Chapter 26: Digestive System SYDNEY Flashcards
Parts of the gastrointestinal tract (alimentary canal)
-food and waste
-food and saliva
-chyme
-digestive organs
-accessory digestive organs
what does food and saliva result in?
bolus
what is chyme?
paste-like material in stomach
what is the gastrointestinal tract?
pathway by which food enters the body and solid wastes are expelled
what does the gastrointestinal tract include?
includes the oral cavity, pharynx, esophagus, stomach, small intestine, large intestine, and anus
functions of the digestive system
-ingestion
-digestion
-secretion
-absorption
-elimination
2 types of digestion
-mechanical digestion
-chemical digestion
what is mechanical digestion?
-physical breakdown
-mastication = chewing
what is ingestion?
first step in the process of digestion and refers to the act of taking food and liquids into your mouth
what is digestion?
process by which the body breaks down the food you eat into smaller, more absorbable molecules.
what is chemical digestion?
-enzymes
-smaller molecules
what is secretion?
process of releasing digestive juices, enzymes, and other substances that aid in breaking down food so that nutrients can be extracted from it
what is absorption?
-process of taking the broken-down nutrients from digested food and delivering them into the body’s circulation system so they can be used to maintain and support various physiological functions.
-primarily takes place in small intestine
what is elimination?
-final stage of digestive process where it helps rid the body of waste and toxins
-primarily take place in large intestine
Parts of the oral cavity
-mouth
-lips to oropharynx
-hard palate & soft palate
-mylohyoid (forms floor of mouth)
-vestibule (outside teeth to lips)
-oral cavity proper (b/t teeth)
what is the biggest muscle in the oral cavity?
tongue
what type of muscle is the tongue?
skeletal muscle
parts of the tongue
-body
-root (lingual tonsil)
-lingual frenulum (tip to the floor of the mouth)
-papillae (superior surface)
functions of the tongue
-sound production
-food manipulation
-swallowing
what is the papillae?
tiny raised protrusions on the tongue that contain taste buds
4 types of papillae
-filiform
-fungiform
-vallate (back of the tongue)
-foliate (edge of the tongue)
which type of papillae has no taste buds and is bristle-like?
filiform
what is the largest part of the tongue?
vallate
functions of saliva
-moistens food
-cleans mouth
-inhibits pathogen growth
-salivary amylase starts digestion
types of salivary glands
-intrinsic
-extrinsic
function of intrinsic gland type
minor salivary gland that continually secrete small amounts of saliva to help maintain oral moisture
function of extrinsic gland type
major salivary gland that are responsible for producing most of the saliva during eating
features of intrinsic gland type
-small
-lingual lipase
-around oral cavity
features of extrinsic gland type
-larger
-multicellular
-pairs
-outside oral cavity
-amylase in saliva
3 types of extrinsic salivary gland types
-parotid glands
-submandibular glands
-sublingual glands
features of parotid glands
function: They produce a watery, enzyme-rich saliva that primarily helps with the initial breakdown of starches
-largest
-anterior to ear, lateral to masseter
-parotoid duct
-empties lateral, superior
features of submandibular glands
function: They produce a mixture of mucus and enzymes and contribute to both digestion and lubrication of the mouth.
-60-70%
-submandibular duct to lingual frenulum
features of sublingual glands
function: They produce thick, mucus-rich saliva, which helps to keep the mouth moist and assists in the initial stages of digestion.
-5%
-multiple ducts beneath & lateral to the tongue
parts of the teeth
-crown
-root
-dentin core
-deciduous
-permanent
what is the enamel a part of?
crown
parts of the root
-dental alveoli
-periodontal ligament
-cementum
-root canal
what is the pulp cavity a part of and what is the function?
-dentin core
-nourishes tooth
what are the deciduous teeth, how many teeth are in this category, and age of teeth?
-baby teeth
-lost
-20 teeth
-6 and 30 months
how many permanent teeth are there?
