Week 9 lecture Notes
Week 9 lecture Notes BIOL 3020-001
Popular in Comparative Anatomy of the Vertebrates
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This 10 page Class Notes was uploaded by Maria Martinez on Saturday October 24, 2015. The Class Notes belongs to BIOL 3020-001 at Middle Tennessee State University taught by Dr. Miller in Fall 2015. Since its upload, it has received 48 views. For similar materials see Comparative Anatomy of the Vertebrates in Biology at Middle Tennessee State University.
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Date Created: 10/24/15
Buccal Cavity Teeth Week 9 Lecture Notes Biology 3020 o Homodont vs Heterodont O O Homodont teeth look alike and have similar functions Heterodont teeth look different serve different functions and are located in different locations 0 Polyphydont vs Diphydont vs Monophydont O Polyphydont vertebrates like amphibians and salamanders will replace their teeth through out their lives Diphydont vertebrate mammals like humans will have 2 sets of teeth deciduous and permanent that will not be replaced after the permanent set if lost Monophydont vertebrates like armadillos have only one set of teeth that won39t be preplaced if lost 0 Theodont vs Pleurodont vs Acrodont O Theodont attachment is present in crocodilians and will result in the teeth being set individually in different sockets Pleurodont attachment is present in lizards snakes and amphibians and will result in the teeth being set around the sides of the mouth attaching to the jaw sides Acrodont attachment is present in some lizards snakes and fishes and results in the teeth resting on top of the jaw 0 Teeth Shape 0 Many vertebrates such as fish and salamanders have conical shaped teeth which will be used for grasping and holding In some amphibians and salamanders the tooth shape is modified going from the conical shape in the larva stage to pedicellate shaped teeth With the pedicellate shape the tooth is divided by two regions separated by the zone of weakness I Uppermost region is the crown I The Zone of weakness is made of keratine and will allow a break point for the two regions I Lower region is the dedical Snakes I Can either have a groove or be hollow I Fangs are elongated teeth found on the tip of the posterior maxillary bone I The venom goes from the mouth through small groove on the outer surface of the tooth to the victim I Have 4 types of fangs o Mammals 1 Opisthoglypha 0 Present in cobras crates cotton snakes 0 Located in the rear of the maxilla o The venom will run through the channel found in the tooth and can be neurotoxic 2 Proteropglypha 0 Located in the front portion of the maxilla and fixed in place 0 Are enlarged but not too enlarged 3 Solenoglypha 0 Present in vipers pit vipes copperheads 0 These fangs are enlarged and have a cavity that runs through the fang o The teeth are fixed the maxillary bone which is shortened and has a loose connection to the cranium so that when the snake strikes the fangs that at rest lay against the palate will distend and move forward for the attack 4 Aglypha o If a snake doesn39t have fangs it is termed aglypha I The tooth shape varies and will also vary in root length I Brachyodont teeth Have short roots in comparison with the roots which are large found in humans and pigs I Hypsodont teeth Have tall crowns and short roots found in deer cattle horses Crowns will be worn and shortened in grazing animals I Bunodont teeth Will have low rounded cusps that are covered in enamel Found in humans and pigs I Lophodont The cusps on these teeth are formed are ridges The ridges will be covered in enamel the rest of the tooth is dentin Allows the tooth to stay rigid to grind the food 0 Found in horses and rodents I Selenodont o The enamel is found in triangular shapes scattered throughout the teeth 0 Allows for teeth to wear unequally for better grinding of vegiatation 0 Found in deer cattle grazing animals I Dogs and cats 0 Have special cheek teeth called carnassial teeth 0 The cusps serve to sheer the food 0 Tusks I modified teeth I Narwhals 0 Have a single tusk that is an elongated upper left incisor o All males have it but only some females have it 0 Largely made up of dentin and has some enamel I Elephants 0 Typically paired 0 Tusks are elongated incisors I Walrus 0 Tusks are elongated upper canines I Hogs 0 Tusks are elongated canines o Animas that lack teeth I Whales 0 Have baleen conelike plates that come off the palate I Some ant eaters Tongue 0 An innovation of Tetrapods o Fishes o For the most part fish lack tongues 0 Bass have primary tongues I Which are eshy material used to help expand the buccal pharyngeal cavity to help suck in food and function to manipulate food in the mouth 0 Lamprey I have little spike like projections on their tongue that are used to rasp off the esh of their prey I