All MCQs

Sensory organs detect stimuli, but the nervous system transmits and processes those signals to produce perception or response.

Touch receptors respond to mechanical deformation of skin. They are mechanoreceptors specialized for pressure or vibration rather than light.

Chemical senses work when molecules interact with receptor proteins. Taste usually detects dissolved chemicals, while smell detects airborne molecules that dissolve in mucus.

The lateral line is used for sensing water movement and vibration. Damage impairs orientation, schooling, prey detection, and predator avoidance.

Echolocation uses sound production and hearing. Reflected sound waves are detected by auditory mechanoreceptors and interpreted by the nervous system.

Nociceptors detect potentially damaging stimuli and generate pain signals. They protect the body by prompting avoidance of injury.

Sensory receptors are specialized for particular stimulus types. Photoreceptors respond to light because their molecules and membranes are adapted for that energy form.

Hormones often travel through blood or body fluids and can produce longer-lasting effects than brief nerve impulses. Their effects depend on target cell receptors.

Nerve signals are fast and precise, making them suitable for immediate responses such as withdrawal, escape, and coordinated movement.

Effectors are organs or cells that carry out responses, including muscles and glands. They respond to neural or hormonal commands.

Motor neurons transmit signals from the nervous system to effectors such as muscles. Damage reduces voluntary or reflex movement.

Sensory neurons carry information from receptors toward the central nervous system. Motor neurons carry commands from the CNS to muscles or glands.