Comparative Anatomy Lecture (Digestive System) PDF

Comparative Anatomy Lecture Dr. James Owen Mirandilla A.Y 2023 – 2024 Topic 4: Digestive System - There 3 apertures present. Made of parts responsible for digestion and absorption of 1. Oropharynx – opens in to the oral cavit...

Comparative Anatomy Lecture Dr. James Owen Mirandilla A.Y 2023 – 2024 Topic 4: Digestive System - There 3 apertures present. Made of parts responsible for digestion and absorption of 1. Oropharynx – opens in to the oral cavity nutrients and elimination of waste products in a form of stool, 2. Nasopharynx – opens into the nasal cavity above feces, or manure. 3. Laryngopharynx – opens into the larynx and esophagus ventrally. Components of Digestive System - (Pharyngeal body) serves as common passage for digestive and respiratory tract. 1. Digestive Tract c. Esophagus 2. Digestive Glands - It is a musculo-membranous tube. 3. Accessory Digestive Structure - Presents 3 segments or portions. 1. Cervical segment – adjacent to the cervical Digestive Tract vertebrae. - Also known as the Alimentary canal 2. Thoracic segment – adjacent to the thoracic - It serves as passageway for food and it extends to the mouth vertebrae. down to the anus. 3. Abdominal segment – when it passes to the hiatus a. Mouth esophagi of the diaphragm. Situated posteriorly. b. Pharynx c. Esophagus Note d. Glandular Stomach and Non Glandular Stomach in o Diaphragm – is the main inspiratory muscle, and it Ruminants separates the thoracic cavity above and abdominal e. Small intestine cavity below (esp. in humans). f. Large intestine o Ingesta passing through esophagus is termed as bolus g. Anus which is slightly alkaline. - It has 4 Concentric Layers, inner to outer layer. Digestive Glands 1. Tunica mucosa - Organs with secretions 2. Tunica submucosa a. Salivary Gland 3. Tunica muscularis b. Liver 4. Tunica adventitia c. Pancreas d. Stomach Accessory Digestive Structure - Mechanical structures inside the mouth a. Teeth b. Tongue c. Cheeks d. Lips e. Soft Palate f. Hard Palate i. Digestive Tract - It is a hollow muscular bag - When the ingesta enters the stomach and mixed with gastric juice it is termed as Chyme which is strongly acidic. - 4 parts of stomach: 1. Cardia 2. Fundus 3. Body 4. Pylorus - It presents 2 sphincters which are made up smooth type muscle that constrict these structures therefore it prevents backflow of ingesta. 1. Cardiac Sphincter – between esophagus and a. Mouth/Oral cavity stomach. - Also known as the buccal cavity. 2. Pyloric Sphincter – between stomach and - Bounded: duodenum of small intestine. Dorsally – by upper set teeth, soft and hard palate. - It has 4 Concentric Layers, inner to outer layer Ventrally – by lower set of teeth, tongue, and the floor 1. Tunica mucosa of mouth 2. Tunica submucosa Rostrally – by upper and lower lips 3. Tunica muscularis Laterally – by left and right cheeks 4. Tunica serosa Caudally – by oropharynx - Gastric glands are made up of 2 types of cells that b. Pharynx composes the gastric juice. Transcribed by: Fi 1 Comparative Anatomy Lecture Dr. James Owen Mirandilla A.Y 2023 – 2024 1. Chief cells – secretes pepsinogen 3. Ileum – last and terminal segment, and it has 2. Parietal cells – secretes hydrochloric acid immunologic functions. There are lymphatic nodules along the ileum small intestine which is Note the Peyer’s Patches. o Pepsinogen – from the suffix –gen is an inactive form of § Fixed part – Duodenum pepsin which is responsible in digesting proteins. § Mesenteric Part or movable part – jejunum and ileum Activated by the hydrochloric acid. - it presents 2 surfaces Note 1. Parietal – facing the outside o Mesentery – also known as the chicharong bulaklak, 2. Visceral – facing the other visceral organs or the which is a connective tissue which is the supporting inside. structure of the intestine to prevent rotation. Present in - It has 2 curvatures: Duodenum, Jejunum, and Ileum. 