Human Brain and Nervous System
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Direct answer
The human neural system divides into the central nervous system — the brain within the cranium and the spinal cord within the vertebral column — and the peripheral nervous system, itself split into a somatic (voluntary) division and an autonomic (involuntary) division. The brain comprises the forebrain (cerebrum, thalamus, hypothalamus), midbrain and hindbrain (pons, cerebellum, medulla oblongata), and is wrapped in three meninges: the outer dura mater, the thin arachnoid and the inner pia mater.
What you must remember
- Cerebrum: the largest part, made of two hemispheres joined by the corpus callosum; its surface grey matter, the cerebral cortex, is the seat of intelligence, memory, voluntary movement and sensory perception, with association areas and even a speech area mapped within it.
- Hypothalamus: controls body temperature, hunger and thirst, circadian rhythms and emotional responses, and regulates the pituitary gland — the thermoregulation and hunger centre questions come from here.
- Thalamus and midbrain: the thalamus is a principal relay station for sensory and motor signalling to the cerebrum; the midbrain connects forebrain to hindbrain and its corpora quadrigemina handle visual and auditory reflexes.
- Hindbrain functions: the cerebellum maintains posture and equilibrium and coordinates voluntary movement; the medulla oblongata controls heartbeat, breathing, blood pressure, vomiting and salivation; the pons links and assists, housing the pneumotaxic respiratory centre.
- Neuron structure: dendrites receive signals, the axon conducts them, and myelination by Schwann cells with gaps called nodes of Ranvier permits fast saltatory conduction.
- Synapse: the functional junction between neurons, chemical synapses using neurotransmitters released across the synaptic cleft, electrical synapses passing current directly.
- Autonomic split: sympathetic and parasympathetic divisions generally act antagonistically on the same viscera — the basis of involuntary control of the gut, heart and glands.
Common confusion
Thalamus and hypothalamus are swapped in a hurry: the thalamus relays, the hypothalamus regulates temperature, hunger, thirst and rhythms. Medulla and cerebellum are the other pair to fix firmly — medulla for vital involuntary functions like heartbeat and breathing, cerebellum for posture, balance and coordination of movement — and note the pneumotaxic centre lies in the pons, not the medulla.
Exam-focused takeaway
NEET-UG frames this chapter as match-the-following between brain part and function, with the hypothalamus, medulla and cerebellum appearing repeatedly. Statement-based questions cover the meninges in order, the corpus callosum and saltatory conduction, while assertion-reason stems test why myelinated fibres conduct faster. Keep the somatic-versus-autonomic and sympathetic-versus-parasympathetic contrasts ready for one-liner statements.
Frequently asked questions
Which part of the brain controls body temperature and hunger?
The hypothalamus, which also governs thirst, circadian rhythms and emotional responses, and controls the pituitary gland.
What are the functions of the cerebellum?
It maintains posture and equilibrium and fine-tunes the coordination of voluntary movements.
Which is the largest part of the human brain?
The cerebrum, whose two cerebral hemispheres are connected by a tract of fibres called the corpus callosum.
Name the three cranial meninges in order.
The outer dura mater, the middle arachnoid and the inner pia mater, which lies in contact with the brain tissue.
What is saltatory conduction?
The jumping of an impulse from one node of Ranvier to the next along a myelinated axon, which greatly speeds up conduction.
What does the medulla oblongata control?
Involuntary vital functions such as heartbeat, breathing, blood pressure, vomiting and salivation.