thoracic regional anatomy

Question 1

functional divisions of CNS

Answer 1

somatic (skin and skeletal muscles), autonomic (organs, smooth muscle, glands)

Question 2

somatic spinal nerves: where do motor go

Answer 2

only to skeletal muscle - cannot function without them

Question 3

somatic spinal nerves: where do sensory go

Answer 3

body wall, not viscera

Question 4

somatic spinal nerves: what might segmental nerves combine to form

Answer 4

plexi, supplying specialised areas (cervical, brachial, lumbosacral)

Question 5

structure of plexi

Answer 5

ventral (efferent), dorsal horn, grey, white matter, ramus (division of mixed spinal cord of back and everything else) vs root (not mixed)

Question 6

diagram of plexi

Answer 6

diagram from slide 24

Question 7

define dermatome

Answer 7

area of skin supplied by single spinal nerve on one side or from single spinal cord level (not vertebral levels) (segmented); T4 is nipple

Question 8

define myotome

Answer 8

part of skeletal muscle supplied by single spinal nerve on one side or from single spinal cord level

Question 9

spinal/segmental nerves

Answer 9

anterior primary rami

Question 10

lateral cutaneous branch

Answer 10

anterior and posterior

Question 11

anterior cutaneous branch

Answer 11

medial and lateral

Question 12

what to motor autonomic nerves innovate

Answer 12

cardiac muscle, smooth muscle, glands

Question 13

what do sensory autonomic nerves innovate

Answer 13

visceral organs

Question 14

what 2 divisions are autonomic nerves divided into

Answer 14

sympathetic (T1 to L2) and parasympathetic (cranial nerves 3, 7, 9, 10 and S2 to S4)

Question 15

sympathetic outflow from spinal cord

Answer 15

emerge from spinal cord at sympathetic ganglia; follow somatic nerves to periphery; oesophagus plexus (heart) and prevertebral plexus (abdominal and pelvic viscera)

Question 16

what sections of neurone do all autonomic motor pathways involve

Answer 16

preganglionic and postganglionic neurones; intermediolateral horn present T1 to L2 as sympathetic cell bodies present there

Question 17

where do pathways to body wall synapse

Answer 17

in ganglia of sympathetic trunk; can go up or down before synapsing depending where going to; postganglionic neurones to heart not in chain

Question 18

where do pathways to viscera synapse

Answer 18

in unpaired ganglia

Question 19

what does the trunk do

Answer 19

takes fibres up or down; rami (grey-unmyelinated, white-myelinated); won’t synapse will synapse outside of chain in heart; to brain synapse in chain but not same level

Question 20

function of sympathetic trunks (T1 to L2)

Answer 20

distribute sympathetic nerves to smooth muscle and glands, body wall synapse in ganglia of trunks, viscera synapse in unpaired ganglia, bring pain fibres back to CNS from viscera

Question 21

significance of fibres from lower T5-T12

Answer 21

reach abdomen in bundles called splanchnic nerves

Question 22

5 sets of nerves containing parasympathetic fibres

Answer 22

oculomotor (III) cranial nerves, facial (VII) cranial nerves, glossopharyngeal (IX) cranial nerves (all head and neck), vagus (X) cranial nerves (most important as supplies viscera of thorax and most of abdomen), sacral (S2-S4) spinal nerves

Question 23

sympathetic nerves to lungs and heart

Answer 23

mainly from T2-T4, passing through cervical and upper thoracic ganglia or sympathetic trunk

Question 24

where are many of the synapses of sympathetic nerves to lungs and heart

Answer 24

in micro-ganglia in pulmonary and cardiac plexuses rather than in trunk ganglia

Question 25

where are splanchnic nerves located

Answer 25

posterior mediastinum

Question 26

greater splanchnic nerve

Answer 26

T5-T9

Question 27

lesser splanchnic nerve

Answer 27

T10-T11

Question 28

least splanchnic nerve

Answer 28

T12

Question 29

define referred pain

Answer 29

pain felt in a part of the body other than its actual source

Question 30

why does referred pain occur

Answer 30

nerves from various parts of the body converge on their way to the spinal cord; e.g. sensory nerves from heart flow into same part of spine that gathers nerve impulses from shoulder

Question 31

pulmonary plexuses

Answer 31

left vagus nerve, right vagus nerve, anterior pulmonary plexus, posterior pulmonary plexus

Question 32

effect on bronchioles of sympathetic nerves

Answer 32

dilate

Question 33

effect on bronchioles of parasympathetic (vagus) nerves

Answer 33

constrict

Question 34

cardiac plexuses

Answer 34

superficial cardiac plexus, deep cardiac plexus

Question 35

effect of sympathetic efferents on heart rate and force of contraction

Answer 35

increase heart rate and force of contraction

Question 36

effect of parasympathetic efferents (vagus) on heart rate and diameter of coronary arteries

Answer 36

decrease heart rate via pacemaker tissue and constrict coronary arteries

Question 37

what do sympathetic afferents relay

Answer 37

pain sensations from heart

Question 38

nerves in inferior mediastinum

Answer 38

sympathetic trunks (each side of posterior mediastinum)

Question 39

sympathetic trunks - none for preaortic ganglia which serve heart

Answer 39

receive branches from spinal nerves T1 - L2; distribute sympathetic nerves to smooth muscle and glands throughout body; nerves to body wall synapse in ganglia of trunks; nerves to internal organs (viscera) synapse in local ganglia; also bring pain fibres back to CNS from viscera; fibres from lower T5 - T12 reach abdomen in bundles called splanchnic nerves

Question 40

stellate ganglion

Answer 40

trunk associated with T1 spinal cord segment