Anatomy 3 Flashcards

1
Q

which muscles do somatic motor nerve fibres stimulate

A

skeletal muscles

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2
Q

how many pairs of spinal nerves are there

A

31

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3
Q

what is a ganglia

A

a bundle of nerve cell bodies outside CNS

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4
Q

how do sympathetic nerve fibres reach the body

A

within splanchnic nerves: cardiopulmonary and abdominopelvic

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5
Q

how do nerve fibres reach the body wall

A
  • sympathetic within the spinal nerves - post synaptic fibres can enter any of the 31 pairs of spinal nerves
  • no parasympathetic
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6
Q

how do sympathetic nerve fibres reach the head

A

follow arteries which supply the same structures eg superior, middle and inferior cervical ganglia

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7
Q

describe the origin of the spinal nerves

A
  • posterior ramus nerve fibres supplies deep muscles of back, intervertbral joints and overlying skin
  • anterior ramus nerve fibres supply most of body - both motor and sensory
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8
Q

how do sympathetic nerve fibres get from CNS to kidneys, ureters and bladder

A
  • leave the spinal cord between T10 and L2 and enter the sympathetic chains (bilaterally)
  • leave the sympathetic chain in the abdominopelvic splanchnic nerves and synpase at the abdominal sympathetic ganglia which are located around the abdominal aorta
  • post synaptic sympathetic nerve fibres pass from the gangllia onto the surface of the arteries which are heading towards the organs they will innervate
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9
Q

what is a periarterial plexus

A

collection of nerve fibres found on the outside of arteries

  • sympathetic
  • parasympathetic
  • visceral afferent
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10
Q

which nerves are involved in the parasympathetic system

A

CN III, VII, X and IX

briefly sacral spinal nerves S2-4

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11
Q

how do parasympathetic nerve fibres get from CNS to kidneys, ureters and bladder

A
  • parasympathetic nerve fibres for kidney and ureter are carried in CNX (down to splenic flexure)
  • those innervating bladder are carried in pelvic splanchnic nerves
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12
Q

pelvic splanchnic nerves

A
  • parasympathetic fibres reach the body structures of hind gut and pelvic organs through these
  • carried in sacral spinal nerves briefly
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13
Q
A
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14
Q

which parts of the renal system are innervated by somatic motor fibres

A

those within the perineum eg the urethra (distal to pelvic floor) and its sphincter (external urethral sphincter and levator ani)

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15
Q

where is pain from the kidney itself felt

A

in the loin area - posterior aspect of flank region

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16
Q

where is pain felt from a calculus obstructing the ureter

A

radiate from loin to groin

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17
Q

where is pain from the bladder felt

A

suprapubic region - midline

18
Q

where is pain from the perineal part of the urethra felt

A

usually quite localised in the perineum

19
Q

how do visceral afferent fibres get from kidneys to CNS

A
  • visceral afferents from the kidneys run alongside sympathetic fibres back to the spinal cord and enter between T11 and L1
  • this is why pain is felt in these dermatomes
20
Q

what is the main differential diagnosis of loin pain

A

muscular pain

21
Q

how do visceral afferent fibres get from ureters to CNS

A
  • run alongside sympathetic nerve fibres and enter spinal cord between T11 and L2
  • pain felt anywhere along this path
22
Q

DD of groin pain

A

hernia

lymphadenopathy

testicular pathology

23
Q

how do visceral afferent fibres get from bladder to CNS

A
  • visceral afferents carrying pain from the superior part of the bladder which touches the peritoneum run alongside sympathetic nerve fibres back to the spinal cord. enter between T11 and L2. pain is percieved in the midline
  • visceral afferent fibres from the rest of the bladder that is not touching the peritoneum run alongside parasympathetic fibres back to spinal cord levels S2-4
24
Q

how do visceral afferent and somatic sensory fibres get from urethra to CNS

A
  • visceral afferent fibres from the proximal urethra (above levator ani and in pelvis) run alongside parasympathetic nerve firbes back to spinal cord levels S2-4
  • somatic sensory from the remaining urethra are carried within the pudendal nerve back to spinal cord levels S2-4
    • pain from this part of the urethra will present as localised pain in the perineum
25
Q

how do pain fibres get from testis to CNS

A
  • testis were embryologically located on posterior abdominal wall
  • visceral afferents run alongside sympathetic fibres back to spinal cord levels T10-L1
  • due to close relationship with scrotal wall, pain from testis can also present localised to scrotum and/or groin (L1 region)
26
Q

how is pain from the distal urethra described

A

localised and sharp pain in the perineum

27
Q

what reflex happens when the bladder fills

A

This is a primitive spinal reflex, which is overridden during toilet training

  • stretch receptors at the end of visceral afferent nerve fibres sense this
  • relay information to CNS via S2-4 (visceral afferents)
  • there is a reflex to empty the bladder by stimulation of the detrusor muscle to contract and inhibition of the internal urethral sphincter (in males) (parasympathetic)
28
Q

how is the reflex to pee overriden

A
  • the somatic motor nervous system gives us voluntary control - innervates external urethral sphincter and levator ani muscles (pudendal nerves - S2-4)
  • AP within inhibitory nerve fibres from the cortex pass inferiorly and inhibit this reflex
29
Q

describe the process of micturition

A
  • detrusor muscle contracts - parasympathetic
  • internal urethral sphincter (males - parasympathetic), external urethral sphincter and levator ani muscles relax (somatic motor - pudendal nerve)
  • anterolateral abdominal wall muscles contract to increase intra-abdominal pressure and force urine out of external urethral orifice (somatic motor nerve fibres )
30
Q
A
31
Q

sciatic nerve roots

A

L4 to S3

32
Q
A
33
Q

where does the iliohypogastric nerve innervate

A

comes from lumbar plexus - L1

34
Q

where does the ilioinguinal nerve innervate

A

comes from lumbar plexus - L 1

35
Q

which nerve arises on the anterior aspect of the psoas major

A

genitofemoral

note lat cutaenous nerve of thigh

36
Q

where does the genitofemoral nerve supply

A

L1 and L2

37
Q

which nerves arises laterally to psoas major

A

femoral - L2-4

passes under the inguinal ligament to enter the anterior compartment of the thigh

38
Q

which nerve arises medially to psoas major

A

obturator (L2-4)

goes through obturator foramen in the pelvis to enter the medial compartment of the thigh

39
Q

which compartment of the thigh is the sciatic nerve in?

A

posterior, enters through via the gluteal region

40
Q

internal urethral sphincter control

A
  • sympathetic stimulate it to contract - occurs during ejaculation
  • para stimulate to relax - allow urine to flow through urethra
41
Q
A