Chapter 14 Digestion Flashcards
Accessory organs of the digestive system
Salivory glands
liver
gall bladder
pancreas
Alimentary Canal
The Tube (24’ long)
mouth
pharynx
esophagus
stomach
small intestine
large intestine
rectum
anus
Mouth
lips
cheeks
hard palate
Soft palate
Uvula
Vestibule
oral cavity
tongue
tonsils
lips
protect the anterior opening
cheeks
form the lateral wall of mouth
hard palate
forms anterior roof of mouth
maxilla and palantine bones
soft palate
muscle arch
forms posterior roof of mouth
uvula
fleshy projection from soft palate
prevents food from entering the nasal cavity during swallowing
vestibule
space between lips and teeth and gums
oral cavity
area contained by the teeth
tongue
attached at the hyoid bone and styloid processes of the skull
lingual frenulum anchors the tonge to floor of mouth
tonsils
Palatine tonsils: on either side of tongue
Lingual Tonsils: posterior of tongue
Mouth Physiology
mastication (chewing)
mixing food with saliva forms bolus
initiation of swallowing by the tongue
allows for the sense of taste
Pharynx Anatomy
Nasopharynx: NOT part of digestive system
Oropharynx: posterior to oral cavity
Laryngopharynx: Below the oropharynx and connected to the esophagus
Esophagus
collapsible muscle tube that propels food into stomach
about 10” long
runs from pharynx to stomach
conducts food by peristalsis (slow rhythmic squeezing)
Stomach anatomy
located on left side of abdomen cavity
food enters cardioesophageal sphincter
food empties in the small intestine at the pyloric sphincter (valve)
Stomach Mucosa
Mucosa
inntermost layer is simple columnar epithelium
mucous neck glands
produce sticky alkaline mucus
gastric glands
situated in gastric pits
secrete gastric juices
Cheif cells
produce protein digesting enzyme pepsinogen
parietal cells
produce hydrochloric acid and intrinsic factor
Stomach physiology
temporary storage tank for food
site of food breakdown
chemical breakdown of protein begins
delivers chyme (foodmixed with gastric juice) to small intestine
Small intestine
muscular tube extending from the pyloric sphincter to ileocecal valve
3 portions: duodenum, jeunum, ileum
mesentery
mesentery
Function of small intestine
completes digestion and absorption of nutrients
Duodenum
jejunum
body of small intestine
ileum
extends from jejunum to large intestine
structural modifications to small intestine
circular folds
villi
microvilli
circular folds
deep folds of mucosa and submucosa
villi
fingerlike structures formed by the mucosa
simple columnar epithelium with microvilli
capillary bed and lacteal: carry away absorbed nutrients
microvilli
tiny projections of plasma
membrane
Chemical digestion in small intestine
enzymes are produced by intestinal cells and the pancreas
pancreas
large intestine
larger in diameter but shorter than small intestine
cecum
appendix
ascending colon
transverse colon
descending colon
sigmoid colon
rectum and anal canal
anus
appendix
lymphatic tissue
extends from the cecum
cecum
sac like first part of large intestine
ascending colon
travels up RS of abdomen
transverse colon
travels across abdonimal cavity
descending colon
travels down the left side of the abdomin
sigmoid colon
enters the pelvis
rectum and anal canal
in pelvis
anus
external anal sphincter: skeletal muscle voluntary control
internal anal sphincter: smooth muscle, involuntary control
normally closed except during defacation
Large intestine function
intestinal flora
bacteria that normally inhabit large intestine
synthesize vitamin K, B12, thiamine and riboflavin
produce intestinal gas
feces
include material that were not digested or absorbed, water (75%), electrolytes, mucus and bacteria
color due to bile pigments altered by intestinal bacteria
defacation
frequency varies from person to person
Accessory digestive organs
teeth
salivary glands
pancreas
liver
gallbladder
teeth
mastication
2 sets:
decisuous
permanent
deciduous teeth
20 teeth fully formed by age 2
permanent teeth
replace deciduous between ages 6-12
full set 32
regions of a tooth
crown
enamel
dentin
pulp cavity
root canal
neck
root
tooth crown
exposed part of tooth
enamel
hardest substance in body
suface of teeth
dentin
found deep to the enamel and forms the bulk of the tooth
pulp cavity
contains connective tissue, blood vessels and nerve fibers of tooth
root canal
where pulp cavity extends to the root of tooth
neck
region in contact with the gum
connects the crown to root
root
cementum
covers outer surface and attaches the tooth to the periodontal membrane
Tooth functions
Salivary glands
three pairs of glands epmty secretions into mouth
Saliva
mixture of mucus and serous fluid
contains salivary amylase to begin starch digestion
Saliva functions
moisten food to help form bolus
dissolves chemicals so they can be tasted
cleanses mouth
pancreas
located posterior and inferior to the stomach
produces digestive enzymes and bicarbonite ions:
secreted into the duodenum
liver
largest gland in the body
located on right side of body inferior to the diaphragm
liver functions
carbohydrate metabolism
lipid metablolism
protein metabolism
storage
bile
carbohydrate metabolism
glycogen storage
lipid metabolism
cholesterol synthesis
protein metabolism
synthesizes plasma proteins
removes amine group from amino acids
liver storage
glycogen, iron, vitamins A, D and B12
blood filtering: removes damaged RBC and foreign substances
detoxification: removes toxins from blood
bile secretion
bile
produced by liver cells (hepatocytes)
emulsifies fats by physically breaking large fat globules into smaller ones
aids in the absorption of fatty acids, cholesterol and fat soluable vitamins
gallbladder
pear shaped sac
located on inferior surface of liver
stores and concentrates bile between meals
biles enters duodenum during meals
Digestive functions
Ingestion
movements
digestion
absorption
defacation
ingestion
taking food in
digestive movements
Digestion
mechanical digestion
mixing food in mouth with tongue
churning food in stomach
segmentation of small intestine
further prepares food for further degradation by enzymes
Chemical digestion
enzymes break down food molecules into their building blocks
carbs are broken to simple sugars
proteins are broken to amino acids
fats are broken to fatty acids and alcohols
absorption
end products of digestion are absorbed in the blood or lymph
food must enter mucosal cells then diffuse into blood or lymph capillaries
defacation
elimination of indigestible or undigested substances fro the GI tract
