All MCQs

Mechanoreceptors detect mechanical forces such as pressure, touch, vibration, stretch, or sound. They convert mechanical stimuli into nerve impulses.

In a withdrawal reflex, receptors detect heat or pain, neurons carry signals, and skeletal muscles act as effectors to move the limb away.

Chemical synapses depend on neurotransmitter release from the presynaptic neuron. Without release, the next neuron or effector receives little or no signal.

Nerve impulses travel rapidly along specific pathways and act on targeted cells. Endocrine signals are often slower and distributed through blood or body fluids.

Reflex arcs can process information through the spinal cord or local neural circuits, producing rapid protective responses before conscious perception.

Myelin forms an insulating sheath around many axons and allows faster saltatory conduction. Damage to myelin slows or disrupts nerve signaling.

The axon carries nerve impulses away from the neuron cell body. Dendrites mainly receive signals, while synapses allow communication with other cells.

Comparative anatomy links structure with function. Skeletons differ because animals face different demands such as swimming, jumping, flying, burrowing, or protection.

Chitin is a tough polysaccharide found in arthropod exoskeletons and fungal walls. Bone is living connective tissue mineralized with calcium salts.

Earthworms use segmental muscles and coelomic fluid to extend, anchor, and pull the body through soil. This is hydrostatic locomotion.

Synovial fluid and smooth cartilage reduce friction in many vertebrate joints. Loss of lubrication increases wear and pain during movement.

Muscles generate force by contracting and pulling. Opposite movements commonly require antagonistic muscle pairs arranged around joints.