Fundamentals of Anatomy and Physiology

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Body Systems

Working Together to

Maintain Homeostasis:^
The Digestive System

Integumentary System

●● The skin protects the organs of the system and pro-vides
vitamin D needed for calcium absorption in the

intestine.^
●● The digestive system provides nutrients for growth

and repair of the integument.^
●● Fat for insulation is deposited beneath the skin in the
subcutaneous tissue.

Skeletal System

●● The bones protect some digestive organs and the hy-
oid bone provides support for the tongue.^
●● Yellow bone marrow stores fat.
●● The digestive system supplies calcium and nutrients
for bone growth and repair.

Muscular System
●● Smooth muscle pushes food and nutrients along the

digestive tract via peristalsis.^
●● Skeletal muscles protect and support the abdominal
organs.

Chapter 16

●● The digestive system provides nutrients such as

glucose- for muscle contraction, growth, and repair.^

●● The liver metabolizes lactic acid after anaerobic

muscle contraction.

Nervous System

●● The nervous system sends impulses for muscular

contractions in the walls of the gastrointestinal tract

for peristalsis to occur.^

●● Nerve impulses coordinate swallowing and

defecation.^

●● The digestive system provides nutrients for the

growth, maintenance, and functioning of neurons

and neuroglia cells.

Endocrine System

●● Hormones help regulate the metabolism of nutrients for

growth and development.^

●● Insulin and glucagon control sugar metabolism.

●● The digestive system provides nutrients to maintain

the endocrine glands.

Cardiovascular System

●● The cardiovascular system distributes, via the blood,

nutrients absorbed in the small intestine to all tissues of

the body.

As the Body Ages

As we age, the entire lining of the gastrointestinal tract changes. The smooth

muscle layer decreases, causing less mobility and thus a decrease in time for

peristalsis to occur. Less mucus is secreted, resulting in less lubrication and some

difficulty pushing food easily along the tract. Enzyme secretions diminish from the

liver, pancreas, and the gastric pits of the stomach.^

Older adults experience a diminished sense of taste. Daily oral hygiene is

critical to avoid the inevitable reduced natural defenses against microorgan-isms

that can cause gum disease and mouth sores. Older adults also experience^

diminished internal sensations and response to pain along the tract. They tend to develop

difficulty with swallowing.

Since the digestive tract is exposed to environmental contaminants over the years, with

reduced mucous membrane lining and less protective connective tissue, the alimentary canal

becomes less protected from toxic contaminants. Older adults are more susceptible to infec-tions

and are more likely to develop cancers and ulcerations of the tract, especially in the colon and

rectum.

Older adults’ liver declines in its ability to detoxify chemicals and contaminants and store

excess sugar in the form of glucose. They experience more frequent constipation and develop

hemorrhoids. In addition, a higher incidence of diverticulosis develops as we age.