Is it correct to say: Confusing reflex action with voluntary action?

Reflex is automatic, spinal-cord mediated. Voluntary involves conscious brain (moving hand deliberately).

Is it correct to say: Saying pituitary secretes only growth hormone?

Pituitary is 'master gland' — secretes GH, TSH, FSH, LH, ADH, oxytocin and prolactin among others.

Is it correct to say: Placing sensory neurons in the motor pathway?

Sensory neuron: receptor → CNS. Motor neuron: CNS → effector. Direction matters.

Is it correct to say: Assuming plants have a nervous system?

Plants respond to stimuli using hormones (chemical signals) — no nerves. Growth movements are tropisms.

Is it correct to say: Confusing endocrine and exocrine glands?

Endocrine: ductless, release hormones into blood. Exocrine: have ducts, release into cavities (sweat, sebum, saliva).

Is it correct to say: Insulin and glucagon both raise blood sugar?

Insulin LOWERS blood sugar (from pancreas β-cells). Glucagon RAISES it (from α-cells).

Formula sheet (PDF) →

Biology · Chapter 3

Control and Coordination

Nervous system, reflex arc, endocrine glands and plant hormones — Maharashtra SSC Science Part 2

5 formulas · 3 solved examples · 6 practice questions · Board weight: 5 marks · Maharashtra State Board Class 10

Not in the 2025–26 syllabus. This chapter is not part of the Maharashtra SSC (Std X) syllabus for 2025–26. It is kept here for reference.

Board Exam Tips

→Diagram of neuron with parts labelled — 3-mark question every SSC.
→Reflex arc with a real-life example (touching hot object) — repeat 3-mark.
→Endocrine glands + their hormones + function table — 4-mark HOTS.
→Plant hormones (auxin, gibberellin, cytokinin, ABA, ethylene) and one function each — 2 marks.
→Distinguish nervous vs hormonal control — SSC comparison ask.

Diagram

Neuron with dendrites, cell body, axon and synapse labelled

Formulas(5)

Reflex Arc SequenceBoard favourite

Stimulus \to Receptor \to Sensory neuron \to Spinal cord \to Motor neuron \to Effector \to Response

Nerve Impulse Speed

v \approx 100 m/s (myelinated)

Neurotransmitter Release at Synapse

Impulse \to C a^{2 +} influx \to Vesicles fuse \to Neurotransmitter release

Auxin Effect on PlantsBoard favourite

Auxin \to Cell elongation \to Phototropism

Feedback Regulation of Hormones

Level high \to Gland stops secretion; Level low \to Gland secretes

Solved Examples

1Solved Exampleeasy4 steps

State any three differences between the nervous and hormonal systems of control.

Signal type

Nervous: electrical; Hormonal: chemical

2Solved Exampleboard4 steps

Explain reflex arc with a labelled diagram. Give one example.

Definition — an automatic response to a stimulus not involving conscious brain

Reflex action

3Solved ExampleHOTS5 steps

A patient has excessive urination and constant thirst. Which hormone deficiency is likely and from which gland? Suggest treatment.

Symptoms — polyuria (excess urine) and polydipsia (excess thirst)

Polyuria + polydipsia

Traps & Common Mistakes

Common Mistakes6

1
Confusing reflex action with voluntary action
✓Reflex is automatic, spinal-cord mediated. Voluntary involves conscious brain (moving hand deliberately).
2
Saying pituitary secretes only growth hormone
✓Pituitary is 'master gland' — secretes GH, TSH, FSH, LH, ADH, oxytocin and prolactin among others.
3
Placing sensory neurons in the motor pathway
✓Sensory neuron: receptor → CNS. Motor neuron: CNS → effector. Direction matters.
4
Assuming plants have a nervous system
✓Plants respond to stimuli using hormones (chemical signals) — no nerves. Growth movements are tropisms.
5
Confusing endocrine and exocrine glands
✓Endocrine: ductless, release hormones into blood. Exocrine: have ducts, release into cavities (sweat, sebum, saliva).
6
Insulin and glucagon both raise blood sugar
✓Insulin LOWERS blood sugar (from pancreas β-cells). Glucagon RAISES it (from α-cells).

Practice Yourself

Practice Yourself6 questions

Q1
State the function of cerebrum and cerebellum.
Q2
Name the hormones secreted by the thyroid gland and their function.
Q3
Give two examples of plant tropisms.
Q4
State one function each of insulin and adrenaline.
Q5
Which structure connects two neurons?
Q6
Name the hormone that helps in ripening of fruits.

Notes

Control and Coordination — Maharashtra SSC

Chapter 3 of Science Part 2. Living organisms coordinate their internal environment and responses to external stimuli through two systems: nervous (fast) and hormonal (slow but sustained).

Nervous system architecture

Central nervous system (CNS): brain + spinal cord.
Peripheral nervous system (PNS): cranial nerves + spinal nerves.
Autonomic nervous system: sympathetic (fight/flight) + parasympathetic (rest/digest).

The neuron — the basic unit

Dendrites: receive signals.
Cell body (soma): processes information.
Axon: transmits impulse.
Myelin sheath: insulates axon, speeds transmission.
Synapse: gap where neurotransmitter is released to the next neuron.

Reflex arc — the fast reaction

Stimulus → receptor → sensory neuron → spinal cord (relay neuron) → motor neuron → effector → response.

Purpose: instant, life-saving reaction without waiting for brain processing.

Endocrine glands — SSC-favourite table

Gland	Hormone	Function
Pituitary	GH, TSH, FSH, LH	Master gland; growth, other glands
Thyroid	Thyroxine	Metabolism
Parathyroid	PTH	Calcium homeostasis
Adrenal	Adrenaline, cortisol	Fight or flight, stress
Pancreas	Insulin, glucagon	Blood sugar
Ovary	Estrogen, progesterone	Female sex characters
Testis	Testosterone	Male sex characters

Plant hormones — five to remember

Hormone	Function
Auxin	Cell elongation, phototropism
Gibberellin	Stem elongation, seed germination
Cytokinin	Cell division, delay ageing
Abscisic acid (ABA)	Stress response, seed dormancy
Ethylene	Fruit ripening

Tropisms — plant movements

Phototropism: response to light.
Geotropism (gravitropism): response to gravity.
Hydrotropism: response to water.
Thigmotropism: response to touch (climbers).
Chemotropism: response to chemicals (pollen tube).

Board vs CBSE

Both boards teach identical material. Maharashtra SSC gives more marks to labelled diagrams (neuron, brain, endocrine chart) — practise clear diagrams.