Also use the tongue to move food around the mouth 0 Tetrapods I Have a secondary tongue which is mobile and eshy Mammals 0 Use tongue to bring food into the mouth Salamanders 0 Their tongue has glands on it to help the prey stick to it so the salamander can eat it Cats 0 Have barb like spikes on their tongue to rasp off the esh of their prey 0 Used for grooming 0 Have a long tongue that wraps around the skull and comes out of the mouth 0 Has barbs on the end of the tongue serrate the prey they hunt inside the trees PharynX Region where the respiratory passage way and digestive tract will cross Near the uvula which helps prevent food from entering the pharynx Glottis is the opening of the pharynx Epiglottis is the esh covering of the glottis Tonsils are located in the opening to the Eustachian tube Alimentary Canal Is the tube that begins at the esophagus continues to the stomach through the small and large intestines and terminates through the rectum Anuscircular muscles that allow the tube to close 4 layers 1 Mucosa Layer I The epithelial surface 2 Submucosa I The connective tissue layer I Where the majority of the blood vessels will be 3 Muscularis Externa I Consists of inner circular muscles that wrap around the lumen 4 Serosa I Outer layer longitudinal muscle layer fibers themselves run through the length of the tube I An epithelial layer that causes constriction of the lumen Esophagus 0 Serves as a passage way of the pharynx to the stomach o the longer the neck the longer the esophagus and vice versa 0 Expands when swallowing and collapses when at rest 0 In most vertebrates has a multiple layered stratified epithelium 0 Provides protection form bacteria getting in the blood stream 0 Associated with some mucus production keeps food lubricated o Peristalsis the wavelike contractions that get the food into the stomach takes place here 0 Reverse peristalsis the wavelike contractions that get the foot out of the stomach into the esophagus vomiting also happens here 0 Amphibians 0 have cilia present in the esophagus to help food movement 0 Sea Turtles 0 Modifies esophagus by lining the esophagus with keratinized projections esophageal papillae that protect the turtle from being stung by the jellyfishes it eats and helps prepare food for digestion 0 Egg Eating Snakes 0 Have a modified esophagus that is pleated to allow expansion over the egg which is wider than them completely and has teethlike projections in it called hypotheses which will slit the egg open as it travels down the digestive tract allowing the snake to have access to the yolk 0 Birds 0 Have a crop a sac like extension of the esophagus that is used for food storage 0 The crop allows the bird to survive longer periods of time without hunting 0 Pigeons and Doves I the crop becomes granular so the lining epithelium layer produced uid called pigeon milk from the crop contents I This is given to the baby bird by either the female or male parent bird 0 Ruminants o The esophagus is modified by developing to 3 chambers of the ruminant stomach the 4th being the true chemical stomach of the animal 0 l Reticulum I Has a mucosa layer that is honeycomb like to grab particles I Retains heavy particles I Functions as a fermentation vat o 2 Rumen I Largest chamber I Storage area the region that begins the food for digestion I Microbial digestion occurs and has papillae for absorption of nutrients o 3 Omasum I Filters what goes into the abomasum and increases the surface area for water absorption 0 4 Abomasum I Granular largest chamber in new born animals I Avoids fermentation in new born animals I New born animals will not have a rumen so the milk they get from their mothers with all the nutrients goes right in the omasum for absorption Stomach 0 Typically has simple epithelium 0 function as storage for food 0 Absent in boneless fish 0 Has a sphincter muscle on both ends which is a muscularis externa modification 0 Cardiac sphincter I keeps the stomach content from going into the eosphagus o Pyloric sphincter I produces mucus 0 Cardiac region I produces mucus o Fundic region I body of the stomach I produces pepsinogen which is activated by HCl to convert to pepsiogen to denature proteins 0 Shape is variable within vertebrates o This is where protein is initiated o Involved in mechanical digestion but churning 0 Birds Crocodilians o the stomach becomes 2 distant regions 0 1 Proventriculus I granular produce secretion to soften food 0 2 Gizzard I highly muscular I the muscle breaks up foodstuff and stores it in gizzards I birds of prey lack gizzards Intestines 0 Small Intestine o Refers to the tube in diameters not length or tube 0 Serves as a major site of nutrient absorptions simple epithelium helps absorb them 0 Important because chemical digestion takes place here I Chemicals from the pancreas release digestion chemicals for