Unit 3 Bio Peripheral Nervous System

How many pairs of spinal nerves do we have?

31 pairs of spinal nerves

Where do they 31 pairs of spinal nerves originate from in the brain?

nerves that originate in the brain are cranial nerves but spinal nerves originate in the spinal cord

1-Olfactory

sensory; innervation of smell

2-Optic

sensory; sensory for vision

3- Oculomotor

motor; move eyeball and constricts pupil

4-Trochlear

motor; move eyeball

5-Trigeminal

both motor and sensory; sensory to face and motor to mastication

6-Abducens

motor; moves eyeballs

7-Facial

both motor and sensory; facial expressions, tears, salvation, taste

8-Vestibulocohlear

sensory; sensory for hearing and balance

9-Glossopharyngeal

both motor and sensory; pharynx, salvation, taste

10-Vagus

both motor and sensory; internal organs in thoracic and abdominal cavities

11-Accessory

motor; neck and back muscles

12- Hypoglossal

motor; tongue muscles

State the function of each of the following nerves and which plexus they arise from: Phrenic Nerve, Median Nerve, Sciatic Nerve, and Femoral Nerve

• Phrenic: innervates the primary muscle of respiration called the diaphragm; cervical plexus

• Median: innervates the muscles within the anterior forearm and is the nerve that can cause issues with carpal tunnel syndrome; brachial plexus

• Sciatic: largest nerve in the body and will provide innervation to all posterior thigh muscles; sacral plexus

• Femoral: innervates muscles of the anterior thigh; lumbar plexus

List the 5 components of the reflex arc and their actions.

• Sensory receptor: detects the stimulus

• Sensory neuron: sends signal toward the CNS

• CNS: intergation will begin that links the sensory and motor neurons

• Motor neuron: takes the information away from the CNS to the effector organ

• Effector organ: can be a gland or a muscle that responds by contracting or secreting

Give an example of a somatic reflex and state the effector used.

the doctor strikes your patellar ligament the quadricep muscle is stretched. the nervous system commands the quadriceps to contract, causing your lower leg to kick out

Give and example of an autonomic reflex and state the effector.

the rapid adjustment of heart rate and blood vessel constriction to keep your blood pressure steady, especially when suddenly standing up