Weekly test

  1. Answer in short on any seven questions:-                                                                        [7X1=7]

       1. a) Write down causes of Gigantism.

Ans 1a) Gigantism is caused by hyper secretion of growth hormone in child.

  1. b) What do you mean by holoblastic cleavage?

Ans 1b) Holoblastic cleavage: – The cleavage in which both cytoplasm & yolk are divided is called holoblastic cleavage.

  1. c) Give the function of uvula.

Ans 1c) Uvula closes internal nostril while swallowing the food.

  1. d) What is spermlysin?

Ans 1d) Spermlysin is a proteolytic enzyme secreted by acrosome of spermatozoa.

  1. e) Give the dental formula of adult man.

Ans 1e) Dental formula of adult man is

    I 2/2, C 1/1, Pm 2/2, M 3/3

  1. f) Where does heart beat originate?

Ans 1f) Heart beat is originated from SA Node.

  1. g) What is yolk plug?

Ans 1g) Yolk plug is the region of megameres which is not covered by micromeres during epiboly.

  1. h) Define double circulation.

Ans 1h) The circulation of blood in which blood returns back two times into heart to complete one course of circulation is called double circulation.

  1. i) What is Payer’s patches?

Ans 1i) Payer’s patches are small mass of lymphatic tissue preset on mucosa layer of ileum of human beings.

  1. j) What is the pattern of 3rd cleavage?

Ans 1j) The pattern of 3rd cleavage is unequal, holoblastic  & horizontal in plane.

  1. Describe in brief on any five:-                                                                                                       [5 X 3=15]

      2. a) Describe gastrulation in frog.

Ans 2a) The events which transform a blastula into a gastrula are collectively called gastrulation.

Gastrulation in frog is occurred in following steps:-

  1. Epiboly:-

In this step micromeres divide more rapidly & cover the megameres except leaving a small area called yolk plug.

Fig – Epiboly
  1. Emboly (Invagination & formation of blastopore ):-

In this step, there is a formation of depression or, groove on the dorsal side of the embryo. The crescentic depression formed because of movement of yolk plug is called archaenteron.

  1. Closure of blastopore:-

The opening of archaenteron is called blastopore.

It is going to be closed by dorsal lip, lateral lip & ventral lip. Micromeres divide rapidly & migrated around the dorsal lip to form lateral lip & ventral lip.


Closure of blastopore



b) Discuss fate of germ layers.

Ans 2b) The entire body of tadpole & adult frog is derived from three germinal layers. These are as follows:-

Ectoderm:- The organs or, structures develop from ectoderm are as follows:-

Epidermis of skin, skin derivatives (glands, hair, nail, feathers, claws etc.), olfactory organs (Nasal epithelium), lens of eye, cornea & conjuctiva , Inner ear(membranous labyrinth), Enamel of teeth, lining of stomodaeum & proctodaeum, anterior pituitary, Brachial skeleton, dorsal root ganglia, sensory nerves, sympathetic nervous system, adrenal medulla, pigment cell. Brain & spinal cord, cranial & spinal motor nerves, Retina & optic nerves, posterior pituitary & pineal body.

Mesoderm: – The organs or, structures develop from mesoderm are as follows:-

Dermis of skin, skull, vertebral column, skeletal muscle & appendicular skeleton, excretory organs, reproductive ducts, parietal peritoneum, visceral peritoneum, muscles of viscera, Heart, pericardium, Blood cells, Blood vessels, spleen, Gonads, Coelom.

 Endoderm: – The organs or, structures develop from endoderm are as follows:-

Lining of digestive tract, Gastric &intestinal glands, Liver, Pancreas, Bile and pancreatic duct, respiratory system, urinary bladder, middle ear & eustachion tube, thyroid, Parathyroid, thymus, lining of vagina & urethra.

c) Write short notes on adrenal virilism and gynecomastia.

Ans 2c) Adrenal virilism: –

It is a disease caused by hypersecretion of sexocerticoides in female.

Sign & symptoms:

  1. Deep voice (sound of less frequency or, same as male)
  2. Appearance of beard & moustache


It is a disease caused by hypersecretion of sexocorticoides in male.

Sign & symptoms:      Increase in size of breast.

d) Explain Coelom formatting in frog.

Ans – 2d) The mesoderm of each side of the embryonic body is subdivided into three distinct regions. These are

i) Dorsally into epimere

ii) Intermediate into mesomere

iii) Ventrally into hypomere

Hypomere splits two equal halves longitudinally & develops a cavity called splanchnocoel. Outer membrane of splanchnocoel is associated with ectoderm to form body wall & inner membrane with endoderm to form gut wall.

