounding (secondary) hairs are shorter and softer They provide the undercoat and may be designated wool hairs because they have little medulla. DYCE, SACK AND WENSING’S TEXTBOOK OF VETERINARY ANATOMY, FIFTH EDITION ISBN: 9780323442640 Hair follicles of the dog: (A) simple follicle present shortly after birth; (B) follicle present during the first few months after birth; (C) complex adult follicle; the primary 18 hair is surrounded by several secondary hairs. Tactile hair     substantially thicker generally protrude beyond the neighboring guard hairs reach deep into the subcutis or even the superficial muscles characterized by the presence of a venous sinus filled with blood and located between inner and outer layers of the dermal sheath  nerve endings responsive contained within the dermal sheath  Topography:  face,  principally on the upper lip and about the eyes,  although others are scattered (in species-variable fashion) on the lower lip, the chin, and elsewhere on the 19 head. Tactile hair Functionality:  nerve endings responsive to mechanical stimulation  the stimulus provided by disturbance of the hair is amplified by wave motion in the blood Development:  follicles of tactile hairs appear early in development, before those of the coat hairs 20 Torus/Tori = A bulging or rounded projection or swelling The term Torus - used in connection with the common integument, denotes a pad. It includes the thick epidermal covering, the dermis, and the subcutaneous cushion, or Pulvinus. 21 Structure: naked, densely cornified epidermis dermis is unremarkable thick, resilient subcutis admixture of collagenous and elastic fibers interspersed with adipose tissue(fat) The footpads are the digital cushions on which animals walk. 22 Ruminants and pigs: Only digital pads called bulb located in the hoof Horse: Only digital pads called frog located in the hoof Functional and in contact with the ground. 25 Nails, Claws, and Hoofs  Similar structures enclosing the distal phalanx appear strikingly different  Local modifications of skin  Serve primarily to protect the underlying tissues  Used for: scratching digging weapon grab the food 30 Equine Hoof Reduces concussion on foot impact Presents three parts: Wall Sole Associated pad (horny structure; it corresponds with the digital bulb of primates and the digital pad of carnivores) 31 Equine Hoof THE WALL strongly curved the sides are sharply inflected to form the so-called bars WALL BAR HEEL DYCE, SACK AND WENSING’S TEXTBOOK OF VETERINARY ANATOMY, FIFTH EDITION ISBN: 9780323442640 32 Equine Hoof space between the bars is occupied by the frog, the part of the footpad that makes contact with the ground FROG WALL BAR HEEL DYCE, SACK AND WENSING’S TEXTBOOK OF VETERINARY ANATOMY, FIFTH EDITION ISBN: 9780323442640 33 Equine Hoof the sole horn that fills the ground surface between wall and frog meets the wall at a junction known as the white line. FROG WALL WHITE LINE (ZONA ALBA) BAR HEEL DYCE, SACK AND WENSING’S TEXTBOOK OF VETERINARY ANATOMY, FIFTH EDITION ISBN: 9780323442640 34 Equine Hoof Periople band of soft horn lies over the external surface of the wall near its junction with the skin it descends with the wall and dries to a protective glossy layer widens at the back of the hoof, where it covers the bulbs of the heels and part of the frog. PERIOPLE CORONET REGION DYCE, SACK AND WENSING’S TEXTBOOK OF VETERINARY ANATOMY, FIFTH EDITION ISBN: 9780323442640 36 CLAWS IN CARNIVORES Compared with a nail that has been laterally compressed. Characteristics: sharp dorsal border epidermis is minimally productive the dermis that covers the unguicular process fuses with the periosteum longitudinal interdigitations between dermal and epidermal laminae strongly bond the claw to the dorsal border of the bone 37 HORNS Horns of domestic ruminants: have osseous bases provided by the cornual processes of the frontal bones are permanent and grow continuously after their first appearance soon after birth. https://design.tutsplus.com/tutorials/h ow-to-draw-animal-horns--cms-31106 39 HORNS 1. Caudal frontal sinus extending into horn; 2. cornual process of frontal bone CLINICAL IMPORTANCE WHEN DEHORNING AN ADULT ANIMAL https://www.slideshare.net/AsadAbdulHannan/comparative-study-of-skull-of-camel-ox frontal sinus extending into horn DYCE, SACK AND WENSING’S TEXTBOOK OF VETERINARY ANATOMY, FIFTH EDITION ISBN: 9780323442640 40 Practice Questions 1. The cornual process in cattle is invaded by the frontal sinus. Practice Questions 2. Using the attached image, name the structure numbered with 4: A. Wall of claw B. Metacarpal pad C. Bulb D. Sole of claw E. Digital pad Practice Questions 3. Which one of the following statements is correct statement regarding wavy wool hairs? A. Are associated with touch receptors B. Are longer and less numerous than the guard hair C. Have cortex D. Provide a ‘topcoat’ E. Provide an ‘undercoat’