Answer:
4.-Hormone is secreted
-Enters bloodstream
-Travels to target cell in another part of body
--------Control of pH in in the duodenum
• As the contents of the stomach enter the duodenum, the low pH acts as a stimulus for S cells
• The stimulated S cells secrete the hormone secretin into the bloodstream
• Circulating secretin reaches target cells in the pancreas
• Target cells in the pancreas respond by releasing bicarbonate into ducts leading into the duodenum
• The release of bicarbonate raises the pH in the duodenum, neutralizing the stomach acid
35.-Local signaling
• Paracrine signaling: secreting cell acts on nearby target cells by discharging molecules of a local regulator into the extracellular fluid
• Synaptic signaling: nerve cell releases neurotransmitter molecules into a synapse, stimulating the target cell
• Signaling cell secretes messenger molecules which only travel short distances
-Long distance:
• Endocrine: specialized endocrine secrete cells secrete hormones into body fluids, often blood. Hormones reach virtually all body cells but are bound by only some cells
• Travels in bloodstream
Explanation:
