ICSE 2018: The diagram given below shows the internal structure of a spinal cord depicting a phenomenon.

ICSE 2018 

Q. The diagram given below shows the internal structure of a spinal cord depicting a phenomenon. Study the diagram and answer the questions: [5]

(i) Name the phenomenon that is depicted in the diagram. Define the phenomenon. 

(ii) Give the technical term for the point of contact between the two nerve cells. 

(iii) Name the parts numbered 1, 2 and 3. 

(iv) How does the arrangement of neurons in the spinal cord differ from that of the brain? 

(v) Mention two ways by which the spinal cord is protected in our body.

Solution:

Structure of Human Sperm

In humans, there are two types of gametes been produced: in females, non-motile egg and in males, motile sperm. 

Millions of sperms race against each other to fertilize the egg. Out of millions of sperms, one sperm wins and succeeds in fertilizing the egg. When the nucleus of a human sperm fuses with egg, the process is termed as fertilization.

In this article, we will study the structure of Human Sperm in details and know about the functions each part of Human Sperm.  We will also answer interesting facts related to Human Sperm and fertilization process such as:

• What is so unique about every sperm which makes it faster than the other sperms? 
• Once a sperm fertilizes an egg, how does it prevent other sperms from entering the egg? How is polyspermy prevented?
• How is sex of a child determined?
• Is it correct to blame women for giving birth to only girl child?

ICSE 2018: Given below are diagrams showing the different stages in the process of fertilization of an egg in the human female reproductive tract.

ICSE 2018 

Q. Given below are diagrams showing the different stages in the process of fertilization of an egg in the human female reproductive tract. [5 marks] 

Study the diagrams and answer the questions: 

(i) Arrange the letters given below each diagram in logical sequences to show the correct order in the process of fertilization. 

(ii) Where does fertilization normally take place? What is ‘Implantation’ that follows fertilisation 

(iii) Mention the chromosome number of the egg and zygote in humans. 

(iv) Explain the term ‘Gestation’. How long does Gestation last in humans? 

(v) Draw neat, labelled diagram of a mature human sperm.

Solution:

ICSE 2018: The diagram given below is that of a structure present in a human kidney.

ICSE 2018: 

The diagram given below is that of a structure present in a human kidney. [5 marks] 

Study the same and answer the questions that follow:

(i) Name the structure represented in the diagram. 

(ii) What is the liquid entering part ‘1’ called? Name two substances present in this liquid that are reabsorbed in the tubule. 

(iii) What is the fluid that comes to part ‘2’ called? Name the main nitrogenous waste in it. 

(iv) Mention the three main steps involved in the formation of the fluid mentioned in (iii) above. 

(v) Name the substance which may be present in the fluid in part ‘2’ if a person suffers from Diabetes mellitus.

Solution:

Mystery behind different eye colors and patterns

Each human being has different eye color - some have brown eyes, some have black, green or blue eyes.  What is the mystery behind different eye colors - black, brown, blue or green? What defines unique pattern seen in our eyes? Why eye color and pattern of one person differs from another? Are our genes responsible for eye color? Is eye color inheritable from parent to offspring?

Let's explore further to find out answers to the above questions.

Types of Immunity - Innate and Adaptive Immunity

Have you ever wondered:

• How does our body overcomes common cold on its own?
• Why humans do not get infected by plant diseases? 
• Why after getting vaccinated, our body becomes immune to that specific disease such as polio?

The answer to the above questions lies in the fact that our body has a defense mechanism called as IMMUNE SYSTEM which recognizes the foreign pathogens, fights against them and destroys them. 

In this article we will discuss about the different types of immunity.

Thyroid Gland - Hormones and their functions

Thyroid gland is a bilobed, butterfly-shaped organ which is the largest endocrine gland in the body. The medical term for thyroid gland is "glandula thyreoidea". It secretes three hormones: T3 hormone, T4 hormone and Calcitonin. 

• Weight: 20-60 grams
• Size: 2-inches long

Wharton described the Thyroid gland for the first time.

Light and Dark Adaptation in Human Eye

Have you ever noticed: 

• When we enter a dark room from outside, immediately the things inside the room do not appear clear. Why?

• Why do we experience dazzling effect, when we come out of cinema hall after noon show?

Have you experienced above mentioned scenarios and wondered why does it happen? How does our eyes adapt to these situations?

If yes, then this article on "Light and Dark adaptation of Human Eye" will help to answer your curiosity.

ICSE 2019: The diagram given below represents a system in the human body.

ICSE 2019:

Q. The diagram given below represents a system in the human body. Study the diagram and answer the following questions: [5 marks]

(i) Identify the system.

(ii) Label the parts marked 5 and 6.

(iii) Name the two hormones secreted by 1.

(iv) Mention the number and the name of the part involved in fertilisation and implantation from the above diagram.

(v) Mention the surgical methods of contraception in

1. Human males    2. Human females

Solution: 

ICSE 2019: The diagram given below represents an endocrine gland in the human body.

ICSE 2019:

The diagram given below represents an endocrine gland in the human body. Study the diagram and answer the following questions: [5 marks]

(i) Identify the endocrine gland. Where is it located?

(ii) Why is the above gland referred to as the ‘master gland’?

(iii) Name the hormone which in deficiency causes diabetes insipidus. How does this

disorder differ from diabetes mellitus?

(iv) Explain the term ‘hormone’. What is the role of tropic hormones in the human body?

(v) Which lobe of the above gland secretes

1. Oxytocin    2. ACTH    3. Growth hormone

Solution: 

ICSE 2019: The diagram given below represents an organ system in the human body.

ICSE 2019:

(a) The diagram given below represents an organ system in the human body. Study the same and answer the questions that follow: [5 marks]

(i) Identify the system.

(ii) Label the parts marked 2 and 4. Mention the function of part 5.

(iii) Name the structural and functional units of the part marked 1.

(iv) What is the fluid that accumulates in part 3? Which is the main nitrogenous waste present in it?

(v) Draw a neat, labelled diagram showing the longitudinal section of part 1.

Solution: