PNS Flashcards
What is a dermatome?
An area of skin that is supplied by a single spinal nerve.
What is a myotome?
Group of muscles innervated by a single spinal nerve.
What is the viscera?
Thoracic, abdomen and pelvic organs.
What do viscera afferent nerves do?
Carry information from the viscera.
Visceral efferent nerves can be split into what 2 categories?
Parasympathetic and sympathetic.
What do sympathetic efferent nerves target?
Viscera and periphery (vasculature and sweat glands).
What do parasympathetic efferent nerves target?
Only viscera.
Collection of cell bodies outside of CNS is known as?
Ganglion.
Collection of cell bodies inside the CNS is known as?
Nucleus.
Neurones in peripheral nerve are arranged in?
Fasciculi.
Nerve layer of connective tissue?
Epineurium
Nerve fascicle layer of connective tissue?
Perineurium
Axon layer of connective tissue?
Endoneurium
How are peripheral nerves classified?
Based on conduction velocity and axonal diameter.
What do Nociceptors detect?
Detect tissue damage, interpreted as pain.
What is a muscle spindle?
Proprioceptor that detecs changes in muscles length.
What is a golgi tendon organ?
Proprioceptor that detects changes in tension in tendons.
What do joint receptors do?
Proprioceptor that is found in joint capsules – detect start and end of movement.
What is a neuromuscular junction?
Specialised synapse between a motor neurone and a muscle fibre.
What is a motor unit?
A single motor neurone with all the muscle fibres it innervates.
What neurotransmitter is released at the preganglionic synapse?
Acetylcholine.
In sympathetic neurone, what neurotransmitter is released at a postganglionic neurone?
Noradrenaline.
In parasympathetic neurone, what neurotransmitter is released at a postganglionic neurone?
Acetylcholine.
What parasympathetic nerves emerge from spinal cord?
Pelvic nerves. S2 to S4.
What cranial nerves have parasympathetic motor nerve fibres?
III, VII, IX and X
Where do sympathetic nerves emerge from in spinal cord?
T1 to L2.
Visceral sensory nerves?
T1-L2, S2-S4 and cranial nerves IX and X
Visceral motor nerves?
Thoracolumbar (T1-L2) and craniosacral outflow (cranial nerves III, VII, IX, X)
Explain sympathetic innervation of heart?
Sympathetic innervation of the heart originates from T1 to T4 of the spinal cord. These presynaptic fibers first travel to either the cervical or the thoracic ganglia of the sympathetic chain, where they synapse and form the sympathetic cardiac nerves that innervate the heart.
Explain sympathetic innervation of the abdominal and pelvic viscera?
Sympathetic innervation of the viscera originates from T5 - L2 of the spinal cord. Nerve fibres synapse in pre-aortic ganglia and go on to innervate the abdominal and pelvic organs.
