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REPTILES
REPTILIAN CHARACTERISTICS Ectothermic Dry body covered with scales
Keratin Toes have claws Well developed lungs Heart is 3-chambered Internal fertilization
Amniotic egg
MAJOR GROUPS OF REPTILES
Order Testudinata (Chelonia) - turtles
Order Crocodilia - crocodiles and allies
Order Squamata - snakes and lizards
TURTLE CHARACTERISTICS Shell
Cryptodira: “hidden-necked” turtles which retract their necks into the shell
Pleurodira: “side-necked” turtles which wrap their heads around the side of the shell
EXTERNAL ANATOMY Tetrapods Head (with a neck)
Beak Shell: connected by a bridge
CarapacePlastron
Scutes Tail Ability to pull head, neck, limbs, tail into
shell
EXTERNAL ANATOMY • Carapace• Scutes• Neck• Head• Tail• Plastron• Beak
Where would the bridge be found?
OVERALL INTERNAL ANATOMY OF THE TURTLE
SKELETAL SYSTEM Internal AND external skeleton
Vertebral column fused to the carapace (and limb girdles)
SKELETAL SYSTEM
Skull
Mandible
SKELETAL SYSTEM Proscapular process Coracoid Scapula Humerus Radius Ulna Metacarpals Phalanges
SKELETAL SYSTEM Vertebrae Pelvic girdle Femur Tibia Fibula Tarsals Metatarsals Phalanges
MUSCULAR SYSTEM Very similar to humans
Deltoid (retraction of forelimbs)Pectoralis major (retraction of forelimbs)TricepsBicepsLatissimus DorsiGastrocnemiusGluteus (retraction of hindlimbs)
MUSCULAR SYSTEM
Retrahens capitis colliqueRetracts head and neck into the shell
Flexor caudae lumbalis Flexor caudae obturator
Draw tail in
DIGESTIVE SYSTEM Some predaceous, some herbivorous
Beak Mouth and Tongue
Excretion of some digestive enzymes in saliva to begin digestive process
Turtles swallow large pieces of food
DIGESTIVE SYSTEM Esophagus
TubularConnects mouth and stomach
Stomach:Digestive enzymes and acids within
decompose the food
Walls of the organs in the digestive system are composed of smooth musclePush the food through the system Aids in decomposition of the food by
churning during the digestive process
DIGESTIVE SYSTEM Liver is the largest organ in the body of
a turtle.Bile production
Gall bladder Pancreas: sliver like gland located next
to the small intestineAids in the digestive process by introducing
digestive enzymes into the small intestine
DIGESTIVE SYSTEM Small and Large Intestine
Villi located on the small intestine wall absorb nutrients
DuodenumThe large intestine absorbs water
Anus
DIGESTIVE SYSTEM
RESPIRATORY SYSTEM Breathe through lungs
Mouth and CloacaRespiration through nose and mouthWhen oxygen levels are low, some turtles
have the ability to take in oxygen through their cloaca
RESPIRATORY SYSTEM Glottis, Larynx, Trachea
The glottis of the turtle is a small opening positioned behind the tongue.
It acts like a barrier between the mouth and the larynx. The larynx is leads to the trachea.
RESPIRATORY SYSTEM Trachea – connection between larynx
and bronchii
BronchiiConnect trachea to lungs
RESPIRATORY SYSTEM Lungs
Directly under the turtle's carapaceBronchii break into tinier tube like
structures called bronchioles. The bronchioles then continue the pattern,
leading to the alveoli Alveoli greatly increase the internal surface area
and increase the efficiency of the lungs.
RESPIRATORY SYSTEM
CIRCULATORY SYSTEM Three chambered heart
2 atria1 ventricle
Partially divided – septum
Surrounded by a pericardium
CIRCULATION THROUGH THE TURTLE Sinus venosus
Pulmonary arteries and veins
Systemic arteries and veins
Aorta
HOW DOES BLOOD CIRCULATE THROUGH THE TURTLE? Left atrium Ventricle Right atrium Sinus venosus Systemic arteries Systemic veins Pulmonary arteries Pulmonary veins Lungs Body Aorta
NERVOUS SYSTEM Olfactory nerve Olfactory lobe Cerebrum (in hemispheres)
Pineal gland between the two hemispheres on dorsal surface
Ventral surface: hypothalamus and pituitary gland: hormones; regulation of body
Optic lobe Choroid Plexus: secretion of cerebrospinal
fluid Cerebellum Medulla oblongata
NERVOUS SYSTEM
EXCRETORY SYSTEM Kidney
Ureters
Urinary bladder (with accessory bladders)
Cloaca
REPRODUCTIVE SYSTEM Internal fertilization Amniotic organisms
Egg is better adapted for life on land All oviparous with no parental care Females:
OvaryOviduct
Male:TestesEpididymusPenis
REPRODUCTION Turtles lay eggs outside of the water
Bury in sand, dirtTypically near a body of water Incubation temperature depends on species
Egg shells can range from soft and leathery to hard and brittle
AMNIOTIC EGG Shell to prevent desiccation
Amnion – encloses embryo within the eggWith amniotic fluid
Allantois – gas exchange, waste excretion
Chorion – gas exchange Yolk sac – nutrition
AMNIOTIC EGG
TURTLE DISSECTION
TURTLE DISSECTION