Metabolism

scroll down

Metabolism Objectives

Define metabolism, including catabolism and anabolism.
Explain how hormones impact appetite.
Describe the potential impacts of anabolic steroids.

People often discuss their “metabolism,” particularly related to how much they eat and whether they gain weight or not. This video explains what metabolism is and how it relates to the calorie-containing nutrients we are consuming.

Metabolism is a combination of all cellular activities, and typically we measure metabolism through the body heat created by cellular activity, including muscle contraction.

Breaking down molecules is called catabolism and building up new molecules is called ___.

Appetite regulation is complex. Several hormones are involved, produced by endocrine cells in different organs.

The appetite story starts simply enough with two hormones: leptin and ghrelin. If leptin levels are high you can feel full or satiated, if ghrelin levels are high, you can feel hungry.

The stomach and adipose tissue play an important role in regulating appetite. The stomach produces ___ that makes us feel ___. Adipose tissue produces many hormones, including ___ that makes us feel satiated.

These two hormones are impacted by a number of factors, not just how much you eat. For example, if you exercise, your stomach tends to increase ghrelin production, and you can get hungrier. That makes sense if your body is trying to keep you from starving, but can work against you if you are trying to lose weight.

And it turns out that even though leptin and ghrelin are the primary hormones that impact appetite, several other hormones do as well. Changes in combinations of these hormones may impact whether a person feels satiated or hungry.

Leptin comes from ___. This hormone not only impacts appetite, it also impacts a variety of organs in diverse ways. And leptin is only one of at least eight hormones produced by fat cells.

This may explain in part why excessive body fat correlates with increased incidence of a wide range of disorders including diabetes, certain cancers, and cardiovascular diseases.

Hormones cause things to happen, and excessive hormones may be problematic.

Anabolic steroids include natural androgens like testosterone and synthetic hormones that act like testosterone. These can be important medications for an individual who is not producing adequate amounts of androgens, which can cause slow muscle growth or loss of appetite.

Anabolic steroids are also taken to attempt to enhance athletic performance through muscle growth and repair.

Adding anabolic steroids can have several harmful impacts on the body, including increased LDLs in the blood plasma increased blood pressure, liver damage, and tissue loss in the left ventricle of the heart. These impacts can be compounded by taking other drugs, like excessive growth hormone.

A repeated message is that even if a hormone occurs naturally in the body, an excessive amount can be harmful. Growth hormone plays an important role in regulating adipocytes and bone density. Too much growth hormone in adults can increase the size of facial features, hands, and feet. It also can increase blood pressure and the risk for certain cancers.