Digestive Flashcards
wWhat are the 2 main types of organs of the digestive system? Which organs make up each type? (6, 6)
- alimentary canal
- mouth, pharynx, esophagus, stomach, SI, LI - accessory organs
- teeth, tongue, gallbladder, salivary glands, liver, pancreas
What are the 6 function of the digestive system?
Ingestion Propulsion Mechanical breakdown Digestion Absorption Defecation
What does mechanical breakdown involve? and where? (3)
- chewing in mouth
- churning in stomach
- segmentation in SI
What does propulsion involve (2)
swallowing (oropharynx)
peristalsis (esophagus, stomach, SI, LI)
Peristalsis and segmentation movements are a result of ___ contraction and relaxation.
smooth muscle
What are the 4 basic layers of the alimentary canal from inner to outermost layer?
Mucosa
Submucosa
Muscularis externa
Serosa
What is the function of the mucosa? (3) What are its 3 sublayers? What do each layer do?
Secretes mucus, digestive enzymes, and hormones
Absorbs end products of digestion
Protects against infectious disease
Three sublayers:
- epithelium secretes mucous/enzymes/hormones
- lamina propria contains capillaries for nourishment/absorption & lymphoid follicles (MALT)
- muscularis mucosae for movement of mucosa
What does mucous do? (2)
Protects digestive organs from enzymes
Eases food passage
what does the submucosa contain? (3)
blood/lymphatic vessels, nerves
What 2 movements is the muscularis externa responsible for? Which muscle is used for each movement? What kind of motion is it? Which muscle is the sphincters made of?
- segmentation = circular muscle (back and forth motion)
- peristalsis = longitudinal muscle (squeezing motion)
sphincter = circular layer
Serosa (visceral peritoneum) is replaced by ___ in the esophagus
adventitia
the mucosa, submucosa, and serosa are made of ___ tissue.
areolar connective tissue
What is the oral cavity bounded by? (4)
lips, cheeks, palate, and tongue
What are the hard and soft palates made of? What are their functions? What hangs from the soft palate?
hard palate = bone; create friction against tongue to help breakdown food
soft palate = skeletal muscle; closes off nasopharynx during swallowing
uvula hangs
What muscle is the tongue made of? What is its function? (5) What attaches it to the floor of the mouth? What enzymes gets secreted and what do they digest (2)?
-skeletal muscle
Functions
- Repositioning and mixing food during chewing
- Formation of bolus
- Initiation of swallowing, speech, and taste
- Lingual frenulum: attachment to floor of mouth
- lingual lipase = simple fats
- amylase = carbs
What is the function of a papillae? What are the 4 types of papillae of the tongue and which one do not contain taste buds?
- give sensations of touch
- filiform (do not contain taste buds), fungiform, vallate, and foliate
What are the major salivary glands? What is the difference between minor salivary glands?
- parotid, submandibular, sublingual (likes outside oral cavity)
- minor scattered throughout oral cavity
What are the functions of saliva? (4)
Cleanses mouth
Dissolves food chemicals for taste
Moistens food; compacts into bolus
Begins breakdown of starch with enzymes
Mumps is the inflammation of ___ gland.
parotid
What are the 2 types of secretory cells in salivary glands? What makes up each? Which ones are found in the paratid, submandibular, and sublingual glands?
serous cells: watery, enzymes, ions, mucin
-parotid & submandibular
mucous cells: mucus
-sublingual
What is the function of the teeth? why are 20 deciduous teeth replaced by 32 permanent teeth?
- Tear and grind food for digestion
- replaced to accommodate change in jaw size
What are the 4 different kinds of teeth and its functions?
incisors - cutting
canine - tear/pierce
premolar - grind/crush
molar - grind
State the dental formulas for both deciduous and permanent teeth.
