Nervous System

Central Nervous System

(CNS): Brain + Spinal cord.
- Brain controls voluntary & involuntary activities.
Peripheral Nervous System (PNS):
- Cranial & spinal nerves.
- Ganglia.
- Motor & sensory pathways.
Cranium: Hollow bones (protects brain).
Neuron: Structural & functional unit; longest cell in the body.
Synapse: Junction between neurons; neurotransmitters (e.g., acetylcholine) transmit signals.

Brain Parts

Cerebrum → Largest brain part; manages intelligence, memory, language, sensory processing, voluntary actions.
Cerebellum → Balance, posture.
Medulla Oblongata → Involuntary functions (breathing, heartbeat, CO₂/pH regulation).
Thalamus → Identifies pain, coldness, hotness.
Hypothalamus → Controls:
- Hormone secretion (e.g., pituitary).
- Starvation, thirst, love.
- Temperature & metabolism.
- Blood pressure & sweating.

Nerves

Sensory / Afferent Nerves: Carry impulses from receptors → brain/spinal cord.
Motor / Efferent Nerves: Carry impulses from brain/spinal cord → working organs.

Reflex Action

Rapid, involuntary response via spinal cord.
Origin: Outside CNS.

Autonomic Nervous System

Sympathetic Nervous System:
- Increases sugar, BP, respiration, RBC count.
- Contracts blood vessels.
- Lowers salivary gland secretion.
Parasympathetic Nervous System:
- Performs opposite functions of sympathetic.

Special Functions

Ear: Maintains balance.
Cochlea: Hearing organ.

Nervous System

Central Nervous System (CNS): Brain + Spinal cord.
- Brain controls voluntary & involuntary activities.
Peripheral Nervous System (PNS):
- Cranial & spinal nerves.
- Ganglia.
- Motor & sensory pathways.
Cranium: Hollow bones (protects brain).
Neuron: Structural & functional unit; longest cell in the body.
Synapse: Junction between neurons; neurotransmitters (e.g., acetylcholine) transmit signals.

Brain Parts

Cerebrum → Largest brain part; manages intelligence, memory, language, sensory processing, voluntary actions.
Cerebellum → Balance, posture.
Medulla Oblongata → Involuntary functions (breathing, heartbeat, CO₂/pH regulation).
Thalamus → Identifies pain, coldness, hotness.
Hypothalamus → Controls:
- Hormone secretion (e.g., pituitary).
- Starvation, thirst, love.
- Temperature & metabolism.
- Blood pressure & sweating.

Nerves

Sensory / Afferent Nerves: Carry impulses from receptors → brain/spinal cord.
Motor / Efferent Nerves: Carry impulses from brain/spinal cord → working organs.

Reflex Action

Rapid, involuntary response via spinal cord.
Origin: Outside CNS.

Autonomic Nervous System

Sympathetic Nervous System:
- Increases sugar, BP, respiration, RBC count.
- Contracts blood vessels.
- Lowers salivary gland secretion.
Parasympathetic Nervous System:
- Performs opposite functions of sympathetic.

Special Functions

Ear: Maintains balance.
Cochlea: Hearing organ. The nervous system controls and coordinates all body activities by transmitting signals between different parts of the body.
It ensures rapid communication via electrical impulses and works in coordination with the endocrine system.
In Bihar, neurological issues like epilepsy, stroke, and poor neural development in malnourished children are public health concerns.

1. Divisions of Human Nervous System

a. Central Nervous System (CNS)

Includes Brain and Spinal Cord
Brain: Control center of body
- Cerebrum: Controls thinking, memory, voluntary actions
- Cerebellum: Balance and muscular coordination
- Medulla oblongata: Involuntary actions (breathing, heartbeat)
Spinal Cord: Relays signals between brain and body; also controls reflexes

📝 PYQ (BPSC): Part of brain that controls heartbeat? → Medulla oblongata
📝 Expected MCQ: Balance and posture are controlled by? → Cerebellum

b. Peripheral Nervous System (PNS)

Composed of nerves from brain and spinal cord
Two types:
- Sensory nerves: Carry signals to CNS
- Motor nerves: Carry signals from CNS to muscles

c. Autonomic Nervous System (ANS)

Controls involuntary functions (e.g. digestion, heart rate)
Has two divisions:
- Sympathetic system: Prepares for action (fight or flight)
- Parasympathetic system: Calms the body

📝 Expected MCQ: Nervous system controlling heartbeat & digestion? → Autonomic nervous system

2. Neuron – The Structural Unit

Basic unit of nervous system
Conducts nerve impulses
Parts:
- Dendrites: Receive signals
- Cell body: Contains nucleus
- Axon: Transmits signal
- Synapse: Junction between neurons for signal transfer

📝 PYQ: Structural unit of nervous system? → Neuron
📝 Expected MCQ: Signals between neurons pass through? → Synapse

3. Reflex Action

Involuntary, quick response to stimuli
Example: Pulling hand away from hot object
Controlled by spinal cord (not brain)
Pathway: Receptor → Sensory neuron → Spinal cord → Motor neuron → Effector

📝 Expected MCQ: Reflex actions are controlled by? → Spinal cord

4. Bihar Relevance – Neurological Health

Malnutrition in children → delays brain development
Lack of neonatal care → neurological disorders in infants
Rising stroke and epilepsy cases in elderly
Mental health issues underreported in rural Bihar
Govt efforts:
- District Mental Health Programme (DMHP)
- RBSK (Rashtriya Bal Swasthya Karyakram) for early disability screening
- Free epilepsy & neuro-drug distribution in PHCs

📝 Expected MCQ: Govt program screening brain disorders in Bihar kids? → RBSK

PYQs + Expected MCQs

📝 PYQ (BPSC): Which brain part controls involuntary actions? → Medulla oblongata
📝 PYQ: Unit of nervous system? → Neuron
📝 Expected MCQ: Brain part for memory and intelligence? → Cerebrum
📝 Expected MCQ: Quick, involuntary response is called? → Reflex action
📝 Expected MCQ: Junction between two neurons? → Synapse

Quick Revision Points

Nervous system = CNS + PNS + ANS
CNS: Brain (Cerebrum, Cerebellum, Medulla), Spinal Cord
PNS: Nerves (sensory & motor)
ANS: Involuntary control (sympathetic/parasympathetic)
Neuron = functional unit
Reflex = fast spinal response
Bihar: Neurological gaps due to malnutrition, poor screening
Schemes: RBSK, DMHP, PHC drug access

Sources Used

NCERT Class 10 Science – Control and Coordination
Lucent GK – Biology Section
Drishti Science Quick Book
EduTeria Bihar Health Capsule
Ghatna Chakra PYQs – BPSC & Teacher Exams
MoHFW Bihar – RBSK and Mental Health Program Data