THE NEUROLOGY

High Yield Facts ⭆ Acetylcholine released in postsynaptic cleft and binds to α-subunit of acetylcholine receptor. When acetylcholine bind a nicotinic AchR, a conformational change occurs in the receptor, resulting in the formation of an ion pore. The opening of a ion pore produces a rapid increase in the cellular permeability of sodium and calcium ions, resulting in the depolarisation and excitation of the muscle cell. It activate the sodium channel and depolarizes the nerve fibers. Direction of transmission of nerve impulse from postsynaptic junction to nerve fibers. Question Which of the following ion channel opens, when acetylcholine (ACh) binds to acetylcholine receptor (AChR) at postsynaptic junction? Potassium (K) Chloride (Cl) Calcium (Ca) Sodium (Na) Acetylcholine Receptors Two types of Acetylcholine Receptor: Muscarinic Type: G-Protein Coupled Receptor. Slow metabolic response through intracellular secondary messenger system involving an increase of intracellula...

High Yield Facts ⭆ Synaptic transmission at the neuromuscular junction begins when an action potential reaches the presynaptic terminal of a motor neuron, which activates voltage dependent calcium channels to allow calcium ions to enter the neuron. Calcium ions bind to synaptic vesicles, triggering vesicle fusion with the cell membrane and subsequent neurotransmitter release from the motor neuron into the synaptic cleft. Motor neurons release acetylcholine (ACh) neurotransmitter, which diffuses across the synaptic cleft and binds to nicotinic acetylcholine ionotropic receptors (nAChRs) on the cell membrane of the muscle fiber. The binding of ACh to the receptor can depolarize the muscle fiber, results in muscle contraction. Normally, Acetylcholine (ACh) binds to α-subunit of Acetylcholine Receptor (AChR) at postsynaptic junction. Which ion is responsible for transmission of impulse from postsynaptic junction to nerve fibers? Chloride (Cl) Calcium (Ca) Sodium (Na) Magnesium (Mg)...

How many spinal arteries supply the human spinal cord? Three Arteries Four Arteries Five Arteries Two Arteries Blood Supply of Spinal Cord Arterial Supply The spinal cord is supplied by Three Longitudinal Arteries : One Anterior Spinal Artery supplies the anterior two-thirds of the spinal cord. Two Posterior Spinal Arteries supply the posterior one-third of the spinal cord. [Mnemonics: Posterior is Paired, Posterior = Paired] Venous Drainage There is a complex network of intrinsic, extrinsic, and extradural systems. The anterior and posterior spinal veins and anterior and posterior radicular veins are freely communicate with the internal vertebral plexus in the epidural space. This drains into the cerebral dural venous sinuses and cerebral veins as well as the external vertebral plexus. The veins of the spinal cord and vertebral column are valveless. Reference: Bosmia AN, Hogan E, Loukas M, Tubbs RS, Cohen‐Gadol AA. Blood supply to the human spinal cord: part ...