In a tooth, ___ is the entry for blood vessels, nerves, which run in the ___.
apical foramen is the entry for blood vessels, nerves, which run in the pulp cavity
___ is the hardest substance in body. What is it used for? What cells produce them? What happens to these cells when the tooth erupts? What does this do?
enamel
force of chewing
Enamel-producing cells degenerate when tooth erupts > no healing if decay or crack
True or false
There are some movement in the root of tooth
true
___ anchors tooth in bony socket
Periodontal ligament
what is dentin?
bonelike material under enamel
(if time) What is in saliva? (7)
water, electrolytes, amylase, lipase, mucin, metabolic waste (urea & uric acid), lysozyme/IgA/defensins (etc. for immune function)
What is the passageway of food through the pharynx? It allwos passage of ___ (3). What cells line the epithelium?
mouth → oropharynx → laryngopharynx
Allows passage of food, fluids, and air
stratified squamous
The esophagus transports ___ from ___ of the mouth to ___,
-transport bolus from mouth (laryngopharynx) to stomach
What is heartburn? What are causes?
Stomach acid regurgitates into esophagus
-Likely with excess food/drink, extreme obesity, pregnancy, running
What is the function of the upper (2) and lower (1) esophageal sphincters?
Upper
- prevent air from entering the esophagus when breathing
- prevent reflux of esophageal contents into pharynx and blockage
Lower
-prevent reflux of stomach acid into the esophagus
What are the 3 layers muscle in the esophagus?
skeletal superiorily
mixed middle
smooth inferiorily
What are the 4 digestive processes of the mouth?
ingestion
Mechanical breakdown - Chewing
Propulsion - Deglutition (swallowing)
Digestion (salivary amylase and lingual lipase)
What body parts do deglutition involve? What are the 2 phases of deglutition? Are they voluntary or involuntary? Where are the control centers? Where do the larynx rise?
tongue, soft palate, pharynx, esophagus
- buccal phase - voluntary contraction of tongue
- pharyngeal-esophageal phase - involuntary by vegas nerve (control center in medulla & pons)
- here, uvula and larynx rise to prevent food from entering respiratory passageways
In the stomach, the bolus becomes ___.
chyme
In the stomach, what is the function of the cardiac and pyloric sphincters?
cardiac sphincter - prevent stomach contents from going back up into the esophagus
pyloric sphincter - controls passage of food down to the small intestine
What is the cardia?
where food enters from the stomach
function of fundus, body, and pylorus (3)
fundus = collect digestive gas body = secretes pepsinogen and HCl pylorus = secretes mucus, gastrin, pepsinogen
What are the 2 mesenteries of the stomach? What do they do?
lesser & greater omentum tether stomach
What is the additional muscle on top of circular and longitudinal found in the stomach, and what does it do?
Inner oblique layer allows stomach to churn, mix, move, and physically break down food
What is the function of rugae? (2)
increase SA for digestion and allow for distensibility of stomach
What cells make up the gastric glands of the stomach?
mucous cells, mucous neck cells, parietal cells, enteroendocrine cells
Gastric juice is mostly produced by these 2 areas of the stomach.
fundus & body
What does the parietal cell secrete? What do those secretions do? What is it also called?
HCl - activates pepsin
intrinsic factor - required for absorption B12 in SI
xynic cell
What does the chief cell secrete? (2) What is it also called?
pepsinogen - digest proteins
lipase - digest lipids
zymogenic cells
Pepsinogen activation is an example of ___
positive feedback mechanism (pepsin turns on more pepsinogen)
What de enteroendocrine cells secrete? (2) What is a specific example? What does that hormone do?
hormones (including gastrin) & paracrines
gastrin = turns on stomach
What is the function of mucous cells?
secrete mucous that protects stomach from HCl
The function of the mucosal barrier is to ___. They have ___ between epithelial cells. The damaged epithelial cells are also ___.
-protect from digestive enzymes
-tight junction (Prevent juice seeping underneath tissue)
replaced by rapidly dividing stem cells
What are the digestive processes that occur in the stomach? (6)
Mechanical breakdown
Denaturation of proteins by HCl
Enzymatic digestion of proteins by pepsin
Delivers chyme to small intestine
Lipid-soluble alcohol and aspirin absorbed into blood
Secretes intrinsic factor for vitamin B12 absorption
What is the one stomach function essential to life? What is it needed for? What is the disease called when do not have enough?
Secretes intrinsic factor for vitamin B12 absorption
B12 needed to mature red blood cells
Lack of intrinsic factor causes pernicious anemia
What produces gastrin? (2) What stimulates its secretion? What is its function? (2)
- pyloric antrun & duodenum
- vagus nerve stimulation (decreased secretion with sympathetic stimulation)
- turns on stomach (↑Enzyme and HCl secretion)