5Anatomical PositionsFor humans: standing erect facing forward, with head level and eyes facing forward, feet flat on the floor and directed forward, and arms are at the sides of the body with palms turned forward.
6Anatomical Position for Animals The animal should either be supine (laying on back facing upward) position with arms out be side
7Planes of ReferenceFrontal plane: vertical plane that divides the body into an anterior/ventral or posterior/dorsal portions.Sagittal plane: vertical plane that divides the body or organ into right and left sides (midsagittal or median plane is down the middle of the body creating equal parts)Transverse plane: divides the body into superior (upper) or inferior (lower) portions.
8Directional Terms Superior/Cranial: toward the upper part/head Inferior/Caudal: away from the head/lower partAnterior/ventral: nearer to or at front of body; stomach sidePosterior/dorsal: nearer to or at the back of body; dorsal fin sideMedial: nearer to midlineLateral: farther away from midline
10Directional Terms Cont. Proximal: nearer to attachment of limb to trunk, nearer to originDistal: farther away from attachment of limb to trunk, farther away from originSuperficial: toward or on surface of bodyDeep: away from surface of body
11Try these… The heart is _______ to liver The stomach is ________ to lungs.The sternum (breastbone) is ______ to the spinal column.The esophagus is ________ to trachea (windpipe).
12Try these… The stomach side of a dog is called ____. The ______ fin is located on the fish’s back.The ______ fin is also known as the tail fin.The head is ______ to the tail.
14SymmetryAsymmetrical: irregularly shaped body, these animals are sessileRadial: divided along any plane, through central axis, into roughly equal halves, these animals are starfish or hydrasBilateral: can be divided down its length into similar right and left halves, these animals can use the anatomical terms such as posterior, ventral, etc.
16Zygote DevelopmentFertilization: sperm (male sex cell) and egg (female sex cell) meetZygote is formed when these cells fertilize and repeatedly divide by mitosisEmbryo: when cell division beginsBlastula: fluid-filled cellGastrulation: cell division continues until one side of the blastula moves inward
17Embryo DevelopmentEctoderm: outer surface of gastrula; develops into skin and nervous systemEndoderm: inner surface of gastrula; develop into the lining of digestive syst.Mesoderm: “middle” between ectoderm and endoderm, eventually turn into muscles, circulatory, excretory, and some respiratroy systems
18Development Cont.Protostome: opening of the gastrula develops into the mouth; examples: snails, earthworms, & insectsDeuterostome: animal whose mouth developed NOT from the opening, but from cells elsewhere on gastrula, examples: sea stars, fish, toads, snakes, birds, & humans
20Bilateral Symmetry & Body Plans Acoelomates: no body cavities; have 3 cell layers - ectoderm, endoderm, & mesoderm; Ex: flatwormsPseudocoelomates: space develops between ectoderm & endoderm, fluid-filled body cavity partly lined w/ mesoderm; one-way digestive tract; ex: roundwormsCoelomate: body cavity fluid-filled space that is completely surrounded by mesoderm; organs & org. systems develop; Ex: earthworms
23Animal Protection & Support Exoskeleton: hard covering on outside of body that provides framework for supportPrevent water lossProtect soft bodyProvide place for muscle attachmentMust molt & shed the old onesFound in invertebrates (insects, crabs, etc)