~20-

Meredith--Hygiene, Chaps. 32 and 34.

Sansum--The Normal Diet.

Cannon--Bodily Changes in Hunger, Fear
Sherman--Chemistry of Food and Nutrition

MeCollum Simonds--The Newer Knowledge of Nutrition

Eddy--Mutrition

Emmerson--Diagnosis of Health

V. EXCRETION, the third determining force in Constructive Hygiene

The objective of the processes of excretion is to neutralize, dilute, and _rgmove
promptly and effectively the products of digestion snd. cell activities.

Excretion may be described as the chemical results of cell activities. These
products are produced by:

Wear and tear on living structures of cells.
Residue from manufacture of cell products.

Death of cells.

(a)
(b)
(c) Wastes due to oxidation within cells.
(a)
(e)

Waste products from foods.

Elimination is the series of processes by which the excretions are prepared and
transported out of the body.

A. TYPES OF EXCRETIONS

1. Internal:

é- External:

Those excretions which are discharged directly by the cell
into lymph or blood stream,

Those excretions discharged by cells upon surfaces that com-
municate with the outside of the body.

Be ORGANS OF EXCRETION

1. Kidneys:

The most important organs of the body which are developed
particularly for purposes of excretion.

a. Description: The kidneys are two organs situated on cither

Ce

side of the front of the spinal column in the region of the
floating ribs behind the stomach, pancreas, and liver. They
arc oval or bean-shaped, abeut 4 or 5 inches long, and 1-5
inehes thick. Color: They are dark in color on account of
the large blood supply.

Structure macroscopically: The kidneys are observed to be
covered with resistant capsule. On the side toward the
spinal colum is a depression (hilum) through which vessels,
ducts, and nerves enter and leave. Inside of this dep. ssion
is an open space called the pelvis of the kidney. a

 

Microscopically: The kidneys have two layers, cortex and

 

medulla, The cortex or outer layer is a special arrangement
of tissue cells and tubules in a way to make possible the
free passage of larger quantities of blood in intimate con-
tact with the special cclls and tubules.