Human Neural System Notes for Class 11 Biology NEET

 

Forebrain, Midbrain and Hindbrain – Easy NEET Notes

18.4.1 Forebrain

Forebrain consists of:

• Cerebrum
• Thalamus
• Hypothalamus

These are the major parts of the forebrain.

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Cerebrum

• Cerebrum is the largest part of the human brain.
• It controls:
  • Thinking
  • Intelligence
  • Memory
  • Learning
  • Speech
  • Voluntary actions

Cerebral Hemispheres

• A deep groove divides the cerebrum into:
  • Left cerebral hemisphere
  • Right cerebral hemisphere

Corpus Callosum

• Both hemispheres are connected by nerve fibres called:
  • Corpus callosum
• It allows communication between the two hemispheres.

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Cerebral Cortex

• Outer layer of cerebrum is called the cerebral cortex.
• It is highly folded to increase surface area.
• It appears grey due to presence of neuron cell bodies.
• Therefore, it is called Grey Matter.

Functions of Cerebral Cortex

It contains:

1. Motor areas → control voluntary movements.
2. Sensory areas → receive sensory impulses.
3. Association areas → involved in:
   • Memory
   • Intelligence
   • Communication
   • Interpretation of sensations

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White Matter

• Inner region of cerebrum contains myelinated nerve fibres.
• Myelin gives white appearance.
• Therefore, inner part is called White Matter.

Easy Difference

Grey Matter	White Matter
Outer region	Inner region
Contains neuron cell bodies	Contains myelinated fibres
Grey in colour	White in colour

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Thalamus

• Cerebrum surrounds the thalamus.
• Thalamus acts as a:
  • Major coordinating centre
  • Relay station for sensory and motor signals

Functions

• Receives sensory impulses
• Transfers impulses to cerebrum
• Helps in motor coordination

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Hypothalamus

• Located at the base of thalamus.
• It controls many important body activities.

Functions of Hypothalamus

• Controls body temperature
• Controls hunger and thirst
• Regulates sleep and emotions
• Contains neurosecretory cells

Hypothalamic Hormones

• Neurosecretory cells produce:
  • Hypothalamic hormones
• These hormones regulate pituitary gland functions.

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Limbic System

• Inner parts of cerebrum with structures like:
  • Amygdala
  • Hippocampus
• Together form the Limbic System.

Functions

• Controls emotions:
  • Fear
  • Anger
  • Pleasure
  • Excitement
• Involved in:
  • Motivation
  • Memory
  • Sexual behaviour

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18.4.2 Midbrain

• Midbrain lies between:
  • Forebrain
  • Hindbrain

Cerebral Aqueduct

• A canal called cerebral aqueduct passes through the midbrain.

Corpora Quadrigemina

• Dorsal side of midbrain has four rounded swellings called:
  • Corpora quadrigemina

Functions of Midbrain

• Controls visual reflexes
• Controls auditory reflexes
• Helps in movement of eyes and head

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18.4.3 Hindbrain

Hindbrain consists of:

1. Pons
2. Cerebellum
3. Medulla oblongata

---

Pons

• Contains nerve fibre tracts.
• Connects different regions of brain.

Functions

• Relays signals
• Helps in respiration control

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Cerebellum

• Surface is highly folded.
• Provides space for more neurons.

Functions

• Maintains body balance
• Coordinates muscular activity
• Maintains posture
• Ensures smooth voluntary movements

NEET Point

• Damage to cerebellum causes:
  • Loss of balance
  • Irregular movements

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Medulla Oblongata

• Connected to spinal cord.

