Vital signs

الMAP مأخذناها البارحة بس important clinically

Venous valve

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Chvostek’s sign

During neuron action potentials, Calcium ions normally help regulate the voltage-gated sodium channels on neurons.
the reduced extracellular calcium concentration (hypocalcemia) decreases the threshold needed to open these sodium channels.

Therefore the neurons are more excitable and may carry out involuntary muscle contractions due to the release of neurotransmitters in the neuromuscular junction

كلنا نعرف الpain والsensation راح ينتقل من الجسم للdorsal horn of the gray matter
At the dorsal horn, the Substantia gelatinosa (SG) acts as a gate which opens at the present of a pain impulse and carries it into the spinal cord
The substantia gelatinosa opens only when the pain fibers are the fastest
In normal condition, sensory fibers are faster than pain fibers
So rubbing a traumatized area (sensory activation) forces the substantia gelatinosa to be closed therefore reducing pain

Activation of A Beta neurons (sensory) activates the SG and closes the gate for A Delta and C neurons
Activation of A Delta and C fibers (pain) deactivates the SG and closes the gate for A Beta

In the 3rd cranial nerve, the efferent fibers that are responsible for pupillary constriction are on the periphery of the nerve. So when an aneurysm or mass compresses the nerve, it'll compromise these fibers and leads to pupillary dilation. This is called surgical 3rd nerve palsy, as opposed to medical 3rd nerve palsy which usually spares the pupillary fibers and is often the result of a neuropathy (like diabetic ophthalmoplegia).

Patients with appendicitis have pain that starts around the umbilicus & migrates to the right lower quadrant