Frogsare carnivorous tailless amphibians which are widely found in India. A diverse variety of frogs can be found all over the world; among them, the Indian frogs are called Rana tigrina. They are vertebrates, coming under the class Amphibia (phylum Chordata). Frogs are cold-blooded animals (poikilotherms) whose body temperature varies according to their environment, hence, they need to protect themselves from extreme heat and cold for maintaining optimum body temperature. Thus, they follow aestivation and hibernation during the summer and winter seasons respectively. Another characteristic feature of frogs is that they camouflage i.e., they can change their skin colour according to their surroundings.
Morphologyof Frogs
Though larvae have tails, adult frogs are tailless. An adult frog has a stout body which is differentiated into head and trunk. Other external features are a pair of nostrils, protruding eyes, a membranous tympanum (ear), slippery/warty moist skin and webbed limbs.
Frogs generally have a slippery moist and highly permeable skin through which they absorb water and respire. Thus, the moist skin acts as a respiratory organ in frogs. Also, the skin is glandular in nature, which produces mucus and toxic substances to warn them of their predators. The colour of the skin can vary from brown and green to vivid colours as per secretions.
The locomotion of frogs takes place with the help of their forelimbs and hind limbs. Frogs are unisexual i.e., they show sexual dimorphism. A male frog is distinguished from a female frog by the presence of vocal sacs and a copulatory pad on forelimbs. A female frog lacks these body features.
Below is an easy and well labelled diagram of frog (Rana tigrina) for your better understanding.
Anatomy
The body plan of frogs consists of well-developed structures which help them in their physiological activities. The body cavity accommodates all the organ systems such as digestive, respiratory, circulatory, excretory, nervous and reproductive systems, whose functions are almost similar to human body systems.
Digestive system
The alimentary canal together with the accessory organs makes up the digestive system of the frog. Since frogs are carnivorous they have short intestine. The alimentary canal begins at the mouth (buccal or oral cavity), passes through the pharynx, oesophagus or food pipe, stomach, small intestines, large intestines, rectum and finally ending at the cloaca. The food particles get digested gradually as they travel through various compartments of the alimentary canal.
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Respiratory system
The amphibian has two modes of respiration – cutaneous respiration and pulmonary respiration. In an aquatic ecosystem, the skin is the respiratory organs where the diffusion of dissolved oxygen takes place. This is called cutaneous respiration. While on land, they use both skin and lungs for respiration. During pulmonary respiration, air entering through nostrils passes to the lungs via the buccal cavity. But during summer and winter sleep, they use only skin for respiration.
Circulatory system
Frogs have a well-developed muscular heart with three chambers- two atria and one ventricle. Blood and lymph help in the transportation of food, air and other substances throughout the body via the network of blood vessels. The blood is composed of plasma and blood cells (RBC, WBC, and platelets).
Excretory system
The frog is a ureotelic animal whose major excretory product is urea. They have a distinguishable excretory system composed of a pair of kidneys, ureters, cloaca and urinary bladder. The kidneys have the structural unit called nephron which filters the blood and excretes out the waste.
Coordination system
The nervous system and the endocrine system together perform the control and coordination in frogs. The endocrine system is composed of the endocrine glands such as pituitary, thyroid, parathyroid, thymus, pineal body, pancreatic islets, adrenals, and gonads. The secretions of these glands called hormones are responsible for metamorphism and other regulatory functions.
The nervous system is divided into CNS and PNS. The brain is distinguished as forebrain, midbrain, and hindbrain which control different parts of the body. The brain is enclosed in the cranium and the vertebral column protects the spinal cord.
Reproductive system
Both male and female frogs have their own reproductive system where gametes for reproduction are produced. Male frog has testes which produce sperms and eject it through the cloaca. In a female frog, a pair of ovaries produce ovum and pass it to oviduct which opens into the cloaca. The cloaca is a common pathway for excretion and reproduction. At a time, 2500 to 3000 eggs are laid which are fertilized externally.
For video lessons on the frog – morphology, and anatomy, download BYJU’S-The Learning App.
Also read: Pelvic Girdle of Frog
FAQs
Morphology of Frogs
What is the morphology and anatomy of frog? ›
Morphology of a Frog
The body of the frog is divisible into head and trunk. Neck and tail are absent in a frog. The skin of the frog has mucus, which makes the skin moist, smooth and slippery. The skin of the frog has the ability to absorb water.
