tailieunhanh - Applied Surgical Physiology Vivas - part 10

Sau đó, một làn sóng perilstaltic thứ cấp là những gì? Nếu sóng perilstaltic chính phối hợp không đầy đủ rõ ràng các viên thức ăn của thực phẩm, một phản xạ vaso-phế vị được bắt đầu khởi tạo một làn sóng thứ hai của perilstalsis. Điều này bắt đầu tại trang web của căng sản xuất bởi các viên thức ăn, và di chuyển xuống. | APPLIED SURGICAL PHYSIOLOGY VIVAS The superior constrictor contracts and food enters the oesophagus. This initiates a perilstaltic wave The medullary respiratory centre is inhibited S 10. How is the food propagated down the oesophagus This final phase is called the oesophageal phase. The swallowing centre initiates a primary perilstaltic wave. This occurs together with relaxation of the lower oesophageal sphincter. 11. Then what is a secondary perilstaltic wave If the primary coordinated perilstaltic wave fails to adequately clear the bolus of food a vaso-vagal reflex is initiated that initiates a secondary wave of perilstalsis. This begins at the site of distension produced by the bolus and moves down. 12. What is the normal resting pressure of the lower oesophageal sphincter 30 mmHg. Note that lower sphincter is not a physical structure but rather an area of high pressure in the lower oesophagus. Failure of normal relaxation during the oesophageal phase of swallowing underlies the pathophysiology of achalasia. SWALLOWING 157 APPLIED SURGICAL PHYSIOLOGY VIVAS S SYNAPSES I - THE NEUROMUSCULAR JUNCTION SYNAPSES I - THE NEUROMUSCULAR JUNCTION NMJ 1. Outline the stages of synaptic transmission. The action potential arrives at the presynaptic neurone which causes the opening of voltage-gated Ca2 -channels concentrated at the presynaptic membrane There is an influx of Ca2 into the presynaptic terminal increasing the intracellular Ca2 . This is the trigger for the release of transmitter into the synaptic cleft by exocytosis Note that the neurotransmitter substance is stored in vesicles found at the nerve terminal. Each vesicle contains a quantum of transmitter molecules The neurotransmitter diffuses across the synaptic cleft and binds onto specific receptor proteins located on the postsynaptic membrane An action potential is generated in the postsynaptic cell The transmitter substance is degraded and its component parts may be recycled through uptake at the presynatic .