Nervous coordination overview — A/L Biology

What must I remember about Nervous coordination overview?

• Coordination is the integration of diverse bodily activities to respond effectively to internal and external stimuli, mediated by two interrelated communication networks: the fast-acting Nervous System and the slower, long-lasting Endocrine System.
• The basic structural and functional unit of the nervous system is the Neuron, comprising cell body (soma), dendrites (receiving inputs), and an axon (transmitting electrical action potentials).
• Neurons are classified functionally into three types: Sensory (afferent) neurons carrying impulses from receptors to CNS, Interneurons (relay neurons) processing information within CNS, and Motor (efferent) neurons carrying commands to effectors (muscles/glands).
• Neuroglia (glial cells) support, insulate, and nourish neurons: Astrocytes (blood-brain barrier), Oligodendrocytes (CNS myelin sheath), Schwann cells (PNS myelin sheath), and Microglia (CNS phagocytes).
• A Reflex Arc is the fundamental neural pathway underlying involuntary, instantaneous responses: Receptor -> Sensory neuron -> Interneuron (in spinal cord/brainstem) -> Motor neuron -> Effector.

Test yourself (1 minute)

1. Nervous vs Endocrine signals

   Nervous communication uses electrochemical action potentials along axons and neurotransmitters across synapses (milliseconds, localized, transient); endocrine uses hormones via bloodstream (seconds to days, widespread, prolonged).

2. Myelination importance

   Myelin sheath formed by Schwann cells or oligodendrocytes acts as an electrical insulator, drastically speeding transmission up to 120 m/s via saltatory conduction.

3. Reflex classifications

   Monosynaptic reflex (knee jerk: sensory directly to motor, no interneuron) vs Polysynaptic reflex (withdrawal reflex: contains one or more interneurons).

Practise Nervous coordination overview questions today

Source: NIE G.C.E. (A/L) Biology Syllabus & Resource Book, Unit 5

What comes next?

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Where does Nervous coordination overview fit in the syllabus?

Year 2 · Term 1