1. Greater Curvature 2. Lesser Curvature - It has 2 extremities: 1. Left – in the area of cardia 2. Right – in the area of pylorus - The entrance is the cardia, left side of the body of stomach. - The exits is the pylorus, right side of the body of stomach. - The stomach is held in position of: Due to the pressure of surrounding organs such as the spleen, liver, and intestine By the esophagus above By the 5 peritoneal folds 1. Gastro–Phrenic – faces the diaphragm The Mesenteric part of the S.I is connected with the dorsal 2. Gastro–Splenic – faces the spleen abdominal wall by a double layer of peritoneum termed the 3. Gastro–Pancreatic – faces the pancreas common mesentery, attached to the dorsal abdominal wall. 4. Lesser Omentum – attached to the lesser o Peritoneum – mesothelial lining of the abdominal curvature cavity. 5. Greater Omentum – attached to the greater o The root of the mesentery is attached to a point closer curvature to the origin of the cranial mesenteric artery under the 1st and 2nd lumbar vertebrae. Note Note o Phrenic – refers to any structure of diaphragm o Pleura is the counterpart of peritoneum, it is located in o Omentum – is a connective tissue that support the the thoracic cavity. stomach. o Mesentery – also known as the chicharong bulaklak, - The interior of the intestine the following features: supporting structure of the intestine. 1. Villi – it refers to the finger-like projections of S.I and helps to increase absorptive surface area. e. Small Intestine 2. Payer’s Patches – scattered nodules lymphoid tissue, the specific roles is for intestinal defenses against pathogens. Note o Pathogens – disease causing organisms. - It is called small intestine due to its diameter, which has smaller diameter than large intestine. - In terms of length, small intestine is longer - It presents 3 segments: 1. Duodenum – it is less movable because it is connected to the stomach. It is where bile duct and pancreatic duct empty the biliary and pancreatic juices. 2. Jejunum – is the longest, most movable, and most absorptive segment of the intestine. Transcribed by: Fi 2 Comparative Anatomy Lecture Dr. James Owen Mirandilla A.Y 2023 – 2024 - Ducts of the Small intestine: § Anal glands – emits odor, has sebaceous or oily 1. Cystic Duct – arising from the gallbladder secretion. 2. Hepatic Duct – arising from the lobes of liver are § Para sinus and glands – located on the either side. lobar ducts which unites forming this duct. § Circum-anal glands – located further back of the skin. 3. Bile Duct – formed upon union of cystic and Note hepatic duct and opens into duodenum. o Anal sac ablation – surgical procedure of excising anal gland which lessen the odor of a dog. g. Anus - Guarded by the sphincter ani externi et interni that controls the release of feces. Note o Vent – is the term used in avian (e.g. chicken) II. Digestive Glands a. Salivary Glands - Refer to the 3 pairs of large glands situated in the side of the faces and adjacent part of the neck. 1. Parotid Gland 2. Mandibular or Submandibular gland 3. Sublingual Gland 4.Dorsal/Accessory and Ventral Pancreatic ducts – Ventral is bigger than dorsal/Accessory duct. In some species, there is only 1 pancreatic duct. f. Large Intestine - it has greater diameter than small intestine. - It extends to from the termination of the ileum to the anus. § Taenia – longitudinal bands running along the outside, made up of muscle that contracts. § Haustra – sacculations caused by the constriction of the taenia at the center. - Types of secretion 1. Serous – watery in consistency. 2. Mucous – thick consistency due to mucin granules. 