What are the internal features of a frog? ›
What are the internal organs of a frog? In the thoracic cavity, you will find the heart and lungs. In the abdominal cavity, you can see the liver, stomach, intestines, kidneys, pancreas, fat bodies, testes (male), or ovaries (female).
What is the external anatomy of a frog? ›
External Frog Anatomy
Many frogs have patterned skin on their dorsal side and a white or yellow ventral side to camouflage them in their aquatic habitat. Frogs have two forelimbs in the front, or anterior end, and two powerful hind limbs in the rear, or posterior, for swimming.
Is the frog internal or external? ›
In most species of frogs, fertilization is external. The male frog grabs the female's back and fertilizes the eggs as the female frog releases them (Figure 2.2B). Rana pipiens usually lays around 2500 eggs, while the bullfrog, Rana catesbiana, can lay as many as 20,000.
What is the basic anatomy of frog? ›
Like humans, frogs are vertebrates, or animals with backbones. The frog body may be divided into a head, a trunk, and limbs. The flat head contains the brain, mouth, eyes, ears, and nose. A short, almost rigid neck permits only limited head movement.
What is anatomy and morphology? ›
Morphology studies the sizes, shapes, and structures of plants, animals, and microbes, as well as the interactions between their parts. Although “anatomy” sometimes refers to the study of biological structure, it typically focuses on both, microscopic and large structural features.
How is frog internal anatomy different from human internal anatomy? ›
Frogs lack several vertebrae and do not have a pelvis. They also have structures not found in the human skeleton i.e. the urostyle. A frog has a 3 chambered heart (2 upper chambers (atria) and only 1 lower chamber) compared to the 4 chambered heart a human has.
Do frogs have internal and external nares? ›
Frogs have a set of internal and external nares (nostrils) through which the frog breathes. Directly behind the nares are two eyes covered by a transparent membrane which acts like a third eyelid to protect the frog's eyes while it swims and eats. Frogs do not have ears like humans.
Do frogs have internal or external ears? ›
Frogs do not have external ears like us. However, they do have eardrums and an inner ear. The frog ear is called a tympanum and is the circle you see behind a frog's eye. Some frogs have small tympanums, while others have ones that are larger than their eyes.
Characteristics used to tell apart male and female frogs:
Loose skin on throat: Males in some species have loose skin on their throat. Enlarged ears: In just a few species, male frogs have larger ears than small frogs. Other traits: A variety of other traits like color and spines can distinguish males from females.
How is the frog's external anatomy adapted for their environment? ›
Moist and soft skin helps the frog to take in dissolved oxygen from water and lungs to breathe when they are on land. At the larval stage of their development, frogs lack functional lungs but are able to take in oxygen through a set of gills. Some frogs also have webbed feet, which is just skin between their toes.
What is the morphology of a frog? ›
Morphology of Frogs
Though larvae have tails, adult frogs are tailless. An adult frog has a stout body which is differentiated into head and trunk. Other external features are a pair of nostrils, protruding eyes, a membranous tympanum (ear), slippery/warty moist skin and webbed limbs.
What is the internal structure of the lungs of a frog? ›
In the anterior section of the body cavity, there are two lungs, one on each side of the heart. They're ovoid, thin-walled, elastic sacs with shallow internal folds or septa that expand the interior surface to generate multiple alveoli chambers. These are separated by septa from one another.
What are the internal parts of the frog heart? ›
The wall of heart consists of three layers- outer epicardium, middle mesocardium and inner endocardium. Internally heart is 3-chambered with two auricles and one ventricles. The two auricles are separated from each other by interauricular septum. Right auricle is larger than left.
What is the morphology of frog skin? ›
Frog skin contains three distinct types of exocrine glands: granular (poison), mucous, and seromucous. The granular gland forms a syncytial secretory compartment within the acinus, which is surrounded by smooth muscle cells. The mucous and seromucous glands are easily identifiable as distinct glands.
What is the morphological structure of the body? ›
Human morphology is the study of the structure of the human body with consideration of its development and vital activity. It includes the study of human histology, anatomy, and embryology. Dental structure in humans is an example of human morphology that is studied through evolution.
What is the anatomy and physiology of frog heart? ›
The frog's heart is three-chambered and it has no partition that separates oxygenated and deoxygenated blood. It has two main chambers namely - Sinus Venosus which receives blood and Conus Arteriosus which departs blood.
What is the morphology of a toad? ›
(A) Dorsal view of head and shoulders of a Duttaphrynus melanostictus with well-developed cranial crests of canthal ridge continuous with supraorbital ridge joining postorbital ridge and a short supratympanic ridge touching the large parotoid gland.