Functions

Controls involuntary activities:

• Breathing
• Heartbeat
• Blood pressure
• Gastric secretions

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Brain Stem

Brain stem includes:

1. Midbrain
2. Pons
3. Medulla oblongata

Functions of Brain Stem

• Connects brain with spinal cord
• Controls basic life processes
• Pathway for nerve impulses

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Quick NEET Revision Points

Forebrain

• Largest and most advanced part
• Includes cerebrum, thalamus, hypothalamus

Cerebrum

• Intelligence and memory centre
• Two hemispheres connected by corpus callosum

Grey Matter

• Outer cortex
• Contains neuron cell bodies

White Matter

• Inner region
• Contains myelinated fibres

Thalamus

• Relay centre for sensory impulses

Hypothalamus

• Controls temperature, hunger, thirst

Limbic System

• Emotional brain

Midbrain

• Visual and auditory reflexes

Cerebellum

• Balance and coordination

Medulla

• Controls involuntary activities

Brain Stem

• Midbrain + Pons + Medulla

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Mnemonics for NEET

Forebrain Parts

“CTH”

• C → Cerebrum
• T → Thalamus
• H → Hypothalamus

Hindbrain Parts

“PCM”

• P → Pons
• C → Cerebellum
• M → Medulla

Brain Stem

“MPM”

• Midbrain
• Pons
• Medulla  

  

  Human Neural System diagram showing CNS, PNS and neuron structure for Class 11 Biology and NEET preparation.

  
  

CBSE Class 11 Biology – Neural System Question Bank

Chapter: Neural Control and Coordination

VERY SHORT ANSWER QUESTIONS (1 MARK)

Q1. What is the structural and functional unit of nervous system?

Answer: Neuron.

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Q2. Name the two divisions of human neural system.

Answer:

1. Central Nervous System (CNS)
2. Peripheral Nervous System (PNS)

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Q3. What does CNS include?

Answer: Brain and spinal cord.

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Q4. Define ganglia.

Answer: Clusters of neuron cell bodies outside CNS are called ganglia.

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Q5. What are afferent fibres?

Answer: Fibres carrying impulses from body organs to CNS.

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Q6. What are efferent fibres?

Answer: Fibres carrying impulses from CNS to organs or muscles.

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Q7. Which nervous system controls voluntary actions?

Answer: Somatic nervous system.

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Q8. Which nervous system controls involuntary activities?

Answer: Autonomic nervous system.

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Q9. Name the two divisions of autonomic nervous system.

Answer:

1. Sympathetic nervous system
2. Parasympathetic nervous system

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Q10. What is a nerve net?

Answer: A network of interconnected neurons found in Hydra.

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SHORT ANSWER QUESTIONS (2–3 MARKS)

Q1. Differentiate between CNS and PNS.

CNS	PNS
Includes brain and spinal cord	Includes nerves associated with CNS
Main control centre	Connects CNS to body organs
Processes information	Transmits impulses

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Q2. Differentiate between afferent and efferent fibres.

Afferent Fibres	Efferent Fibres
Carry impulses to CNS	Carry impulses from CNS
Sensory nerves	Motor nerves
Receptors → CNS	CNS → Effectors

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Q3. Write functions of sympathetic nervous system.

Answer:

• Prepares body during stress.
• Increases heartbeat.
• Dilates pupil.
• Raises blood pressure.
• Called “fight or flight” system.

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Q4. Write functions of parasympathetic nervous system.

Answer:

• Conserves body energy.
• Slows heartbeat.
• Stimulates digestion.
• Helps body relax.
• Called “rest and digest” system.

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Q5. Name the three parts of neuron and write their functions.

Part	Function
Cell body	Controls metabolic activities
Dendrites	Receive impulses
Axon	Carries impulses away

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LONG ANSWER QUESTIONS (5 MARKS)

Q1. Explain the divisions of human nervous system.

Answer:

The human nervous system is divided into:

1. Central Nervous System (CNS)

• Includes brain and spinal cord.
• Main control and coordination centre.
• Processes information.

2. Peripheral Nervous System (PNS)

• Includes all nerves connected to CNS.
• Divided into:
  • Afferent fibres
  • Efferent fibres

Further divisions of PNS

(a) Somatic Nervous System

• Controls voluntary actions.
• Connected to skeletal muscles.

