Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5519_Библиотеки_им_академика_М_И_Перельмана.pdf
Chapter 6 Nervous System, SpecialSenses, and Endocrine System 131
insulin deciency. Patients with diabetes have numerous
symptoms including excessive thirst (polydipsia), coronary artery damage, and increased risk for heart disease,
diabetic retinopathy, and poor healing of wounds.
Type 1 diabetes mellitus (T1DM) occurs before the
age of 30 and is less common but severe. The pancreatic
cells in the islet of Langerhans are destroyed and unable
to produce insulin. When diabetes develops only during
pregnancy, it is called gestational diabetes. This type of
diabetes usually disappears after the birth.
Diabetes is determined by evaluating blood glucose
levels. A single fasting blood test may indicate an initial problem but continued monitoring is required. Diet,
exercise, and oral antidiabetic medication are used to
treat diabetes. Occasionally, injectable insulin is required
to maintain proper glucose levels.
Preparing for Externship
Cultural Connection
The U.S. Department of Health and Human Services,
specically the Indian Health Services Division,
stated that American Indians and Alaskan Natives
have a 2.2 times higher risk of developing Type 2
Diabetes Mellitus than non-Hispanic whites. It is
estimated that 30% of this population has prediabetes and will probably develop diabetes mellitus.
The American Diabetes Association has awareness
programs that include education and counseling on
the ways to avoid developing diabetes. The slogan
“Awakening the Spirit” focuses on ways to encourage people to create a healthy pathway in their life.
These chapters on anatomy and physiology include
information about the various body systems that
may be a special area of practice in the medical field. For example, this chapter discusses the
nervous and endocrine systems. A neurologist
and endocrinologist are the specialists that treat
patients who have disorders of these body systems. Your school will select the externship site
Chapter Recap
● The nervous system is comprised of nerve cells called
neurons, which form bers and ultimately build the
nerves.
● Chemicals called neurotransmitters are necessary for
the nerves to send their signals through a series of
synapses.
● The sympathetic and parasympathetic nervous
systems have very different and specic functions
regulating the functions in the body.
● Numerous diseases and disorders of the nervous
system can lead to the inability of organs and muscles
to function properly. Some of these conditions cause
intense nerve pain and occasionally paralysis of
regions of the body.
assignment. You may find yourself at a specialty
medical practice. Prior to starting the externship
course, research as much as you can about the typical patients disorders, the procedures performed,
and treatments for the various conditions. While
doing your research, review the basic medical
terms and abbreviations associated with this type
of special practice.
● The central nervous system that includes the brain
and spinal cord relies on the bony vertebrae and
meninges for protection and the cerebrospinal uid
to cushion and provides nourishment to the spinal
cord.
● The special senses of the body allow us to
experience our external and internal environment.
These senses include sight, sound, taste, smell, and
touch.
● The endocrine glands and the hormones secrete and
regulate a majority of the function in the body.
● Hypersecretion and hyposecretion of hormones are
the most common reasons for the disorders of the
endocrine system.
132 Section II Anatomy and Physiology
Online Resources for Students
Resources for students available on thepoint.
lww.com include the following:
● Audio Glossary
● Animations
Exercises and Activities
Certication Preparation Questions
1. Which of these structures are found in the
CNS?
a. Peripheral nerves
b. Brain and spinal cord
c. Midbrain and visceral nerves
d. Sympathetic nerves
e. Somatic nerves and cerebellum
2. Which of these is the whitish covering over the
axons?
a. Meninges
b. Synapse
c. Myelin
d. Neurons
e. Gray matter
3. Which of these is NOT an effect of the
sympathetic nervous system?
a. Constricts blood vessels
b. Dilates bronchial tubes
c. Dilates pupils
d. Increases blood pressure
e. Raises heart rate
4. Which of these is used to measure the electrical
activity of the brain?
a. PET
b. LP
c. MRI
d. CT
e. EEG
5. The abbreviation MTBI refers to a condition that
has another term which is:
a. stroke.
b. concussion.
c. epilepsy.
d. meningitis.
e. hydrocephalus.
