1. Phylum
    2. 1. Classification of Animals
    2. Protozoa
    3. Porifera
    4. Coelenterata
    5. Platyhelminthes
    6. Nemathelminthes
    7. Annelida
    8. Earthworm
    9. Arthropoda
    10. Cockroach
    11. Mosquito
    12. Honey bee and Silk moth
    13. Mollusca
    14. Echinodermata
    15. Hemichordata
    16. Chordata
    17. Pisces
    18. Amphibia
    19. Frog
    20. Reptile
    21. Aves
    22. Mammalia
    23. Rabbit bone
  2. Animal Behaviour and Adaptation
    3. 24. Animal behaviour
    25. Animal adaptation
    26. Migration
  3. Developmental Biology
    4. 27. Development of Animals
    28. Development of Frog
  4. Human Biology
    5. 29. Tissues
    30. Sense organs
    31. Digestive system
    32. Circulatory system
    33. Respiratory system
    34. Nervous system
    35. Endocrine system
    36. Reproductive system
    37. Excretory system
    38. Skeletal system
    39. Basic concept of Immunology
    40. Human diseases
  5. Evolutionary Biology
    6. 41. Origin of Life
    42. Organic Evolution
    43. Theories of Evolution
    44. Evolution of Human beings
    45. Horse Evolution
Phylum
19. Frog
GENERAL
▢ Frog (Rana tigrina):
❖ Classification:
◉ Phylum: Chordata
◉ Group: Craniata
◉ Subphylum: Vertebrata
◉ Division: Gnathostomata
◉ Superclass: Tetrapoda
◉ Class: Amphibia
◉ Order: Anura
◉ Genus: Rana
◉ Species: tigrina
❖ Differences between Frog and Toad:
◉ Frog (Rana):
◈ 1: Usually diurnal
◈ 2: Mainly aquatic
◈ 3: Skin is smooth and slippery
◈ 4: Skin with relatively few poison glands
◈ 5: Parotid glands absent
◈ 6: Lower jaw is triangular
◈ 7: Tongue is bifurcated
◈ 8: Upper jaw with teeth, lower jaw without teeth
◈ 9: Hindlimbs are well webbed and webs are skinny
◈ 10: Internal vocal sacs are present
◈ 11: Omosternum is present
◈ 12: Eggs are laid in irregular spawn
◉ Toad (Bufo):
◈ 1: Usually nocturnal
◈ 2: Lives on land among stones in damp places
◈ 3: Skin always rough, nearly dry, wrinkled, and warty
◈ 4: Skin abundantly supplied with poison glands
◈ 5: Parotid glands present
◈ 6: Lower jaw is semi-circular
◈ 7: Tongue is entire
◈ 8: There are no teeth
◈ 9: Hindlimbs are well webbed and webs are fleshy
◈ 10: Internal vocal sacs are absent
◈ 11: Omosternum is absent
◈ 12: Eggs are relatively smaller and deposited in chain-like strings
❖ Habit and Habitat:
◉ Distribution: Cosmopolitan
◉ Habitat: Amphibious or Sternohygrous
◉ Breeding: Must descend into pond water for copulation and egg deposition
◉ Feeding Behaviour:
◈ Tadpole: Herbivorous
◈ Adult Frog: Carnivorous (feeding on spiders, insects, worms, insect larvae, etc.)
◈ Cannibalism: Feeds on its tadpoles and small frogs
◈ Prey Capture: Prey is caught alive, small prey captured by sticky tongue
◉ Locomotion: Swims in water, leaps, jumps, and walks on land
◉ Breeding Behaviour: Involves croaking, copulation, and oviposition
◉ Croaking:
◈ Male Frog:
■ 1: Narrow abdomen
■ 2: Presence of vocal sacs
■ 3: Amplexusary pads (copulatory pads)
◈ Female Frog:
■ 1: Wider abdomen
■ 2: No vocal sacs
■ 3: No amplexusary pads
◉ Poikilothermic: Cold-blooded animal
◉ Suspended Animation:
◈ Hibernation: Winter sleep
◈ Aestivation: Summer sleep
❖ External Features of Frog:
◉ Shape and Size:
◈ 1: Body bilateral symmetry, spindle-shaped, dorsoventrally flattened, streamlined with bluntly pointed ends, lacks neck
◈ 2: No exoskeleton, skin surface smooth and slimy
◉ Body Division:
◈ Head:
■ 1: Large, triangular, flattened, forms snout; not completely marked off from trunk
■ 2: Mouth, external nostrils, eyes, and ear drums present
■ Mouth: Large, terminal, semicircular wide opening bounded by hard immovable lips
■ External Nostrils: Two, small circular openings, only respiratory in nature
■ Eyes: Large, bulging, dorsolateral, thick pigmented, immovable upper eyelid, rudimentary lower eyelid
■ Nictitating Membrane: Transparent, movable, functional
■ Tympanic Membrane: Circular, located behind and below the eye, supported by a firm cartilaginous ring
■ Brown Spot: Small lightly coloured spot just in front of the eyes, said to mark the third eye
■ Neck: Absent
◈ Trunk:
■ 1: Short, broad, flattened with characteristic dorsal hump
■ 2: Possesses two pairs of limbs
■ Forelimbs:
● 1: Short with upper arm, forearm, and hand (manus)
● 2: Hand consists of palm and four nailless fingers, no thumb
■ Hind Limbs:
● 1: Longer, with thigh (femur), shank (crus), and foot (pes)
● 2: In resting stage, hind limbs arranged in Z-shape
● 3: Feet have elongated ankles and five webbed but nailless toes, adapted for swimming and jumping
● 4: Subarticular pads present under each joint of toes
■ Cloacal Aperture: Common opening for faecal matter, urine, sperms, and eggs
■ Tail: Absent
◈ Skin:
■ 1: Thin, smooth (naked without scales), slippery due to mucus
■ 2: Loosely attached to body wall due to subcutaneous lymph spaces
■ 3: Skin colour changes to match surroundings (darker in damp, cool places, lighter in sunshine)
