This MCQ module is based on: Human Brain, Spinal Cord and Voluntary Responses
TOPIC 22 OF 50
Human Brain, Spinal Cord and Voluntary Responses
🎓 Class 10
Science
CBSE
Theory
Ch 6 — Control and Coordination
⏱ ~17 min
🌐 Language: [gtranslate]
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6.1.3 The Human Brain — Command Headquarters
The human brain sits inside the skull cushioned by a fluid called cerebrospinal fluid and three protective membranes (meninges). It is divided, for study, into three main regions — fore-brain, mid-brain and hind-brain.
Fore-brain — the Thinking Part
The fore-brain is dominated by the large, folded cerebrum. This is the region responsible for all voluntary actions (walking, writing, speaking), conscious thinking, memory, reasoning and the processing of senses — the cerebrum contains separate "areas" for hearing, smell, sight, touch and taste. When you smell a rose, olfactory receptors in the nose send impulses to the fore-brain, which interprets them and you recognise the smell.
Mid-brain — the Relay Station
The mid-brain is small but important — it acts as a relay between the fore-brain and the hind-brain, and controls reflexes of the eye and ear (for example, pupil constriction in bright light).
Hind-brain — Balance, Heart-beat, Breathing
The hind-brain has three parts:
- Cerebellum — a small, wrinkled region behind the cerebrum. It controls the precision of voluntary actions and maintains posture and body balance. Walking in a straight line, riding a bicycle and picking up a pencil without dropping it all depend on the cerebellum.
- Medulla oblongata — controls involuntary life-sustaining actions such as the heart-beat, blood pressure, breathing, vomiting and salivation. Damage here can be fatal.
- Pons — relays signals and helps regulate sleep and breathing rhythm.
Voluntary, Involuntary and Reflex Actions
Not every movement the body makes is decided in the same place. Three separate categories exist:
| Type | Under conscious control? | Controlled by | Examples |
|---|---|---|---|
| Voluntary | Yes | Fore-brain (cerebrum) | Writing, walking, talking, kicking a ball |
| Involuntary | No — automatic | Mid-brain & hind-brain (medulla) | Heart-beat, breathing, digestion, blood-pressure regulation |
| Reflex | No — automatic and rapid | Spinal cord (brain not primarily involved) | Withdrawing hand from flame, knee-jerk, sneeze, blink |
Tip: Involuntary actions (like heart-beat) keep running even when you are fast asleep. Reflex actions (like pulling away from heat) only occur when a stimulus triggers them.
6.2 Coordination in Plants
Plants neither have neurons nor muscles, yet they sense and respond. A shoot bends towards light, a root grows down into the soil, a tendril winds around a stick — all without a single nerve. How?
Plants use two broad kinds of movement:
- Immediate, non-growth movements — like the rapid folding of Mimosa pudica leaves on being touched. These are caused by quick water changes in specialised cells.
- Slow, growth-dependent movements — called tropisms. The plant part grows more on one side than the other and therefore bends.
Mimosa pudica — The "Touch-me-not"
When you touch a Mimosa leaf, it folds inwards within a second or two. This is a non-directional response — the leaf folds the same way whichever side you touch. It is produced by loss of water (and hence turgidity) from special swollen bases called pulvini. Since the whole plant is not growing, the movement is nastic, not tropic.
Tropic Movements
A tropism is a directional movement caused by growth. Depending on the stimulus, plants show four main tropisms:
| Tropism | Stimulus | Example |
|---|---|---|
| Phototropism | Light | Shoot bends towards light (positive); root away (negative) |
| Geotropism | Gravity | Root grows downward (positive); shoot grows upward (negative) |
| Hydrotropism | Water | Roots grow towards moisture in soil |
| Chemotropism | Chemicals | Pollen tube grows down the style towards sugars in the ovule |
Activity 6.2 & 6.3 — Which way do roots and shoots go?
Setup 1 (Activity 6.2): Sow four bean seeds in damp cotton inside a transparent tumbler. After 2–3 days, when the seeds sprout, turn the tumbler on its side and keep it in the dark for another 2 days.
Setup 2 (Activity 6.3): Take a potted plant and place it near a window so that light comes only from one side. Rotate the pot every few days; observe over a week.
Predict: In setup 1, will the roots continue in the original direction, or bend? In setup 2, which way will the shoot grow?
Setup 1 Result: The roots bend and grow downward again, even though the tumbler is on its side — proof of positive geotropism. The shoots bend upward — negative geotropism.
Setup 2 Result: The shoot bends towards the window side (positive phototropism). Auxin, a plant hormone, accumulates on the shaded side and causes faster growth there, making the shoot tip turn towards the light.
Interactive — Control Centre Matcher
Match each function with the correct brain region, then click Check.
Thinking and memory
Maintaining balance while riding a cycle
Regulating heart-beat and breathing
Pupil contraction in bright light (eye reflex)
Competency-Based Questions
A boxer takes a blow to the back of his head and loses his balance but remains conscious. A doctor says the impact has affected the hind-brain.
Q1. Which region of the hind-brain is most likely injured, and why did the boxer stay conscious? L3 Apply
The cerebellum is most likely injured because it controls balance and posture. Consciousness and thought are handled by the cerebrum (fore-brain), which was not directly damaged.