● Competency Evaluation Forms
● Harris CareTracker Case Studies
● Interactive Games & Activities
● Certication Preparation Question Bank
● Videos
6. Excessive pressure of the aqueous humor causes:
a. cataracts.
b. glaucoma.
c. myopia.
d. retinopathy.
e. corneal abrasion.
7. The pinna is located:
a. in the middle ear.
b. behind the eardrum.
c. at the opening of the outer ear.
d. in the inner ear.
e. inside the cochlea.
8. Which of these is produced in the pituitary and
stimulates the production of hormone in the
adrenal cortex?
a. FSH
b. TSH
c. ACTH
d. GH
e. LH
9. Epinephrine is produced in the:
a. thyroid gland.
b. pancreas.
c. adrenal gland.
d. parathyroid gland.
e. posterior pituitary.
10. A condition occurring in adults that causes
enlargement of the hands and facial features is:
a. gigantism.
b. hypothyroidism.
c. goiter.
d. Addison disease.
e. acromegaly.
Internet Resource
For more information on brain disorders caused from
injury to the brain, visit the Web site for the Brain Injury
Association of America at www.biausa.org
Digestive System and
7
Nutrition
Chapter Objectives
● Describe the function of the digestive system.
● List the organs of the digestive tract and describe
their specic function.
● List the accessory organs of digestion and describe
how they assist the digestive system.
● Explain the process of absorption in the digestive
system.
● Explain the purpose of bile.
● Describe the muscular contraction of the digestive
system.
● Describe common disorders of the digestive tract
and the accessory organs.
● Describe the roles of minerals and vitamins in the
body.
● Explain the use of protein, carbohydrates, and fats
in the body.
● Compare saturated and unsaturated fats.
● Describe common nutritional disorders.
CAAHEP & ABHES Competencies
CAAHEP
● Describe structural organization of the human body.
● Identify body systems.
● List major organs in each body system.
● Describe the normal function of each body system.
● Identify common pathology related to each body
system including signs, symptoms, and etiology.
● Analyze pathology for each body system including
diagnostic measures and treatment modalities.
ABHES
● List all body systems, their structure, and functions.
● Describe common diseases, symptoms, and
etiologies as they apply to each system.
● Identify diagnostic and treatment modalities as they
relate to each body system.
133
134 Section II Anatomy and Physiology
Chapter Terms
Anorexia
Appendicitis
Chyme
Cholecystectomy
Cholelithiasis
Cirrhosis
Defecation
Diverticulosis
Endoscopy
Gastritis
Abbreviations
BMR
GERD
GI
Case Study
Mary Ann Gibson is a 14-year-old and a new
patient of the clinic. She recently relocated to this
area with her family. When the family moved, she
had to leave behind her friends that she has gone
to school with since rst grade. She is entering the
new high school as a freshman this year. She is
accompanied by her mother who is concerned that
HBV
HCL
Hepatitis
Ingestion
Mastication
Nausea
Oral thrush
IBD
IBS
Mary Ann is losing weight although she seems to
have a good appetite and eats regularly. Mary Ann
is reluctant to step on the scale to obtain her height
and weight. Rosa, the medical assistant, continues
to escort her to the examination room. Mary Ann
asks Rosa quietly if she can see the doctor without
her mother in the room.
Parotitis
Peristalsis
Ulcerative colitis
Villi
Vomiting
LES
LDL
In this chapter, we will explore the digestive system including the organs of digestion and the accessory organs that
are necessary for proper digestion of food. We will examine how nutrition is processed in the digestive tract for use
by the body cells.
C
O
G
THE DIGESTIVE SYSTEM
The primary function of the digestive system is to process
the nutrients from the foods we eat into usable nutrients
that supply each body cell with the energy necessary to
perform specic actions in the body. Digestion, absorption, and elimination are the major processes that take
place in the digestive tract. Digestion is the process of
breaking down the nutrients into simple chemicals that
can be used by the body cells. Absorption is the transfer
of these chemicals from the digestive tract to the blood
in the circulatory system where they will be transported
to the body cells. Products that cannot be digested are
eliminated as waste material.