■ 4: Metachrosis (protective coloration)
◈ Epidermis:
■ 1: Thin, non-vascularized, stratified epithelium
■ Stratum Corneum: Dead, non-nucleated, flat, dry, outermost layer
■ Stratum Germinativum: Innermost layer, composed of active columnar cells
◈ Dermis:
■ 1: Inner layer, vascular, thicker than epidermis
■ 2: Composed of connective tissue, muscle fibers, blood vessels, capillaries, glands, chromatophores
■ 3: Divided into stratum spongiosum and stratum compactum
■ Stratum Spongiosum: Loose, spongy layer, contains connective tissue, blood vessels, and chromatophores
■ Stratum Compactum: Made of muscle fibers and connective tissue
◉ Functions of Skin:
◈ 1: Protective, sensory, provides texture to body
◈ 2: Respiratory structure (permeable to water)
◈ 3: Nutritive
◉ Body Cavity/Coelom:
◈ 1: Fluid-filled space in the trunk
◈ 2: Covered by parietal and visceral peritoneum
◈ 3: Pericardial cavity surrounds the heart
◈ 4: Pleural cavity surrounds the lungs
◈ 5: Abdominal cavity in the abdominal region
DIGESTIVE SYSTEM
▢ Alimentary_Canal:
❖ General_Information:
◉ Length: Short, as the adult animal is carnivorous
◉ Parts:
    ■ Mouth:
    ● Description: Wide, terminal, horizontal, bounded by upper and lower jaws
    ● Characteristics:
    1. Lower jaw is movable
    ■ Buccopharyngeal_Cavity:
    ● Description: Dorsoventrally flattened wide space between upper and lower jaws
    ● Teeth:
    ⟣ Lower_Jaw: Devoid of teeth
    ⟣ Upper_Jaw:
    1. Semicircular row of submarginal maxillary teeth
    2. Two patches of vomerine teeth between internal nares and bulging of eyes
    ⟣ Types_of_Teeth:
    1. Incisor
    2. Premolar
    3. Molar
    ⟣ Dentition:
    1. Homodont
    2. Acrodont
    3. Polyphyodont
    ⟣ Function_of_Teeth: Teeth are small, sharp, backwardly directed, meant for preventing escape of prey, not for mastication
    ⟣ Dental_Formula: Absent
    ● Tongue:
    ⟣ Description: Large, muscular, sticky, bifid at its tip
    ⟣ Characteristics:
    1. Protusible, retractile
    2. Attached anteriorly, free posteriorly
    3. Taste buds are absent
    4. Taste papillae are present
    ⟣ Mechanism_of_Darting:
    1. Presence of protractor + retractor hypoglossal muscles
    2. Presence of lymph in sublingual lymph sinus
    ● Pharynx:
    ⟣ Contains:
    1. Openings of eustachian tubes
    2. Gullet (for oesophagus)
    3. Glottis (for respiratory passage)
    ⟣ In_Male: Openings of vocal sacs may be seen
    ⟣ Epiglottis: Absent
    ⟣ Digestion: No digestion due to the absence of salivary glands
    ■ Oesophagus:
    ● Description: Short, broad tube, less developed
    ● Function: Secretes pepsinogen, which is activated in the stomach
    ■ Stomach:
    ● Description: Large, broad, curved muscular sac on the left side of the body cavity
    ● Parts:
    1. Cardiac part (anterior)
    2. Pyloric part (posterior) with pyloric sphincter
    ● Gastric_Glands:
    1. Chief/Peptic (Zymogen) glands: Secretes Pepsinogen
    2. Oxyntic cells: Secretes HCl
    3. Mucous glands: Secretes mucin
    ● Functions:
    1. Storage
    2. Mechanical mixing
    3. Chemical modification of food
    ■ Small_Intestine:
    ● Absence_of:
    1. Brunner's glands
    2. Crypts of Lieberkuhn
    ● Parts:
      ➢ Duodenum:
      ⬦ Description: U-shaped, receives hepatopancreatic duct
      ⬦ Absence_of:
      1. Ampulla of Vater
      2. Sphincter of Oddi
      ➢ Ileum:
      ⬦ Description: Contains villi for increasing absorptive surface area
      ⬦ Function: Secretes intestinal juice (succus entericus)
    ■ Rectum:
    ● Description: Ileum dilates posteriorly to form Rectum
    ● Function: Absorption of water, ions/salts
    ■ Cloaca:
    ● Description: Common chamber where rectum, ureters, oviducts, and urinary bladder open
    ● Function: Leads to the outside through cloacal aperture
    ■ Anus:
    ● Description: Opening of rectum into cloaca
    ● Function: Normally kept closed with the help of anal sphincter
❖ Associated_Digestive_Glands:
◉ Liver:
◈ Description: Largest gland and organ in the body
◈ Lobes:
  1. Right lobe
  2. Middle lobe (bears gall bladder)
  3. Left lobe
◈ Histology: Liver is a branched tubular gland, each lobule consisting of hepatic cells
◈ Blood_Supply:
  1. Hepatic artery (oxygenated blood)
  2. Hepatic portal vein (freshly laden with digested food)
◈ Secretion:
  1. Bile salts (sodium taurocholate, sodium glycolate)
  2. Bile pigments (bilirubin, biliverdin)
◈ Functions:
  1. Emulsification of fat
  2. Glycogenesis
  3. Production of RBCs during embryonic stage
  4. Storage of copper and iron, production of Vitamin A
  5. Production of prothrombin and fibrinogen (blood coagulation)
  6. Production of heparin
◉ Pancreas:
◈ Description: Second largest gland, mixed gland
◈ Histology: Branched grape-like gland consisting of acini with a central space
◈ Secretion:
  1. Pancreatic juice (alkaline, contains enzymes)
  2. Enzymes: Trypsinogen, Amylopsin (Amylase), Steapsin (Lipase)
◈ Endocrine_Function:
  1. Insulin (converts excess glucose into glycogen)
  2. Glucagon (converts glycogen into glucose)
◉ Intestinal_Spleen: Present
CIRCULATORY SYSTEM
▢ Blood_Vascular_System:
❖ Blood:
◉ Description: Mobile fluid connective tissue of reddish color.
◉ Parts:
◈ Plasma:
■ Description: Colourless fluid, non-living constituent
■ Composition: Contains 90% water
◈ Blood_Corpuscles:
■ Types:
    ⟣ Erythrocytes:
    ➢ Description: Oval, nucleated, biconvex cells with reddish respiratory pigment hemoglobin
    ⟣ Leucocytes:
    ➢ Description: Colorless, nucleated cells of five types
    ➢ Characteristics:
    1. Some are phagocytic
    2. Others produce antibodies
    ⟣ Thrombocytes:
    ➢ Description: Spindle-shaped, nucleated cells involved in blood coagulation
❖ Heart:
◉ Description: Triangular, thick-walled, muscular, reddish pulsatile sac
◉ Location: Midventrally in thorax between two lungs
◉ Covering: Pericardium (fluid-filled double membranous thin bag)
◉ Structure:
◈ Chambers:
  1. 2 auricles
  2. 1 ventricle
◈ Separation:
  1. Auricles separated by interauricular septum
  2. Auricles and ventricle separated by coronary sulcus
  3. Auriculo-ventricular aperture guarded by four-flapped valve
  4. Chordae tendineae support the valve
◈ Ventricle: Contains fissures and ridges called columnae cornae
◉ Sinus_Venosus:
◈ Description: Triangular sac on the dorsal side of the heart
◈ Function: Receives blood from three venacava (2 pre-cavals, 1 post-caval)
◈ Opening: Into right auricle via sinu-auricular aperture guarded by two valves
◉ Truncus_Arteriosus:
◈ Description: Tubular structure on the ventral side of the heart
◈ Structure:
■ Conus_Arteriosus:
● Description: Thick-walled proximal portion
● Function: Contains a longitudinal spiral valve dividing into two cavities (cavum aorticum and cavum pulmocutaneum)
■ Synangium:
● Description: Thin-walled distal portion
● Function: Divided into two chambers (dorsal and ventral)
● Aortic_Trunks:
  1. Left aortic trunk
  2. Right aortic trunk
● Arches:
  1. Carotid artery
  2. Systemic artery
  3. Pulmocutaneous artery
■ Valves:
  1. Three semilunar valves between ventricle and pylangium, and between pylangium and synangium
◉ Working_of_Heart:
◈ Cardiac_Cycle: Completes in 0.94 sec
◈ Heart_Rate: 64 beats/minute
◈ Flow_of_Blood:
  1. Blood from body enters sinus venosus and then right auricle
  2. Blood from lungs enters left auricle
  3. Auricular Contraction: Closure of sino-auricular valve, opening of auriculo-ventricular valve
  4. Blood from right auricle (deoxygenated) and left auricle (oxygenated) flows into ventricle
  5. Ventricular Contraction: Closure of auriculo-ventricular valve, opening of semilunar valves
  6. Blood exits through truncus arteriosus to different aortic arches
❖ Blood_Vessels:
◉ Arterial_System:
◈ Arteries:
■ Function: Carry blood away from heart to organs
■ Characteristics: No valves, except pulmonary arteries (carry deoxygenated blood)
■ Components:
  1. Truncus arteriosus
  2. Carotid arch
  3. Systemic arch
  4. Pulmocutaneous arch
◈ Truncus_Arteriosus:
■ Divides_Into:
  1. Right and left branches
  2. Three arches from each branch (carotid, systemic, pulmocutaneous)
◈ Capillaries:
■ Description: Fine hair-like vessels connecting arteries and veins
◈ Venous_System:
■ Veins:
● Function: Carry blood from body to heart
● Characteristics: Contain semilunar valves
● Components:
  1. Pulmonary veins
  2. Systemic venous system (2 precavals, 1 postcaval)
■ Pulmonary_Veins: Bring oxygenated blood from lungs to left auricle
■ Systemic_Veins:
  1. External jugular
  2. Innominate
  3. Subclavian
◈ Portal_Systems:
■ Renal_Portal_System:
● Description: Blood from hind limbs passes through kidney for filtration
● Components:
  1. Femoro-renal vein
  2. Sciatic vein
  3. Dorsolumbar vein
  4. Oviduct
■ Hepatic_Portal_System:
● Description: Blood from digestive organs passes through liver for detoxification
● Components:
  1. Anterior abdominal vein
  2. Hepatic portal vein
  3. Gastric, intestinal, splenic veins
▢ Lymphatic_System:
❖ Lymph:
◉ Description: Colorless fluid filtered from blood or tissue fluid
◉ Characteristics:
  1. Contains fewer leucocytes
  2. No erythrocytes or thrombocytes
  3. Acts as intermediary between blood and tissues
❖ Lymph_Vessels:
◉ Description: Lymph capillaries join to form vessels with valves to prevent backflow
◉ Components:
  1. Lymph sinuses
  2. Lymph nodes
❖ Lymph_Hearts:
◉ Description: Two pairs of lymph hearts propel lymph into veins
◉ Function:
  1. Anterior lymph heart empties into subclavian vein
  2. Posterior lymph heart empties into femoral vein
❖ Absence_in_Mammals: No lymph hearts in mammals
EXCRETORY SYSTEM
▢ Kidneys:
❖ Location: Outside coelom in sub-vertebral lymph sinus
❖ Attachments:
◉ Adrenal Gland: Attached to ventral surface