3. Mixed – is made up serous and mucoid type. - Has 3 segments: I. Caecum – principal site for microbial Note fermentation in post-gastric fermenter (e.g. rabbit o Most salivary gland including in human, has a mixed and horse) type secretion except for parotid gland which has serous § Microbial fermentation is important to produce VFA type secretion while in dogs it is mixed type. (Volatile Fatty Acid) including acetic–, propionic– and o Mixed type is the bench mark of most salivary gland. butyric– acid which is a source of energy. o Zygomatic gland also known as the orbital gland which is the 4th salivary gland in dogs. It is located near the Note zygomatic bone and it has mixed type secretion. o Appendix – counterpart of caecum in humans, it is a o Molar gland is the 5th salivary gland in cats, it is a mixed rudimentary structure and non-functional. type secretion. o Rumen – principal site of microbial fermentation in gastric fermenters (e.g. ruminants). - Ducts of Salivary Glands: o Energy source of humans is glucose, which is the 1. Parotid duct – opens opposite 3rd upper cheek propionic acid. tooth at salivary papilla. 2. Submandibular duct – open opposite to the lower II. Colon – it is the principal site for water and canina teeth at sublingual caruncle. electrolyte reabsorption it has 3 portions: 3. About thirty short sublingual ducts opens through 1. Ascending part small papillae on the sublingual fold. 2. Transverse part 4. One major and 3 or 4 minor zygomatic ducts in 3. Descending part dogs open near the last upper cheek tooth. III. Rectum – last segment of large intestine, serves as b. Liver temporary storage site for feces prior defecation. - it is regarded as the nutritional guardian of the body At the junction of rectum and anus are: Transcribed by: Fi 3 Comparative Anatomy Lecture Dr. James Owen Mirandilla A.Y 2023 – 2024 - it has biliary secretion therefore it is considered as the § Left lobe is simple largest gland. § Right lobe is bears the caudate process and an omental or papillary process. Note o In terms of relative mass, skin is the largest organ. o In terms of density, Lungs is the lightest organ. It has clear spaces inside which is termed as pulmonary alveoli. - it serves as the drug biotransformation or detoxification. Note o Aspirin administered to cats it can lead to toxicity, cat’s liver is normally deficient in the enzyme called glucuronyl transferase. o Chocolate is bad for dogs, dog’s liver is normally deficient in CYP1a2/Theobromines (not sure xD) that metabolize methylxanthines or theobromine. - it secretes bile that is temporarily stored in the gallbladder, emulsifies fats. CCK or Cholecystokinin promotes the release of bile from the gallbladder. The § The depression or fossa in the liver is called fossa Cholecystokinin constricts the smooth muscle in the vesicae feleae it is where gallbladder is sunken. gallbladder after a fatty meal. Note o Which animal does not have fossa vesicae feleae the answer is horse, because horse does not have gallbladder. - At the visceral aspect a Porta is present. Certain structures enters and exits the porta. Enters: a. Portal Veins b. Hepatic artery c. Hepatic plexus Exits: a. Ducts b. Lymphatics - 6 Ligaments of the liver 1. Coronary 2. Falciform - has hepatic lobule is the structural unit of the liver and 3. Round it is a 6-sided structure in microscopic anatomy while 4. Right triangular in macroscopic anatomy, it has 3-4 lobes. 5. Left triangular 1. Left hepatic 6. Caudate 2. Right Hepatic c. Pancreas 3. Median/quadrate lobe – located between left - Located between the duodenal loop of the small and right lobe. intestine. 