The gastrointestinal (GI) tract, also called the alimentary canal, is a hollow passageway that begins at the
mouth and ends at the anus where waste products are
eliminated. The accessory organs that are not actually
part of the canal are the salivary glands, liver, and pancreas. They supply the necessary substances that further
help to break down the food into chemicals that the
body can use. Figure 7-1 is a diagram of the entire GI
tract from the mouth to the anus.
C
O
G
THE MOUTH
The oral cavity is the rst part of the alimentary canal. The
mouth has many structures that initially start the digestive process. The process of taking food into the mouth is
called ingestion. The teeth, tongue, cheeks, and lips help
in this process.
Mastication is the process of chewing the
food. The teeth grind the food and the tongue, cheeks, and
lips hold the food in the mouth and move the food around.
There are different shapes of the teeth allowing different
Case Question
A
F
F
How would you handle Mary Ann’s
request if you were the medical assistant?
Chapter 7 Digestive System and Nutrition 135
Mouth
Pharynx
Trachea
Liver (cut)
Gallbladder
Duodenum
Common bile duct
Pancreas
Parotid
Sublingual
Submandibular
Large intestine
(transverse colon)
Small intestine
Salivary
glands
Esophagus
Stomach
Diaphragm
Spleen
Cecum
Appendix
Rectum
Anus
functions in breaking down the food. The incisors are
cutting teeth. The cuspids (canines) are used for gripping
and tearing food, and the molars are used for grinding.
The tongue has taste buds that allow us to recognize
the difference between sweet, sour, bitter, and salty. The
food mixes with saliva, the secretion from the salivary
glands. There are three pairs of salivary glands that
contribute this secretion:
Parotid—at the back of the mouth in front of the ear;
r
these become inamed when someone has the mumps.
Submandibular—beneath the lower jawbone,
r
mandible.
Sublingual—under the tongue.
r
glands.
Now, it is time to swallow the food through the
process called deglutition.
Sigmoid colon
Parotid
duct
Parotid
gland
Submandibular
duct
Submandibular
gland
Figure 7-1 The digestive system.
(Reprinted from Cohen BJ. Memmler’s
The Human Body in Health and Disease.
13th ed. Philadelphia, PA: Wolters
Kluwer; 2014.)
Tongue
Sub
ducts
Sublingual
gland
Figure 7-2 Salivary glands. (Reprinted from Cohen
BJ. Memmler’s The Human Body in Health and Disease.
13thed. Philadelphia, PA: Wolters Kluwer; 2014.)
lingual
136 Section II Anatomy and Physiology
The Pharynx
We commonly know the pharynx as the throat. There
are three sections of the pharynx:
Nasopharynx—upper part of the pharynx at the back
r
of the nose
Oropharynx—middle section of the pharynx that is
r
visible when the mouth is open
Laryngopharynx—lower part of the pharynx that lies
r
above the larynx (voice box)
When the food moves from the mouth to the pharynx, it is now called a bolus, a small bit of food that has
been chewed, mixed with saliva, and now is ready for
the stomach.
The Esophagus
The esophagus extends from the pharynx to the
stomach. It is a muscular structure about 10 inches
long. The bolus of food is not changed but is lubricated
with mucus produced by the lining of the esophagus.
This structure is made of smooth muscle, which uses
peristalsis to move the food along down to the stomach. The esophagus passes through the diaphragm
through an opening called the esophageal hiatus.
Thisis a common place for hernia formation, which we
will discuss later.
The Stomach
The stomach is located in the upper, left part of the abdominal cavity. It is a muscular organ that continues grinding
the food and missing it with the digestive juices secreted in
the stomach. The stomach has a greater and lesser curvature, which shapes the stomach. The uppermost rounded
part of the stomach is the fundus. The lower end of the
stomach leading to the small intestine is the pylorus.
The stomach has two sphincter muscles, which regu-
late the size of an opening:
Lower esophageal sphincter (LES)—also called the
r
cardiac sphincter because of its location close to the
heart. This sphincter controls the ow of food from
the esophagus into the stomach.
Pyloric sphincter—this sphincter muscle is located at
r
the end of the stomach and regulates the ow of food
into the small intestine.