◉ Gonad: Attached to antero-ventral end
❖ Level: Both kidneys lie at the same level
❖ Developmental Stages:
◉ Tadpole: Pronephric
◉ Adult: Mesonephric
❖ Structure:
◉ Cortex and Medulla: Not differentiated
◉ Composition: Made of uriniferous tubules (nephrons)
◉ Nephrons per Kidney: 2000–2500
◉ Nephron Details:
◈ Bowman's Capsule: Double-walled structure
◈ Glomerulus: Bunch of capillaries inside Bowman's capsule
◈ Malpighian Body: Bowman's capsule + Glomerulus
◈ Blood Supply:
■ Afferent Arteriole: Brings blood to glomerulus
■ Efferent Arteriole: Takes blood away from glomerulus
◈ Tubule Connections:
  1. Connected to Bidder's canal
  2. Connected to Longitudinal Collecting duct
◈ Nephrostomes: Present on ventral surface of each kidney
▢ Ureters: A pair of ducts carrying urine from kidneys to bladder
▢ Urinary Bladder: Stores urine before release
▢ Cloaca: Common chamber for release of urine and other wastes
▢ Excretion Type:
❖ Tadpole: Ammonotelic
❖ Adult: Ureotelic
❖ During Hibernation and Aestivation: Uricotelic
UROGENITAL SYSTEM
▢ Sexual Dimorphism:
  1. Presence of vocal sacs in males
  2. Presence of amplexusary pads in males
▢ Copulation: Actual copulation is absent; frogs perform amplexus (pseudo-copulation)
▢ Male Reproductive System:
❖ Testis:
◉ Covering: Surrounded by tunica albuginea
◉ Attachment: Connected to kidney by mesorchium (a peritoneal fold)
◉ Cells:
◈ Sertoli/Nurse Cells: Support, hold, and nourish developing sperms
◈ Leydig Cells: Located in connective tissue; secrete sex hormones
◉ Vasa Efferentia: Arise from testis, join Bidder's canal, and open into urinogenital duct
❖ Copulatory Organs: Absent in frogs
▢ Female Reproductive System:
❖ Ovaries:
◉ Attachment: Connected to dorsal abdominal wall by mesovarium
◉ Structure:
◈ Theca Externa: Outer layer
◈ Theca Interna: Forms stroma
◈ Follicle Cells: Protect, surround, and nourish oocytes
❖ Oviducts:
◉ Feature: Each oviduct dilated to form ovisac before opening into cloaca
◉ Uterus: Absent
▢ Reproduction and Development:
❖ Egg:
◉ Yolk: Present at vegetal pole (telolecithal), faces downward in water
◉ Animal Pole: Forms the head region
❖ Fertilization: External
❖ Cleavage: Holoblastic
❖ Gastrulation Processes:
  1. Involution
  2. Epiboly
  3. Invagination
  4. Yolk plug formation
❖ Embryonic Cavity: Archenteron
❖ Egg Type: Oviparous
❖ Development:
◉ Type: Indirect, via tadpole larva
◉ Tadpole Features:
◈ Skeleton: Entirely cartilaginous
◈ Feeding: Herbivorous
❖ Metamorphosis:
◉ Hormone: Thyroxine (from thyroid gland)
◉ Note: Nervous system remains unchanged
❖ Hormones:
◉ Present:
  1. Estrogen
◉ Absent:
  1. Progesterone
◉ Type: Steroid hormones
NERVOUS SYSTEM
▢ Overview: Nervous system includes Central Nervous System (CNS), Peripheral Nervous System (PNS), and Autonomous Nervous System (ANS)
▢ Central Nervous System (CNS):
❖ Components:
  1. Brain
  2. Spinal Cord
❖ Brain:
◉ Location: Lodged in cranial cavity of the skull
◉ Protective Coverings:
  1. Outer thick Duramater
  2. Inner thin Piamater
◉ Subdural Space: Filled with cerebrospinal fluid (shock-absorbing)
◉ Matter Distribution: White matter is external over optic lobes and medulla oblongata; elsewhere grey matter is external
◉ Parts:
◈ Forebrain (Prosencephalon):
■ Olfactory Lobes:
● Structure: Two anterior swollen lobes
● Cavity: Rhinocoel (olfactory ventricle)
● Function: Controls sense of smell
■ Cerebral Hemispheres (Cerebrum):
● Structure: Pair of large oval lobes fused together
● Cavity: Lateral ventricles / Paracoel (1st and 2nd ventricles)
● Connection: Lateral ventricles open into Diocoel via Foramen of Monro
● Corpus Striatum:
⟣ Location: Ventral side of each lateral ventricle
⟣ Structure: Reticular structure joined by anterior commissure
⟣ Composition: Medullated nerve fibres and brown nerve cells
■ Diencephalon:
● Cavity: Diocoel (Third Ventricle)
● Roof: Anterior choroid plexus (vascular piamater)
● Ventral Structures:
  1. Optic chiasma
  2. Pituitary body (infundibulum + hypophysis)
● Lateral Walls: Optic thalami
● Other Features:
⟣ Brown Spot: Remains of pineal stalk
⟣ Pineal Body: Vestige of third eye
● Function: Controls metabolism of carbohydrates, proteins, and fats
◈ Midbrain (Mesencephalon):
■ Optic Lobes:
● Structure: Two rounded hollow structures (corpora bigemina)
● Cavity: Optocoel
● Connection: Connected to 4th ventricle by Iter (Aqueduct of Sylvius)
● Function: Controls sight
■ Crura Cerebri:
● Structure: Two longitudinal ridges forming floor of midbrain
● Function: Connect cerebral hemispheres with medulla oblongata
◈ Hindbrain (Rhombencephalon):
■ Cerebellum:
● Structure: Transverse ridges behind optic lobes
● Development: Not well developed in frog
● Function: Coordination of muscular actions and balance
■ Medulla Oblongata:
● Structure: Posterior conical part of brain
● Roof: Posterior choroid plexus
● Cavity: Metacoel (4th ventricle), connects anteriorly to Iter and posteriorly to central canal
● Function: Controls involuntary activities and reflexes
● Continuation: Continues as spinal cord
❖ Spinal Cord:
◉ Structure: Sub-cylindrical, flattened, lies in neural canal of vertebral column
◉ Continuation: Posteriorly into urostyle as Filum terminale or Cauda equina
◉ Features:
◈ Fissures:
  1. Dorsal fissure
  2. Deeper ventral fissure
◈ Canal: Central canal surrounded by grey matter, then white matter
◈ Horns: Grey matter forms dorsal and ventral horns
◈ Roots: Leads into dorsal and ventral roots of spinal nerves
◉ Function: Center for reflex actions and pathway for stimuli to and from brain
▢ Peripheral Nervous System (PNS):
❖ Definition: Nerves arising from CNS
❖ Cranial Nerves:
◉ Origin: Arise from brain
◉ Count: 10 pairs in frog (Accessory and Hypoglossal absent)
❖ Spinal Nerves:
◉ Origin: Arise from spinal cord
◉ Count: 10 pairs (9 in Rana tigrina)
◉ Structure: Mixed nerves arising through intervertebral foramina by dorsal and ventral roots
▢ Autonomous Nervous System (ANS):
❖ Definition: System of ganglia and nerves controlling involuntary activities
❖ Divisions:
◉ Sympathetic Nervous System:
◈ Structure: Two ganglionated cords along spinal cord
◈ Ganglia: 9 or 10 per chain
◈ Path: Enters skull via 10th (vagus) nerve, ends at Gasserian ganglia
◈ Function: Stimulates organs via chemical Sympathin
◉ Parasympathetic Nervous System:
◈ Structure: Small ganglia on walls of organs, connected to cranial/spinal nerves
◈ Function: Moderates organ function via acetylcholine
◈ Note: Functions opposite to sympathetic system
RESPIRATORY SYSTEM
▢ Mode of Respiration: Amphibious (aquatic and aerial), due to living both in water and on land
▢ Types of Respiration:
❖ Bucco-pharyngeal Respiration:
◉ Mechanism:
  1. Exchange of gases occurs through the lining of the buccopharyngeal cavity
  2. Mouth, glottis, and gullet are closed; nares are open
◉ Conditions: Performed during rest on land or while floating in water
◉ Oxygen Intake: Accounts for ~5% of total oxygen
❖ Cutaneous Respiration:
◉ Mechanism:
  1. Respiratory surface is skin
  2. Skin is thin, moist, and richly supplied with blood capillaries
  3. Dermis acts like alveoli for gas exchange
◉ Conditions: Occurs all the time; especially in water, hibernation, and aestivation
◉ Oxygen Intake: Accounts for ~30% of total oxygen
◉ Note: Waxing the skin causes asphyxia and death
❖ Pulmonary Respiration:
◉ Mechanism: By lungs
◉ Conditions: Occurs when oxygen demand is high, e.g., during swimming or jumping
◉ Oxygen Intake: Accounts for ~65% of total oxygen
◉ Organs Involved:
◈ External Nares: With membranous valves
◈ Olfactory Chambers:
◈ Internal Nares:
◈ Buccopharyngeal Cavity: Air passes through glottis into lungs via laryngotracheal chamber
◈ Laryngotracheal Chamber:
■ Function: Voice box (sound-producing organ)
■ Features:
  1. Has two vocal cords, glottis opening, and bronchus
  2. Male frogs have vocal sacs acting as resonators
■ Cartilages:
● Unpaired:
  1. Cricoid cartilage
● Paired:
  1. Arytenoid cartilage
● Note: Thyroid cartilage absent but thyroid gland present
◈ Lungs:
■ Structure:
  1. Pair of lungs, pinkish, highly vascular, without lobes
  2. Freely suspended in peritoneal cavity
■ Layers:
  1. Outer: Single peritoneal wall
  2. Middle: Unstriped muscle + connective tissue
  3. Inner: Septa divide inner surface into alveoli
■ Function: Exchange of gases between air and blood capillaries
❖ Branchial Respiration:
◉ Stage: Tadpole (larval stage)
◉ Characteristics:
  1. Aquatic; cannot survive outside water
  2. External gills: 3 pairs
  3. Internal gills: 4 pairs
  4. Gill pouches: 5 pairs
▢ Respiratory Center: Located in Medulla oblongata
▢ Ventilation Process:
❖ Muscles Involved:
◉ Sternohyoid (Sternohyal):
◈ Origin-Insertion: Hyoid to coracoids and clavicles
◈ Function: Contraction lowers buccopharyngeal floor → inspiration
◉ Petrohyoid (Petrohyal):
◈ Origin-Insertion: Hyoid to near pro-otics of skull
◈ Function: Contraction raises buccopharyngeal floor → expiration
❖ Muscle Contractions:
◉ Pulmonary Respiration: 2 contractions of each muscle per cycle
◉ Bucco-pharyngeal Respiration: 1 contraction of each muscle per cycle
❖ Bone Involved: Mentomeckelian bone is associated with respiration mechanism
▢ Physiology of Respiration:
❖ Three Steps:
  1. Breathing or External Respiration
  2. Gaseous Transport
  3. Internal/Tissue/Cellular Respiration (Biological oxidation)
SKELETAL SYSTEM
▢ Vertebrae:
❖ 1st / Atlas:
◉ Type: Acoelous / Amphiplatyan
◉ Features:
  1. Flat on both sides
  2. Seen in mammals (Hyman) [IOM 2018]
❖ 2nd to 7th (Typical vertebrae):
◉ Type: Procoelous
◉ Features:
  1. Concave on one side and convex on another
❖ 8th:
◉ Type: Amphicoelous
◉ Features:
  1. Concave on both sides
❖ 9th:
◉ Type: Acoelous
◉ Features:
    ❖ 10th / Urostyle:
    ◉ Type:
    ◉ Features:
      1. The spiral valve is present in:

      [MOE-2008]

      • Conus Arteriosus
      • Bulbous arteriosus
      • In between right and left auricle
      • Auricle and ventricle
      2. Which of the following has a 3-chambered heart?

      [MOE-2008]

      • Frog
      • Snake
      • Crocodile
      • Lizard
      3. The only acoelous vertebra in frog is the:

      [MOE-2063]

      • VII vertebra
      • VIII vertebra
      • IX vertebra
      • X vertebra
      4. The phalangeal formula of frog's foot is:

      [MOE-2063]

      • 0, 2, 2, 3, 3
      • 2, 2, 3, 4, 3
      • 2, 2, 3, 3, 4
      • 2, 3, 3, 3, 3
      5. Which of the following is present in frog but absent in mammal?

      [MOE-2063]

      • stratum germinativum
      • Malphigian layer
      • Mucous glands
      • Sebaceous gland
      6. What is the name of muscles involved in respiration of frog?
      • Internal and External Intercostal muscle
      • Petrohyal and sternohyal muscle
      • False and true vocal cords
      • Lingual and orbital muscle
      7. The eighth vertebra of frog is k/a:

      [MOE-2060, 2002]

      • amphicoelous
      • acoelus
      • procoelus
      • opisthocoelus
      8. Venous system of frog differs from that of mammal in the presence of:

      [MOE-2062]

      • Hepatic portal system
      • Renal portal system
      • Three venacava
      • Hepatic vein
      9. Combining makes innominate vein in frog:

      [MOE-2062]

      • Lingual mandibular
      • Internal jugular and sub-scapular
      • Brachial and musculo-cutaneous
      • Hepatic portal and anterior abdominal
      10. Blood from back side of frog is collected by:

      [MOE-2002]

      • Iliac
      • Dorsolumbar
      • Femoral
      • Sciatic
      11. The dermis of frog is distinguishable into:

      [MOE-2002]

      • Stratum compactum and stratum lucidum
      • Stratum spongiosum and stratum compactum
      • Stratum spongiosum and stratum granulosum
      • Stratum germinativum and stratum compactum
      12. Frog reproduction involves:

      [MOE-2058]

      • The clasping in which the male inseminates the female
      • Nest building by the male who then gets the female to lay eggs in the nest
      • A male and female pairing which is permanent association
      • Sperm and egg release in the water
      13. Which of the following is longest in frog?

      [MOE-2057, 2055]

      • large intestine
      • small intestine
      • oesophagus
      • stomach
      14. Pulmonary respiration means respiration by:

      [MOE-2056]

      • Skin
      • Pharynx
      • Buccal cavity
      • Lung
      15. Portal system carries blood:

      [MOE-2056]

      • to capillaries
      • from capillaries
      • from capillaries to capillaries
      • from liver to intestine
      16. The urostyle to frog is supposed to be made of smaller bones urostyle is:

      [MOE-2055]

      • 9th vertebra
      • 8th vertebra
      • 10th vertebra
      • Sacral vertebra
      17. The tadpole of frog feeds upon;

      [MOE-2055]

      • Insects
      • Aquatic plants
      • Floating organisms
      • Fishes
      18. In frog which of the following is common in digestion and respiration:

      [MOE-2055]

      • Pharynx
      • Larynx
      • Oesophagus
      • Trachea
      19. Malpighian body comprises of:

      [MOE-2054]

      • Glomerulus
      • Bowman's capsule
      • Glomerulus and Nephron
      • Glomerulus and Bowman's capsule
      20. Anterior abdominal vein in frog is formed by pelvic vein:

      [MOE-2054]

      • ventral femoral
      • dorsal femora
      • ventral sciatic
      • dorsal sciatic
      21. Ilium of the pelvic girdle in frog articulates with transverse process of:

      [MOE-2052]

      • 7th vertebra
      • 8th vertebra
      • 9th vertebra
      • Urostyle
      22. Liver of frog consists of:

      [IOM 2006]

      • single lobe
      • two lobes
      • three lobes
      • four lobes
      23. In frog, blood flows to right auricle from:

      [IOM 2005]

      • venacava
      • sinus venosus
      • pulmonary artery
      • all
      24. Dentition in frog is:

      [IOM 2004]

      • Homodont
      • Heterodont
      • Thecodont
      • Biodont
      25. The hindbrain of frog consists of:

      [IOM 2004]

      • Optic lobe
      • Medulla oblongata and cerebellum
      • Optic lobes and medulla oblongata
      • Diencephalon and medulla oblongata
      26. Cavity that appears during embryogenesis of frog is:

      [IOM 2002, 2001]

      • Blastocoel
      • Archenteron
      • Coelom
      • Alimentary
      27. Which is not involved in respiration of frog?

      [IOM 2001]

      • Diaphragm
      • Lungs
      • Skin
      • Buccal cavity
      28. How many teeth are found in the lower jaw of frog?

