Nerves of the Thoracic Cavity

Question 1

Afferent neurons

Answer 1

Receive and transport impulses to the CNS; sensory innervation from the skin and organs (sight, sound, taste, smell)

Question 2

Efferent neurons

Answer 2

Transport impulses away from CNS to the rest of the body; motor innervation of skeletal, smooth, cardiac mm. and glands

Question 3

Somatic neurons

Answer 3

Innervate the body wall (structures outside the body cavities); cutaneous surfaces, striated muscle, tendons, and joints

Question 4

Visceral neurons

Answer 4

Innervate the viscera (structures within the body cavities); smooth muscle and glands are considered viscera regardless of location; mucosal surfaces, walls of visceral organs, exocrine glands, vascular structures

Question 5

General neurons

Answer 5

Present in all spinal nerves

Question 6

Special neurons

Answer 6

Only present in cranial nerves, not spinal; afferent (sensory) nerves

Question 7

GSE

Answer 7

General Somatic Efferent; all skeletal muscle innervation is considered GSE

Question 8

Dorsal branches of thoracic spinal nerves

Answer 8

Provide motor innervation to epaxial mm. (GSE) via medial branch and sensory innervation from skin via cutaneous lateral branches (GSA)

Question 9

Ventral branches of thoracic spinal nerves

Answer 9

Become intercostal nn. which provide motor innervation to mm. of thoracic wall (GSE); also has lateral and ventral cutaneous brr. that carry sensory fibers from the skin of the thoracic wall (GSA)

Question 10

Phrenic n.

Answer 10

Arises from C5-C7 spinal nerves, courses ventral to hilus of the lung

Somatic innervation to the diaphragm (skeletal m.) - GSE; important to inspiration

Question 11

CNS

Answer 11

Brain and spinal cord

Question 12

PNS

Answer 12

Nerve roots, spinal nerves, cranial nerves, ganglia

Question 13

Ganglia

Answer 13

Collections of nerve cell bodies located outside of CNS; may be afferent or efferent

Question 14

Spinal n.

Answer 14

Consists of dorsal, ventral, meningeal, and communicating brr.

Question 15

Function of PNS

Answer 15

Interprets sensory information from somatic (skin, connective tissue, and skeletal m.) or viscera (thoracic, abdominal, and pelvic organs, serous membranes, blood vessels and lymphatics) and provides a motor response via motor to skeletal m. in somatic or motor to smooth/cardiac mm. and glands in visceral

Question 16

Autonomic nervous system

Answer 16

Controls involuntary reactions, maintains homeostasis, responds to stress
Divided into parasympathetic and sympathetic nervous divisions
Includes visceral motor system (smooth m., cardiac m., glands)
An (at least) 2 neuron system - 1st neuron (pre-ganglionic) is located in CNS, 2nd neuron (post-ganglionic) is located within PNS

Question 17

Sympathetic nervous system

Answer 17

Pre-ganglionic cells located in the thoracolumbar (T1-L5) region of spinal cord

Post-ganglionic cells located in cervical, thoracic, or abdominal ganglia

Pre-ganglionic fibers are typically shorter than post-ganglionic fibers

Question 18

Parasympathetic nervous system

Answer 18

Pre-ganglionic cells located in the brainstem and sacral region of spinal cord (craniosacral region)

Post-ganglionic cells located on terminal ganglia on the structures innervated

Pre-ganglionic fibers are typically longer than post-ganglionic fibers

Question 19

Vagus n. (Cranial Nerve X)

Answer 19

Arises from the brainstem (medulla oblongata) and courses caudally in the neck with sympathetic nerve fibers as part of the vagosympathetic trunk.

Provides visceral motor innervation to thoracic and abdominal organs

Question 20

Recurrent laryngeal nn.

Answer 20

Has right and left nn. arises within the thorax and courses cranially along the trachea to innervate the larynx

Question 21

Vagal branches

Answer 21

Vagus n. splits into dorsal and ventral branches in the caudal region of the heart. Will form with ventral and dorsal vagus n. branches from the other side to make the ventral and dorsal vagal trunks

Question 22

Vagal trunks

Answer 22

Unification of dorsal/ventral vagal branches to form dorsal/ventral vagal trunks. Courses with the esophagus through the diaphragm to innervate abdominal viscera

Question 23

Vagosympathetic Trunk

Answer 23

Composed of the vagus n. and the sympathetic trunk.

Vagus n. - pre-ganglionic parasympathetic fibers (GVE) fibers course caudally to innervate thoracic and abdominal organs
Provide motor functions to skeletal muscles - esophagus
Sensory (GVA) fibers course cranially to the brain from thoracic and abdominal organs

Sympathetic trunk - pre and post-ganglionic sympathetic (GVE) fibers course cranially to smooth muscle and glands in the head

Question 24

Neurotransmitters

Answer 24

Acetylcholine - used in the pre and postganglionic neurons in the sympathetic and parasympathetic nervous systems. Also used in the post-ganglionic neuron and target organ in the parasympathetic nervous system

Norepinephrine - used in post-ganglionic neuron and target organ in the sympathetic system