The lining of the stomach has folds called rugae. The
folds expand allowing the stomach to enlarge as we eat.
Figure 7-3 is a diagram of the stomach and demonstrates
the rugae.
Esophagus
Esophageal hiatus
Lower esophageal sphincter (LES)
Pyloric
sphincter
Pylorus RugaeDuodenum
Lesser
curvature
Body
Oblique
Muscle layers
Circular
Longitudinal
Fundus
Greater
curvature
Figure 7-3 Stomach. (Reprinted
fromCohen BJ. Memmler’s The Human
Body in Health and Disease. 13th ed.
Philadelphia, PA: Wolters Kluwer; 2014.)
Chapter 7 Digestive System and Nutrition 137
The stomach produces gastric juices that are used to
further dissolve the bolus of food into a liquid form that
can be more easily absorbed into the bloodstream. These
gastric juices are:
Hydrochloric acid (HCL)—an extremely strong acid
r
that breaks down protein and destroys foreign organisms. HCL production starts prior to food entering
the stomach. This is done so when the food does enter
the stomach it immediately starts breaking it down.
Pepsin—an enzyme that combines with the HCL to
r
turn the bolus into a semiliquid.
The semiliquid formed from the HCL, pepsin, and
the bolus of food is now called chyme. It is ready to
enter into the small intestine.
Small Intestine
This is the longest part of the digestive tract at
approximately 20 feet. There are three sections of the
small intestine:
Duodenum
r
Jejunum
r
Ileum
r
The mucous lining of the small intestine secretes
mucus that will protect the intestine from the strong
acid chyme. Carbohydrates and proteins undergo a nal
digestive process in the small intestine. The liver and
pancreas secretions are now added to the contents of
the small intestine. Most of the nutrients and water will
be absorbed in the small intestine. These substances are
absorbed through the villi and microvilli found on the
mucosal lining of the small intestine.
projections and microvilli are smaller microscopic projections. They both provide signicantly increased surface area for absorption of the nutrients and water as
those substances travel through the intestine.
Villi are nger-like
Large Intestine
The next part of the alimentary canal is the large
intestine. It is approximately 5 foot long and much
wider than the small intestine. The large intestine begins
in the lower right region of the abdomen with a structure called the cecum, a pouch. The small and large
intestines are separated by a valve called the ileocecal
valve (ileum + cecum). This valve permits food to enter
the large intestine from the small intestine and then
closes so nothing can ow backward. A small nger-like
projection is found at the base of the cecum. This is the
vermiform appendix that we just usually call the appendix. The remaining parts of the large intestine include:
Transverse colon—extends across the abdomen from
r
the right side to the left side lying below the liver,
stomach, and spleen.
Descending colon—extends downward from the
r
transverse colon to the sigmoid colon.
Sigmoid colon—the end of the colon that forms an
r
“S” shape as it approaches the rectum.
Rectum—the part of the alimentary canal that stores
r
the indigestible food before it is eliminated from the
body.
Anal canal and anus—the nal portion of the alimen-
r
tary canal that leads to the outside of the body; the
anus is a sphincter muscle that controls the expulsion
of the waste from the body.
The large intestine is responsible for reabsorbing water
and forming the waste material into a substance called
feces or stool.
ing this material through the large intestine.
is the term used for the process of eliminating the waste
from the body. The anal sphincter allows voluntary control over this process. Bacteria, normally found in the
colon, produce vitamin k, necessary for proper clotting.
The bacteria do not cause disease, unless allowed to
enter other areas of the body through contamination.
Peristalsis is the rhythmic action of mov-
Defecation
The Peritoneum
Although the peritoneum is not considered to be an organ,
it contains the organs of the abdominal cavity. It is a serous
membrane that lines the cavity and covers the organs. There
are two layers, the parietal and the visceral. The parietal
peritoneum lines the wall of the cavity and the visceral peritoneum covers the organs. Two other structures that are
subdivisions of the peritoneum are the mesentery and the
omentum, greater and lesser. The mesentery attaches from
the posterior abdominal wall to the small intestine. The
greater omentum extends from the stomach into the pelvic
cavity and up the transverse colon. The lesser omentum,
which is smaller, extends between the stomach and the liver.