(b) Autonomic Nervous System

• Controls involuntary activities.
• Divided into:
  • Sympathetic nervous system
  • Parasympathetic nervous system

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Q2. Describe the structure of neuron with labelled points.

Answer:

Neuron is the structural and functional unit of nervous system.

Parts of neuron:

1. Cell Body

• Contains nucleus and cytoplasm.
• Contains Nissl’s granules.
• Controls cell activities.

2. Dendrites

• Short branched fibres.
• Receive nerve impulses.

3. Axon

• Long fibre.
• Carries impulses away from cell body.

Direction of impulse:

Dendrite → Cell body → Axon

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MULTIPLE CHOICE QUESTIONS (MCQs)

Q1. Structural and functional unit of nervous system is:

A. Axon
B. Neuron
C. Muscle fibre
D. Ganglia

Answer:

✅ B. Neuron

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Q2. Hydra possesses:

A. Brain
B. Spinal cord
C. Nerve net
D. Ganglion

Answer:

✅ C. Nerve net

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Q3. CNS consists of:

A. Brain and nerves
B. Brain and spinal cord
C. Nerves and ganglia
D. Axon and dendrites

Answer:

✅ B. Brain and spinal cord

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Q4. Afferent fibres are:

A. Motor fibres
B. Sensory fibres
C. Mixed nerves
D. Connector fibres

Answer:

✅ B. Sensory fibres

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Q5. Fight or flight response is controlled by:

A. Parasympathetic NS
B. Somatic NS
C. Sympathetic NS
D. CNS

Answer:

✅ C. Sympathetic NS

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Q6. Nissl’s granules are present in:

A. Cell body
B. Axon
C. Myelin sheath
D. Synapse

Answer:

✅ A. Cell body

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Q7. Dendrites function ki to:

A. Carry impulses away
B. Receive impulses
C. Protect neuron
D. Form myelin sheath

Answer:

✅ B. Receive impulses

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Q8. Somatic nervous system controls:

A. Digestion
B. Heartbeat
C. Voluntary actions
D. Blood pressure

Answer:

✅ C. Voluntary actions

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ASSERTION AND REASON QUESTIONS

Q1.

Assertion (A):

Afferent fibres are sensory fibres.

Reason (R):

They carry impulses from organs to CNS.

Answer:

✅ Both A and R are true and R is the correct explanation of A.

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Q2.

Assertion (A):

Sympathetic nervous system slows heartbeat.

Reason (R):

It conserves energy during rest.

Answer:

❌ Both Assertion and Reason are false.

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Q3.

Assertion (A):

Neuron is the structural and functional unit of nervous system.

Reason (R):

Neuron can transmit nerve impulses.

Answer:

✅ Both A and R are true and R is the correct explanation.

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CASE STUDY QUESTIONS

Case Study 1

A student accidentally touches a hot pan and immediately withdraws his hand. The sensory receptors send impulses to the CNS, and the CNS sends commands to muscles.

Questions:

Q1. Which fibres carry impulses to CNS?

Answer: Afferent fibres.

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Q2. Which fibres carry impulses from CNS to muscles?

Answer: Efferent fibres.

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Q3. Which system controls skeletal muscles?

Answer: Somatic nervous system.

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Q4. Name the control centre of body.

Answer: CNS.

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STATEMENT-BASED QUESTIONS

Q1. Identify True/False

(i) CNS includes brain and spinal cord.

✅ True

(ii) Parasympathetic nervous system prepares body for emergency.

❌ False

(iii) Axon receives impulses.

❌ False

(iv) Hydra has nerve net.

✅ True

(v) Dendrites are short branched fibres.

✅ True

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MATCH THE COLUMN

Q1.

Column A	Column B
(A) Afferent fibres	(i) Carry impulses from CNS
(B) Efferent fibres	(ii) Receive impulses
(C) Dendrites	(iii) Carry impulses to CNS
(D) Axon	(iv) Carry impulses away

Answers:

A → iii
B → i
C → ii
D → iv

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Q2.

