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