C
O
G
The digestive tract needs the assistance of the accessory
organs and their secretions in order to carry out the process of digestion. In the mouth, the salivary glands provide
the rst secretion, saliva. This substance moistens the food
and begins the process of digestion. From there as the food
travels through the alimentary canal, the liver, gallbladder,
and pancreas add secretions to help complete the process.
THE ACCESSORY ORGANS
The Liver
Ascending colon—the portion that extends up the
r
right side of the abdomen from the cecum to the
transverse colon.
Located in the upper right quadrant of the abdomen
below the diaphragm, the liver is the largest accessory
organ. Blood is delivered to the liver through the hepatic
138 Section II Anatomy and Physiology
Diaphragm
Liver
Gallbladder
Cystic duct
Common bile duct
Duodenum
Common
hepatic duct
Pancreatic duct
Spleen
Pancreas
Figure 7-4 Accessory organs of
the digestive system. (Reprinted
from Cohen BJ. Memmler’s The
Human Body in Health and Disease.
13th ed. Philadelphia, PA: Wolters
Kluwer; 2014.)
artery. This vessel carries oxygen-rich blood to the liver.
Blood is also delivered through the hepatic venous portal system. This system of veins carries blood from the
gastrointestinal tract with a lower concentration of oxygen. This blood will be ltered by the liver, one of the
main functions of this organ. Once ltered, some of the
blood will be transported to the kidneys to be ltered
for elimination of waste products from the body. The
liver has several functions:
Stores glycogen, a form of glucose for use when the
r
glucose level needs to be restored
Produces blood plasma proteins, such as albumin,
r
globulins, and clotting factors
Produces bile—essential for metabolizing fats
r
Destroys old red blood cells and eliminates the
r
by-product called bilirubin (bilirubin is the substance
that gives color to stool)
Stores iron and vitamins
r
Detoxies chemicals and metabolizes drugs including
r
alcohol
Converts waste products for excretion by the kidneys;
r
an example is urea, a waste product of protein
metabolism
The Gallbladder
A primary function of the liver is to produce bile
necessary to breakdown fats. When bile leaves the liver,
it is carried through ducts to the gallbladder where it
is stored until it is needed. The common hepatic (liver)
duct joins with the cystic (gallbladder) duct to form the
common bile duct. Bile ows through the common bile
duct and empties into the duodenum where the process
of fat breakdown takes place.
The Pancreas
The pancreas is located in the upper left quadrant of the
abdomen behind the stomach. It is an endocrine and exocrine gland. The endocrine portion secretes insulin directly
into the bloodstream. We are interested in the exocrine
function of the pancreas. This gland produces enzymes
that are secreted into pancreatic ducts, which connect with
the bile duct and lead to the small intestine. These enzymes
digest fats, carbohydrates, and fats. The pancreas also
releases sodium bicarbonate, which neutralizes the acidic
contents of the small intestine. See Figure 7-4 showing the
location of the accessory organs of the digestive system.
C
O
G
Now that we have explored the organs of the digestive
tract, let’s recap the process from beginning to end.
END-TO-END PROCESS
Digestion
After taking food into the mouth, the teeth chew the
food into smaller pieces and saliva mixes with the food
to make it soft and moist and easier to swallow. The
digestive process has now begun. From the mouth, the
food travels down the esophagus and into the stomach.
Here, it will mix with hydrochloric acid and enzymes.
The food mixes and further breaks down into a semiliquid substance called
the pyloric sphincter of the stomach into the duodenum
of the small intestine. While in the small intestine, bile
from the liver and pancreatic secretions are added to
the chyme causing further digestion of the food we ate.
Now we are ready for the absorption process.
chyme. The chyme moves through
Chapter 7 Digestive System and Nutrition 139
Absorption
The products of digestion are ready to be absorbed
into the bloodstream. Most of the absorption will take
place in through the villi of the small intestine. These
tiny structures have minute blood vessels and capillaries
supplying them where the absorption takes place. Most
of the fat will not be absorbed into the bloodstream
but will be absorbed into the lymphatic system through
the permeable membrane. The lymphatic vessels carry
lymph uid with the fat droplets to the veins close to
the heart. The fat will eventually be moved through
the blood to the liver for processing. In the large intestine, the bacterial action produces vitamin K and some
B vitamins, which are absorbed from the large intestine.
