Week 7 Lecture Notes
Week 7 Lecture Notes BIOL 3020-001
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This 11 page Class Notes was uploaded by Maria Martinez on Friday October 9, 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 39 views. For similar materials see Comparative Anatomy of the Vertebrates in Biology at Middle Tennessee State University.
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Date Created: 10/09/15
Week 7 Lecture Notes Biology 3020 Vertebrae Includes the centrum the neural arch hemal arch transverse process zygophyses prezygophyses and post zygophyses Zygophyses 0 There is a pair of zygophyses found anteriorly and posteriorly on the vertebrae 0 Serve to link up the vertebrae to one another Prezygophyses o Are located on the anterior end of the vertebrae o Articulates surfaces that face up and inward on the vertebrae Post zygophyses o Are located on the posterior end of the vertebrae o Articulate surfaces that face down and outward Regional Vertebral Variations Caudal vertebrae have neural arches Sacral vertebrae link up With the neck and girdle Lumbar vertebrae have long transverse processes and no ribs Thoracic vertebrae have ribs connected to them Cervical vertebrae includes the neck may or may not have ribs connected to them Number of vertebrae Is variable Some snakes and legless amphibians 0 Have over 200 vertebrae ultimately increasing agility Frogs 0 Have about 9 vertebrae Which reduces agility Lizards 0 When their tail breaks off it does so within the vertebrae Salamanders 0 When they shed their tails it does so between the vertebrae Birds 0 The body is fairly rigid except for the neck because they more cervical vertebrae which gives them more mobility and allows them to increase neck length Cervical Vertebrae Atlas Axis Most mammals including humans have 7 vertebrae present except for sloths who have 510 and the manatees who have 5 This variation is because of a mutation of the Hox gene which is associated with segmentation To distinguish between thoracic and lumbar vertebrae looking at the ribs is key If the ribs are connected to the vertebrae it s most likely thoracic and if not then it is most likely lumbar vertebrae The lower two cervical vertebrae may have just stayed in the cervical region instead of shifting down during evolution The 1St vertebrae Also known as C1 Links up to the condyle of the skull The 2nd vertebrae Also known as C2 Allows neck movement Absent in fish Salamander o Vertebrae allow it to look up and down Amphibians and Frogs 0 Have a double occipital condyle that allows for up and down head movement Nonmammilian Amniotes Reptilian Vertebrates 0 Have a single condyle 0 Develop an atlas and axis 0 Both of these characteristics will give lizards and alligators better head movement Mammals 0 Have a double occipital condyle 0 Have a modified atlas and axis the axis centrum loses the neural arch and shifts posteriorly to fuse onto the axis centrum 0 Have the odontoid process a tooth like process on the axis which allows rotational and lateral movement on the axis and up and down movement on the atlas Ribs are associated with the vertebral column and attach to the vertebrae most muscular tissue associated with the ribs are extended or connective tissue Myomere 0 Muscle whose attachments takes place in between muscle placements 0 Develop to help strengthen myocepta to have more efficient bonding stabilize myocepta Form in 2 regions 1 Transverse Horizontal Septum o Separates the dorsal ventral muscle mass 0 Where the dorsal ribs develop 2 Myocepta 0 Where the ventral ribs develop Intermuscular Ribs 0 Found in rough sh like the carp o Essentially have a lot more bones so they are considered rough Janess Fish 0 Don t have any ribs Sharks 0 Have short ventral ribs Bonyfish teleost fish 0 Only have ventral ribs Fish 0 Ribs are not prominent Tetrapods 0 Have dorsal ribs 0 Ancestrally had ribs associated with every vertebrae Thoracic Region 0 Have long ribs that support the pectoral girdle and fuse to the sternum Lumbar Region 0 Ribs are reduced and connect vertebra column to pectoral girdle In many groups they are used to get greater locomotion In and vertebrates they are used for protection and respiration Here we see the shift of function from locomotion to respiration Ancestra11y the ribs have 2 heads 1 Capitulum o Articulates to the body vertebra 2 Tuberculum o Articulates to the transverse process Lumbar ribs only have one head The more heads present the more mobility Amphibians and Fish 0 Ribs are reduced and will not meet up with the sternal plate because they don t have one Salamander 0 Have bright colorations that depict toxic skin secretions from the glands Have spots or bumps that become warts on their backs and this indicated poison glands Their vertebral column will be located in the center of the back and the ribs Will come off of the vertebral column into spinelike ends 0 These Will serve as mechanical devices to help push out poison OO Frogs and Toads o Ribs are absent and the transverse processes present are the remnants of the ribs 0 Caecilian amphibians do have ribs regardless of being limbless o In fact because of their serpentine locomotion the Caecilian amphibians have well developed ribs Reptiles Crocodiles and Snakes 0 Have significant variation in rib structure Snakes lack a sternum so the ribs don t completely encompass the body 0 Some snakes like cobras can move their ribs out stretching the skin to make the hood around the head 0 Lizards Draco Lizard or ying dragon 0 Can outstretch their ribs stretching their skin out resembling a parachute and use that to glide down from high places 0 In the thoracic and lumbar ribs the proximal region is typically ossified and the distal region is typically cartilaginous o This makes it exible and good for expansions and contraction of the chest Turtles 0 Have extended ribs that Will modify and grow together to become the outer shell or the carapace Birds 0 The cervical ribs become fused o The thoracic ribs have unicate processes Which are small sections of bone that link up adjacent to the ribs and help solidify the body as well as form muscle attachment Mammals o Cervical ribs are absent except for in the mammals Who lay shelled eggs like the platypus 0 Some mammals have cervical ribs in embryo but they are lost id development 0 The thoracic ribs are moveable and used for respiration Stemum The midventral component that sometimes connects to the ribs Provides ventral support to the ventral girdle Used With limbs for locomotion therefore if there are not front limbs there Will usually not be a sternum Fish 0 Lack a sternum Amphibians 0 Some salamanders have a stemal plate along the middle of their chest that is cartilaginous and variant in size Frogs and Toads 0 Have some shoulder girdle bones that fuse to form the sternum Legless Reptiles and Snakes 0 Lack a sternum Turtles 0 Stemum is absent but the lower component of the shell or the plasteron replaces the sternum Legged Lizards 0 Have a bone like the sternum Crocodile 0 Has a sternal plate made out of cartilaginous bone that tends to shrivel Birds 0 Have a welldeveloped sternum called carina or keel o The keeled sternum increases the surface area for better ying o Bats and moles have a keeled sternum 0 Most non ying birds Will have a at sternum Mammals 0 Have a sternum composed of indiVidual stenebrae that fuse together 0 Last stenebrae is the Xiphoid process 0 Have a segmented sternum Appendicular Skeleton Girdle o A skeletal component that braces limbs or fins 0 Allow for muscular projections that function for limb movement and act as a stable base of movement 0 In tetrapods it Will support the base of the body 0 2 types of Girdles 1 Pectoral Girdle 0 Associated With the front limbs 0 Found immediately after the base of the skull and is a composite structure 0 Produced by 2 different skeletal structures 1 Cartilage 0 Some bones originate form cartilage and some may remain cartilaginous for life Will form to limbs and fins support Where the majority of the muscles attachments happen The limbfin bones connect to the endochondral components The endochondral consists of the scapula superscapula and coracoid from oil The most impoant conmonents are in the pectoral find 0 As long as limbs become prominant so do these 0 The other true component associated With the pectoral girdle is the glenoid fossa Which also allows for muscle attachment 0000 O 2 Dermal Bone Intramembranous Bone Some undergo intramembranous ossification Includes the clavicle and collarbone both move away from the cervical components The cleithrum is lost in mammals The port temporal braces the skull in the fish the pectoral girdle is braced up against the skull itself The interclavicle associated with tetrapod and fuses to the clavicle found in between vertebrae and forms the furcular wishbone In mammals the clavicle becomes limited and links up anteriorly to the sternum In cats The clavicle oats in the muscle it doesn t have a skeletal connection This gives them more front limb mobility oating clavicle is common in running animals 2 Pelvic Girdle supports pelvic fins or limbs entirely endochondral in origin Fish 0 Originates as two triangular bones that come together the point in which they come together is called the pelvic symphysis 0 These triangular bones are where the fins will attach o The triangular bones are not attached to the vertebral column 0 The pelvic girdle will ossify in fish but not in sharks Tetrapods 0 Most groups consist of 3 bones I Ilium dorsally located makes contact with sacrum I Ischium ventrally located I Pubistwo bones that come together at midline and fuse o Pelvic girdle will make a connection with the vertebral column allowing for identification of the sacrum 0 Have a pubic symphysis a broad long section that will make contact with the pubis o In mammals there is a hormone that spreads the pubic symphysis during child birth Birds 0 The pubis don t come together so there is no pubis symphesis Snakes 0 Don t have a pelvic girdle Monotremes and Marsupials 0 Have a 4th bone in the pelvic girdle 0 It s the epipubicprepubic bone extends from the pubis to the abdominal wall and gives it support 0 It is believed that the epipublic bone supports the pouch on the opossum Fins Functions in steering preventing yawing rolling or pitching When the fish is swimming and also aids in breaking The fins are folds of skin sandwiching skeletal elements These skeletal elements straighten the fin Fin rays Are cartilaginous Have lepidotrichia hair like structures on the fin Have Certotrichia unsegmented carotene like structures in sharks Have Actinotrichia unsegmented and formed out of true carotene found in the distal parts to help support the fins found in bony fish 0 The fin rays do not touch the pelvic girdle OOOO Pterygiophores fin bearing bones Radial Pterygiophores small fin bearing bones closer to the fin Basal Pterygiophores large fin bearing bones Paired fins 0 Include the pectoral and pelvic fins Median Fins 0 Include the dorsal caudal and anal fin Adipose Fin o On the median but has no skeletal support so really its just esh 0 Found on catfish or carp Advanced Teleost Fish 0 Have a pectoral fin that is moved up on to the body and pelvic fin that moves anteriorly Pectoral Fin 0 O O Braced on the axial skeleton Used for steering Has a larger skeleton that the pelvic girdle Paired Fins O Categorized by the similarity between the ancient ancestor of the fish and the modern fish Category 1 Lobefish I Are the present day Sarcopterygians or Flesh finned fishes I The Ptyergiophores are prominent and extended off the body the eshy proximal proportion of the fin I Have a lot of muscle I Ultimately gave rise to the tetrapods I Have two types of fins Paddle like esh finned and Biscernial finned Category 2 The Finfold Fin I Have a broad base I Sharks and rays fall into this category I In male sharks the pelvic fins are modified to have special skeletal structures known as claspers that develop from modified basal pterygiophores Category 3 Rayfin I The majority of fish fall into this category I Have very little skeleton esh connects into fin I Support comes from the lepidotrichia I Basals Pterygiophores are absent I Radial Pterygiophores are tiny I Do not have good fin support as it is just supported by the fin rays Median Fins O O O Formed from large neural spines Lizards use them for thermal radiation and defense In fish they function to prevent roll Dorsal Fin 0 Forms along the medium midline above the neural spines Caudal Fin 0 Near medium ventral septum 0 Become laterally compressed forming hyperals which Will help support fins in fishes