Organisation of nerves in thorax Flashcards Preview

LSS 1 - Thorax anatomy, Respiratory and Circulatory system > Organisation of nerves in thorax > Flashcards

Flashcards in Organisation of nerves in thorax Deck (80)
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1
Q

Where do somatic nerves innervate?

A

Skin and skeletal muscles

2
Q

Where do autonomic/visceral nerves innervate?

A

Organs, smooth muscle

3
Q

What are the functions of somatic spinal nerves?

A

Motor - skeletal muscle only

Sensory to body wall NOT viscera

4
Q

What do segmental nerves combine to?

A

Plexi - supply specialised areas

5
Q

What type of innervation enters the posterior dorsal horn?

A

Sensory

6
Q

What type of innervation leaves the ventral horn?

A

Motor - to muscles

7
Q

What is the difference between the posterior root and ramus?

A

Root: Sensory nerves
Ramus: Post. has sensory and motor nerves and Ant. has all others (skin/muscle)

8
Q

What is a dermatome?

A

Area of skin which is supplied by a single spinal nerve on one side/from a single spinal cord

9
Q

What is a myotome?

A

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

10
Q

What are spinal levels?

A

The levels on innervation which the spinal nerves innervate

11
Q

What spinal levels innervate the arm?

A

C5-8 and T1

12
Q

Why is T1 spinal level relevant?

A

Cardiac referred pain

13
Q

Why is T3 spinal level relevant?

A

3rd and 4th intercostal space

14
Q

Why is T4 spinal level relavant?

A

Nipple line, 4-5th interspace

15
Q

Why T6 spinal level relevant?

A

Xiphoid process

16
Q

Why is T10 spinal level relevant?

A

Navel

17
Q

Why is T12 spinal level relevant?

A

Pubis

18
Q

Where do IC nerves originate?

A

Only from spinal cord - so can be spinal or segmental - anterior 1ry rami

19
Q

Where are IC nerves present in the thorax?

A

Under the ridge of the ribs, between the innermost and internal layers

20
Q

How many IC nerves do we have?

A

11 pairs and 1 subcostal

21
Q

What kind of innervation do the IC muscles carry?

A

Both motor and sensory

22
Q

Where does the lateral cutaneous branch of IC nerves supply?

A

The anterior and posterior IC spaces, supplies skin

23
Q

Where does the anterior cutaneous branch of IC nerves supply?

A

The lateral and medial IC spaces, including skin outside of chest wall

24
Q

What nerves supply the IC muscles?

A

The IC nerves from the anterior ramus

25
Q

At which level does the IVC cross the diaphragm?

A

T8

26
Q

What does the phrenic nerve motor fibres supply?

A

Skeletal muscle of the diaphragm

27
Q

Where are the phrenic nerves derived from?

A

Anterior Rami of C3-5

28
Q

What kind of nerves are the phrenics?

A

Somatic so no autonomical function or visceral distribution

29
Q

What do the sensory fibres of the phrenic supply?

A

Central diaphragm, pleural covering, mediastinal pleura and pericardium (peritoneum on inf surface of diaphragm)

30
Q

Where do sympathetic nerves have cell bodies?

A

Thoraco-lumbar cord

31
Q

How do the symp nerves reach their destination?

A

Travel with vessels

32
Q

Where do the autonomic motor nerves innervate?

A

Cardiac muscle, smooth muscle and glands

33
Q

Where do the autonomic sensory nerves innervate?

A

Visceral organs

34
Q

Where does the parasympathetic division originate from?

A

Brainstem CNIII, VII, IX, X and S2-4 - craniosacral

35
Q

Where does the sympathetic division originate from?

A

T1-L2

36
Q

Where do sympathetic pathways to body wall synapse?

A

In ganglia of sympathetic trunk

37
Q

Where do symp pathways to viscera synapse?

A

In unpaired ganglia

38
Q

What do the sympathetic trunks do?

A

They take fibres up or down the body

39
Q

What is the intermediate/lateral horn?

A

Place where efferent cell bodies send out signals to be relayed

40
Q

What happens when the nerve gets to the paravertebral ganglion?

A

Either synapse onto a different nerve and ride on spinal nerve (blood vessels) OR to prevertebral ganglion to synapse on viscera
OR transmitted up or down symp trunk and then synapse

41
Q

What symp nerve supplies the brain?

A

T1

42
Q

Where is there not a lateral horn?

A

Outside T1, superior to T1 and inferior L2

43
Q

Where do the symp trunks receive branches from?

