Monkey Frog

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The monkey frogs are a group of species of tree frogs (Phyllomedusa hypocondrialis, phyllomedusa sauvagii, etc.) which are characterized by long limbs and a lack of webbing between their toes. This last trait allows them to grasp branches and to climb trees in the manner of a monkey (thus the name).

Certain species produce hallucinogens in their skin.

Kingdom: Animalia

Phylum: Chordata

Class: Amphibia

Order: Anura

Frogs and Toads have a fairly simple structure. Broad bodies, no identifiable neck, no tail and four legs They have a wide mouth and tiny nostrils on their snout. Prominent eyes for almost 360' vision. And moist smooth or rough skin. The links above explore the many different and unusual features of frog biology. From their movement, vision, breathing, skin, hearing, temperature control, and smell to their strange reproduction processes Frogs and toads have a 'lycra' type skin that protects them from from injury and disease. It comes in wonderful variations of colour and patterns. Frog skin is water permeable, this means it can let water in and out. Frogs don't often drink with their mouths, they absorb water through their skin. They have a 'seat pouch', an area on their bellies which is designed for water absorption. They absorb through capillary action from water or a moist surface. In many species glands are modified to produce toxins and other substances that will repel predators. Some frog skin toxins are being researched as potential pain medications. Frogs have a huge variety of skin colours and patterns. Colours can help warn predators that the frog may be poisonous. And many frogs change the colour of their skin to change their heat absorption rate so controling their temperature. Also water and other secretions help sustain temperature.

Patterned skin can help camouflage the frog, so it sinks into the background, out of the sight of predators. All frogs regularly shed their skin, most eat the shed skin for nutrition and water. In dry environments, some frog have been known to retain their skin as a cocoon to keep in water.

Contents 1 ANATOMY 1.1 General Body Features 1.2 Skeleton and Muscles 1.3 Circulatory System 1.4 Skin and Respiratory System 1.5 Digestive and Excretory Systems

[edit] ANATOMY

The body structure, or anatomy, of the frog is very similar to the anatomy of man. Both man and the frog have the same kinds of organs and systems of organs. The frog's anatomy, however, is much simpler.

[edit] General Body Features

As in other higher vertebrates, the frog body may be divided into a head, a short neck, and a trunk. The flat head contains the brain, mouth, eyes, ears, and nose. A short, almost rigid neck permits only limited head movement. The stubby trunk forms walls for a single body cavity, the coelom. Man's internal organs are housed in one of three distinct hollow cavities--the chest, the abdomen, and the pelvis. The human chest is separated from the abdomen by a powerful muscular partition, the Thoracic diaphragm. There is no such partition in the frog's coelom. All the frog's internal organs, including the heart, the lungs, and all organs of digestion are held in this single hollow space.

[edit] Skeleton and Muscles

The frog's body is supported and protected by a bony framework called the skeleton. The skull is flat, except for an expanded area that encases the small brain. Only nine vertebrae make up the frog's backbone, or vertebral column. The human backbone has 24 vertebrae. The frog has no ribs. The frog does not have a tail. Only a spikelike bone, the urostyle, remains as evidence that primitive frogs probably had tails. The urostyle, or "tail pillar," is a downward extension of the vertebral column. The shoulders and front legs of the frog are somewhat similar to man's shoulders and arms. The frog has one "forearm" bone, the radio-ulna. Man has two forearm bones, the radius and the ulna. Both frog and man have one "upper arm" bone, the humerus. The hind legs of the frog are highly specialized for leaping. The single "shinbone" is the tibiofibula. Man has two lower leg bones, the tibia and the fibula. In man and in the frog, the femur is the single upper leg (thigh) bone. A third division of the frog's leg consists of two elongated anklebones, or tarsals. These are the astragalus and the calcaneus. The astragalus corresponds to the human talus. The calcaneus in the human skeleton is the heel bone. As in other vertebrates, the frog skeleton is moved by muscles. Skeleton-moving muscles are made of skeletal, or "striated," muscle. Internal organs contain smooth muscle tissue.

[edit] Circulatory System

The frog heart is the only organ contained within the coelom which has its own protective covering. This is the pericardium (see Heart). There are two upper chambers of the heart, the right atrium and the left atrium. The frog heart, however, has only one lower chamber, a single ventricle. In man, the lower heart chamber is divided into two compartments, the right ventricle and the left ventricle. Oxygen-laden blood and oxygen-poor blood containing waste gases are present together in the frog ventricle at all times. The oxygen-laden and oxygen-poor bloods, however, do not mix. Such mixing is prevented by a unique arrangement of the frog's heart. Instead of "perching" on top of the ventricle, the right atrium dips downward into the ventricle. This causes oxygen-poor blood entering the right atrium to pass all the way down to the bottom of the ventricle. Meanwhile, oxygen-laden blood is received by the left atrium and enters the same single ventricle. The pool of oxygen-poor blood at the bottom of the ventricle holds up the oxygen-laden blood and prevents it from sinking to the bottom. When the oxygen-poor blood flows from the ventricle into vessels leading to the lungs, the oxygen-laden blood tries to "follow" it. The lung vessels, however, are filled with oxygen-poor blood, blocking the oxygen-laden blood and forcing oxygen-laden blood to detour into the arteries. These carry the oxygen-laden blood to the tissues. Frog blood has both a solid and a liquid portion. The liquid plasma carries solid elements such as red blood cells and white blood cells.

[edit] Skin and Respiratory System

The frog is covered by a soft, thin, moist skin composed of two layers, an outer epidermis and an inner dermis. The skin does not merely protect the frog but helps in respiration (see Respiratory System). An extensive network of blood vessels runs throughout the frog's skin. Oxygen can pass through the membranous skin, thereby entering directly into the blood. When a frog submerges beneath the water, all its respiration takes place through the skin. Oxygen is obtained directly from the water. The frog does not breathe through its skin alone. Adult frogs have paired, simple, saclike lungs. As in man, air enters the body through two nostrils, passes through the windpipe, and is received by the lungs (see Lungs). The mechanism of breathing, however, is different in the frog from that in man. In humans breathing is aided by the ribs, the diaphragm, and the chest muscles. The frog has no ribs or diaphragm, and its chest muscles are not involved in breathing. A frog may breathe by simply opening its mouth and letting air flow into the windpipe. However, it may also breathe with its mouth closed. The floor of the mouth is lowered, causing the frog's throat to "puff out." When the nostrils open, air enters the enlarged mouth. Then, with nostrils closed, the air in the mouth is forced into the lungs by contraction of the floor of the mouth.

[edit] Digestive and Excretory Systems

The frog's mouth is where digestion begins. It is equipped with feeble, practically useless teeth. These are present only in the upper jaw. The frog's tongue is highly specialized. Normally, the tip of its tongue is folded backward toward the throat. From this position the frog can flick it out rapidly to grasp any passing prey. To better hold this prey, the tongue is sticky. Food passes from the frog's mouth into the stomach by way of the esophagus. From the stomach, the food moves into the small intestine, where most of the digestion occurs. Large digestive glands, the liver and the pancreas, are attached to the digestive system by ducts. A gall bladder is also present (see Digestive System). Liquid wastes from the kidneys travel by way of the ureters to the urinary bladder. Solid wastes from the large intestine pass into the cloaca. Both liquid and solid waste material leave the body by way of the cloaca and the cloacal vent.