Explanation

(a) Hormones - These are chemical substances secreted by endocrine/ductless glands, directly into the blood/ circulatory system, which on reaching a target organ, stimulate activity of that organ.

(c)(i) Effects of over-secretion: -

1. Over active/Hyperactive/Irritable/nervous.
2. Excessive growth/gigantism
3. Loss of weight
4. Enlarged thyroid gland/exothalmic goitre
5. Accelerated/increased heartbeat
6. Protrusion/bulging out of eyeball.

(ii) Effects of under-secretion: -

1. Cretinism/dwarfism in children.
2. Overweight/increase in subcutaneous fat/obesity.
3. Physical/mental sluggishness in adults.
4. Reduced heart rate.
5. Lowered/reduced metabolic rate/ myxceodema.
6. Goitre formation/hyperplastic goiter.

(d) Labels: Receptor organ, sensory neurone, intermediate/relay neurone; motor neurone, synapse, spinal cord, ventral root, dorsal root, effector organ, spinal nerve. 
 

• What is the quadrant when x-4 is divided by x²+3x-8? Answer this

  1 Answers   ·   Mathematics   ·   1 hour ago
• how to write a semi formal letter? Answer this

  1 Answers   ·   English Language   ·   6 hours ago
• What is the probability that pupil ohosen at random will pass the rest if the pass mark is :? Answer this

  1 Answers   ·   Mathematics   ·   6 hours ago