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COURSE CODE: CHEM 3
COURSE TITLE: BIOCHEMISTRY
MODULE 13
URINE, FECES AND SWEAT
Upon completion of the module, the students should be able to:
1. Discuss the formation and excretion of waste products.
2. Enumerate the parts of the excretory system.
3. Identify the composition of urine, feces, and sweat.
Good day! Our lesson for today is all about URINE, FECES AND SWEAT. For your preliminary
activity
about
the
lesson,
kindly
read
the
instruction
below.
https://www.healthline.com/health/sweat-what-is-it
https://www.vox.com/2015/1/22/7871579/poop-feces
https://www.doctorfox.co.uk/news/incredible-facts-about-urine/
Answer the following 10 Fun Facts Question about Urine, Feces and Sweat:
1. How long can a human hold their pee?
2. What is the longest someone has gone without peeing?
3. How fast is urine produced?
4. How many times should you pee a day?
5. What is poop actually called?
6. What is in the poop?
7. What are the 7 types of poop?
8. Name three body parts which do not experience sweating.
9.What are the three sweat glands?
10. Does sweating burn fat?
Answers will be submitted at the Canvas-Assignment Section
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The excretory system is a vital biological system that removes excess and waste products
from the body to maintain homeostasis. Most of these products are in fact used and broken-down
components of metabolism that leave the body in the form of urine, sweat, or feces.
Kidney in the Bible
The kidneys, always used in the plural (kelayot), are mentioned more than 30 times in the
Bible. In the Pentateuch, the kidneys are cited 11 times in the detailed instructions given for the
sacrificial offering of animals at the altar. Whereas those instructions were for purification
ceremonies at the Temple, sacrificial offerings were made subsequently in seeking divine
intervention for the relief of medical problems. In the books of the Bible that follow the Pentateuch,
mostly in Jeremiah and Psalms, the human kidneys are cited figuratively as the site of temperament,
emotions, prudence, vigor, and wisdom. In five instances, they are mentioned as the organs
examined by God to judge an individual. They are cited either before or after but always in
conjunction with the heart as mirrors of the psyche of the person examined.
There is also reference to the kidneys as the site of divine punishment for misdemeanors,
committed or perceived, particularly in the book of Job, whose suffering and ailments are legendary.
In the first vernacular versions of the Bible in English, the translators elected to use the term “reins”
instead of kidneys in differentiating the metaphoric uses of human kidneys from that of their
mention as anatomic organs of sacrificial animals burned at the altar. This initial effort at linguistic
purity or gentility has progressed further in recent versions of the Bible, in which the reins are now
replaced by the soul or the mind. The erosion may have begun in the centuries that followed the
writing of the Bible, when recognition of the kidneys as excretory organs deprived them of the
ancient aura of mysterious organs hidden deep in the body but accessible to the look of God.
At approximately the same time, Greek analytical philosophy argued that the brain, which
is never mentioned in the Bible, was the most divine and sacred part of the body. This argument
gained ground in the past century, when the functions of the brain were elucidated, and ultimately
established in the 1960s, when salvaging the kidneys for transplantation necessitated a change in
the definition of death as irreversible brain function. It is ironic that advances in understanding
kidney function and in nephrology that made kidney transplantation feasible may have contributed,
albeit indirectly, to the gradual elimination of the metaphoric mention of human kidneys in the
Bible.
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URINE, FECES, and SWEAT
Excretion means getting rid of waste products. Lungs, kidneys, and skin are organs of
excretion. If the wastes are not removed, body tissues may fill with poisonous waste products. If
water collects in the tissue, it may cause swelling. Fever, poisoning, coma, and death may result
from waste building up in tissue.
The kidneys are a pair of organs that are found on either side of the spine, just below the
rib cage in the back. Kidneys: filter waste materials out of the blood and pass them out of the body
as urine. regulate blood pressure and the levels of water, salts, and minerals in the body. A human
kidney is a reddish-brown colored organ shape like bean. It is about 10 cm in length, and weighs
140 to 160 g (5 to 6 oz), and is similar in shape to the kidney beans sold at the supermarket. During
its circulation through the body, blood passes through the kidneys. The kidneys remove excess
water, minerals, and urea, a protein waste, from the blood.
Kidney
The kidneys filter the blood and rid the
body of wastes. Approximately one
million nephrons (right) compose each
bean-shaped kidney (left). The filtration
unit of the nephron, called the glomerulus,
regulates the concentration within the
body of important substances such as
potassium, calcium, and hydrogen, and
removes substances not produced by the
body such as drugs and food additives.
Cancers that originate in the filtration
tissues of the kidney, called renal cell
cancer, account for 85 percent of all
cancers of the kidney. A small percentage of cancers originate in the renal pelvis, a cavity in the
center of each kidney.
In the kidney, waste filtered from the blood form liquid called urine. Urine is carried through two
long tubes, called the ureters, which is about 25 to 30 cm (10 to 12 in) long and about 0.5 cm (0.2
in) in diameter. The ureter empties into a hollow, muscular sac called the urinary bladder. The
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bladder stores the urine. A valvelike flap of tissue at the point of entry into the bladder prevents
urine from flowing backward into the ureter. The urinary bladder is able to expand and contract
according to how much urine it contains. As it fills with urine, the walls of the bladder stretch and
become thinner, with the bladder itself lengthening to 12.5 cm (5 in) or more and holding up to
about 0.5 liter (1 pt) of urine. A ringlike sphincter muscle surrounds the bladder’s outlet and
prevents spontaneous emptying.
Urine is excreted in the bladder and out of the body through a tube called urethra. In females, the
urethra is about 3.8 cm (1.5 in) long and is strictly a urinary passage. In males, the urethra is about
20 cm (8 in) long; it passes through the penis and also serves to convey semen during sexual
intercourse.
Bladder
The bladder is a muscular storage organ for
urine produced by the kidneys. The average
adult bladder can hold about half a liter (about 1
pt) of liquid. Urine exits the bladder through a
tube called the urethra. Emptying the bladder is
a reflex reaction, one that takes children several
years to learn to control.
People whose kidneys do not function properly can have their blood cleaned by a kidney dialysis
machine. Blood circulates from the body into the machine. The machine removes waste and returns
the blood to the body.
Functions of Kidneys
Ridding the body of wastes through the production of urine.
Maintain water balance, ensuring that the amount of water in body tissues remains at a
constant level.
Control calcium levels in the blood to maintain healthy bones.
Aid in regulating the acid-base balance of the blood and body fluids so that all body
processes can proceed smoothly.
By controlling salt levels, the kidneys help regulate blood pressure.
Stimulate the body to make red blood cells, the primary component of healthy blood.
Properly functioning kidneys are so vital to health that if they cease to function, death
follows within days.
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Skin
Skin and hair, fingernails, and toenails make up the integumentary system. The skin forms
a barrier that helps prevent harmful microorganisms and chemicals from entering the body, and it
also prevents the loss of life-sustaining body fluids. It protects the vital structures inside the body
from injury and from the potentially damaging ultraviolet rays of the sun. The skin also helps
regulate body temperature, excretes some waste products, and is an important sensory organ. It
contains various types of specialized nerve cells responsible for the sense of touch.
The skin is the body’s largest organ—that of an average adult male weighs 4.5 to 5 kg (10
to 11 lb) and measures about 2 sq m (22 sq ft) in area. It covers the surface of the body at a thickness
of just 1.4 to 4.0 mm (0.06 to 0.16 in). The skin is thickest on areas of the body that regularly rub
against objects, such as the palms of the hands and the soles of the feet. Both delicate and resilient,
the skin constantly renews itself and has a remarkable ability to repair itself after injury.
Structure of the Skin
The skin consists of an
outer, protective layer
(epidermis) and an inner,
living layer (dermis). The
top layer of the epidermis is
composed of dead cells
containing keratin, the
horny protein that also
makes up hair and nails.
Body Waste Products
Urine
Urine, pale yellow fluid produced by the kidneys, composed of dissolved wastes and excess
water or chemical substances from the body. It is produced when blood filters through the kidneys,
which remove about 110 liters (230 pints) of watery fluid from the blood every day. Most of this
fluid is reabsorbed into the blood, but the remainder is passed from the body as urine. Urine leaves
the kidneys, passes to the bladder through two slender tubes, the ureters, and exits the body through
the urethra. A healthy adult can produce between 0.5 to 2 liters (1 to 4 pints) of urine a day, but the
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quantity varies considerably, depending on fluid intake and loss of fluid from sweating, vomiting,
or diarrhea.
