Download CPDIGESTIVE

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project

Document related concepts

Liver wikipedia , lookup

Liver transplantation wikipedia , lookup

Bile acid wikipedia , lookup

Liver cancer wikipedia , lookup

Ascending cholangitis wikipedia , lookup

Bariatric surgery wikipedia , lookup

Pancreas wikipedia , lookup

Transcript
• Most animals ingest chunks of food
Figure 21.1E
21
21.2 Overview: Food processing
occurs in four stages
Small
molecules
Pieces
of food
Mechanical
breakdown
Nutrient
molecules
enter body
Chemical breakdown
(enzymatic hydrolysis) cells
Undigested
material
Food
1 INGESTION
2 DIGESTION
3 ABSORPTION
4
ELIMINATION
Figure 21.2
TEETH
Incisors
Canine
Premolars
Molars
Tongue
“Wisdom”
tooth
Salivary
glands
Opening of a
salivary gland duct
Figure 21.5
•
21.4 The human digestive
HUMAN
DIGESTIVE
SYSTEM
system consists of an
alimentary canal and
When food is
swallowed, it glands
is moved through
accessory
the alimentary canal by peristalsis
– Peristalsis is rhythmic muscle contraction in the
walls of the digestive tract
– Ringlike sphincter muscles regulate the passage
of food
Oral cavity
Mouth
Tongue
Salivary
glands
Pharynx
Esophagus
Liver
Stomach
Pyloric
sphincter
Gallbladder
Pancreas
Small
intestine
Stomach
Small
intestine
Large
intestine
Rectum
Anus
Figure 21.4
21.8 The stomach stores food
and breaks it down with acid
and enzymes
• The stomach mixes food with gastric juice
– The gastric juice contains pepsin, which begins
the hydrolysis of protein
21
21
•
major organ of chemical
digestion and nutrient
Alkaline pancreatic
juice neutralizes stomach
absorption
acids
– Its enzymes digest polysaccharides, proteins,
nucleic acids, and fats
• Bile emulsifies fat droplets for attack by
pancreatic enzymes
– It is made in the liver and stored in the gall
bladder
Bile
Liver
Stomach
Gallbladder
Bile
Duodenum of
small intestine
Acid chyme
Pancreas
Figure 21.10A
• The lining of the small intestine is folded and
covered with tiny, fingerlike villi
– Villi increase the absorptive surface
• Nutrients pass through the epithelium of the
villi and into the blood
– The blood flows to the liver
– The liver can store nutrients and convert them to
other substances the body can use
21.11 The large intestine
reclaims water
• Undigested
material passes
to the large
intestine, or
colon
Large
intestine
(colon)
End
of small
intestine
– Water is
absorbed
– Feces are
produced
Small
intestine
Rectum
Anus
Nutrient
flow
Appendix
Cecum
Figure 21.11
INTERIOR OF INTESTINE
Blood vessel
with blood
en route to
the liver
Nutrient
absorption
Nutrient
absorption
Microvilli
Epithelial
cells
Lumen
Muscle
layers
Circular folds
Villi
Blood
capillaries
Lymph
vessel
EPITHELIAL
CELLS
Nutrient
absorption
INTESTINAL WALL
VILLI
Figure 21.10B