Human nervous system structure — A/L Biology

What must I remember about Human nervous system structure?

• The human nervous system is divided anatomically into the Central Nervous System (CNS: Brain and Spinal Cord) and the Peripheral Nervous System (PNS: 12 pairs of cranial nerves and 31 pairs of spinal nerves).
• The Brain consists of three major divisions: Forebrain (Cerebrum, Thalamus, Hypothalamus), Midbrain, and Hindbrain (Cerebellum, Pons, Medulla Oblongata); midbrain, pons, and medulla oblongata together constitute the Brainstem.
• Cerebrum is the seat of consciousness, intelligence, memory, emotion, and voluntary control, divided into left and right hemispheres connected by the Corpus Callosum.
• Cerebellum coordinates voluntary muscle movements, maintaining posture, balance, and fine motor skills; Medulla Oblongata houses vital autonomic centers for respiration, cardiovascular control, and swallowing/vomiting reflexes.
• The Autonomic Nervous System (ANS) regulates involuntary visceral functions through two antagonistic subdivisions: Sympathetic ('fight or flight', thoracolumbar outflow) and Parasympathetic ('rest and digest', craniosacral outflow).

Test yourself (1 minute)

1. Protective coverings of CNS

   Three meninges (Dura mater, Arachnoid mater, Pia mater) and Cerebrospinal Fluid (CSF) in subarachnoid space and ventricles act as shock absorber and metabolic exchange medium.

2. Spinal cord cross-section anatomy

   Butterfly-shaped inner Grey Matter (unmyelinated cell bodies, dorsal/ventral horns) surrounded by outer White Matter (myelinated ascending and descending nerve tracts).

3. Hypothalamus homeostatic hub

   Regulates body temperature, hunger, thirst, circadian rhythms, and forms the direct neuroendocrine link to the pituitary gland.

Practise Human nervous system structure questions today

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

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Year 2 · Term 1