Download 4. filled with teeth: a. two sets of dentitions: d ec i d uo us t e et h 1 . n

4.
fi l l e d with teet h:
a.
t w o sets o f dent i t i o ns:
d ec i d uo us t e et h
1.
n um b er 2 0,
2.
er u pt f r om 6 - 32 mo nths,
3.
l ost b et w e en 6 - 12 years.
p er m an e nt ( s e co nd ar y ) teet h
1.
n um b er 3 2,
2.
er u pt f r om 6 yrs - adul t h oo d.
b.  function: to break food into smaller
pieces.
- increasing surface area of food;
- increasing effectiveness of digestive
enzymes.
III
A. 4. Oral Cavity/ Teeth (continued)
c. 4 types with different functions:
! incisors = front teeth;
1. break food into bite-size pieces;
! cuspids = canine (eye) teeth;
1. grasp and tear food;
! bicuspids = grinding food particles;
! molars = grinding food particles
d.
!
Tooth
!
Structure:
c rown = exposed area of tooth;
root = area below gum (gingiva);
!
e n a mel =covering on crown; Ca+ salts; hardest
substance in body;
! dentin = bulk of tooth.
III.
A.
5.
O r al C avity (continued)
Salivary Glands secrete saliv a.
a. digestive functions:
-lubric ation,
- bind food together,
- begi n dig estio n o f carbohydrates.
1. Enzyme = salivary amylase;
2. breaks polysaccharide s i nto
disaccharid es;
a. starch ----> disaccharid es.
b.
three types of salivary glands:
-parotid = largest; lies over masseter,
-submandibular = floor of mouth; lateral,
-sublingual = floor of mouth, medial.
III. Digestive Organs ( co ntinu ed )
B. Pharynx:
1. throat;
2. passagew ay of fo od i nt o esop hagus;
3. Swallowing m ec ha nism (deglutition ):.
a. Chew f oo d & mix with saliva into bolus at
b ac k of ph arynx;
b. Swallowing reflex triggered (involunt ary):
-epigl ottis closes over larynx ( no
breat hing ),
-mus cles i n low er pharynx relax,
- esoph ag us opens & food moves in.
C. Esophagus:
1. passageway for food from pharynx to stomach;
2. location: mediastinum; behind trachea;
3. many mucous glands;
4. movement of food:
a. gravity;
b. peristaltic waves from esophagus meet
gastro- esophageal sphincter muscle,
c. sphincter muscle relaxes,
d. food moves into stomach all at once.
I I I.
Digestive Organs ( co ntinu ed )
D. Stomach (Gastric)
1.
d escription = J-shaped, p ouch-lik e or ga n;
2.
l oc ation = under diaphragm; le ft side;
3.
c ap acity = 1 liter;
4.
P arts of Stomach:
a.
c ar diac region - aroun d esophagus
b.
f un dic region - large ballooned area
c.
pyloric region - ne ar du od en um
-The py loric regio n n arrows i nt o py loric
c an al.
-The
py loric s p hinct er
muscl e l ies
b etwee n pylorus & du od en um.
d.
great er c urvat ure
e.
l es ser c urvat ur e
f.
b ody
5.
Mucosal Structure
a. Macroscopic rugae (mucosal folds
b. Microscopically, these rugae are formed
by:
-gastric villi that project into the lumen
which result in the formation of;
-gastric pits that are located between
the gastric villi.
1.
gastric glands are located along
these gastric pits
a.
gastric juice is secreted by these
gastric glands.
D.
S t om a c h (Gastric)
6.
G as t r i c Juic e:
a.
c om p ose d o f:
- m u cus,
F un ct i o n: l u br i c at i on, pr ot e ct io n o f
m u co s a fr om digestion;
- di g es t i ve enzyme p e ps in,
F un ct i o n:
pr ot ein
digestion
(i nto
p e pt ide s );
- hy droc hl oric a ci d (HCl),
F un ct i o ns:
1.
d en at ur es pr ot e i ns,
2.
kills m icr o b es i n fo o d,
- i nt r i ns ic fact or,
F un ct i o n: aids a bs or pt io n o f Vit am i n
B 1 2.
