Chapter 23 Digestive System Flashcards
what is the difference between the alimentary canal and the accessory organs?
alimentary canal is the site of actual food passing through and nutrients being absorbed
accessory organs will not have food passing directly through, but still aid in digestion
what are the 6 organs of the alimentary canal in order?
mouth
pharynx
esophagus
stomach
small intestine
large intestine
how long is the entire alimentary canal if relaxed
30 feet
what are 6 accessory organs that assist in digestion?
salivary glands
teeth
tongue
liver
gallbladder
pancreas
describe what happens to food during ingestion
physically taking food into digestive tract via mouth
describe what happens to food during propulsion
peristalsis allows food to propel towards anus
describe the directional movement of peristalsis
waves of coordinated smooth muscle contractions leading only towards anus
describe what happens to food during mechanical digestion
physical forces break food apart
can either be from chewing or segmentation
what is another word for chewing?
mastication
describe the movement of food in segmentation
alternating contractions of nonadjacent segments allowing food to move back and forth to mix with digestive juices
describe what happens to food during chemical digestion
chemicals break down macromolecules
what are the types of chemicals used in chemical digestion
nonspecific - attacks all kinds of organic food molecules
specific - attack specific type of organic molecules
name an example of a nonspecific chemical used in chemical digestion
acid in our stomach
what do carbohydrates get broken down into?
sugar/ monosaccharides
what do proteins get broken down into?
amino acids
what do fats get broken down into?
fatty acids
describe what happens to food during absorption
intake of nutrients occur
describe what happens to food during defecation
elimination of indigestible substances through feces
what are the nutrients that get absorbed?
digested food molecules
vitamins
minerals
water
what are the four layers of the alimentary canal walls in order of inner to outer layers
mucosa
submucosa
muscularis externa
serosa
what are the three layers found within the mucosa?
epithelium
lamina propria
muscularis mucosae
what is the function of the mucosa?
secretion of mucus, enzymes, and hormones
absorption of nutrients
protection from pathogens
what is the structure/function of the epithelium within the mucosa?
simple columnar epithelium: secretion, absorption, protection
contains goblet cells: aids in secretion
what is the function of goblet cells?
exocrine glands that secrete mucus into the lumen of the alimentary canal
what is the structure/ function of the lamina propria of the mucosal layer?
loose areolar connective tissue
contains blood vessels: to deliver and collect nutrients
contains lacteals: for fat transport
contains immune cells: for immune surveillance
what is the structure/ function of the muscularis mucosae?
thin layer of smooth muscle responsible for SMALL local movements
what is the structure/function of the submucosa?
irregular connective tissue
contains blood vessels, nerves and lymphatic vessels
contains intrinsic submucosal nerve plexus to regulate glands and muscularis mucosae
what is the structure of the muscularis externa?
contains 2 layers of smooth muscle
-inner circular layer
-outer longitudinal layer
what is the function of the muscularis externa? what allows for this function?
responsible for big movements such as peristalsis and segmentation
intrinsic myenteric nerve plexus between 2 layers of smooth muscle
what is the function of the serosa?
protect and connect
what is the structure of the serosa?
2 layers
-inner areolar connective tissue
-outer simple squamous “mesothelium”
what is another name for serosa?
visceral peritoneum
what are the layers of the peritoneum?
parietal peritoneum (lines body wall)
visceral peritoneum (lines organs)
what is the structure of mesentery?
layer of peritoneum attaching some organs to the abdominal wall
what is the function of the mesentery?
route for vessels and nerves
hold organs in place
stores fat
what is the difference between intraperitoneal organs and retroperitoneal organs?
intraperitoneal - are suspended from the abdominal wall by a mesentery
retroperitoneal - are attached directly to the abdominal wall
what is the benefit of the organs being intraperitoneal?
it allows for freedom of movement during digestion
what are examples of intraperitoneal organs?
stomach
jejunum
ileum
transverse colon
sigmoid colon
what is the benefit of the organs being retroperitoneal?
organs cannot be hypermobile and twist and knot themselves
what are the examples of retroperitoneal organs?