Mechanism of Controlling Digestion
The nervous system plays a major role in regulating or
controlling digestion. The sympathetic system decreases
activity in the digestive tract and the parasympathetic
system stimulates or increases activity. You may recall
from the discussion of the sympathetic system that stress
has an effect on the function of this system. Digestive
disturbances may be more frequent during times of
stress. Our senses act to stimulate our digestive system
into action. When you smell food, for example a hot cinnamon roll fresh out of the oven, your mouth will start
watering getting ready with saliva to mix with the rst
bite you take. Sometimes, the very thought of something
good to eat will start stimulating the digestive process
into action. After the saliva production, the stomach
starts secreting its juices getting ready to receive the food
from the mouth. From there, the intestines are stimulated to get ready to receive the chyme from the stomach.
Throughout the process, the nerve impulses regulate the
rate of ow through the digestive system.
Mechanism of Controlling
Appetiteand Hunger
Hunger and appetite differ in that hunger is the need
for food and appetite is a desire for food but not necessarily the need for it. We develop hunger and appetites
based on factors such as our emotional state and force
of habit. When we say we are hungry for a specic food,
we are drawing off our memory of that food. The hypothalamus regulates our sensation of hunger telling us
when we are hungry and when we have had enough to
eat. As we eat and ll the digestive tract, this too signals
our body to stop consuming food therefore decreasing
our hunger.
We eat because we are hungry or have an appetite,
but we need to eat to provide energy for our body to
function properly. The metabolic rate relates to overall energy requirements. It is the rate that cellular
respiration converts nutrients into ATP, necessary for
cell function. Metabolic rate changes from person to
person. Age, body composition, gender, activity, and thyroid function can all affect the metabolic rate. The basal
metabolic rate, BMR, is the calculation of the amount of
energy needed to minimally maintain life functions. As
we begin to look at nutrition requirements, it is important to understand what a calorie is. A kilocalorie is the
amount of heat needed to raise 1 kg of water 1 degree
centigrade. Calorie is the simple term used to describe a
kilocalorie.
C
O
G
Proper nutrition is critical to the overall health of our
cells. Let’s begin by looking at the three basic nutritional needs, proteins, carbohydrates, and fats. Most
nutritional guidelines recommend that our daily intake
should be 15% to 20% from protein, 55% to 60% from
carbohydrates, and 30% or less from fats. These values
are based on a normal, healthy individual who participates in a moderate exercise plan. Diets are altered to
meet the needs of the individual. For example, a diabetic
patient may want to increase the protein and decrease
the carbohydrate amounts.
NUTRITION
Carbohydrates
Carbohydrates are a primary source of energy digested
into simple sugar before they are absorbed into the
bloodstream. The liver converts them into glucose as a
usable form of energy. If the body does not need the
immediate supply of glucose, the liver converts the glucose into glucagon, which is stored until needed. If there
is an overabundance of glucose and glucagon, it then
converts to fat and is stored in the liver and in adipose
tissue (fatty tissue). Carbohydrates are found in fresh
fruits, vegetables, and whole grains. There may be
limited amounts of carbohydrates in beans and nuts.
Carbohydrates are also in desserts and foods with added
sugar. These types of carbohydrates should be limited in
the daily diet since they add little nutritional value.
Fats
Fats are another critical nutrient; however, not all fat
is the same. Fats give the body energy to work properly; however, it is harmful to eat too many. The body
uses carbohydrates for initial energy and then depends
on calories from fat. Fats help absorb vitamins A, D, E,
and K, which are the fat-soluble vitamins. A benet of
fat stored in the body is that it insulates us and protects
some organs. Fat has 9 calories per gram, compared
to 4 calories per gram provided by proteins and carbohydrates. Essential fatty acids are necessary for brain
140 Section II Anatomy and Physiology
development and blood clotting, but the body cannot
manufacture these. We need to include some fat in the
daily diet to ensure we are getting the essential fatty
acids, which are linoleic and linolenic acid.
Saturated and Unsaturated Fatty Acids
Saturated fats are responsible for increasing the lowdensity lipids (LDL), the bad cholesterol. A person with
a high LDL will be at a greater risk for heart attack
and stroke. Saturated fats are primarily found in animal products such as butter, cheese, and whole milk.
Saturated fats are those that are solid when at room
temperature. They increase the cholesterol buildup in
arteries leading to clogged and blocked arteries.
Unsaturated fats can help lower the LDL cholesterol.
These fats are in a liquid form when at room temperature. There are monounsaturated fats such as olive and
canola oil and polyunsaturated fats including safower,
corn, and soy oil.
Trans-fatty acids are a type of fat that form when
vegetable oil hardens. This process is called hydrogenation. These fats are frequently used in foods to keep
them fresh for a longer time. These fats can raise LDL
cholesterol levels in the blood and should be limited in
the daily diet.
Proteins
Proteins are necessary in the body to build, strengthen,
and repair cells and tissues. They are involved in muscle contractions and movement. Protein is not stored
in the body the same as carbohydrates and fats. When
more protein is available in the body than required,
it is broken down for energy or will be converted to
triglycerides. When protein is diminished in the diet, the
body will use the structural proteins found in muscle tissue. Carbohydrates and fats are used for energy before
proteins so are called protein-sparing nutrients. Protein
foods should be part of the daily diet since they are not
stored in the body. Proteins are found in animal products and some plants. All of the essential amino acids are
found in animal protein. Amino acids are the building
blocks of protein. Most of the plant proteins lack one
or more of the essential amino acids. Vegetarians that
do not eat any animal protein must obtain the necessary amino acids by combining vegetables and grains
to ensure that they receive all the essential amino acids.
The B vitamins and vitamin C are water soluble, which
means that they are dissolved in the body uid and not
stored in the body so are used on a daily basis then need
to be replaced regularly with the food we eat. The fatsoluble vitamins A, D, E, and K are stored in fat and
used as needed. An overabundance of these vitamins
may lead to a toxic condition so should be taken in
large doses. Essential vitamins and their basic function
include:
Vitamin A—needed for healthy mucus membranes,
r
skin and eye pigments
Vitamin B6—helps form red blood cells
r
Vitamin B12—necessary for metabolism and maintain
r
central nervous system
Vitamin C—an antioxidant that promotes healthy
r
teeth and gums, promotes wound healing
Vitamin D—helps the body absorb calcium for
r
healthy teeth and bones; the sunshine vitamin since it
is produced by the body by being in the sun
Vitamin E—formation of red blood cells and helps
r
body use vitamin K
Vitamin K—necessary for coagulation of blood cells
r
Biotin—metabolism of proteins and carbohydrates
r
Niacin—helps maintain healthy skin and nerves
r
Folate—formation of red blood cells
r
Pantothenic acid—metabolism of food
r
Riboavin—body growth and production of red
r
blood cells
Thiamine—helps body cells change carbohydrates
r
into energy
There are minerals that the body needs in larger amounts
that include calcium, phosphorus, magnesium, sodium,
potassium, chloride, and sulfur. Also, there are trace minerals found in smaller amounts that include iron, manganese,
copper, iodine, zinc, cobalt, uoride, and selenium.
C
O
G
The digestive system has many structures that can
become diseased and not function properly. The organs
can become infected, have structural problems, or malfunction due to dietary issues. We will examine some of
the conditions that affect the digestive system including
the accessory organs.
DISORDERS OF THE
DIGESTIVE SYSTEM
Minerals and Vitamins
Minerals and vitamins are equally essential to the body
as proteins, carbohydrates, and fats. Minerals are necessary for many functions including uid balance and
blood clotting. Vitamins are essential for metabolism.
Vitamins are classied as water soluble or fat soluble.
Mouth and Teeth
When there is a problem in the mouth with the soft tissue,
gums, tongue, or the teeth, it may hinder our ability to eat
certain foods, which might affect our intake of nutrition.
When we have problems in this area, we avoid eating specic foods. For example, if there is a sore in the mouth, we