Week 8 - Nervous System

Question 1

Label the following diagram below:

Answer 1

Ventral roots = motor

Dorsal roots = sensory

Question 2

A relative increase in sympathetic outflow to cardiac muscle would cause the heart rate to ________________________________. Conversely, a relative increase in parasympathetic outflow to cardiac muscle would cause the heart rate to ____________________________________.

Answer 2

A relative increase in sympathetic outflow to cardiac muscle would cause the heart rate to INCREASE. Conversely, a relative increase in parasympathetic outflow to cardiac muscle would cause the heart rate to DECREASE.

Question 3

Identify the following four (4) nerves in this cadaver image below:

Answer 3

VAGUS NERVE

• Right vagus nerve – runs parallel to the trachea and passes posteriorly to the superior vena cava and the right primary bronchus.
• Left vagus nerve (Fig 3) – enters the superior mediastinum between the left common carotid and the left subclavian arteries. It descends anteriorly to the aortic arch, before travelling posterior to the left bronchus.

The left recurrent laryngeal nerve arises from the left vagus nerve as it passes the aortic arch. It loops under the arch, to the left of ligamentum arteriosum, before continuing its journey to the larynx in the tracheal-oesophageal groove.

PHRENIC NERVE

From the anterior surface of the anterior scalene muscle, the phrenic nerves (roots C3, C4 and C5) enter the superior mediastinum lateral to the great vessels. They then descend anteriorly into the middle mediastinum, passing anteriorly to the hilum of the lungs.

Question 3

Identify the following four (4) nerves in this cadaver image below:

Answer 3

VAGUS NERVE

• Right vagus nerve – runs parallel to the trachea and passes posteriorly to the superior vena cava and the right primary bronchus.
• Left vagus nerve (Fig 3) – enters the superior mediastinum between the left common carotid and the left subclavian arteries. It descends anteriorly to the aortic arch, before travelling posterior to the left bronchus.

The left recurrent laryngeal nerve arises from the left vagus nerve as it passes the aortic arch. It loops under the arch, to the left of ligamentum arteriosum, before continuing its journey to the larynx in the tracheal-oesophageal groove.

PHRENIC NERVE

From the anterior surface of the anterior scalene muscle, the phrenic nerves (roots C3, C4 and C5) enter the superior mediastinum lateral to the great vessels. They then descend anteriorly into the middle mediastinum, passing anteriorly to the hilum of the lungs.

Question 4

Which neurotransmitters work on which receptors in the nervous system?

Answer 4

Question 5

Concerning the muscle layers of the thorax and abdomen, the neurovascular plane (the plane in which the nerves and their accompanying arteries and veins course around the body wall) is between which two layers? Please select the answers.

Answer 5

= The intercostal nerves and blood vessels run between the intermediate and deepest layers of muscles

Neurovascular bundles are located between the internal intercostal muscle and the innermost intercostal muscle. The neurovascular bundle has a strict order of vein-artery-nerve (VAN), from top to bottom.

Question 6

Label the roots of the brachial plexus

Answer 6