1. Nervous vs Hormonal Control:
Nervous: Fast (milliseconds), short-lived effect, uses electrical impulses via neurons, localized
response.
Hormonal: Slow (seconds to hours), long-lasting effect, uses chemical messengers (hormones) via blood,
widespread response.
2. Voluntary vs Involuntary Actions:
Voluntary: Controlled by brain (cerebrum), done consciously (e.g., writing, walking).
Involuntary: Not under conscious control, controlled by medulla or spinal cord (e.g., heartbeat, digestion).
3. Reflex Action vs Walking:
Reflex: Immediate, involuntary, controlled by spinal cord, doesn't require thinking.
Walking: Voluntary, controlled by cerebrum, requires thought and coordination from cerebellum.
4. How does Phototropism work? Auxin accumulates on the
shaded side of the shoot. This side grows faster, causing the shoot to bend towards light (positive
phototropism).
5. Why do roots grow downwards? Positive geotropism. Roots
grow towards gravity. Auxin on lower side inhibits growth there, making upper side grow faster and bend
downwards.
6. Thigmotropism example: Tendrils of pea plants wrap around
support. Contact stimulus causes differential growth, making tendril coil around the support.
7. Diabetes: Caused by deficiency of Insulin from pancreas.
Blood glucose level rises (hyperglycemia). Treatment: Insulin injections.
8. Goitre: Caused by deficiency of Iodine (required for
Thyroxine). Thyroid gland enlarges. Prevention: Use of iodized salt.
9. Dwarfism vs Gigantism:
Dwarfism: Deficiency of Growth Hormone in childhood → Short stature.
Gigantism: Excess of Growth Hormone in childhood → Abnormally tall stature.
10. Adrenaline (Fight or Flight): Released during
stress/danger. Effects: Increased heart rate, dilated pupils, more blood to muscles, increased breathing.
Prepares body for emergency action.
11. Brain Diagram Labels: Cerebrum (thinking), Cerebellum
(balance), Medulla (involuntary actions), Pons (connects brain parts), Hypothalamus (links to endocrine).
12. Reflex Arc Diagram: Stimulus → Receptor → Sensory neuron
→ Spinal cord → Motor neuron → Effector → Response.
