Skin and Digestion Quiz Review

A Body in Balance

Homeostasis is the process by which an organism's internal environment is kept stable in spite of changes in the external environment.

Which of the following are examples of homeostasis:

  1. A frog is cold-blooded, meaning that its body temperature changes with the environment. 
  2. A dog does not have sweat glands, therefore he pants to maintain a constant body temperature when the day is warm.
  3. A fish will become less active as the water temperature cools and become more active when the water temperature is warmer because its body temperature changes with the environment.
  4. A plant freezes and dies when the temperature drops below 0 degrees C.
  5. A human maintains a body temperature of 37 degrees C when the air temperature is 25 degrees C.

If you chose 2 and 5 you understand the concept of homeostasis.  Organisms in examples 1, 3 and 4 are not able to maintain a constant condition in spite of changes in the external environment.

Adrenaline

Adrenaline is a hormone associated with the "fight or flight " response to stress or danger.  Some physiological changes that take place include:

  • Pupils dilate
  • Breathing rate increases
  • Heart rate increases
  • Digestion decreases
  • Peripheral blood vessels constrict

Skin

Find the following structures on the diagram.

  • Epidermis- the outer layer of skin including the keratin layer of dead surface cells
  • Sweat gland- located in the subcutaneous layer, the duct rises through the dermis ending in a pore opening on the skin surface
  • Oil gland- a sebaceous gland found in the dermis opening into the shaft of the hair follicle
  • Hair follicle- located in the subcutaneous layer it is the place from which hair grows

Test yourself on skin anatomy.

Digestive System

X. The salivary gland secretes enzymes that digest starches in the mouth where digestion begins.

C. Peristalsis is the rhythmic wave-like smooth muscle contractions that move food down the esophagus to the stromach.

D. Most of the mechanical digestion of food takes place in the stomach.  Hydrochloric acid aids pepsin in the chemical digestion of proteins. 

F.  Chyme enters the small intestine where digestion continues and nutrients are absorbed into the blood stream across villi.

E. Enxymes produced by the pancreas continue protein and carbohydrate digestion in the small intestine. Amylase digests carbohydrates to glucose.  Trypsin completes protein digestion. Lipase aids fat digestion.

A. Bile is produced in the liver.

Y. Bile is released by the gall bladder into the small intestine when fat digestion takes place.

B. Water is absorbed in the large intestine.  Final digestion is done by bacteria that are helpful making substances such as vitamin K.

Villi are tiny finger-like projections forming the small intestinal lining.  The villi greatly increase the surface area of the small intestine.  This epithelial tissue allows nutrients to be absorbed across the cells into the blood stream.  A thick slippery mucus coating facilitates absorption by osmosis and diffusion across the villi.  Peristalsis, involuntary muscle contractions, moves chyme through the intestines.

Test yourself on digestive system anatomy.

Return to Fourth Marking Period