digestive Flashcards
What region of the body is the appendix found?
right inguinal ((right illac region)
What region of the body is the bladder found?
hypogastric (pubic region)
What region of the body does the gallbladder sit?
right hypochondriac region
Where does the skeletal muscle stop in the alimentary canal?
About 2/3 of the way down the esophagus. The rest is smooth muscle.
What is propulsion?
Moving stuff from the front of the tube to the back of the tube
What are voluntary types of propulsion?
Swallowing
What are the involuntary movements of the GI tract?
Peristalsis and segmentation
Where does peristalsis occur in the GI tract?
in the entire GI tract
What is peristalsis?
continuous slow movement of substances in boluses that are going all the way down the tube.
-squeezes above bolus
What is segmentation?
squeezing above and below the boluses of food
- mixes the contents together.
- peristalsis keeps moving it down.
Where is segmentation important?
small intestine
What are the four layers of the alimentary canal?
Mucosal
submucosal
muscularis externa
serosa
Describe the mucosal layer
- lining epithelium +lamina propria (ct)
- muscularis mucosa
What is the function of the muscularis mucosa?
dislodges stuff that is irritating the lining
Describe the submucosal layer
- CT tissue. lots of vasulature and nervous tissue. glands are embedded here.
- very elastic
Describe the musuclaris externa
- most cases has two layers of smooth muscle but may have 3.
- deep is the circularly arranged
- above that is the longitudinally arranged.
- responsible for segmentation and peristalsis
Describe the serosa
-visceral peritoneum
What lines most of the GI tract?
Simple columnar epithelium
Glands embedded in the submucosa dump where?
In the lumen, the duct portion is continuous with the mucosal layer.
What tissue makes the serosa?
simple squamous
What is mesentery?
when the two sides of the serosa come together and form a double layer of simple squamous epithelium with vessels and nerves in the middle of it.
What are the differences between smooth muscle cells and skeletal muscle cells/cardiac muscle cells?
No striations, not multinucleate (nucleus is centrally placed)
What function like z-discs in the smooth muscle cells?
dense bodies
How do smooth muscle cells contract
- intermediate filametns line up like a chain linked fence attaching to the dense bodies.
- the contractile proteins slide along one another but in random directions causing a corkscrew type of contraction
What do the gap junctions do in smooth muscle cells in the GI tract?
Allow for electrical coupling. some cells may not be innervated but the adjacent cell may be allowing the cell next to it to contract as well.
What is the peritoneum?
The serous membrane of the abdominopelvic cavity.
What are the two ventral mesenteries?
lesser omentum and the falciform ligament
What are the dorsal mesenteries?
the greater omentum - - hangs off of the greater curvature of the stomach, transverse mesocolon, mesentery proper (attached to the small intestine), sigmoid mesocolon.
What is the purpose of the ventral mesenteries
to attach these organs to the ventral body wall
Which organs have mesentery?
Stomach, ileum & jejunum, transverse colon, sigmoid colon
Which mesentery is associated with the stomach?
greater and lesser omentum
Which mesentery is associated with the liver
falciumform ligament, lesser omentum
Which mesentery is associated with the ileum & jejunum
mesentery proper
Which mesentery is associated with transverse colon
transverse mesocolon
Which mesentery is associated with sigmoid colon
sigmoid mesocolon
Which organs are not associated with mesentery
duodenum, ascending colon, descending colon, rectum, pancreas
What anchors your lips or labia to the gingivaee (gums)
the superior and inferior labial frenulums
What anchors the tongue to the floor of the oral cavity?
LINGUAL FRENULUM
Which ducts open right next to the lingual frenulum?
the submandibular ducts
where are the sublingual ducts found?
along the sublingual fold inferior to the tongue next to the submandibular duct opening
Where is the parotid gland and what is it?
by the ear
- salivary gland that secretes enzymes with it.
- duct cuts across cheek and opens around the second molar
Describe the structure of the tongue
Has external and internal muscles
Internal muscles: change the shape of the tongue and are not attached to any bones, anchored to the external muscles
External muscles: are attached to bones of the skull and hyoid and change the tongues position
-work together to dodge your teeth while chewing.
