NATS 1610 Lecture Notes - Lecture 4: Blood Vessel, Blood Sugar, Coagulation
1 Oct 2015
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Nats 1610 lecture 4 - the living body within the living world. Homeostasis-the tendency toward a relatively stable equilibrium between interdependent elements, especially as maintained by physiological processes. There are 2 types of homeostatic control mechanism : 1 negative feedback system ( reverses a change) The response of the stimulus leads to change, here the change is fed back to the receptor. In positive feedback the response of the system reinforces the effect of the original stimulus. It secretes the hormones glucagon and insulin , and digestive enzymes . Glucagon prompts liver to break down glycogen to glucose , and liver releases glucose into blood steam. Insulin lowers blood glucose by actions at : liver (stops glycogen conversion to glucose ), muscle ( uptake of glucose) and adipose ( uptake of glucose) The mechanism that stops bleeding and involves 3 events. 2 platelet aggregation (example of positive feedback) plugging hole in blood vessel (platelet plug) .
