Ch 19Neural Control and Coordination — Class 11 Biology, concept-first.

The neuron (nerve cell) is the structural and functional unit of the nervous system. Each neuron is a highly specialised cell built to receive, integrate and transmit information in the form of electr…

A resting (non-conducting) neuron maintains a difference in electrical charge across its plasma membrane, called the resting membrane potential, with the inside of the membrane about 70 millivolts mor…

Generating an action potential at one point of the axon is only the first step; the impulse must then travel (be conducted) along the full length of the axon until it reaches the axon terminals.

A synapse is the specialised junction across which an impulse in one neuron (the presynaptic neuron) influences a second neuron or an effector cell (the postsynaptic cell).

The human nervous system as a whole is organised into two principal divisions that work together. The central nervous system (CNS) comprises the brain and the spinal cord, enclosed and protected withi…

The forebrain is the largest, most anterior and most highly developed part of the human brain, and it comprises the cerebrum together with the thalamus, the hypothalamus and the limbic system.

Below the forebrain lie the midbrain and the hindbrain, structures that are older in evolutionary terms and control many of the body's essential, largely automatic functions.

The spinal cord is a long, cylindrical part of the central nervous system enclosed within the vertebral column, running as a direct downward continuation of the medulla oblongata from the base of the…

The peripheral nervous system (PNS) is made up of all the nerve fibres, nerve trunks and ganglia (clusters of neuron cell bodies) that lie outside the brain and spinal cord, and its job is to connect…

The autonomic nervous system (ANS) is the involuntary, largely self-regulating division of the peripheral nervous system that controls the activity of the internal organs — smooth muscle in the walls…

A reflex action is a rapid, automatic, involuntary and highly stereotyped response of the body to a particular stimulus.

The eye is the principal sense organ of vision, and its wall is built of three concentric layers surrounding an internal system of a lens and fluid-filled chambers that together focus light onto a lig…

The ear is the sense organ responsible for two quite distinct senses — hearing (detecting sound) and equilibrium/balance (detecting the position and movement of the head) — and it is structurally divi…

Parkinson's disease and Alzheimer's disease are both progressive (worsening over time), currently incurable disorders of the nervous system that become considerably more common with advancing age, but…

This chapter has traced how the human nervous system detects, processes and responds to information. The neuron, in its various forms (multipolar, bipolar and unipolar), is the basic signalling unit;…