duodenum
liver
pancreas
ascending colon
descending colon
when did retroperitoneal organs lose their original mesentery?
during fetal development
what is the structure/function of the oral cavity?
struct: is continuous with oropharynx
funct: only site of ingestion
what is the top and bottom lip called?
labium superious oris
labium inferius oris
where does our upper lip begin? our bottom lip?
bottom border of nose
border of chin
what is the red/pinkish part of our lips called?
vermillion of the lips
what tissue is the vermillion composed of?
nonkeratinized stratified squamous epithelium
what is the labial frenulum? how many do we have?
flap of tissue connecting lips to gums
2: superior and inferior labial frenulum
what is the only skeletal muscle we have that has only one attachment point called?
the tongue
what is the lingual frenulum?
connects tongue to floor of oral cavity
what is the function of the tongue?
licking, tasting, food bolus formation
what is a bolus?
chewed up food
what was wrong with sawa’s lingual frenulum?
it was shorter than normal (she had a tongue-tie)
what are the four types of papillae called
filiform papillae
fungiform papillae
vallate papillae
foliate papillae
what is the structure/function of the filiform papillae?
conical in shape
contains keratin (white)
roughens surface to be able to lick semisolids
what is the structure/function of the fungiform papillae?
round (like a mushroom)
houses taste buds for tasting
where are filiform and fungiform papillae found?
anterior surface of tongue
which papillae is most abundant?
filiform papillae
what is the structure/function of vallate papillae?
V-shape
“wall” between body and root of tongue
houses taste buds for tasting
where is the location of vallate papillae?
back of tongue
what is the structure and location of the foliate papillae?
ridges on lateral sides of posterior tongue
what is the function of foliate papillae?
house taste buds BUT only in use during infancy and early childhood
what are the taste bud containing papillae?
fungiform
vallate
foliate (but only active in childhood)
what are the 2 types of salivary glands?
extrinsic salivary glands
buccal (intrinsic) salivary glands
which Type of salivary gland produces the most saliva?
extrinsic salivary glands
where are extrinsic salivary glands located? how many are there?
outside oral cavity
3 main pairs
where are buccal salivary glands located? what is their size in comparison to extrinsic?
inside oral cavity mucosa
smaller
what are the four functions of saliva?
- dissolves food which allows for tasting
- cleans mouth (innate immunity)
- lubricates for swallowing
- contains enzymes which begin chemical digestion
Is saliva hypertonic or hypotonic?
99% water, making it hypotonic
what protective proteins are found in saliva?
IgA
lysozyme
what digestive proteins are found in saliva?
mucin
alpha amylase
lingual lipase
what is the function of alpha amylase in our saliva
break down carbohydrates
what is the function of lingual lipase in our saliva?
break down fats
what is the function of mucin in our saliva?
protein that makes mucus allowing for lubrication
how much saliva do we make?
1 liter of saliva per day
which nervous system is responsible for activation of parotid glands?
parasympathetic nervous system
what are the factors that increase saliva production?
sensory input (seeing/smelling food)
chemoreceptors in mouth
mechanoreceptors in mouth
what is xerostomia?
dry mouth
what causes xerostomia?
activation of sympathetic nervous system
dehydration
what is halitosis?
bad breath
what does xerostomia cause?
increased cavities
difficulty talking and swallowing
slow food digestion
what is the function of teeth?
mechanical digestion
mastication
what are the three main parts of a tooth?
crown (exposed part of tooth)
neck
root (embedded in jaw)
what are the three layers of the teeth?
enamel
dentin
cementum
which layer of teeth is the hardest?
enamel
can enamel be replaced?
no
what is the structure/function of cementum?
calcified connective tissue
covers entire root
helps to anchor tooth inside socket
what is the structure/ function of dentin?
bone-like material (not as hard as enamel)
surrounds pulp cavity
can new dentin be made?
yes
what is within the pulp cavity?
blood vessels and nerves
Without sufficient, saliva mouth won’t be washed out, allowing for bacteria to accumulate causing cavities