proteins carbohydrates fats and nucleic acids I Lumen epithelium produces intestinal juice forms unicellular cells to secrete mucus and enzymes I Liver makes bile and sends it to the gallbladder for it to be released into the stomach o Bile functions as emulsifying agent breaking up large globs into small globs increasing surface area to enhance absorption I Proteins are broken down to amino acids Nucleic acids are broken down to nucleotides Carbohydrates are broken down to monosaccharides like glucose 0 Teleost Fishes I Have a ring of blind ending sacs called the pyloric sphincter that Within it has pyloric caeca Which lay on the stomach lining secreting enzymes and increases surface area for absorption 0 Sharks I Have the spiral valve a mucosal lining the stomach that spirals down creating a funneling effect that increases surface area for absorption I Is present in cartilagenous fish 0 Mammals I Have villi fingerlike projections that extend inward on the lining that Will fold inward to increase surface area for absorption I There are 2 types of villi o 1 Capillaries 0 Exit intestines and link up with other blood vessels to form veins 0 Form a hepatic portal system that has a capillary bed on either side of the vein that travels to the liver 0 Will carry glucose for a short term amount of time o If the glucose levels in the blood are high it will modify it to glycogen and this is done by the liver 0 Liver cells convert the glucose to glycogen to be stored in the liver and skeletal muscles 0 Capillaries also carry amino acids to the liver that are converted to amine to be cleared out of the body as urine 0 Amino acids are not stored in the capillaries o 2 Lacteals O O 0000 Cecum Are a component of the lymphatic system Called 39lymphatic capillaries39 as they have lymphatic vessels This is important because travel directly to the heart They have a one way ow of material Nutrient go from the lumen to the heart In mammas they carry fatty acids and this is an evolutionary adaptation that happened for rapid energy 0 Increases microbe fermentation 0 Herbaceous animals have a long cecum while carnivorous animals have a short cecum with ruminants as an exception The food goes into the cecum to be digested but not absorbed Such is the case of horses and rabbits whose cecum serves as digestion and sends the bolus out as specialized droppings Practicing corpophagy they eat these specialized droppings and by the second passage they will be able to have nutrient break down for absorption Large Intestine 0 Filled with microbes and functions as a microbial fermentation center of indigestible material and releases nutrients as waste products 0 In humans vitamins K and B are regulated in the dryness of the feces and how much water absorbed in the large intestine o If the feces is dry it has spent a long time in the large intestine o If the feces is wet it has spent a short time in the large intestine Respiratory System Oxygen to get to the cells for combustion to make metabolic water Oxygen is the last acceptor in the electron transport chain Has respiratory membranes 0 Where oxygen enters and leaves the body 0 Respiratory membranes bust be both thin and moist to diffuse oxygen 0 There is a variation in the amount of oxygen that can be extracted from air and water Ventilation o The movement of air in and out of respiratory membranes 0 Plays part in evolution from aquatic animals to terrestrial animals Skin 0 Allows for transcutaneous respiration When used as a respiratory membrane 0 Salamanders o Rely solely on skin to get oxygen 0 Important because they produce large surface area for respiration 0 External gills 0 Found in larval fishes toads and tadpoles 0 Internal gills 0 Found in adult fishes o Are highly vascularized meaning there is a lot of blood ow 0 The more blood the more oxygen 0 Have gill arches I Provide structural support 0 Have gill raches and gill filaments I Gill filaments consist of projections exiting from the gill arch made of the primary and secondary lamellae that both increase surface area for oxygen absorption 0 Primary lamellae 0 large projections large blood vessel and capillary exchange occurs here 0 Secondary lamellae o Crescent projections o The oxygen enters the secondary lamellae then the primary moving water ow in one direction While oxygen is moved the opposite direction 0 This creates a 39counter current arrangement39 increasing circulation to increase absorption 0 Air has more oxygen than water 0 There is more oxygen in cooler water than there is in warm water 0 Water separates the lamellae allowing the exchange to go on so When fish are out of water and the lamellae are compressed the fish does not get enough oxygen to survive 10 Some fish have modified their operculum to store water for a While and are able to be out of the water for a small period of time