- g astrin,
F un ct i o n: r e g ulat ory h or m on e.
7. Four types of gastric cells in Gastric Glands:
a. Mucous cells secrete mucus;
b. Chief cells secrete pepsin;
c. Parietal cells secrete HCl & intrinsic
factor;
d. G-cells secrete gastrin.
8. Regulation of Gastric Secretions:
a. Hormone = Gastrin;
b. When stomach fills, the hormone gastrin is
released.
c. Actions:
-increases secretions from gastric glands;
-increases mixing action;
-contracts gastroesophageal sphincter;
-relaxes pyloric sphincter.
9. Gastric Absorption = Minimal (5%)
10. Gastric Movements:
a. mixing of bolus of food + gastric juice =
chyme;
b. Peristaltic waves of stomach push chyme
toward pyloric sphincter; it relaxes; food
moves into duodenum a little at a time!!!
E. Pancreas
1. Secretes pancreatic juice into a pancreatic
duct; pancreatic duct leads to duodenum
(small intestine);
2. Location: posterior to stomach; left side;
3.
Function of pancreatic juice:
Contains four classes o f enzymes that break
d own:
a. Carbohydrates
-(amylase) ---> disaccharides;
b. Fats/Triglyc erid es
-(lipases) - - - > 2 f at t y a cids +
monoglyc eride;
c. Proteins
-(proteinases) ---> peptides;
d. Nucleic Acids
-(nucle ases) ---> nucleotides.
4. Regulation of pancreatic secretions:
a. Hormone = Secretin;
-causes release of pancreatic juice into
duodenum;
b. Activation:
-When duodenum fills with acidic chyme,
- secretin is released,
-which stimulates the release of
pancreatic juice into duodenum.
F. Liver (Hepatic).
1. Location: below diaphragm / right side
2. Structure: 2 lobes
a. large right & small left;
b. each lobe is made up of:
-Hepatic lobules =functional unit of the
liver
1. hexagon shaped around a central
vein;
3. Functions:
a. metabolism of carbohydrates, lipids &
proteins,
b. storage (glycogen, Vitamin A, B 12, D, iron),
c. filtering of blood,
d. destruction of toxic chemicals,
e. production/secretion of bile.
**For free:
Cirrhosis of the liver:
weakness
fatigue
loss of appetite
nausea
vomiting
weight loss
abdominal pain and bloating when fluid accumulates in
the abdomen
itching
spiderlike blood vessels on the skin
4.
Blood Supply:
a. from 2 so urces:
-hepatic artery (oxygenate d blood);
-hepatic portal vein (deoxygenated blood
filled with newly absorbed nutrients
from small intestine).
b. blood enters the liver sin usoids where
h epatocytes remove the followin g:
-oxygen,
-nutrients (stored or use d to make new
materials),
-poisons (detoxified or store d).
5.
6.
Liver Phagocytosis:
-Kupffer's cells (liver macro phages)
Bile
a. compositio n:
- bile salts (digestive function)
- bile pigments
- cholesterol
- electrolytes
b.
f unction: Emulsific ation of f at
mol ecules!
-Definition: Emulsification = breaking up of
f at globules i nto small dro plets
(increases
SA
and
i n creases
e ffectiveness of lipases ).
Gall Bladder:
1.
2.
3.
4.
Stores bile between meals;
Location: underside
of
l i v er,
connected via cystic duct;
Bile can flow to small intestine by either of 2
routes:
the liver or gall bladder (see below);
Bile secretion, storage, flow:
From l iver:
F rom Gall Bladder:
Hepatic duct
C y s t i c Duct
COMMON *
BILE DUCT
Duodenum