Transcript Anatomical Position and Directional Terms

Animal Kingdom
What is an animal?
Obtain food (heterotroph)
 Eukaryotic
 Multicellular
 Sexual Reproduction (mostly)
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Major Phylas of Animals
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Porifera: sponge
Coelenterata: jellyfish, coral
Platyhelminthes: flat worms
Achelminthes: round worms
Annelida: segmented worms
Arthropoda: insects, crustaceans, spiders
Mollusca: clams, snails, slugs
Echinodermata: starfish, brittle sea star
Chordata: vertebrates (mammals, reptiles,
fish, birds, amphibians)
Anatomical Position and
Directional Terms
Anatomical Positions
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For 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.
Anatomical Position for Animals
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The animal should either be supine
(laying on back facing upward) position
with arms out be side
Planes of Reference
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Frontal 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.
Directional Terms
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Superior/Cranial: toward the upper part/head
Inferior/Caudal: away from the head/lower
part
Anterior/ventral: nearer to or at front of body;
stomach side
Posterior/dorsal: nearer to or at the back of
body; dorsal fin side
Medial: nearer to midline
Lateral: farther away from midline
Directional Terms Cont.
Proximal: nearer to attachment of limb
to trunk, nearer to origin
 Distal: farther away from attachment of
limb to trunk, farther away from origin
 Superficial: toward or on surface of
body
 Deep: away from surface of body
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Try 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).
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Try 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.
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Symmetry
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Asymmetrical: irregularly shaped body,
these animals are sessile
 Radial: divided along any plane, through
central axis, into roughly equal halves, these
animals are starfish or hydras
 Bilateral: can be divided down its length into
similar right and left halves, these animals
can use the anatomical terms such as
posterior, ventral, etc.
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Zygote Development
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Fertilization: sperm (male sex cell) and egg
(female sex cell) meet
Zygote is formed when these cells fertilize
and repeatedly divide by mitosis
Embryo: when cell division begins
Blastula: fluid-filled cell
Gastrulation: cell division continues until one
side of the blastula moves inward
Embryo Development
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Ectoderm: outer surface of gastrula;
develops into skin and nervous system
 Endoderm: 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
Development Cont.
Protostome: opening of the gastrula
develops into the mouth; examples:
snails, earthworms, & insects
 Deuterostome: animal whose mouth
developed NOT from the opening, but
from cells elsewhere on gastrula,
examples: sea stars, fish, toads,
snakes, birds, & humans
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Bilateral Symmetry & Body
Plans
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Acoelomates: no body cavities; have 3 cell
layers - ectoderm, endoderm, & mesoderm;
Ex: flatworms
 Pseudocoelomates: space develops
between ectoderm & endoderm, fluid-filled
body cavity partly lined w/ mesoderm; oneway digestive tract; ex: roundworms
 Coelomate: body cavity fluid-filled space that
is completely surrounded by mesoderm;
organs & org. systems develop; Ex:
earthworms
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Animal Protection & Support
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Exoskeleton: hard covering on outside
of body that provides framework for
support
– Prevent water loss
– Protect soft body
– Provide place for muscle attachment
– Must molt & shed the old ones
– Found in invertebrates (insects, crabs, etc)
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Animal Protection & Support
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Endoskeleton: protects internal organs
& provide internal brace for muscles to
pull against
– Made of calcium carbonate
– Found in vertebrates & sea stars
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Animals Also Have the ability to
move!!
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Sessile: doesn’t move during adult life
– Examples: sponges
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Motile: ability to move
– Humans, dogs, etc.