      [IOM 2000]

      • No
      • 2
      • 3
      • 4
      29. Tadpole of frog is:

      [IOM 2000]

      • Herbivorous
      • Carnivorous
      • Insectivorous
      • Omnivorous
      30. Brachial and musculo-cutaneous veins in frog unite to form:

      [IOM 1998]

      • innominate vein
      • external jugular vein
      • subclavian vein
      • post caval vein
      31. Septo-maxillary bones are present in the skull of:

      [IOM 1998]

      • rabbit
      • man
      • rat
      • frog
      32. Yolk plug is seen in:

      [IOM 1997, 1996]

      • Blastula
      • Gastrula
      • Morula
      • Cleavage
      33. CNS develops at:

      [IOM 1997]

      • Blastulation
      • Gastrulation
      • Neurulation
      • Cleavage
      34. RBC of frog is:

      [IOM 1997]

      • elliptical, non-nucleated, biconcave
      • elliptical, nucleated, biconvex
      • oval, non nucleated, biconvex
      • oval, nucleated, biconcave
      35. 100 primary oocytes form:

      [IOM 1997]

      • 100 ova
      • 200 ova
      • 400 ova
      • 50 ova
      36. Egg of frog is:

      [IOM 1996]

      • Microlecithal
      • Megalecithal
      • Mesolecithal
      • Telolecithal
      37. Paracoel is found in:

      [IOM 1996]

      • Optic lobe
      • Cerebrum
      • Cerebellum
      • Medulla oblongata
      38. The blood cell in frog, which is found in maximum number and acts as scavenger is:

      [BPKIHS 2000]

      • Neutrophil
      • RBC
      • Eosinophil
      • Platelets
      39. Which of the following vertebra is amphicoelus in frog?

      [MOE 2060, 2002]

      • Eight vertebrae
      • Ninth vertebrae
      • Typical vertebrae
      • Axis
      40. Tadpole of frog feeds upon:

      [MOE 1999]

      • Insects
      • Aquatic plants
      • Floating organisms
      • Fishes
      41. In frog, which of the following is common in digestion and respiration

      [MOE 1999]

      • Pharynx
      • Larynx
      • Oesophagus
      • Trachea
      42. A frog must swallow air if the lungs are to be expanded. This is connected with the fact that frog:
      • Has no vagus nerves
      • Has no diaphragm
      • Is relatively low form of life
      • Normally breathes
      43. In frog, glottis is controlled by the muscle of:
      • Vocal cords
      • Sternum
      • Arytenoid cartilage
      • Pectoral girdle
      44. Skin of frog does not possess:
      • Mucous glands
      • Chromatophores
      • Epidermis
      • Scales
      45. In frog protein digestion is completed in:
      • Duodenum
      • Rectum
      • Stomach
      • Ileum
      46. One of the ear ossicle of frog:
      • Malleus
      • Columella auris
      • Incus
      • Auricle
      47. Fertilization of frog takes place in
      • Water
      • Uterus
      • Fallopian tube
      • Oviduct
      48. Frog hibernates during
      • Winter
      • Spring
      • Summer
      • autumn
      49. Male frog can croak louder than females because being
      • Vocal sacs
      • Larger in size
      • Stronger
      • Larger sound box
      50. Croaking of frog is
      • Hunger call
      • Danger call
      • Musical note
      • Sex call for female
      51. The glands present in the skin of frogs are
      • Sweat and mucous
      • Sweat and mammary
      • Mucous and poisonous
      • Sweat and sebaceous
      52. Mucus helps frog in making
      • Dry skin
      • Moist skin
      • Rough skin
      • Thick skin
      53. The colouration of frog and other amphibians is due to
      • Keratin
      • Algae upon skin
      • Chromatophores
      • Irridescence of skin
      54. Chromatophores in skin of frog are found in stratum
      • Corneum
      • Compactum
      • Germinativum
      • Mostly spongiosum
      55. Layer of actively dividing cells in skin of frog is termed as stratum
      • Malpighi
      • Corneum
      • Compactum
      • Spongiosum
      56. When a frog in transferred from 20°C to 30°C its body temperature
      • Falls to 15°C
      • Rises to 30°C
      • Falls to 12°C
      • Remain unchanged
      57. Which of the following is mainly used in capturing the prey of frog?
      • Lips
      • Teeth
      • Tongue
      • Head
      58. In frog the surface of attachment of tongue is
      • Palatine
      • Sphenoid
      • Pterygoid
      • Hyoid apparatus
      59. The structure present in man but absent in frog is
      • Pancreas
      • Thyroid gland
      • Adrenal gland
      • Salivary gland
      60. Stomach of frog does not have

      [IOM 2069]