Composition of Urine
The composition of urine is determined by the quantities of substances which must be
removed by the kidneys from the blood in order to maintain the composition of the blood and other
fluids within physiological limits. In general, the gross amount of substances excreted in the urine
is proportional to the quantity of protein eaten.
The average urine voided daily is 1,500 ml. In this fluid would be found 60 grams solids.
Normal urine is composed of the following:
Water
Inorganic salts
Nitrogenous organic compounds
Urea, the principal product of protein metabolism, represent 80 – 90% of the total urinary
nitrogenous substance in urine.
Uric Acid is the chief end product of urine metabolism.
Creatinine and creatine
Hippuric acid
Indican, purine, and other amino acids
Non – nitrogenous organic compound
Traces of glucose
Glucononic acid
Acetone bodies
Oxalates
Salt of other organic aids
Organic sulfur compounds
By studying the composition of urine, we can understand through the products formed and
excreted in the urine, the processes of body metabolism. It can also be an aid in the diagnosis and
treatment of pathological states.
Characteristic of Urine
Color – the color of normal urine is amber yellow. This is due to the pigment urochrome which is
yellow. Urorythryn and uroporphyrin which usually are deeper in color are also present in small
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amounts. The less the volume of the urine, the more intense the color marked deviation from the
normal color is indicative of the presence of either hemoglobin bile pigment or melanin.
Volume – The rate of secretion of urine is not constant and depends upon a number of factors:
More urine is secreted during the day than at night, but the reverse in the case of the night workers.
The food, and fluid intake
The temperature and humidity of the atmosphere
Mental excitement and exercise
Young children excrete more urine in proportion to their body weight than in adults. The normal
output for an average adult in 24 hours is from 1000 to 1500 cc. Salty and spicy foods as a rule
induce diuresis and certain beverages have a decidedly diuretic influence. High protein diet results
in a larger output of urine. Pathologically, the volume of urine is increase as a result of injury to the
posterior pituitary gland. Increased urinary output is termed polyuria. Increases flow of night urine
is frequently one of the earliest symptoms of chronic kidney disease called nocturia.
Specific Gravity – Normal urine has a specific gravity of 1.030 but usually it is within the limit of
1.015 to 1.025.
Reaction – Urine may be neutral, acid or alkaline having a pH range from 4.8 to 7.5. Protein diets
give rise generally to highly acidic urine. This is due to the sulfur containing amino acids which is
oxidized to sulfuric acid. Alkaline urine is secreted when there is predominance of vegetables and
fruits in the diet since they have an alkaline ash.
Odor – Freshly drawn urine should have an aromatic odor. A putrid or strongly ammoniacal smell
would point to decomposition by bacteria, probably occurring in the urinary bladder.
Turbidity – Normal urine is perfectly clear and transparent. On standing there is likely to separate
out a faintly cloudy flocculence which is believed to be nucleoprotein or mucoid together with some
epithelial cells.
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Feces-meconium
Feces, also stool, excreta, or residual waste materials, evacuated from the bowels. Through
peristalsis (involuntary intestinal contractions) and digestion, partly digested food begins to assume
the aspects of feces when it passes from the small intestine to the large intestine. In a healthy
digestive system, feces consist of undigested and indigestible food products such as mucous
secretions and cellulose; traces of intestinal juices from the liver, the pancreas, and other digestive
glands; undestroyed enzymes; leucocytes; epithelial cells; cellular debris from the intestinal walls;
fat globules; nitrogenous protein products; mineral salts; water; and large numbers of bacteria.
Probably one-third of the weight of human stool is composed of bacterial debris; an average of 100
billion bacteria are excreted daily by each human being. More than 75 different kinds of bacteria
are found in stool. The unpleasant odor of human feces is chiefly due to the presence of the tworinged organic compound skatole, C9H9N.
Medically, the examination of feces is an important diagnostic procedure. Both gross and
microscopic analyses are used to determine whether the digestive organs are functioning properly.
For example, a light-colored or fatty stool may indicate a pancreas disturbance, and a black stool
may indicate excessive bile functioning. Constipation may produce a hard stool, and those of
persons with indigestion may be soft and watery. The most important use of microscopic analysis
of feces is to determine the kinds of parasites present, especially as related to disease.
In diseases of the pancreas, proteins are not well digested, and an excess of muscle fibers
may be present in the stool (azatorrhea). An ulcer or cancer in the stomach or large intestine causes
small amounts of blood to be present in the feces. Larger amounts of blood produce a black stool.