4. Caudate lode – arise for the right lobe. - Yellow to pinkish structure o Papillary process – extension of caudate - Has 2 portions: process, it is attached to the caudate lobe. 1. Exocrine portion (pancreatic acinar cells) – the - it is situated obliquely against the visceral surface of pancreatic juice is derived from the acinar cells, the diaphragm. and it is made-up of pancreatic amylase which - It presents 3 surfaces digest carbohydrates, lipase digest fats, 1. Parietal Surface – surface facing the outside, trypsinogen and chymotrypsinogen involved in convex portion of the liver. protein digestion. 2. Visceral surface – opposite side of parietal surface, flat to concave. 3. Circumference – consist of a. Dorsal Boarder as represented by parietal surface b. Ventral Boarder as represented by the visceral surface c. Lateral border which connects the dorsal and lateral boarder. - 2 deep fissures divide the liver into 3 lobes: 1. Central – also the same with quadrate lobe 2. Left Lateral 3. Right Lateral Transcribed by: Fi 4 Comparative Anatomy Lecture Dr. James Owen Mirandilla A.Y 2023 – 2024 Note III. Accessory Digestive Structures o Digestion of carbohydrate begins in the mouth due to a. Teeth the presence of salivary amylase or ptyalin in the saliva. 2. Endocrine portion (Islet of Langerhans) – under the microscope, there are 4 types of cells: 1. Alpha cells – secretes glucagon 2. Beta cells – secretes insulin 3. Delta cells – secretes somatostatin 4. F-cells – secretes polypeptides Note o Insulin promotes the uptake of glucose from blood to - Are essential for chopping, grinding, and chewing the tissues. food. - The tooth articulates with alveolus of the mandible of - For macroscopic description maxilla. 1) 2 surfaces: - 4 types a. Dorsal – surface above 1. Incisors – also known as the “nipper” teeth, b. Ventral – surface below implanted in the incisive bone and the body of 2) 3 borders mandible. a. Right – facing the right side of the body Note b. Left - facing the left side of the body o Ox and sheep have no upper incisors, the dental pad c. Posterior - facing the posterior side of rakes over their function. the body o Incisors, Canines, and Premolars are present in 3) 3 angles: temporary dentitions. a. Duodenal angle – near the duodenum 2. Canines – are the “holding” teeth implanted b. Splenic angle – near spleen behind the interalveolar space. c. Right angle – faces the right side of the 3. Premolars and Molars body - Are the grinding teeth forming the side of d. Spleen the dental arch. - Pre-molars are anterior - “Cheek Teeth” includes pre-molars and molars. - In Horses, “wolf tooth” refers to the first pre- molar. § Carnassial teeth or the cutting teeth the 3 roots. Dogs has 2 pairs of carnassial teeth. 1. Last upper premolar 2. First lower molar - For description: 1) 3 surfaces: - it is located inside the abdominal cavity and 1. Occlusal – surface in contact with upper set associated with other digestive organs of teeth - It is the graveyard organ of the body, and it filters 2. Labial – facing the lips dead RBC. 3. Lingual – facing the tongue - It is encapsulated organ which is situated to the left 2) 4 layers median plane in close relation to the left part of the 1. Cementum greater curvature of the stomach or rumen in the case 2. Enamel – hardest tissue ox and sheep. 3. Dentine – 3rd hardest tissue - It presents: 4. Pulp cavity 1) 2 surfaces a. Parietal – facing outside b. Visceral – facing inside 2) 2 borders a. Anterior – facing the cranial b. Posterior - facing the caudal 3) 2 extremities a. Dorsal (base) – wide portion b. Ventral (apex) – pointed portion - The spleen I attached by: 1. Hilus 2. Gastro-splenic omentum – from the hilus part of the greater curvature of stomach Note In the case of horse, suspensory ligament from o 2nd hardest tissue is the bone. base to left crus of diaphragm and left kidney. 3) 3 regions: Transcribed by: Fi 5 Comparative Anatomy Lecture Dr. James Owen Mirandilla A.Y 2023 – 2024 1. Crown – protruding from the gums, covered c. Soft palate with enamel - Is a Musculo-membranous curtain that separate that 2. Neck – junctions between crown and root mouth cavity from pharynx. 