      • Fundic part
      • Cardiac part
      • Pyloric part
      • All of these
      61. Which of the following parts is not a part of the small intestine of frog?
      • Ileum
      • Jejunum
      • Duodenum
      • None of these
      62. In frog, digestion of fats occurs mostly in
      • Rectum
      • Stomach
      • Duodenum
      • Small intestine
      63. Which of the following structure is not concerned with breathing in frog?
      • Skin
      • Lungs
      • Diaphragm
      • Buccal cavity
      64. Respiratory pigment in blood of frog Is
      • Myoglobin
      • Cytochrome
      • Haemoglobin
      • Haemocyanin
      65. Contraction of sternohyal muscles during breathing in frog
      • Closes glottis
      • Opens the nostrils
      • Raises floor of oral cavity
      • Lower floor of oral cavity
      66. In RBC of frog are
      • Oval and nucleated
      • Circular and nucleated
      • oval and non nucleated
      • Circular and non nucleated
      67. Chordae tendinae in heart of frog is found in the wall of
      • Ventricle
      • Left auricle
      • Right auricle
      • Sinus venosus
      68. Frog heart is
      • One chambered
      • Two chambered
      • Three chambered
      • Four chambered
      69. Pylangium in frog is found in
      • Atrium
      • Ventricle
      • Sinus venosus
      • Conus arteriosus
      70. Spiral valve is present in
      • Sinus venosus of frogs heart
      • Right auricle of rabbit heart
      • Pylangium of the conus arteriosus of frog heart
      • Synangium of the conus arteriosus of frog's heart
      71. When heart of frog is cut it will
      • Not beat at all
      • Stop beating soon after
      • Continue to beat for a long time if kept dry
      • Continue to beat for a long time if kept moist.
      72. The venous system of frog differs from that of rabbit in having
      • Hepatic vein
      • Three venacava
      • Renal portal system
      • Hepatoportal system
      73. Main excretory organs in a frog are
      • Skin
      • Lungs
      • Kidney
      • Malpighian tubules
      74. The urinary bladder of frog opens into
      • Ureter
      • Uterus
      • Urethra
      • Cloaca
      75. Chief nitrogenous waste product present is urine of frog is:
      • Urea
      • Uric acid
      • Allantoin
      • Ammonia
      76. Number of spinal nerves in frog is
      • Ten only
      • Ten pairs
      • Twelve pair
      • Twenty pairs
      77. Which of the following is absent in frog?
      • External ear
      • Middle ear
      • Internal ear
      • None of these
      78. Bidders canal in frog is found in
      • Liver
      • Testis
      • Ovary
      • Kidney
      79. Bidders canal is meant for passage of:
      • Ova
      • Urine
      • Sperms
      • All of these
      80. In frog the ureter is a urinogenital duct in
      • Male
      • Female
      • Male and female
      • Male or female
      81. The development of frog is
      • Direct
      • Indirect
      • Parthenogenetic
      • None of these
      82. Which of these are never present in frog ovary?
      • Oogonia
      • Corpus luteum
      • Ovarian follicles
      • Germinal epithelium
      83. Astragalus and calcaneum are found in
      • Forelimb of frog
      • Hindlimb of frog
      • Wing of bird
      • Skull of rabbit
      84. Digital formula of forelimbs in frog is
      • 0, 2, 2, 3, 3
      • 0, 2, 3, 3, 3
      • 0, 3, 2, 3, 3
      • 2, 2, 3, 3, 3
      85. Mammalian brains differs from frog brain in having

      [IE - 2003]

      • Olfactory lobe
      • Corpus collosum
      • Cerebellum
      • Hypothalamus
      86. Metamorphosis occurs in:

      [IE - 2004]

      • Frog
      • Rabbit
      • Man
      • Snake
      87. Harderian glands are found in
      • Rabbit
      • Frog
      • Man
      • Earthworm
      88. In frog's heart, there are muscular ridges which are called
      • Purkinje fibres
      • Myonemes
      • Telodendria
      • Columnae carneae
      89. In frog, oviduct is the modification of
      • Wolffian duct
      • Bidder's canal
      • Metanephric duct
      • Mullerian duct
      90. Bidder's canal of frog is present in:

      [BPKIHS-2013]

      • Liver
      • Kidney
      • Testes
      • Urinary Bladder
      91. In frog, vasa efferentia opens into:

      [BPKIHS-2014]

      • Urinogenital duct
      • Epididymis
      • Uriniferous tubule
      • Bidder's canal
      92. The third eye possessed by remote ancestors of frog is marked by:

      [BPKIHS-2014]

      • Nictitating membrane
      • Brow spot
      • Vestigial organ
      • Plica semilunaris
      93. Bidder's canal in frog is found in relation to:

      [IOM-2013]

      • Kidney
      • Testis
      • Ovary
      • Liver
      94. Rectum in frog opens into:

      [BPKIHS-2015]

      • Urinary bladder
      • Cloaca
      • Anus
      • Bidder's canal
      95. Major function of bile in case of frog is:

      [MOE 2014, 2012]

      • Emulsification of fats for digestion
      • Regulate the process of digestion
      • Digest fats by enzymatic activity
      • Remove waste products
      96. During hibernation, frog respires with the help of:

      [MOE 2014]

      • External gills and lungs
      • Moist skin
      • Gills and bucco-pharyngeal cavity
      • External gills
      97. Chordae Tendinae in frog is found in

      [MOE 2014]

      • Ventricles of heart
      • Ventricles of brain
      • Right auricle
      • Sinus venous
      98. Vasa efferentia in frog's testis open into the:

      [MOE 2013]

      • Transverse collecting tubules
      • Urino-genital duct
      • Bidder's canal
      • Seminal vesicle
      99. Anterior abdominal vein in Rana tigrina is formed joining the:

      [MOE 2013]

      • Two sciatic veins
      • Two pelvic veins
      • Pelvic & sciatic veins
      • Renal portal and femoral veins
      100. In frog, inspiration is the effect of:

      [MOE 2012]

      • Contraction of sternohyoid muscle
      • Relaxation of Pterohyoid muscles
      • Enlarging of entire body
      • Enlarging of lungs only
      101. Sinus-venosus in frog is formed by the union of

      [MOE 2012]

      • Two precaval and one postcaval
      • One precaval and one post caval
      • One precaval and one aorta
      • Two aorta
      102. The surface for tongue attachment in frog is

      [KU 2014]

      • Palatine bone
      • Quardratojugal
      • Hyoid
      • Pterygoid
      103. Stratum corneum of frog is

      [KU 2014]

      • Living, nucleated, flat
      • Living, non-nucleated, flat
      • Dead, non-nucleated, flat, dry
      • Dry, nucleated, dead, flat
      104. Exoskeleton is absent in

      [KU 2013]

      • Scoliodon
      • Frog
      • Rabbit
      • Fowl