Column A	Column B
(A) Sympathetic NS	(i) Rest and digest
(B) Parasympathetic NS	(ii) Fight or flight
(C) Somatic NS	(iii) Voluntary control
(D) CNS	(iv) Brain and spinal cord

Answers:

A → ii
B → i
C → iii
D → iv

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IMPORTANT CBSE/NEET ONE-LINERS

• Neuron is the structural and functional unit of nervous system.
• Hydra possesses a nerve net.
• CNS consists of brain and spinal cord.
• Sensory fibres are afferent fibres.
• Motor fibres are efferent fibres.
• Sympathetic system = fight or flight.
• Parasympathetic system = rest and digest.
• Dendrites receive impulses.
• Axon carries impulses away from cell body.
• Internal Links
• Cell Structure and Function Notes
• Animal Kingdom NEET Notes
• Structural Organisation in Animals
• Chemical Coordination and Integration
• Locomotion and Movement Notes
• Biomolecules Class 11 Notes
• Breathing and Exchange of Gases
• Body Fluids and Circulation
• Neural Control and Coordination MCQs
• Human Physiology Complete Notes
• Nissl’s granules help in protein synthesis.

Internal Links

Cell Structure and Function Notes

Animal Kingdom NEET Notes

Structural Organisation in Animals

Chemical Coordination and Integration

Locomotion and Movement Notes

Biomolecules Class 11 Notes

Breathing and Exchange of Gases

Body Fluids and Circulation

Neural Control and Coordination MCQs

Human Physiology Complete Notes

HUMAN BRAIN

                              │

        ┌─────────────────────┼─────────────────────┐

        │ │ │

    FOREBRAIN MIDBRAIN HINDBRAIN

        │ │ │

        │ │ ┌──────────┼──────────┐

        │ │ │ │ │

        │ │ PONS CEREBELLUM MEDULLA

        │ │

        │ │

 ┌──────┼───────────┐ │

 │ │ │ │

CEREBRUM THALAMUS HYPOTHALAMUS

 │ │ │

 │ │ │

 │ │ ├─────────────────────────────┐

 │ │ │ │

 │ │ Controls: Neurosecretory

 │ │ • Body temperature cells secrete

 │ │ • Hunger hypothalamic

 │ │ • Thirst hormones

 │ │ • Emotions

 │ │

 │ Sensory & motor

 │ relay centre

 │

 ├──────────────────────────────────────────────────────┐

 │ │

Two cerebral hemispheres Limbic system

 │ │

 │ │

Connected by Includes:

CORPUS CALLOSUM • Amygdala

 │ • Hippocampus

 │

 ├───────────────────────────────┐

 │ │

GREY MATTER WHITE MATTER

 │ │

Outer cerebral cortex Inner myelinated fibres

 │ │

Contains neuron Gives white appearance

cell bodies

 │

 ├──────────────────────────────────────────────┐

 │ │ │

Motor areas Sensory areas Association areas

 │ │ │

Voluntary Receive sensory Memory, learning,

movements impulses intelligence,

                                           communication

────────────────────────────────────────────────────────────

MIDBRAIN

 │

 ├── Cerebral aqueduct present

 │

 ├── Corpora quadrigemina

 │ • Four rounded lobes

 │

 └── Functions

         • Visual reflexes

         • Auditory reflexes

────────────────────────────────────────────────────────────

PONS

 │

 ├── Connects brain regions

 └── Helps in respiration

CEREBELLUM

 │

 ├── Highly folded surface

 ├── Coordinates muscles

 ├── Maintains posture

 └── Maintains balance

MEDULLA OBLONGATA

 │

 ├── Connected to spinal cord

 └── Controls involuntary actions

         • Breathing

         • Heartbeat

         • Blood pressure

         • Gastric secretion

────────────────────────────────────────────────────────────

BRAIN STEM

 │

 ├── Midbrain

 ├── Pons

 └── Medulla oblongata

Function:

• Connects brain and spinal cord

• Controls basic life activities