Chapter 1.4 - 1.5 Requirements for Human Life & Homeostasis

What is Oxygen?

A key component of chemical reactions that keep the body alive including the reactions that produce ATP

What are nutrients?

A substance in food & beverages that provides essential energy, materials for growth, and maintenance of bodily functions.

What are the three basic classes of nutrients?

Water (most critical), Enegy-yielding + body building nutrients, Micronutrients (such as vitamines)

Functions of water in the human body?

1. body’s functional chemicals are dissolved & transported in water

2. Chemical reactions of life take place in water

3. Largest component of cells, blood, & fluid between cells

4. Makes up 70% of an adults body mass

5. Regulates internal temperature + cushions, protects, and lubricates joints and many body structures

What are Energy Yielding Nutrients?

1. Primarily carbohydrates & lipids - while proteins supply amino acids that are the building blocks of the body itself

2. Break down of carbs & lipids can be used in the metabolic processes that convert them into ATP

Body needs them in large amounts

What are micronutrients and their values?

• Participate in many essential chemical reactions + processes

• The body can store some in its tissues and draw from them if you fail to consume them in your diet for a few days (or weeks)

  • Some, such as vitamines b or c are not water-soluble and cannot be stored, so must be consumed everyday or 2

What is narrow range of temperature

Death resulting from heat-stroke or exposure to cold, happens because the chemical reactions upon which the body depends can only take place within a narrow range of body temp (just above to just below 98.6°F or 37°C). Outside this range, physiological functions fail.

What is a set point

A specific range of values within which a physiological variable, such as temperature or glucose levels, is maintained in the body to ensure proper functioning.

What is negative feedback

A regulatory mechanism in which the body's response to a stimulus decreases the effect of that stimulus, helping to maintain homeostasis.

• goes on throughout the body at all times

What are the 3 basic components of Negative feedback?

1. A sensor (receptor) monitors a physiological value — which is reported to the..

2. Control center, which compares value to the normal range— If the value deviates too much from the set point, it activates the…

3. Effector — which causes a change to reverse the deviation and restore homeostasis.

What is positive feedback

Intensifies a change in the body’s physiological condition rather than reversing it

• only normal when there is a definite end point, such as childbirth or blood clotting.