A

T1-L2

44
Q

What is the role of the symp trunks?

A

Distribute symp nerves to smooth muscle, glands throughout the body

45
Q

What does the symp trunk bring back to CNS from viscera?

A

Pain fibres

46
Q

What are spanchnic nerves?

A

Bundle of fibres from lower than T5-12 that reach the abdomen

47
Q

What are the important parasymp nerves?

A

Vagus (CNX) which supplies viscera of thorax and abdomen

48
Q

What is the path of the vagus?

A

Emerges through jugular foramina to thorax, through diaphragm and to supply the abdomen

49
Q

Where is the biggest outflow of symp system?

A

T1 - efferents can make way up to head or to heart and pulmonary plexi

50
Q

What are the names of the presymp ganglia to the heart and lungs?

A

Superior, middle and inferior ganglia

51
Q

Where are many of the synapses located for the symp nerves to heart and lungs?

A

Micro-ganglia in pulm and cardiac plexi rather than trunk ganglia

52
Q

What are the functions of symp and parasymp nerves in pulm plexus?

A

Symp: dilate bronchioles

Parasymp (Vagus) constricts bronchioles

53
Q

What are the functions of symp and parasymp nerves in cardiac plexus to do with the heart (efferents)?

A

Symp: ^ HR and force of contraction
Parasymp: decrease HR via pacemaker tissue and constrict coronary arteries

54
Q

What are the enlargements present on the plexus?

A

Where post-ganglionic nerves are located

55
Q

Where is the vagus nerve located?

A

Anterior to aortic arch

56
Q

What is the path of the left recurrent laryngeal nerve?

A

Comes down and wraps around aorta and then moves back up again to larynx

57
Q

What is the path of the right recurrent laryngeal nerve?

A

Comes down and wraps around right subclavian artery

58
Q

How many branches does the vagus nerve have?

A

Left and right

59
Q

What eventually happens to the vagus nerve?

A

Forms the oesophageal plexus

60
Q

Where are the oesophageal plexus located?

A

Either anterior (left vagus) or posterior (right vagus) side of oesophagus

61
Q

What is the function of the parasymp and symp nerves in the cardiac plexus to do with relaying (afferents)?

A

Symp: Relay pain sensations from heart
Parasymp: Relay BP and chem info from heart

62
Q

Where does the deep cardiac plexus sit?

A

Between the aortic arch and trachea

63
Q

Where does the superficial cardiac plexus sit?

A

In front of the aortic arch

64
Q

What does the cardiac plexus do?

A

Distribute nerves to heart so opposing actions can occur

65
Q

Where does cardiac visceral pain relay back to?

A

Tends to relay back from heart to spinal cord T1-4

66
Q

Why is different pain felt between pericardium and heart?

A

Pericardium supplied by somatic phrenic nerves to C3-5 and cardiac pain supplied back to spinal cord to T1-4

67
Q

Where does CNX arise?

A

Medulla and leaves skull through jugular formaina

68
Q

What vessel does CNX follow from brain?

A

Common carotid artery (posterolateral)

69
Q

How does the left vagus pass by the lungs?

A

Crosses ant to aortic arch and posterior to left hilum

70
Q

How does right vagus pass by lungs?

A

Crosses posterior to right lung root

71
Q

What happens to the vagus after the oesophageal plexi?

A

Separate to form ant and post oesophageal/gastric nerves (cross diaphragm at T10)

72
Q

What is the function of the parasymp and symp nerves in the oesophageal plexus to do with relaying (afferents)?

A

Symp: Pain sensations from oesophagus
Parasymp: Senses normal physiological info from oesophagus

73
Q

What are the parasymp branches of vagus?

A

To chest and abdomen - control smooth and cardiac muscle, glands)

74
Q

What do the parasymp NOT supply?

A

Blood vessels

75
Q

What type of nerves are the recurrent laryngeal nerves?

A

NOT parasymp - Somatic (supplies most skeletal muscles of larynx)

76
Q

Where does vagus get a large sensory content?

A

From gut and lungs (enteroreceptor)

77
Q

What do the plexi receive as well as parasymp nerves?

A

Symp fibres which are distributed via these plexi into heart and lungs/abdomen

78
Q

What is the enteric NS?

A

Plexus of ganglia and axons within the oesophageal wall

79
Q

What is the function of the intrinsic nerves of the oesophagus?

A

Coordinates the activity of oesophagus and can be up/down-regulated by autonomic nerves

80
Q

Compare the positions of phrenic vs vagus

A

Phrenic is further anteriorally than the vagus

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