STRUCTURAL

ORGANISATION IN
ANIMALS
 ORGAN AND ORGAN SYSTEM

• Tissues organise to form organ which form organ system .

• This type of organisation is essential for more efficient and better
coordinated activities of an organism
• Organ is made up of one or more type of tissues .
• For example- Heart consist of all four type of tissue –Epidermis ,
Muscular , connective and neural.
WHAT WE ARE
GOING
TO STUDY
NOW???
MORPHOLOGY
AND
ANATOMY OF
FROG
• Frog belong to class Amphibia of phylum
chordata.
• Most common species Found in India is Rana
Tigrina.
• They are cold blooded or Poikilotherms.
• They have ability to change their colour to hide
from their enemies(Camouflage).
• This protective colouration is called Mimicry.
• Frog are not seen during peak summer and winter.
• During this time they take shelter in deep burrows.
• Summer sleep- Aestivation
• Winter sleep- Hibernation
 MORPHOLOGY OF FROG
• The skin is smooth and slippery due to the presence of Mucus.
• The skin of a frog is always moist.
• The colour of Dorsal side is generally Olive green with dark spots.
• Ventral side of frog is yellow in colour.
• The body of frog is divisible into Head and Trunk.
• Neck and tail is absent.
• Above mouth pair of Nostril is present.
• Eyes are bulged and protected with Nicitating membrane.
• On the side of the eye a membrane Tympanum is present.
• Forelimbs and Hindlimbs
present.
• Hindlimbs ( 5 digit) are larger and
muscular than Forelimbs(4 digit).
• Feets are Webbed.
• They exibhit sexual Dimorphism.
• Male and female frog can be
distinguish by sound producing
Vocal cord and copulatory pad on
the first digit of four limbs.
 Digestive system
• It consist of Alimentary canal and
Digestive glands.
• Alimentary canal is short as they are
Carnivores.
• Length of their Intestine is
reduced.
• Bilobed tongue – Mouth –
Oesophagus – Stomach –
Intestine – Rectum – Cloaca.
• In stomach HCL and Gastric
juices are present
• Formation of Chyme takes place.
• Bile juice emulsify the Fats.
• Pancreatic juice break down the
Carbohydrate and Protein .
• Villi and Microvilli are present in
intestine.
 Respiratory System
• Frog respire on land as well as in water.
• In water Skin act as a aquatic respiratory organ
(Cutaneous respiration)
• Dissolved oxygen is exchanged through the process
of Diffusion.
• Buccal cavity , skin and lung act as a respiratory
organ on land. (Pulmonary respiration)
• Lungs are pair of elongated , pink coloured sac like
structure.
• It is present on upper side of Trunk.
• Air enters through Nostrils into the Buccal cavity
then to lungs.
• During Hibernation and Aestivation Gaseous
exchange takes place through skin .
 Circulatory system
• They have well developed Closed vascular
system.
• Vascular system consist of Heart , Blood and
Blood vessel.
• Heart is situated at the upper part of the body.
• Heart is 3 Chambered.
• There are 2 Atria and 1 ventricle .
• Heart is covered by a membrane called
Pericardium.
• A triangular structure called Sinus venosus join the
right atrium
• It receives the blood through main vein Vena cava.
• The ventricles open into a sac like Conus arteriosus on
the ventral side of heart
• The blood is carried by Artery to all part of the body.
• Vein collect the blood from all part of the body .
• Special venous connection is present between
1)Liver and intestine—Hepatic portal system.
2)Kidney and lower part—Renal portal System.
 Blood
• Blood is composed of Plasma and
cells.
• Blood cell are composed of
1)RBC
2)WBC
3)Platelets
• RBC are nucleated and contain
Haemoglobin.
• Blood carries Nutrient , Gases and
water to respective sites.
 Excretory System
• Excretory system consist of Kidney , Cloaca , Ureter and Urinary bladder
• Kidney are compact , dark red and bean like structure present posteriorly on the
body cavity on both side of vertebral Column
• Kidney is composed of Nephrons or Uriniferous tubule.
• Two Ureter emerge from kidney in the male frog.
• Ureter act as Urinogential duct which opens into Cloaca.
• In Females the ureter and oviduct open seperately in Cloaca.
• Thin walled Urinary bladder is present ventral to the rectum which also open in
Cloaca.
• Frog is Ureotelic Animal.
• Waste product are carried by blood to the kidney where they are filtered.
 Nervous system
• System of Control and
coordination is highly evolved.
• They have both Neural system
as well as Endocrine System.
• Chemical coordination is
achieved by Harmones.
 Endocrine gland found in
FROG
• 1-Pituitary Gland (Estrogen)
• 2-Thyroid Gland
• 3-Parathyroid Gland ( Calcium concentration)
• 4-Thymus
• 5-Pineal Body (Luminous)
• 6-Pancreatic iselets
• 7- Adrenal Gland
• 8-Gonads
• The nervous system is
divided into three part
• 1-CNS ( Brain & Spinal
cord)
• 2-PNS (Cranial & Nerves)
• 3-ANS ( Sympathetic &
Parasympathetic)
 BRAIN
There are ten pair of Cranial nerve.
• Brain is enclosed in bony Structure called Brain
box.
• Brain is divided into three part-Fore , Mid & Hind.
• Forebrain has Olfactory lobes , Paired cerebral
hemisphere and Dincephalon.
• Mid brain has pair of optic nerves.
• Hind brain has Cerebellum and Medulla.
• The medulla passes out through the Foramen
Magnum and continues to Spinal cord.
 Sense Organs
• Frog has a different sense Organs
• 1-Touch – Sensory Papillae
• 2-Taste- Taste buds
• 3-Smell- Nasal epithelium
• 4- Vision – Eyes
• 5-Hearing – Tympanum
• Only Eyes and Internal ears are well developed and Rest
are the cellular aggregation around nerve ending .
• Frog has Simple eyes
• External ear are absent only Tympanum can be seen
externally
• Ear is an organ of Hearing and balancing
 Reproductive System
• They have well developed Male and female reproductive system
• Male system consists of pair of yellowish Ovoid testis.
• Testes are adhered to the upper part of kidney by a double fold
of Peritoneum called Mesorchium.
• Vas efferentia are 10-12 in number that arise from Testis.
• They finally connect to Urinogential duct which opens into
Cloaca.
• The Cloaca is small median chamber that is used to pass Faecal
matter , Urine & Sperm
 Female Reproductive system
• It include Pair of Ovaries.
• The Ovaries are situated near
Kidney but no functional
connection is there
• A pair of Oviduct arise from ovary
opens into the Cloaca seperately.
• Fertilisation is External.
• A mature female can lay 2500-3000
Ova at a time