Nutrients - carbohydrates, proteins, and fats.
The
pyramid of nutrition (Fig. 31.1,
another
idea, vegan) Movie
Now Choosemyplate.gov/
Carbohydrates and proteins contain an average of 4.1
calories per gram.
Fats have 9.3 calories per gram.
BMI (Body Mass Index) (Fig. 31.2)
Fiber
Essential Substances for Growth
Essential nutrients,
such as essential amino
acids.
Essential minerals
trace elements
Vitamins are essential organic
nutrients that often act as cofactors for cellular enzymes. (Vitamins)
Digestion
(movie)
Mechanical digestion
Chemical digestion.
Types of Digestive Systems
Gastrovascular cavity (Fig. 31.3) and feeding
One-way digestive tracts (Fig. 31.4)
herbivores.
carnivores.
Omnivores
Vertebrate Digestive Systems
tubular gastrointestinal tract and accessory organs.
Ex: The human digestive system - (Fig. 31.5). The bird's digestive system (Fig. 31.7).
Carnivores have shorter intestines
for their size than do herbivores,
which have long, convoluted intestines as well as chambers where bacteria can
digest cellulose. (Fig. 31.15a) and (Fig. 31.15b).
Ruminant
digestion. rumens
(Fig.
31.14) house bacteria
where cellulose breakdown occurs.
Coprophagy
Vitamin K.
The tubular gastrointestinal tract of
vertebrates has four layers. (Fig.
31.6)
mucosa.
submucosa.
A double layer of muscle
tissue.
serosa
The Mouth and Teeth
Teeth.
(Fig. 31.8).
Teeth and
diet
Children
have 20 teeth and adults have 32 teeth. (Fig. 31.9).
Periodontal
disease
Processing Food in the Mouth - the tongue helps mix the food with saliva from salivary glands.
Swallowing.
(Fig. 31.10).
The soft palate is raised, closing
off the nasal cavity, and muscles push the food past the larynx with its protective epiglottis,
and into the esophagus, a muscular
tube leading to the stomach.
Peristalsis. (Fig. 31.11).
Cardiac sphincter.
Structure and Function of the Stomach (Fig. 31.12)
Muscular sac
Hydrochloric acid and pepsin
chyme.
For years,
it was believed that ulcers were
caused by excess stomach acid. Now it is known that they are caused by the bacterium Helicobacter
pylori. Excess stomach acid can aggravate the ulcers, however. Movie
Pyloric sphincter.
Digestion and Absorption: The Small Intestine (Fig. 31.13)
Completes the chemical breakdown
of food and is the major site of absorption
of nutrients.
Duodenum
Ileum
Microvilli
Accessory
digestive organs
Pancreas (Fig. 31.16)
digestive enzymes
bicarbonate to neutralize
the acidity
liver
bile
glycogen
insulin Fig. 32.2
incidence of diabetes
gallbladder
Concentration of Solids: The Large Intestine
The
large intestine, or colon, compacts
and stores feces, and reabsorbs water.
Feces are propelled toward the rectum,
and they are eventually expelled through the anus.
The organs of the digestive tract (Fig. 31.17)
Problems with the appendix - appendicitis
Symptoms of appendicitis
*Abdominal pain (located in the lower
right side)
* Fever
* Reduced appetite
* Nausea and vomiting
Treatment - appendectomy
Colorectal Cancer Risk Factors
* Polyps. Most -- perhaps all --
colorectal cancers develop in polyps. Polyps are benign
* Age. (over
the age of 50)
* Family history. Close relatives of
a person who has had colorectal cancer have a higher than average risk of
developing the disease.
* Familial polyposis.
An inherited condition in which hundreds of polyps develop
and can become cancerous.
* Diet. Higher risk in people whose
diet is
high in fat
low in fruits and vegetables
low in high-fiber foods
* Ulcerative colitis. Causes
inflammation of the lining of the colon increasing risk.
Colorectal Cancer Symptoms
The
symptoms of colorectal cancer can be
*
Fresh blood in the stools
* Lasting change in normal bowel habits (diarrhea or constipation)
* Unexplained weight loss
* Pain in the abdomen or rectum
* Straining feeling in the rectum
* anemia
Age is
an important factor
Sometimes a cancer of the bowel can cause a blockage. The symptoms of this are
*
Constipation
* Feeling bloated
* Griping pains in the abdomen
Colorectal Cancer Screening
Stool testing
* 'fecal occult blood test'
* a test for blood hidden in the stool
Examining the inside of the bowel
* sigmoidoscopy - examines only the last third of the
colon
* colonoscopy - examines the entire colon
* Polyps - removed
and biopsied - Removal
Elimination of nitrogenous wastes and osmoregulation
(Balancing salts and water)
ammonia
urine.
urea
uric acid
Human excretory system (Fig. 32.13a) and kidney (Fig. 32.13b)
renal cortex
renal medulla
nephron (Fig. 32.13c).
Bowman's capsule
glomerulus.
loop of Henle.
collecting duct.
urine
ureter
urinary bladder
urethra.
