Biology
The diagram given below is an external view of the human brain. Study the same and answer the questions that follow:
(i) Name the parts labelled A, B and C in the diagram.
(ii) State the main functions of the parts labelled A and B.
(iii) What are the structural and functional units of the brain? How are the parts of these units arranged in A and C?
(iv) Mention the collective term for the membranes covering the brain.
(v) What is the function of Cerebrospinal fluid?
Answer
(i) The parts labelled A, B and C are:
- A → Cerebrum
- B → Cerebellum
- C → Spinal Cord
(ii) The functions are mentioned below:
- Cerebrum (Part A) — It is the seat of intelligence, consciousness and will power. It controls all voluntary activities.
- Cerebellum (Part B) — It coordinates muscular activities and maintains balance of the body.
(iii) Neurons / nerve cells are the structural and functional units of the brain.
In part A (Cerebrum), Outer grey matter has cytons and inner white matter has axons.
In part C (Spinal Cord), Outer white matter has axons and inner grey matter has cytons.
(iv) Meninges
(v) Cerebrospinal fluid(CSF) acts like a cushion to protect the brain / spinal cord from injuries and shocks.
Related Questions
In a homozygous pea plant, axial flowers (A) are dominant over terminal flowers (a).
(i) What is the phenotype and genotype of the F1 generation if a plant bearing pure axial flowers is crossed with a plant bearing pure terminal flowers?
(ii) Draw a Punnett square board to show the gametes and offsprings when both the parent plants are heterozygous for axial flowers.
(iii) What is the phenotypic ratio and genotypic ratio of the above cross shown in (ii).
(iv) State Mendel's Law of Dominance.
(v) Name two genetic disorders commonly seen in human males.
The diagram given below represents a section of the human heart. Answer the questions that follow:
(i) Which parts of heart are in the diastolic phase? Give a reason to support your answer.
(ii) Label the parts numbered 1 and 2 in the diagram. What type of blood flows through them?
(iii) What causes the heart sounds 'LUBB' and 'DUP'?
(iv) Name the blood vessels that supply oxygenated blood to the heart muscles.
(v) Draw neat labelled diagrams of a cross section of an artery and a vein.
Give appropriate biological / technical terms for the following:
(i) The type of immunity that exists in our body due to our genetic makeup.
(ii) The suppressed allele of a gene.
(iii) The accessory gland in human males whose secretion activates the sperms.
(iv) An apparatus that measures the rate of water uptake in a cut shoot due to transpiration.
(v) The kind of twins formed from two fertilised eggs.
(vi) A pair of corresponding chromosomes of the same size and shape, one from each parent.
(vii) The mild chemical substance which when applied on the body kills germs.
(viii) The type of waste generated in hospitals and pathological laboratories.
(ix) The antiseptic substance in tears.
(x) Cellular components of blood containing haemoglobin.
Give biological reasons for the following statements:
(i) Some women have facial hair like beard and moustache.
(ii) Cutting of trees should be discouraged.
(iii) In some xerophytes leaves are modified into spines.
(iv) There is frequent urination in winter than in summer.
(v) The left ventricle of the heart has a thicker wall than the right ventricle.