Human Body Functions

Where this fits in the syllabus

Grade 11 · Term 3

Key points to revise

Revise Human Body Functions fast with concise, exam-ready key points

About O/L Science: O/L Science integrates physics, chemistry, and biology into a single subject across Grade 10 and 11.

• Skeletal system: support, protection, movement, blood cell production, mineral storage
• Muscular system: voluntary (skeletal) vs involuntary (smooth/cardiac); antagonistic pairs
• Excretion: kidneys (urea, water, salts via urine); lungs (CO₂); skin (sweat)
• Endocrine vs nervous: hormones = slow, widespread, long-lasting; nerves = fast, specific

Must know

• Liver: deaminates amino acids → ammonia → urea (ornithine cycle)
• Reflex arc: stimulus → receptor → sensory neuron → relay neuron → motor neuron → effector
• Antagonistic muscles: bicep contracts → arm bends; tricep relaxes (and vice versa)
• Joints: ball-and-socket (hip, shoulder — all directions); hinge (knee, elbow — one plane)

Source: NIE O/L Science Grade 11 — Unit 9: Human Biology

Study these first

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In the Syllabus