Transcript The Digestive System

Unit 3: Animal Anatomy &
Physiology
Components of
The Digestive System II
Components of the Digestive System
Organ
Comments
Function
10) small
intestine
duodenum: 1st part of
the small intestine
1. finishes off chemical
digestion for all nutrients
produces intestinal fluid
(more enzymes to
digest all nutrients)
receives secretions from
pancreas & gall bladder
mucus also protects
from acidity & enzymes
(3 parts)
total of
6.2 m in
length
but only
2.5 cm
wide
jejunum & ileum: middle
& last sections
lined with finger-like villi
peristalsis occurs
2. absorption of digested
food into blood stream
villi increase surface
area
3. keeps food moving
along
Components of the Digestive System

Small Intestine
surface area of small intestine is greatly increased by:
1. lining of small intestine has folds
2. folds contain villi (finger-like projections)
3. villi contain microvilli
total surface area of small intestine = area of professional tennis court
Components of the Digestive System

Small Intestine
Duodenum
Small
Intestine
Jejunum
Ileum
.
Components of the Digestive System
Organ
7) liver
Comments
Function
large multi-lobed organ 1. stores excess glucose
(A) filling most of the
as glycogen
abdominal cavity
2. filters out & breaks
cirrhosis:
down toxic compounds
scar tissue forms from
from blood
damage by alcohol &
(detoxification)
drugs
3. makes bile
breaks down large fat
droplets into smaller
ones (called
emulsification)
.
Components of the Digestive System
Organ
8) gall
bladder
Comments
small sac under the
liver (H)
connected to the liver
by the bile duct (J)
gall stones
crystallized bile
J
Function
stores bile & sends it to
the duodenum
(1st part of the small
intestine)
.
Components of the Digestive System
Organ
Comments
9) pancreas
long feather–shaped
organ
sends pancreatic
secretion to
duodenum via the
pancreatic duct
Function
1. makes insulin
2. makes pancreatic
secretion containing:
enzymes which digest
proteins, carbs &
lipids
.
Components of the Digestive System
Organ
13) large
intestine
(colon)
(5 parts)
total of
1.5 m in
length &
6.5 cm wide
Comments
1. caecum
2. ascending colon
3. transverse colon
4. descending colon
5. sigmoid colon
feces: undigested waste
contain enormous
numbers of bacteria
peristalsis
Function
1. reabsorb water &
minerals from digestive
secretions & compact
feces
2. produce vitamins B & K
& help further digest
waste
3. move feces along
.
Organ
14) rectum
Comments
muscular organ at
the end of the colon
3 sphincters:
1. entrance of rectum
2. internal sphincter
3. external sphincter
anus
opening through which
feces are egested when
sphincters are relaxed
Function
1. stores feces
2. control egestion
Large Intestine (frames the small intestine)
 Shorter than small intestine
 Diameter is much greater
 Cecum
 First part of the large intestine, attached is the
appendix
 Colon
 Main portion of the large intestine
 Water and dissolved minerals are absorbed
 Intestinal bacteria help break food down further
 Bacteria produce vitamin B-12 , K and some amino
acids
Large intestine completes the process!
 Any undigested material (feces) passes into
rectum from the colon. Feces moves through
anal canal and out the anus.
 Anus has a ring of circular muscle
called the anal sphincter.
Large Intestine
Cecum
Traverse colon
Descending colon
Ascending colon
Cecum
Sigmoid colon
Rectum
Anus
Anal canal
Large intestine
endoscope:
a narrow instrument with a camera at its tip
placed inside digestive tract to view the
inner lining
can locate ulcers, polyps or tumours
colonoscopy
ENDOSCOPE VIDEOS
DUODENUM
DUODENUM VILLI
NORMAL COLON
ENDOSCOPE VIDEOS
NORMAL COLON 2
PARASITIC WORM
REMOVAL OF PARASITIC
IN COLON
WORMS IN COLON
ENDOSCOPE VIDEOS
COLON JAUNDICE
DIARRHEA
cause
result
danger
bacterial infections, allergies,
alcohol, food poisoning, etc.
irritate intestinal walls
peristalsis occurs too fast
feces move through too quickly
not enough water or minerals
are reabsorbed
feces remain very watery
danger of dehydration
loss of minerals (electrolytes)
needed for body functions
CONSTIPATION
not enough fibre or water
in diet to stimulate
peristalsis
feces move through too
slowly
too much water is
reabsorbed
feces become very dry
more time for toxic
substances & food
additives to be absorbed
hemorrhoids: blood vessels
around anus are torn &
bleed during egestion
higher probability of colon
cancer
DIARRHEA
treatment
avoid foods that stimulate
peristalsis (ex. fibre)
drink plenty of fluids,
especially those that contain
electrolytes (ex. gatorade)
CONSTIPATION
eat high fibre food
drink lots of water
regular exercise
(stimulates peristalsis)
laxatives (ex. prunes –
natural laxative)
pharynx
1
epiglottis
4
esophagus
5
9
liver
gall bladder
bile duct
small 14
intestine
19
2
3
salivary glands
6
stomach
7
cardiac sphincter
8
pyloric sphincter
12
pancreas
13
pancreatic duct
transverse colon 22
ascending colon 21
descending colon 23
colon 20
10
11
duodenum 15
jejunum 16
ileum 17
18 ileo-caecal sphincter
appendix
rectum
25
tongue
24
anus
26
sigmoid colon
Homework
 Small Intestine & Large Intestine Worksheet
 Page 188 # 1, 2, 5, 10
Magazine Ad from the 1930’s
The Movement of Food
 Peristalsis – alternate waves of contraction and
relaxation of muscles in the organ wall.
 Circular muscles push food ahead from
contracting behind, when long. muscles are
relaxed.
 Longitudinal muscles in front of food contract
pushing food back, when circ. muscles are
relaxed.
Figure 10.15
The Movement of Food
 Rhythmic Segmentation – mix up partially
digested food in intestine.
 Circular muscles push it back and forth while
food stays in same place.
Figure 10.16
.
Components of the Digestive System
Organ
1
2
3
Comments
11) ileocaecal
sphincter
ring of muscle at the
end of small intestine &
beginning of the large
intestine
12) appendix
tiny sac (3) found on
the caecum (2)
appendicitis:
inflammation caused
by bacteria (swells &
could burst)
Function
keeps digested food in the
small intestine
allows more time for
digestion & absorption
function unknown
believed to be left over
from our evolutionary past
Still the Small Intestine…
Differ only slightly from the duodenum.
 Jejunum (2.5 m)
 Contains more folds and intestinal glands than duod.
 Breaks down remaining protein and carbohydrates
 Ileum (3 m)
 Fewer and smaller villi
 Absorbs nutrients
 Pushes undigested material into large intestine
Components of the Digestive System

Large Intestine