Week 5 Lecture Notes
Week 5 Lecture Notes BIOL 3020-001
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This 4 page Class Notes was uploaded by Maria Martinez on Friday September 25, 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 33 views. For similar materials see Comparative Anatomy of the Vertebrates in Biology at Middle Tennessee State University.
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Date Created: 09/25/15
Week 5 Lecture Notes Biology 3020 Middle Ear Fish don t have inner ears Most will have poor hearing Use the saccule or lagena to hear Some rely on sound waves in the vibrations on their bodies to hear because they don t have external ears to gather sound Have a swim bladder a hydrostatic organ that regulates air inside the lungs to move around is located on top of the vertebrae Some can form Weberian ossicles these are modified ribs and vertebrae that are connected to the swim bladder and when vibrations hits the gasfilled organs that information will travel up into the inner ear functioning as the middle ear are located between the ear and swim bladder have evolved independently ultimately have 3 methods of communication 1 Direct soundwave vibrations in the water 2 Weberian Ossicles 3 Extensions of the swim bladder In tetrapods The inner ear begins to replace some gill slits with the tympanic membrane usually 10X larger than the oval window in order to amplify the sound calumella also known as the stapes extracalumella Bullfrogs the males will have bigger ear drums than the females have external tympanic membrane that will capture those sounds and cause the stapes to vibrate sending that message into the inner ear In amphibians the operculum rests in the oval window Will have a muscle that links the scapula to the calumella called calumella s muscle Will have muscle that links up to the operculum and the scapula called operculum s muscle These muscles allow frogs to hear and feel vibrations on the ground have the Amphibian Papillae a specialized sensory receptor that is sensitive to low frequency vibrations Salamanders lack the tympanic membrane ear drum their ear links up to the squamosal bone and this allows them to use the jaw as a tympanic membrane to ear vibrations in the ground All reptiles except snakes and birds Have a calumella set up like the amphibians Snakes connect their calumella to their quadrate bone so like the salamander hear out of their jaw only mammals have 3 ear bones 1 Stapes 2 Incus 3 Mallus All will have a dentary and a squamosal joint Lagena In amniotes the longer the lagena is the better the hearing will be Forms J shape Curls in mammals and becomes so large it overshadows the other parts of the ear forming the vestibule Has 3 ducts called scala present 1 Scala vestibule 2 Lagena cochlear duct 3 Scala tempane Test 2 Starts Here Skeletal System made up of cartilage or bone preskeletal blastoma clusters of mesenchyme cells mesenchyme cells are undifferentiated and develop into specialized cells are also called young cells Will form preskeletal blastomas that Will eventually develop into bones or Whatever other structure in specific locations to specific tissues fibroblast cells secrete fibers that create a matrix osteoblasts give turn to osteocytes then into bones chondroblasts develop into chondrocytes then into cartilage Intramembranous Bones Dermal Bone Bones developed from embryonic cells directly to bones ex parietal bone Originate from skin phylogenically Endochondral Bone Cartilage Replacement Bone Bone developed from Within cartilage meaning that is if cartilage then develops into bone Axio Skeletal System Develops in conjunction to the CNS skull vertebrae ribs Slltull is a composite structure formed embryonically from 3 major components 1 Neurocranium Develops in all vertebrates Develops initially from cartilage Develops to protect the brain and sense organs can be referred to as the Chondocraniam 2 Sphlanchnocranium Also known as Visceral Cranium Develops in association with the pharyngeal arches and jaws Originates as cartilage Includes the palatoquadrate upper jaw Meckel s cartilage lower jaw articular bone quadrate bone hyomendibular 3 Duranatochranium Originates as bone Forms to surround the neurocranial and sphlanchnocranium elements