What is the function of the genioglossus muscle
Provides the tongue with tone so that it does not slide back into your throat.
Are the bumps on your tongue taste buds?
no
Describe the vallate papillae (cirucmvallate papillae)
Anterior to the terminal sulcus.
-has taste buds associated with it.
Describe the fungiform papillae
taste buds are associated
on the anterior 2/3
look like little mushrooms
describe the filiform papillae
no taste buds assocaited
function in making food move posteriorly
look like white bumps on the surface of the tongue
Explain the muscular proces of swallowing
- Suprahyoid muscle: contracts and pulls the larynx up causing the epiglottis to cover the opening of the larynx.
- Pharyngeal contrcitor muscle: begins to squeeze pushing food into the esophagus
- Infrahyoid muscle: pulls the larynx back to it’s original position.
What are the layers of the esophagus
Mucosa: non-keratinized stratified squamous epithelium
Submucosa: mucous glands
Muscularis externa: top 1/3 is skeletal muscle – then there is a transition of skeletal and smooth muscle. By 2/3 of the esophagus there is only smooth muscle (circular and longitudinal layer)
NO SEROSA
What is the esophagus
collapsible tube extending from the pharynx to the stomach
Where is there an abrupt change in the musocal lining of the alimentary canal?
Right at the cardiac sphincter the mucosal lining changed to simple columnar epithelium
What happens in the stomach?
Food is stored for about 4 hours and is churned to turns into chyme
first site of protein breakdown
widest part of the alimentary canal
What are the muscles layers of the muscularis externa in the stomach?
Oblique, circular, longitudinal
How is the cardiac sphincter/pyloric sphincter made and what is it’s purpose?
Thicker circular layer of the muscularis externa
-closes off the stomach so that none of the acid or chyme goes back up into the esophagus
What are rugae?
non-permanent folds in the lining of the stomach. when the stomach is distended they disappear.
What are gastric pits?
pits with ducts that lead to gastric glands that are multicellular exocrine glands that secrete chief cells and parietal cells into the lumen of the stomach.
-found in the mucosal layer.
What do chief cells make? what do parietal cells make? what do they both make when combined?
pepsinogen; HCL; pepsin
What is pepsin?
the enzyme that breaks down proteins
What is the small intestine
Longest part of the alimentary canal and the site of the most enzymatic digestion
Where do most digstive enzymes get secreted from?
The pancreas; acessory organ
What are plicae circularis?
permanent circular folds in the small intestine (visible without microscope)
what are haustra?
caused by tenia coliea (contracted longitudinal layer of the muscularis externa) causing bulges in the colon
what are epiploic appendages?
sacs of fat hanging off of the tenia colae and no apparent function
Is there serosa in the rectum? why
NO because it is retroperitoneal
What are anal columns and anal sinuses?
ridges in the anal canal right before the pectinate line and anal sinuses are the gaps in between the ridges.
What happens to the mucosal lining at the pectinate line?
there is a sharp transition between simple squamous epithelium to stratified squamous
What do we call the part outside of the anal canal, past the pectinate line?
the anus
What happens to the lining of the anus?
transitions from a non-keratinized stratified squamous to a keratinized stratified squamous
What type of muscles are the internal and external anal sphincters?
internal = smooth external = skeletal
What muscle controls whether or not the anus opens?
internal anal sphincter
What is the levator ani muscle?
lifts the anus up and out a little bit to help with defacating
skeletal muscle
What are hemmorhoidal veins?
all of the veins associated with the mucosal and submucocal layer of the anus and genital region
What are hemmorhoids?
varicose veins in the anus. enlarged, very itchy.
Internal hemmorhoid: above the pectinate line (don’t feel them but bleed more)
External hemmorhoid: below the pectinate line, hurt more but don’t bleed as much.
Why do we have goblet cells in the simple columnar epithelium of the colon?
because as you move more distal in the colon, water is being absorbed and the mucus serves a lubricating agent so that the feces does not damage the walls of the colon
