Anatomy FoM 4 Flashcards
Constituents of peripheral nervous system
Cranial nerves and spinal nerves
What is sensory information?
Information received by the CNS from external/internal environments of body
What is motor information?
Information transmit from CNS to skeletal muscle by SNS
to cardiac, smooth muscles by ANS
2 types of neuron
Afferent, efferent
What is afferent neuron?
carry sensory information to CNS
What is efferent neuron?
carry motor information from CNS
What is nerve plexus?
Network of nerve fibres that allow multiple nerve fibres to be distributed in a single peripheral nerve
What is ganglion?
Collection of neuronal cell bodies outside CNS
Where does spinal cord starts and ends?
Lower border of foramen magnum
Intervertebral disc between L1,L2
Which part does spinal cord continuous with?
Medulla oblongata
Conus medullaris
Spinal cord consisted of?
Grey matter, white matter, central canal
What causes white colour of white matter?
Myelinated axons within nerve fibres
Why does vertebral column longer than spinal cord?
During embryonic development, vertebral column grows more rapidly than the spinal cord
Where does lumbar, sacral and coccygeal spinal cord crowded at?
T11-L2
Relationship between vertebral spine and spinal cord segments
Cervical: 1 lower
Upper thoracic : 2 lower
Lower thoracic : 3 lower
What is nerve fibre consisted of?
Axon, Schwann cells, myelin sheath
Two bundles of axons of spinal nerve
Ventral root, dorsal root
Role of dorsal roots&rootlets
Transmit sensory information to spinal cord
Role of ventral roots&rootlets
Transmit motor information from spinal cord
Where does pseudo unipolar sensory neurons located?
Dorsal root ganglia
What is dense irregular CT that surround group of fascicles?
Epineurium
What is sheath of specialised cells that surround each fascicle?
Perineurium
What is loose CT that surround each individual nerve fibres and blood vessels?
Endoneurium
How many spinal nerve pairs there are?
31
Where does multipolar motor neurone located?
Ventral horn
Where do spinal nerves emerge from?
Intervertebral foramen
Characteristics of dorsal and ventral rami
Branches of spinal nerve, which contains both sensory and motor fibres
Which segments do spinal nerves emerge from intervertebral foramen above?
C1-C7
Which segments do spinal nerves emerge from intervertebral foramen below?
C8, thoracic, lumbar, sacral
What posterior muscle and its overlying skin does dorsal rami innervate?
Erector spinae
In what types of nerve do ventral ramus form?
Intercostal nerve
Intercostal nerve’s lateral cutaneous&anterior cutaneous branch
Where does intercostal nerves innervate?
Intercostal muscles
Skin (by cutaneous branch)
Abdominal wall muscles and overlying skin
Size comparison of dorsal and ventral ramus
Dorsal < Ventral
What does cutaneous receptors sense?
Touch
Pressure
Pain
Temperature
Myotome
A region of skeletal muscle innervated by a single spinal nerve/spinal segment
What are the basic components of somatic reflex arc?
Sensory receptor
Sensory neuron
Motor neuron
Skeletal muscle fibre
Where does somatic plexus supply?
Skin, voluntary skeletal muscle, joints from ventral rami
What type of somatic plexuses present?
Cervical
Brachial
Lumbar
Sacral
Where does cervical plexus supply and which spinal nerves?
Skin and muscles of head, neck, shoulder
C1-C4
Where does brachial plexus supply and which spinal nerves?
Axillary (Shoulder region)
Musculocutaneous (BBC)
Radial (posterior arm, forearm, hand)
Ulnar (anterior forearm, hand)
Median (anterior forearm, hand)
C5-T1
Lumbar plexus
L1-L4
Which nerve supplies anterior aspect and which nerve supplies medial aspect of thigh?
Anterior - femoral
Medial - obturator
What is segmental root value of femoral and obturator nerves?
L2-L4
Sacral plexus
L4,L5,S1-S4
Which nerve supplies posterior aspect of thigh, leg and foot?
Sciatic nerve (leaving pelvis and enter buttock)
What is segmental root value of sciatic nerve?
L4-S3
Why is radial nerve named ‘radial’?
It goes through radial groove at posterior aspect of humerus
Supply arm extensor
At which weeks of pregnancy does limb develops?
4th-8th
At which trilaminar disc does skin and skeletomuscular system develop?
Skin - ectoderm
Skeletomuscular - mesoderm
What happens at week 4 of embryonic development?
Form apical ectodermal ridge
Limb grows in proximo-distal growth
AER promotes cell proliferation in mesenchyme (cells to form cartilage, muscle)
What happens at week 6 of embryonic development?
Distal parts of limb buds form hand plates and footplates
Digits form by apoptosis
What does complete absence and partial absence of limb called?
Complete - Amelia
Partial - meromelia
What is toxins/drugs which may disrupt molecular signalling within the limb bud?
Teratogens
(e.g. thalidomide)
In which direction does upper and lower limb rotate?
Upper limb - laterally
Lower limb - medially
Where is cerebrospinal fluid?
In subarachnoid space
At which level lumbar puncture occurs?
L3-L4
How many cranial nerves?
12 pairs (I-XII)
What is one exception of cranial nerve that innervates structures in thorax and abdomen?
Vagus nerve (X)
What is cauda equina consisted of?
Nerve roots
What muscle innervated by femoral nerve?
Quadriceps femoris
Rectus femoris
Iliacus
What muscle innervated by sciatic nerve?
Hamstring
