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4 What are typical and common patterns of motility in different parts of gastrointestinal tracts? (8 Points)

The common patterns of motility in different parts of gastrointestinal tracts is peristalsis.

The typical patterns of motility at stomach is receptive relaxation for store of food. The typical patterns of motility at small intestine is segmentation for turning food into smaller particles and helping absorption.

The typical patterns of motility at large intestine is mass movement for pushing the contents in the colon into the next downstream segment.

5 What are functions of thyroid hormones ? (8 Points) (1) Because T3 acts by inducing DNA transcription, its effects on tissue are the result of protein synthesis, primarily the synthesis of enzymes. (2) Thyroid hormones are required for normal growth throughout life. (3) Thyroid hormones affect basal metabolic rate, metabolism, the cardiovascular system, and the nervous system. (4) Symptoms of thyroid hormone excess or deficiency can be predicted from their normal effect.

6 How does the human body’s reflex response to cold? (8 Points)

When a fall in core body temperature is detected by the hypothalamus, the reflex compensation involves reducing heat loss and generating more heat by increasing metabolic rate and through shivering. (1) Objective of body is to reduce heat loss and increase heat production. (2) Reducing heat loss occurs by decreasing skin blood flow and through behavioral responses. (3) Increasing heat production occurs through metabolic effects of thyroxin and catecholamines as well as by shivering. (4) Sustained exposure to extreme cold depresses hypothalamic temperature control mechanism and produces dilation of skin vasculature.

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