The Peripheral Nervous System and Reflexes

A collection of flashcards covering key concepts from Chapter 13 on the Peripheral Nervous System and Reflexes.

What are the four parts that the Peripheral Nervous System (PNS) consists of?

1. Sensory Receptors and Sensations 2. Transmission Lines: Nerves and Their Structure and Repair 3. Motor Endings and Motor Activity 4. Reflex Activity

What types of stimuli do Mechanoreceptors respond to?

Touch, pressure, vibration, and stretch.

What is the role of Proprioceptors in the body?

They respond to stretch in skeletal muscles, tendons, joints, and ligaments, informing the brain of body movements.

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

Exteroceptors respond to external stimuli, interoceptors respond to internal stimuli from viscera and blood vessels, and proprioceptors respond to the position and movement of the body.

What are the components of a reflex arc?

1. Receptor 2. Sensory neuron 3. Integration center 4. Motor neuron 5. Effector

What is the function of cranial nerve I (Olfactory Nerve)?

Sensory nerves of smell.

How many pairs of spinal nerves are there in the human body?

31 pairs, which are mixed nerves.

What is the role of the Phrenic Nerve?

It innervates the diaphragm, crucial for breathing.

What are dermatomes?

Areas of skin innervated by cutaneous branches of a single spinal nerve.

What is a stretch reflex?

A reflex that maintains muscle length and coordination in response to increased muscle length.

What occurs during a tendon reflex?

It prevents damage from excessive stretch by relaxing the contracting muscle.

What is the clinical significance of testing somatic reflexes?

It assists in assessing the condition of the nervous system and can indicate degeneration or pathology.

What are the two types of spinal reflexes?

Somatic reflexes, which activate skeletal muscles, and autonomic reflexes, which activate visceral effectors.

What do nociceptors respond to?

Pain-causing stimuli such as extreme heat or cold, excessive pressure, and inflammatory chemicals.

Which cranial nerve is responsible for motor functions in facial expression?

Cranial Nerve VII (Facial Nerve).

What happens if both phrenic nerves are severed?

The diaphragm becomes paralyzed leading to respiratory arrest, requiring mechanical respiration.

What do the spinal nerves divide into shortly after exiting the foramen?

Three branches: dorsal ramus, ventral ramus, and meningeal branch.

What are the main nerves arising from the Brachial plexus?

Axillary, musculocutaneous, median, radial, and ulnar nerves.