PNS Human A&P

What does the PNS include?

Sensory receptors, sensory fibers, and motor fibers.

What is a ganglion?

a cluster of nerve cell bodies outside the CNS.

What is the function of sensory receptors?

respond to environmental stimuli, causing graded potentials that lead to nerve impulses.

How are sensory receptors classified?

By stimulus type, body location, and receptor structure

What are mechanoreceptors?

respond to touch, pressure, vibration, and stretch.

What are thermoreceptors?

sensitive to changes in temperature.

What are photoreceptors?

respond to light energy

What are chemoreceptors?

respond to chemicals

What are nociceptors?

detect pain-causing stimuli like extreme temperature, pressure, or chemicals.

What is the difference between exteroceptors, interoceptors, and proprioceptors?

Exteroceptors respond to stimuli from outside the body, interoceptors respond to internal stimuli and proprioceptors detect stretch in muscles and joints.

What is the role of simple receptors?

Simple receptors are modified dendritic endings of sensory neurons that monitor general sensory information like touch, pain, temperature, and muscle sense.

What are special sense receptors?

Receptors for vision, hearing, equilibrium, smell, and taste, housed in complex sense organs.

What is the difference between sensation and perception?

Sensation is the awareness of stimuli, while perception is the interpretation of those stimuli in the brain.

What are the levels of neural integration in sensory systems?

Receptor level, circuit level and perceptual level.

What is referred pain?

when pain from one body region is perceived as coming from another region, due to shared nerve pathways.

What is the function of mixed nerves?

carry both sensory and motor fibers, allowing impulses to travel both to and from the CNS.

What are the types of spinal nerves?

Sensory nerves carry impulses toward the CNS, and motor nerves carry impulses away from the CNS.

What is a ganglion?

a cluster of neuron cell bodies outside the CNS.

How are spinal nerves classified?

cervical, thoracic, lumbar, sacral, and coccygeal

How do spinal nerves exit the vertebral canal?

exit through the intervertebral foramen, except for C1-C7, which exit above their corresponding vertebra.

What is the difference between roots and rami?

Roots are purely sensory or motor, while rami are mixed, carrying both sensory and motor fibers.

What are nerve plexuses?

networks of nerves that contain fibers from multiple spinal nerves, allowing muscles to receive input from more than one spinal nerve.

What is the function of the phrenic nerve?

controls the diaphragm, a major muscle for breathing, and receives fibers from C3-C5

What does the brachial plexus serve?

innervates the upper limb, formed by C5-T1.

What is the function of the femoral nerve?

innervates the anterior thigh muscles.

What is the function of the sciatic nerve?

innervates the lower limb

What is a dermatome?

a specific area of the skin that receives sensory input from a single spinal nerve.

What are the properties of reflexes?

involuntary, fast, stereotyped responses to stimuli. They require stimulation, are quick, involuntary, and occur in a predictable way.What are the two types of reflexes?

What are the two types of reflexes?

Inborn (intrinsic) reflexes are unlearned, while learned (acquired) reflexes result from practice, like driving a car.

What are somatic reflexes?

activate skeletal muscles and are often tested to assess nervous system function.

What is the patellar tendon reflex?

a type of stretch reflex where tapping the patellar ligament causes the quadriceps to contract.

What is the role of tendon organs in reflexes?

prevent muscle damage by triggering a reflex to relax the muscle if tension is too high.

What is the difference between somatic and autonomic reflexes?

Somatic reflexes activate skeletal muscles, while autonomic reflexes activate smooth or cardiac muscle and glands.