3. Root – part of tooth arising from the alveolus - Describe as having: of either mandible or maxilla. It is covered 1. Base with the cement. 2. Free border § Pulp cavity – is innervated by the 5th CN and blood 3. Two surfaces: supply is derived from the infraorbital and mandibular a. Oral – is in the mouth alveolar branches of the internal maxillary. b. Aboral – is in the pharynx - Anterior pillars are 2 short, thick folds which run from Note the free boarder of the oral surface of either side of o Largest Cranial Nerve: 5th CN or the Trigeminal nerve, the tongue arises from the brain with 3 branches which are the - Posterior pillars run from the free boarder of the aboral ophthalmic, Maxillary, and Mandibular branch. surface to meet over the commencement of the o Longest Cranial Nerve: 10th CN or the Vagus nerve, esophagus. extends to the thorax up to the abdominal region. - Between the diverging anterior and posterior pillars o Shortest Cranial Nerve: 4th CN or the Trochlear nerve, there is tonsillar sinus, which houses the tonsil. innervates the extraocular muscles of the eyeball o Dental formula in chicken: 0 Note o Tonsils – are the lymphoid aggregates in the mouth, counterpart of Peyer’s Patches in the ileum. b. Tongue o Lymphoid patches/aggregates – plays a role in - Supported in a muscular sling formed by the immunity, pathogens will be filtered by the tonsils. mylohyoid muscles. - Situated on the floor of mouth, between the rami of - It has 3 intrinsic muscles: mandible. 1. Levator veli palatini - Having: 2. Tensor veli palatini 1. Root 3. Palatinus 2. Body - it has 1 extrinsic muscle: 3. Apex 1. Plato-pharyngeus - The dorsum of the tongue refers the free dorsal surface. d. Hard Palate - Mucous membrane of the dorsum is papillated. - Bounded in front and on either side by the alveolar - 4 types of Papillae: arches. 1. Filiform – bristle like, does not bear taste buds - It is continuous with the soft palate behind. 2. Fungiform – mushroom shaped - The bony basis of the hard palate is formed by 3. Foliate – leaf-shaped palatine process of: 4. Vallate – V-shaped pattern at the caudal aspect 1. Pre-maxilla 2. Maxilla Note 3. Horizontal part of the palatine bones o 5th basic taste sensation is umami which is responsible for the detection of MSG or monosodium glutamate Comparative Notes - The last 3 types of papillae bear taste buds Esophagus - Blood supply of the tongue is achieved by paired Horse lingual and sublingual arteries which are branches of Ø Voluntary as far as the base of the heart the external maxillary artery. Ox/Sheep Ø Easily dilatable and voluntary throughout Pig Ø Voluntary till last few inches near the cardia Dog Ø Voluntary throughout Ø Constricted ventrally at origin by thick layer of mucous glands. Constriction is known as isthmus oesophagi that is only present in dogs. Monogastric Stomach Horse Ø Average capacity is 3 gallons. - Motor nerve supply of the tongue is from the Ø Non-glandular is separated from glandular region by an hypoglossal nerve or the 12th CN. irregular ridge called margo plicatus. - Sensory nerve supply is from 2 sources: Ø The non-glandular left extremity in the horse is termed 1. Lingual which is a branch of the mandibular saccus caecus. nerve, which supplies the anterior two-thirds. Pig 2. Glossopharyngeal nerve or the 9th CN, supplies Ø Average capacity is 2 gallons the posterior third. Ø Left extremity has a blind pouch–the diverticulum ventriculi. Transcribed by: Fi 6 Comparative Anatomy Lecture Dr. James Owen Mirandilla A.Y 2023 – 2024 Ø The prominence of fat and fibrous tissue projects into the - The anterior end or fundus is in the xiphoid region. pylorus from the wall of the lesser curvature–the torus - Well-developed in young cattle. pyloricus. ! Rumen functions as a fermentation