1.5 - Nerves of the Thorax Flashcards

1
Q

What do somatic spinal nerves provide somatic sensory innervation to?

A

Body wall but NOT to viscera

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2
Q

Whats a dermatome?

A

An area of skin that is supplied by a single spinal nerve on one side or from a single spinal cord level

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3
Q

What is a myotome?

A

Part of a skeletal muscle that is supplied by a single spinal nerve on one side or from a single spinal cord level

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4
Q

How many intercostal nerves are there?

A

11 intercostal + 1 subcostal

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5
Q

What are the branches of the intercostal nerves?

A

There is a lateral cutaneous branch (anterior and posterior branches) and an anterior cutaneous branch (medial and lateral branches)

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6
Q

What structures do the phrenic nerves provide sensory and motor innervation to?

A

Motor = diaphragm

Sensory:

Central diaphragm

Mediastinal pleura

Pericardium

Peritoneum of central diaphragm

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7
Q

Where do sympathetic preganglionic neurones to the body wall synapse?

A

In the ganglia of the sympathetic trunk

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8
Q

Where do sympathetic preganglionic neurons to the viscera synapse?

A

In unpaired ganglia

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9
Q

The sympathetic trunk receive which spinal nerves?

A

T1-L2

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10
Q

What is the significance of sympathetic fibres in spinal nerves T5-T12?

A

These are the thoracic splanchnic nerves that carry sympathetic fibres to the abdomen.

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11
Q

What are the five sets of nerves that contain parasympathetic fibres?

A

Occulomotor (III)

Facial (VII)

Glossopharyngeal (IX)

Vagus (X)

Sacral spinal nerves (S2-S4)

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12
Q

Which spinal nerves do sympathetic fibres to the heart and lungs come from?

A

T2-T4 passing through cervical and upper thoracic ganglia

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13
Q

Where do many of these fibres synapse?

A

In ganglia of the pulmonary and cardiac plexuses rather than in the trunk ganglia

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14
Q

What effect do sympathetic and parasympathetic nerves have on bronchioles?

A

Sympathetic - Bronchodilation

Parasympathetic - Bronchoconstriction

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15
Q

What are the effect of sympathetic and parasympathetic efferents to the heart?

A

Sympathetic - increase heart rate and force of contraction (inotropic and chronotropic effect)

Parasympathetic - decrease heart rate and vasoconstrict coronary arteries

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16
Q

What are the roles of sympathetic and parasympathetic afferents from the heart?

A

Sympathetic - relay pain sensations from the heart

Parasympathetic - relay blood pressure and chemical information from the heart

17
Q

Where does the vagus nerve arise and where does it leave the skull?

A

Vagus nerves arise in the medulla and it leaves the skull via the jugular foramina

18
Q

Describe the path of descent of the vagus nerve.

A

The two vagus nerves pass postero-laterally to the common carotid arteries.

Right vagus passes posterior to the right lung root

Left vagus nerve crosses over anterior to the aortic arch and then posterior to the left main bronchus

19
Q

What are roles of sympathetic and parasympathetic efferents from the oesophageal plexus?

A

Sympathetic - relays pain sensation from the oesophagus

Parasympathetic - senses normal physiological information from the oesophagus

20
Q

Branches of the vagus provide sensory content from…?

A

Gut and Lungs

21
Q

State a feature of the left recurrent laryngeal nerve. What does it innervate?

A

Its not parasympathetic. Innervates the skeletal muscle of the larynx.

22
Q

How do the vagi in the posterior and anterior mediastinum differ?

A

In the posterior part of the oesophagus, you form the posterior oesophageal nerve which mainly takes right vagal fibres through the diaphragm to the abdominal viscera.

The left vagus provides fibres to the oesophageal plexus and then continutes as the anterior oesophageal nerve.

23
Q

What is the position of the phrenic nerve relative to the vagus nerve?

A

Vagus nerves are posterior

24
Q

What are the left and right main branches from the coronary arteries?

A
Right main branches:
Sino-atrial nodal
artery
Right marginal
artery
Posterior
descending artery
Left main branches:
Circumflex
artery
Left anterior
descending
(LAD)
25
Q

What is the difference between left and right dominant in terms of coronary arteries?

A

Right dominant (2/3) - PDA and SAN coronary arteries come off the right coronary artery

Left dominant (1/3) - PDA comes off the left circumflex artery. SAN artery comes of the left coronary

The dominant will serve the posterior wall of the left ventricle.