Q2. (MCQ) Which of these is an involuntary action controlled by the medulla? L1 Remember
(c) Heart-beat and breathing.
Q3. A scientist removes the top half of the Mimosa petiole and then touches a leaflet. No folding is observed. Explain. L4 Analyse
The folding response depends on pulvini (swollen bases) connected to the leaf stalk. Cutting the petiole breaks the communication path and water-pressure changes cannot reach the leaflet, so no folding occurs.
Q4. Differentiate between tropic and nastic movements with one example each. L2 Understand
Tropic movements are directional and depend on the direction of stimulus — e.g. shoot bending to light (phototropism). Nastic movements are non-directional and independent of stimulus direction — e.g. Mimosa leaf folding on touch.
Q5. True/False — "A plant's shoot bending towards light is because auxin makes the lighted side grow faster." Justify. L4 Analyse
False. Auxin accumulates on the shaded side (away from light) and makes that side grow faster, so the shoot bends towards the light.
Assertion–Reason Questions
Options: (A) Both true, R explains A. (B) Both true, R does not explain A. (C) A true, R false. (D) A false, R true.
Assertion: Roots show positive geotropism.
Reason: Roots grow away from the direction of gravity.
(C) — A is true (roots grow downward, towards gravity), R is false.
Assertion: The cerebellum is called the "little brain".
Reason: It is responsible for maintaining posture and balance.
(B) — Both are true but R does not explain the name; the name refers to its smaller size.
Assertion: Mimosa leaf folding is a tropic movement.
Reason: The response depends on the direction of the touch.
(D) — A is false (it is nastic, not tropic), R is false too; but since A is false, answer is (D) with R meant to contrast: actually R is false. Correct choice: A is false — the movement is non-directional; final answer (D) because A is false while R is independent. Best fit: option where A is false.
Frequently Asked Questions — Brain, Spinal Cord & Voluntary Responses
What is brain, spinal cord & voluntary responses in Class 10 Science (CBSE board)?
Brain, Spinal Cord & Voluntary Responses is a key topic in NCERT Class 10 Science Chapter 6 — Control and Coordination. It explains structure and function of the human brain and spinal cord and control of voluntary/involuntary actions. Core ideas covered include central nervous system, peripheral nervous system, forebrain, midbrain. Mastering this subtopic is essential for scoring well in the CBSE Class 10 Science board exam because board papers repeatedly test these concepts through MCQs, short answers and long-answer questions. This part gives a complete, exam-ready explanation with activities, diagrams and competency-based practice aligned to NCERT.
Why is central nervous system important in NCERT Class 10 Science?
Central nervous system is important in NCERT Class 10 Science because it forms the foundation for understanding brain, spinal cord & voluntary responses in Chapter 6 — Control and Coordination. Without a clear idea of central nervous system, students cannot answer higher-order CBSE board questions involving peripheral nervous system, forebrain, midbrain. Board papers regularly include 2-mark and 3-mark questions on this concept, and competency-based questions often link central nervous system to real-life situations. Building clarity here pays off directly in board marks.
How is brain, spinal cord & voluntary responses tested in the Class 10 Science CBSE board exam?
The CBSE Class 10 Science board exam tests brain, spinal cord & voluntary responses through a mix of 1-mark MCQs, 2-mark short answers, 3-mark explanations with examples, 5-mark descriptive questions (often with diagrams or balanced equations) and 4-mark competency-based questions. Expect direct questions on central nervous system, peripheral nervous system, forebrain and application-based questions drawn from NCERT activities. Students who follow NCERT thoroughly and practice this chapter's questions consistently score in the 90%+ range.
What are the key terms to remember for brain, spinal cord & voluntary responses in Class 10 Science?
The key terms to remember for brain, spinal cord & voluntary responses in NCERT Class 10 Science Chapter 6 are: central nervous system, peripheral nervous system, forebrain, midbrain, hindbrain, cerebrum. Each of these concepts carries exam weightage and regularly appears in the CBSE board paper. Write clear one-line definitions of every term in your revision notes and revisit them before the exam. Linking these terms visually through a flowchart or concept map makes recall easier during the Class 10 Science board exam.
Is Brain, Spinal Cord & Voluntary Responses included in the Class 10 Science syllabus for 2025–26 CBSE board exam?
Yes, Brain, Spinal Cord & Voluntary Responses is a part of the NCERT Class 10 Science syllabus (2025–26) prescribed by CBSE. It falls under Chapter 6 — Control and Coordination — and is examined in the annual board paper. The current syllabus retains the full treatment of central nervous system, peripheral nervous system, forebrain as per the NCERT textbook. Because CBSE bases every board question on NCERT, studying this part thoroughly ensures complete syllabus coverage and guarantees marks from this chapter.
How should I prepare brain, spinal cord & voluntary responses for the CBSE Class 10 Science board exam?
Prepare brain, spinal cord & voluntary responses for the CBSE Class 10 Science board exam in three steps. First, read this NCERT part carefully, highlighting definitions and diagrams of central nervous system, peripheral nervous system, forebrain. Second, solve every in-text question and end-of-chapter exercise — CBSE questions often come directly from NCERT. Third, practice competency-based and assertion-reason questions to sharpen reasoning. Write answers in the exam-style format (point-wise with diagrams) and time yourself. This method delivers confidence and full marks in the board exam.
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