Human Anatomy and Physiology - Peripheral Nervous System

These flashcards cover key terms and concepts related to the peripheral nervous system, including structures, functions, types of receptors, reflexes, and clinical implications.

Peripheral Nervous System (PNS)

Consists of all neural structures outside the brain and spinal cord; links the body to the external environment.

Sensory Receptors

Specialized structures that respond to environmental changes (stimuli) and can lead to nerve impulses.

Mechanoreceptors

Sensory receptors that respond to touch, pressure, vibration, and stretch.

Thermoreceptors

Sensory receptors that detect changes in temperature.

Photoreceptors

Sensory receptors that respond to light energy, such as those found in the retina.

Chemoreceptors

Receptors that respond to chemical stimuli, including those for smell and taste.

Nociceptors

Pain receptors sensitive to harmful stimuli, such as extreme temperatures or pressure.

Exteroceptors

Receptors that respond to stimuli from outside the body, commonly found in the skin.

Interoceptors

Receptors that respond to stimuli from within the body, such as from internal organs.

Proprioceptors

Receptors that monitor the position and movement of body parts, located in muscles and joints.

Reflex Activity

An automatic response to a stimulus that involves sensory input and motor output.

Afferent Nerves

Nerves that carry sensory impulses toward the central nervous system.

Efferent Nerves

Nerves that carry motor impulses away from the central nervous system.

Regeneration of Nerve Fibers

The process by which damaged peripheral nerve axons can regenerate if the cell body remains intact.

Cranial Nerves

Twelve pairs of nerves that emerge directly from the brain, primarily responsible for sensory and motor functions in the head and neck.

Spinal Nerves

31 pairs of mixed nerves that arise from the spinal cord and innervate the body excluding the head.

Somatic Reflexes

Reflexes that activate skeletal muscles and involve conscious control.

Autonomic Reflexes

Reflexes that activate visceral effectors (smooth muscle, cardiac muscle, glands) and are not under conscious control.

Stretch Reflex

A reflex that helps maintain muscle tone and posture by causing a muscle to contract in response to being stretched.

Tendon Reflex

A polysynaptic reflex that prevents muscle damage by causing muscle relaxation in response to excessive tension.

Babinski's Sign

An abnormal reflex in response to stroking the sole of the foot in adults, indicating possible damage to the corticospinal tract.

Hilton's Law

Any nerve serving a muscle that produces movement at a joint also innervates that joint and the skin over that joint.

Dermatome

An area of skin that is mainly supplied by a single spinal nerve root.