Bleeding from the lower portion of the intestine or from the anus (as a result of hemorrhoids)
produces unaltered blood in the stool, coloring it bright red.
Characteristics of Feces
Color – Adult fecal material is normally brown. The normal color of feces is due to hydrobilitubin
and stercobilin, derived from bile pigment. However, the color of feces also depends upon the nature
of the diet. Fats and water lighten up the color, while bile pigments darken it. In starvation, the
feces are reduced in quantity and almost black in color, but their chemical constitution is essentially
unaltered. The diet of the human fetus is entirely liquid, but shortly after the child is born it
evacuates a semisolid, dark greenish-brown fecal mass known as meconium.
Odor – The odor of feces is due to the indole and skatole, which are produced by enzymatic action
in the amino acid tryptophan, and other gases like methane, hydrogen sulfide, etc.
Reaction – the normal reaction is slightly alkaline. pH is 7 – 7.5.
Consistency – This varies from a thin pasty discharge to a firmly formed stool. However, this also
depends on the diet.
Amount – About 80 to 120 grams of feces per day are eliminated. In addition variable amount of
gas is formed, and components of the mixed gases will vary with the diet. On a high milk diet, the
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predominant gas is hydrogen; on a vegetable diet, methane; and on meat or mixed diet, nitrogen in
small cases of these gases, as well as CO2 and H2S, are present.
Sweat
Sweat is an important means of getting rid of body heat since heat is used in evaporation.
At moderate temperatures this evaporation keep pace with the secretion and no actual drops
of sweat form. This is called insensible perspiration. With higher temperature, the sweat
become more active and secrete more freely. Evaporation is faster unless with the humidity
of the air is high.
Insensible perspiration range from 300 to 700 cc per day; sensible perspiration may be any
additional quantity up to about 500 cc.
Characteristics
It has a specific gravity of about 1.002 to 1.003.
A pH range from 5.2 to 7.3.
Composition
Sweat is mostly water.
Urea is present and certain inorganic salts, NaCl and some potassium salts. Sweat is said to
have one fifteenth to one half as high a concentration of sodium chloride as blood plasma.
In case of mines and blast furnace operators as much as 10 to 15 liters may be lost in eight
hours of work, with each liter containing 3 g of NaCl. This represents tremendous depletion
of salts in intestinal fluid. When these stores are gone, first plasma and then the cells suffer.
Violent cramps and may result from the combine loss of salt and fluids. To guard against
this, the drinking water of such workers should contain 0.1% of NaCl. In fever, patients may
loss large amounts of moisture and electrolytes in perspiration. This should be replaced if
ill effects are to be prevented. An increased intake during hot weather has been
recommended for most people because of this loss of salt in the perspiration. Only in cases
of renal edema would this be inadvisable.
Nitrogen – Usually less than 0.1 g of nitrogen is secreted in the perspiration each day, but if
sweating is profuse, as much 0.2 g may be eliminated.
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Write an Overview about Urinalysis using the format below:
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The principal function of the urinary system is to maintain the volume and composition of
body fluids within normal limits. One aspect of this function is to rid the body of waste products
that accumulate as a result of cellular metabolism, and, because of this, it is sometimes referred to
as the excretory system.
Although the urinary system has a major role in excretion, other organs contribute to the
excretory function. The lungs in the respiratory system excrete some waste products, such as carbon
dioxide and water. The skin is another excretory organ that rids the body of wastes through the
sweat glands. The liver and intestines excrete bile pigments that result from the destruction of
hemoglobin. The major task of excretion still belongs to the urinary system. If it fails the other
organs cannot take over and compensate adequately.
The urinary system maintains an appropriate fluid volume by regulating the amount of water
that is excreted in the urine. Other aspects of its function include regulating the concentrations of
various electrolytes in the body fluids and maintaining normal pH of the blood.
In addition to maintaining fluid homeostasis in the body, the urinary system controls red blood cell
production by secreting the hormone erythropoietin. The urinary system also plays a role in
maintaining normal blood pressure by secreting the enzyme renin.
REFERENCES
Ubalde, M. (2019). Biochemistry for Allied Health Sciences. EDRIC Publishing
House Peña ,P et. al, (2015). Biochemistry Laboratory Manual C & E Publishing, Inc.
H. de Guzman & J. Duldulao, Module (Compilation) for Biochemistry.
Prepared by:
JAMAICA J. DULDULAO
PROFESSOR
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