FROGS EXTERNAL ANATOMY

FROGS EXTERNAL ANATOMYWesleyan University-Philippines (CONAMS)THE FROGS HEAD

Frogs Buccal Cavity

GENERAL FEATURES:

Coelom contains all the internal organsBrain, nose, eyes, mouth, earsSkeleton and MusclesSUPPORTED BY A BONY FRAMEWORK (SKELETON)SKULL IS FLAT (ENCASES THE BRAIN)THERE ARE ONLY 9 VERTEBRAE (HUMANS HAVE 24)NO RIBSNO TAIL (ONLY UROSTYLE A DOWNWARD EXTENSION OF THE VERTEBRAL COLUMN)ONE FOREARM, THE RADIO-ULNAONE UPPER ARM BONE, THE HUMERUS

HIND LEGS ARE SPECIALIZED FOR LEAPINGSINGLE SHINBONE, THE TIBIO-FIBULASINGLE UPPER LEG BONE, THE FEMURWITH TWO ELONGATED ANKLEBONES OR TARSALS : A. Astragalus like the human talus B. Calcareus human heel boneMuscles are same with other vertebrates The Circulatory SystemHeart only organ in the coelom with its own protective covering , the pericardiumWith two upper chambers left and right atriumWith one lower chamber ventricleBut there is no mixing of oxygenated and unoxygenated blood because of the unique arrangement of the heartFrogs blood also has liquid and solid portionThe Skin and Respiratory SystemCovered with soft, thin moist skin-- comprised of an outer Epidermis and and inner dermis Functions: Protection and respiration(An extensive network of blood vessels run through the skin, oxygen pass through the membranous skin, directly into the blood. When submerged in water, all respiration takes place in the skin. Oxygen is directly taken from water)Respiration also takes place in simple sac like lungsDifferent from humans ***

Open mouth

Closed mouth

Open nostrils

Closed nostrils

Air into the windpipeThe floor of the mouth is lowered, causing it to puff out Air enters in large mouth Air in mouth forced into the lungs by contraction of the mouth floorThe Digestive & Excretory SystemMouth --- where digestion beginsWith feeble, practically useless teeth (upper jaw only)With highly specialized tongueTip of the tongue folded backward toward the throatVery sticky tongueMouth esophagus stomach small intestines large intestines (all digestive glands are attached by ducts) cloacaLiquid wastes from kidneys ureters urinary bladder cloacaNervous system and Sense organsWith highly developed Nervous system brain, spinal cord and nerves MEDULLA -- regulates automatic functions such as digestion and respirationCEREBELLUM-- controls body posture and muscular coordinationCEREBRUM -- small in frog, very large in humans (involved in many important life processes)No. of cranial nerves No. of Spinal Nerves FROG 1010 PAIRSHUMAN1230 PAIRSNOSTRILS 2 SIMPLE HOLESNO LONG NASAL PASSAGESMELL IS REGISTERED IN THE OLFACTORY LOBESEYE IS CRUDE

FIXED LENSE CANT CHANGE FOCUSPoorly developed eyelids dont moveWith 3rd eyelid, nictating membrane

NO EXTERNAL EAREARDRUMS (TYMPANIC MEMBRANES ARE EXPOSED)With only one bone in the middle ear (humans have 3)Semicircular canals help maintain balanceTERMINOLOGY IN ANATOMY