trap for the digestion of Dog herbivorous foods. Ø Average capacity is 4 pints ! Two muscular lips form a channel which continues with the Ø Pear-shaped and distensible. esophagus termed esophageal groove, it begins at the cardia. It passes ventrally on the medial wall of the atrium Ruminant Stomach and reticulum. It ends at the reticulo-omasal orifice, from ! the stomach of Ox and sheep is compound compared to there it is continued to the abomasum by the omasal the simple stomach of other domestic animals. groove. ! It consists of 4 parts: ! Esophageal groove is only present in baby ruminants. 1. Rumen (Paunch) ! Esophageal groove has spiral course as follows 2. Reticulum (honeycomb) § B – backwards 3. Omasum (manyplies, book, or bible) § O – outwards 4. Abomasum (true stomach or rennet) § D – downwards § F – forwards Note § I – Inwards o In small young cattle or calves, the abomasum/rennet secretes renin which curdle milk. Small Intestine ! The rumen, reticulum, and omasum are collective termed Horse as Proventriculi, they are dilation in the walls of the Ø 70 feet in length about 6 inches from the pylorus. abdominal esophagus Ø The duodenum has pouch called diverticulum ! The rumen, reticulum, and omasum mucous membrane duodeni. are covered with stratified squamous epithelium and thus Ø The ventral pancreatic and hepatic ducts open in the they are non-glandular. diverticulum duodeni. ! Abomasum represent the true glandular stomach. Ø The dorsal or accessory pancreatic duct opens on a small papilla opposite to the diverticulum. ! Microbial fermentation takes place in the rumen, but the Ox true stomach is the abomasum. Ø 130 feet in length. ! Esophagus enters stomach at an area known as the atrium Ø Commences with a sigmoid flexure. ventriculi. It is situated at the vertebral extremities of the 8th Ø Bile duct opens in the ventral part of the small intestine and 9th ribs, slightly to the left of the mid-line. Ø No ventral pancreatic duct. Ø The dorsal pancreatic duct opens 1 foot further back. Sheep/Goat Ø 80 feet in length Ø Bile duct is joined by the ventral pancreatic duct to form a common bile duct. Ø no accessory pancreatic duct. Ø The common bile duct opens into the duodenum about 1 foot from the pylorus. Pig Ø 60 feet in length Ø Bile duct opens 2 inches from pylorus. Ø a single pancreatic duct opens 5 inches beyond this. Dog Rumen Ø 13 feet in length - occupies most of the left half of the abdominal Ø Bile duct and ventral pancreatic duct open 2 inches cavity from the 7th intercostals space to the pelvic beyond the pylorus inlet Ø Dorsal pancreatic duct opens 2 inches further back. - Mucous membrane varies in form either foliate, filiform, or club shaped. Large intestine Reticulum It should be noted that only the horse has a large and small - Anatomically it is the most anterior and smallest colon. of the non-glandular stomach - The greater part lies on the left side of the median Horse plane opposite ribs 6th, 7th, and 8th. Ø Caecum - Mucous membrane of the interior is thrown into - blind, comma-shaped sac. ridges forming the typical honeycomb - It is approximately 4 feet long, situated to right to appearance. median plane. Omasum - Described as having: - Lies chiefly on the right side of the mid-line from a. Body the 7th to the 11th ribs. b. Base Abomasum c. Apex – lies on the abdominal floor about 4 - An elongated sac which lies chiefly on the inches from the xiphoid cartilage abdominal floor. Transcribed by: Fi 7 Comparative Anatomy Lecture Dr. James Owen Mirandilla A.Y 2023 – 2024 Has 4 taenia which cause 4 rows of sacculation or - Horse haustra. Ø No gallbladder Ø Colon Ox - Large colon Ø not divided into lobes o commences at the base of the caecum Ø deep umbilical notch on right border and terminated under the left kidney by Ø well-marked renal notch becoming