BIOL373 Lecture Notes - Lecture 23: Gastric Inhibitory Polypeptide, Myenteric Plexus, Submucous Plexus
2 Sep 2019
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Long" reflexes, integrated in cns: sensory info from gi tract to cns. Include cephalic reflexes" in response to sight, smell, thought of food, effects of emotion: efferent limb always autonomic, parasympathetic. Cns: has glial support cells (similar to astrocytes of cns, diffusion barrier capillaries surrounding ganglia are not very permeable (similar to blood-brain barrier, acts as integrating center gut function can be regulated without cns. Pancreatic secretion: factor from intestine that stimulated pancreatic secretion called secretin, general term coined for blood-borne regulators: hormones. Digestion begins in the mouth: saliva secretion under autonomic control softens and lubricates food, digestion: salivary amylase, some lipase, antimicrobial: lysozyme, immunoglobulins chewing (mastication) transfer to stomach (deglutition) Swallowing reflex: swallowing reflex integrated in medulla, sensory afferents in cranial nerve ix and somatic motor and autonomic neurons mediate reflex. Transition into the stomach: lower esophageal sphincter guards entry into stomach, tonically contracted ring of smooth muscle.
