Page 145 - Biology_Form_3

Biology for Secondary Schools

Hyperthyroidism Disorder caused by excessive production of
thyroid hormones, often due to Graves’ disease,
resulting in weight loss, rapid heartbeat, and
nervousness

Hypoglycaemia Abnormal low level of glucose in the blood.
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Hypothalamus Brain structure that links the nervous system to
the endocrine system by regulating the pituitary
gland’s hormone secretion
Hypothyroidism A condition where the thyroid gland produces
insufficient thyroid hormones, leading to
symptoms like fatigue, weight gain, and slowed
metabolism

Impulse Signal that travels along the length of the nerve
fibre
Incus (anvil) One of the three ear ossicles
Inner ear Inner part of the ear beyond the middle ear.
Insulin Hormone produced by the pancreas that lowers
blood sugar levels by facilitating glucose
uptake into cells
Intercalated discs Permeable membrane foldings joining the cells
of cardiac muscle
Interneurones Nerve cells that connect sensory and motor
neurones for signal processing
Iris Part of the eye that surrounds the pupil

Kidney stone Small, hard mass in the kidney that chiefly
forms from deposits of phosphates and urates

Lens Structure in the eye that focuses light coming
through it

Loop of henle U-shaped part of a kidney tubule
Meninges Three layers of membranes covering the brain
Midbrain Middle part of the brain

Motor neurone Neurone that conducts nerve impulses away
from the brain or spinal cord to an effector
organ

Nephrone One of the numerous filtering units of the
kidney that remove wastes from the blood

138 Student’s Book - Form Three

23/10/2025 11:52:50
BIOLOGY FORM 3 FINAL EDITED 16.09.2025.indd 138
BIOLOGY FORM 3 FINAL EDITED 16.09.2025.indd 138 23/10/2025 11:52:50 KAMISHNA

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