Fig- T.S. of Neurula showing coelom formation

As a result a cavity is developed between gut wall and body wall. This cavity remains lined by mesoderm is called coelom.

e) Give the structure, locations and modifications of simple cuboidal epithelium.

Ans 2e) Structure of cuboidal epithelium:-

Its cells are cube shaped & possess a central spherical nucleus.

Cuboidal Epithelium

Location: –

This tissue is found in lining of salivary & pancreatic duct, collecting ducts of nephron, secretory cells of salivary, sweat & thyroid gland etc.

Modification:- To perform different functions it modifies its structure some of them are as follows:-

Ciliated cuboidal:- The cuboidal epithelium of which free surface of cells certain cilia is called ciliated cuboidal epithelium.

It is found in lining of central canal of spinal cord, in nephron etc.

Ciliated Cuboidal Epithelium

Brush bordered cuboidal:-

The cuboidal epithelial tissue of which free surface of cells contain microvilli is called brush bordered cuboidal epithelium.

It is found in proximal convoluted tubules of nephron.

Brush bordered cuboidal Epithelium


f) Write a short note on disorder of thyroid gland.

Ans 2f) Disorder of thyroid gland is called thyroidism.

Hypothyroidism:- This disorder is occurred because of hyposecretion of thyroid hormone or, thyroxine.


It is caused by less secretion of thyroxine in infants.

Sign and Symptoms:-


Deficiency of thyroxine in later life gives rise to a condition known as myxoedema.

Sign and Symptoms:-

Reduction of metabolic rate accompanied by decreased oxygen consumption.

Heart beat & body temperature is decreased

This causes the face & eyelids to become puffy due to accumulation of fat & water in the sub-cutaneous tissue.


Because of less secretion of thyroxine size of thyroid gland is increased in yhe influence of TSH secreted by Pituitary gland.


The phenomenon of over secretion by the thyroid gland is called hyperthyroidism.

Grave’s disease or, Exophthalmic goiter:-

It is caused by hyperthyroidism.

Bulging of eye-balls

The enlarged thyroid is overactive & secretes excessive amount of thyroxine.

High metabolic rate

Rapid heart rate

Rise in body temperature.

g) Write down the characteristic of human tooth.

Ans2g) – Tooth of human being is the thecodont, it means tooth lodged in the socket of jaw bone.

Tooth of human being is diphyodont. It means human gets two sets of teeth on its life time. 1st set of teeth is called milk teeth & 2nd set is permanent set of teeth.

Tooth of human being is heterodont. It means teeth of human are different in structure and functions. Like Incisor, Canine, pre-molar & molar teeth.

  1. What is heart beat? Discuss origin and conduction of heart beat in human heart.

Ans 3)- The rhythmic contraction (systole) & relaxation (Diastole) of heart is called heart beat.

Human heart is myogenic it means heart beat is originated from special modified muscular tissue.

Structures related to Origin & Conduction of heart beat:

  1. Sinu- auricular Node (SA-Node) or pace maker:-

It is a special modified neuro-muscular tissue. It is located in the dorsal wall of right auricle just above the opening of superior vena-cava.

  1. Auriculo – ventricular node (AV- Node) or, pace setter:-

It is also modified neuro- muscular tissue but it can’t originate the nerve impulse itself. It can produce nerve impulse after stimulation by SA – Node. It is located in the dorsal wall of right auricle near auriculo-ventricular sulcus.

  1. Bundle of His:-

                       It is a bundle of specialized nerve fibres originates from AV- Node. It runs in inter ventricular septum upto the apex or, posterior part of heart.

At posterior part it bifurcates into right & left half. These branches further divided in to fine thin thread nerve fibres called Purkinjii fibres. It forms a net like structure in the wall of both ventricles.

Fig- Diagramatic representation of conducting system of human Heart showing SA – Node and AV – Node

Origin & Conduction of heart beat:-

Heart beat is originated in the form of nerve impulse. Nerve impulse is followed by contraction of muscles of heart.

Heart beat is originated from SA-Node & transmitted to the wall of both auricles to make auricular systole.

Nerve impulse produced by SA-Node stimulates Av-Node to generate nerve impulse for systole of ventricles. Nerve impulse originated by  AV-Node is transmitted to the wall of both ventricles through Bundle of His & purkinijii fibres.

  1. Describe the structure and function of Pituitary Gland with suitable diagram.

Ans- (See the Pituitary gland in Endocrinology Section Course of Zoology XII)


Define alimentary canal. Explain its structure by taking the reference of human being.

Ans- See in the Digestive system section Course of Zoology XII. Structure of tooth and tongue is no necessary to explain.