small colon. Ø caudate process visible from the parietal surface. o It is approximately 10 feet in length. Sheep o It consists of 4 parts which are named Ø same as ox but caudate process is not visible from according to their position. parietal surface a. Right ventral colon – ventral Pig diaphragmatic flexure Ø parenchyma has a Morocco leather appearance b. Left ventral colon – pelvic flexure Ø well divided into 4 main lobes. c. Left dorsal colon – dorsal Ø Caudal vena cava is embedded in parenchyma diaphragmatic flexure Ø No renal impression d. Right dorsal colon Ø Gallbladder is sunk in a fossa - Small colon Dog o Commence at the termination of the large Ø Parietal surface is extremely convex colon behind the saccus caecus of the Ø Gallbladder is visible on parietal surface. stomach and is continued at the pelvic inlet as rectum. Pancreas o Approximately 12 feet in length and 4 inches Horse in diameter. Ø Has dorsal and ventral ducts o Has 2 taenia and 2 rows of haustra. Ø Ventral ducts are larger, it enters to the duodenum Ø Rectum accompanied by bile duct at diverticulum duodeni o Extend from the pelvic inlet to the anus Ø Dorsal or accessory duct ends on papilla opposite the o As its termination has a flask-shaped dilation diverticulum duodeni. – the ampulla recti Ox Ox/sheep Ø Quadrilateral in shape Ø Caecum Ø Has only dorsal duct which enters the duodenum 1 - has no taenia or haustra foot after the bile duct. - has a spiral twist Sheep - small and finger-like Ø Has only ventral duct Ø Colon has 2 parts: Ø It unites with hepatic duct and enters duodenum as 1. Spiral portion – ansa spiralis, it is arranged against common bile duct. the right flank in double elliptical coils between Pig mesentery. The coils are alternatively centripetal Ø Triradiate in shape and centrifugal. Ø Has a single duct Note Dog o Centripetal – towards the center Ø Comprised of left and right branches which meet at o Centrifugal – away from the center acute angle behind pylorus Ø 2 ducts present 2. Terminal potion – ansa distalis Spleen Horse Ø Triangular in shape Ø Suspensory ligament present Ox Ø Elongated with thin rounded extremities Ø Short hilus Ø No suspensory ligament Sheep Ø Same as ox but triangular Ø Short hilus - Centripetal and Centrifugal coils are attached to Ø No suspensory ligament each other by areolar tissue. Pig - The colon is cylindrical, located on the left side Ø Strap-like and has 3 taenia. Ø Long hilus - Colon is arranged in the 3 close, double spiral Dog coils in the mesentery which reach the floor of the Ø Falciform or hook shape abdomen. Ø Long narrow Ø Rectum Ø Hilus is in longitudinal ridge - No ampulla Soft palate Liver Horse Transcribed by: Fi 8 Comparative Anatomy Lecture Dr. James Owen Mirandilla A.Y 2023 – 2024 ØLong, precluding oral breathing and vomiting ØTonsil is diffuse being situated in: a. Sinus b. Root of tongue c. Soft palate Ox/sheep Ø Bean-shaped Ø Circumscribed tonsil situated in sinus Pig Ø Frequently has small median prolongation termed the uvula Ø 3 tonsils situated in a. Pharynx b. Soft Palate c. Sinus Dog Ø Fusiform or leaf shaped Ø Situated in sinus Hard palate Horse Ø Divided into 2 equal portion by the central raphe Ø Palatine ridges or rugae extend the whole length of the palate Ox Ø Anterior portion forms the prominent dental pad Ø The rugae extend only 2/3 of the length of the palate Ø All but the last few are serrated on free borders Sheep Ø Distinguished from the ox by the fact that the rugae are not serrated Ø Opening of the naso-palatine ducts form a prominent V on either side of the central incisive papilla Pig Ø Long and narrow, equal in width throughout Ø Both rugae and median raphe well marked Ø Incisive papilla is prominent anteriorly Dog Ø Widest about the 4th cheek tooth Ø Median raphe usually replaced by a ridge Transcribed by: Fi 9