An Introduction to Endocrinology Quiz

See Homeostasis. Option D is correct because baroreceptors (pressure sensors in the walls of large blood vessels such as the aorta) are mechanoreceptors, nerve endings that respond to physical deformation. When blood pressure rises, the vessel wall is stretched, the baroreceptors fire more often, and this afferent signal (a signal travelling towards the control centre) reaches the cardiovascular centres, so that the heart and blood vessels can adjust and bring the pressure back towards normal. This is homeostasis (the maintenance of a stable internal environment) working through negative feedback. The receptor detects the stimulus, the control centre compares it with the set point (the value the body tries to hold) and the effectors (the organs that carry out the response) oppose the change. Sensory receptors can be sorted by what they detect: chemicals, temperature, position and movement, pain, and mechanical force. A simple memory aid is that the word mechanical sits inside mechanoreceptor, so think of anything that is pushed, pulled or stretched.

• Type: baroreceptors are mechanoreceptors, which respond to physical deformation.
• Site: the walls of large blood vessels such as the aorta.
• Trigger: a rise in blood pressure stretches the wall, so they fire more often.
• Pathway: an afferent signal reaches the cardiovascular centres.