Comparative Anatomy Chordate Body Plan

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1 Comparative Anatomy Chordate Body Plan
Kardong Chapters 2 & 4 Part 3

2 "Numerous studies have demonstrated that students retain little of our lectures, and research on determining the “average attention span,” while varying, seems to congregate around eight to ten minutes (“Attention Span Statistics,” 2015), (Richardson, 2010). "  

3 Pharynx (fair-inks) with slits
Figure Pharyngeal arches lateral view and (b) ventral cross section. Pharyngeal arches- associated with slits Anamniotes (lower vertebrates)- have gill slits Amniotes- have slits in embryo but gills never form Endodermal pouches- pharyngeal pouch that grows toward surface of animal; give rise to glandular tissue Ectodermal groove- pharyngeal groove on outside that grows toward each pouch

4 Embryonic Features Figure 3.2. Embryo pharyngeal arches.
Figure Embryo development at 1 month.

5 Aortic arches housed within pharyngeal arches
In tetrapods, 1st pharyngeal slit becomes auditory tube and middle ear cavity Aortic arches housed within pharyngeal arches (b) Figure Early pharyngeal devel. of shark (a) early stage (b) later stage .

6 1st (mandibular) arch- mandibular and maxillary portions
Figure Fate of the pharyngeal arches. 1st (mandibular) arch- mandibular and maxillary portions 2nd (hyoid) arch Other arches are numerically named Most vertebrates have 6 pairs of arches

7 Figure 3.6. Pharyngeal arches.
Each pharyngeal arch contains a cartilage, artery, mesoderm component, and cranial nerve.

8 General Body Plan Head Trunk Tail
Figure Sagittal section of craniate embryo.

9 Head Head Cephalization- development of sense organs
Protective covering of dermal bone (not replacement bone) or cartilage Figure Head region (internal view).

10 Trunk Somites- muscle masses beside notochord; embryonic structures that give rise to muscle and bone Coelom- body cavity between gut and body wall, lined by peritoneum Figure Gut region. Figure Coelom.

11 Trunk (cont.) Other visceral organ cavities: Heart- pericardium
Lungs- pleura Abdomen- peritoneum Figure Pericardium & cavity. Figure Pericardium and pleural cavities.

12 Tail From vent/anus to end of the body. Somites and notochord
Innervations Dorsal and ventral aorta Food storage, defense, locomotion

13 Pituitary Development
Figure 3.13. Stomodeal ectodermal plate pushes inward and forms pocket (Rathke’s pouch) that leads to anterior lobe This invagination meets the dienchephalon’s infundibular process which forms the posterior lobe Figure 3.14.

14 Morphological Characteristics of Vertebrates
Divided into two superclasses: Pisces and Tetrapoda Demonstrate bilateral symmetry Distinguishing features of vertebrates: Presence of notochord Pharynx with slits Dorsal tubular nervous system Developed vertebrae Post anal tail

15 Notochord Most primitive endoskeletal structure
Jawless fish- notochord long and enlarged Cartilagenous fish- notochord surrounded by cartilagenous vertebrae Bony fish and amphibians- notochord surrounded by larger vertebrae Amniotes- notochord almost lost

16 Notochord (cont.) In mammals, between successive centrums are disks
Within disks, the notochord is mostly replaced with pulpy nucleus Figure Vertebrae. Figure MRI scan of vertebrae.

17 More Vertebrate Features
Dorsal nervous system CNS- brain and spinal cord Anamniotes- 10 pairs of cranial nerves Amniotes- 12 pairs of cranial nerves Vertebral column Backbones Post anal tail Figure Vertebral column.

18 Anatomical Symmetry and Planes
Figure Anatomical terminology. Figure Anatomical terminology.

19 Cranial Nerves Olfactory Optic Oculomotor Trochlear Trigeminal
Abducens Facial Vestibulocochlear Glossopharyngeal Vagus Amniotes (2 more): Spinal Accessory Hypoglossal Figure Mammalian cranial nerves.