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What initiates the positive feedback loop in blood clotting?
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Injury to a blood vessel causes platelets to adhere and release chemicals, recruiting more platelets to form a platelet plug.
What is the difference between negative and positive feedback mechanisms?
Negative feedback maintains balance by counteracting changes, while positive feedback amplifies responses for specific processes.
Describe the process of negative feedback in blood glucose regulation when levels are low.
Low glucose levels are detected by Glut receptors, the pancreas produces glucagon, which causes the liver to release glucose into the bloodstream, increasing blood glucose levels.
What triggers the release of insulin from the pancreas?
High blood glucose levels detected by Glut receptors trigger insulin release from pancreatic alpha cells.
How does the hypothalamus contribute to body temperature regulation in hot conditions?
In hot conditions, the hypothalamus signals vasodilation to increase heat loss, increases sweat production for evaporative cooling, and inhibits shivering.
How does the body detect changes in temperature?
Changes in temperature are detected by thermoreceptors in the skin.
How does suckling lead to milk production and ejection?
Suckling activates mechanoreceptors that signal the hypothalamus to stimulate prolactin for milk production and oxytocin for milk ejection.
Explain the role of glucagon in blood glucose regulation.
Glucagon signals the liver to release stored glucose into the bloodstream, raising blood glucose levels when they are low.
What are the physiological responses to cold as part of body temperature regulation?
Responses include vasoconstriction to reduce heat loss, shivering to increase heat production, and inhibiting sweat production to prevent cooling.
What is the role of insulin in maintaining blood glucose levels?
Insulin facilitates glucose uptake by body cells, lowering blood glucose levels.
How does vasoconstriction affect body temperature?
Vasoconstriction reduces blood flow to the skin, minimizing heat loss and conserving body heat.
Explain the positive feedback mechanism in the birthing process.
Cervical stretch activates stretch receptors, the hypothalamus and posterior pituitary release oxytocin, causing uterine contractions, which further stretch the cervix.
Describe how prolactin and oxytocin function in lactation.
Prolactin, released from the anterior pituitary, stimulates milk production, while oxytocin, from the posterior pituitary, facilitates milk ejection during nursing.
What is the role of the hypothalamus in the birthing process?
The hypothalamus releases oxytocin via the posterior pituitary in response to cervical stretch, leading to uterine contractions.
What effector organs are involved in the temperature regulation system under cold conditions?
The primary effector organs are blood vessels (vasoconstriction) and muscles (shivering).
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