32 teeth
4 types of permanent teeth
-incisors
-canines
-premolars
-molars
what are the incisors?
front teeth and are designed for cutting and slicing food
what are the canines?
pointed teeth located on either side of the incisors, puncturing/tearing food
what are the premolars?
larger and have a flat biting surface with one or more cusps.
what are the molars?
largest and strongest teeth in the mouth, designed for grinding and crushing
refers to the cheek side of a tooth or the oral cavity
buccal
refers to the tongue side of a tooth or the oral cavity
lingual
chewing surface of a tooth; It is the top surface of the tooth that comes into contact with the opposing tooth when biting and chewing.
occlusal surface
describe a location or direction that is closer to the midline of the dental arch or closer to the front of the mouth
mesial
describes a location or direction that is farther away from the midline of the dental arch or closer to the back of the mouth
distal
parts of the pharynx
-oropharynx
-laryngopharynx
what is the vagus nerve, also known as the cranial nerve X (CN X) responsible for?
the vagus nerve has a pharyngeal branch in which muscles are innervated - process by which nerves supply signals to muscles, allowing them to contract and perform various functions. (ex: swallowing)
what is the glossopharyngeal nerve (cranial nerve IX) responsible for?
responsible for providing sensory innervation to the back of the throat, including the tonsils, the soft palate, and the back of the tongue.
3 phases of swallowing
-voluntary phase
-pharyngeal phase
-esophageal phase
what happens in the voluntary phase?
pushing food to hard palate
what happens in the pharyngeal phase?
-contact in oropharynx
-“gag reflex”
-larynx raises (epiglottis covers)
what happens in the esophageal phase?
-involuntary
-peristalsis
2 planes used to describe anatomical planes
-median plane (vertical plane)
-transumbilical plane (horizontal plane)
4 quadrants of the abdomen
-left upper
-left lower
-right upper
-right lower
features of the peritoneal cavity
-potential space
-visceral peritoneum
-parietal peritoneum
which organs are covered and not equally covered?
-intraperitoneal - completely
-retroperitoneal - only anterior surface of organ covered
specific retroperitoneal organs
kidneys, duodenum, pancreas, ascending colon, descending colon
Abdominopelvic cavity & linings
-peritoneal cavity
-mesenteries
-mesentery proper
-peritoneal ligament
-greater omentum
-lesser omentum
features of mesenteries
-folds of peritoneum
-contain nerves/vessels
-GI organs
where are the small intestines?
mesentery proper
feature of peritoneal ligament
-double layer of peritoneum
-no vessels/nerves
types of mesentery
-greater omentum
-lesser omentum
features of greater omentum
-between greater curvature of stomach and transverse colon
-inferior to pelvic cavity, then returns
features of lesser omentum
-connects lesser curvature of stomach to the liver
4 layers of digestive organs
-mucosa
-submucosa
-muscularis
-adventitia
features of mucosa
-around lumen (innermost layer)
-epithelial tissue (also supporting connective tissue & muscle)
features of submucosa
-areolar or dense irregular connective tissue
-vascular supply
-nerve supply
-sometimes lymph tissue and mucin glands
features of muscularis
-smooth muscle
-inner layer
-outer layer
-peristalsis by contractions
features of adventitia
-areolar connective tissue
-serosa if visceral peritoneum
where is the esophagus and how long?
-pharynx to stomach
-25 cm
features of the esophagus
-mediastinum: anterior to bodies
-esophageal hiatus: through diaphragm
-wall
what is the esophagus wall made up of/
-stratified squamous epithelium
-skeletal & smooth muscle
importance of mostly left upper quadrant of the stomach
-responsible for receiving food from the esophagus and beginning the process of mechanical and chemical digestion
-presence of the stomach in this area is vital for the breakdown of food into chyme: a partially digested mixture that will eventually enter the small intestine for further processing and absorption of nutrients.
greater curvature of stomach
-outer, more convex, and longer curve of the stomach
- site where most of the stomach’s blood vessels
lesser curvature of stomach
- inner, more concave, and shorter curve of the stomach
-where the stomach is attached to the liver by the lesser omentum. This connection helps support and stabilize the stomach
sections of the stomach
-cardia
-fundus
-body
-pylorus
where is the esophageal sphincter located?
cardia
features of the fundus
-dome-shaped
-above cardia
features of the pylorus
-terminal region
-funnel to small intestine
-pyloric sphincter: controls flow of chyme
features of the stomach wall
-gastric folds aka rugae
-muscularis
-mucosa
-cell type distribution
-peptic ulcer
what is rugae?
prominent, ridged or wrinkled folds of the mucosa (the inner lining) in the stomach
features of muscularis
-3 layers
-churning/blending
cells types found in gastric pits
-surface mucous cells
-mucous neck cells
-parietal cells
-chief cells
-gastric pits
tissue of mucosa in stomach wall
-simple columnar epithelium
features of surface mucosa cells
-continuous secretion
-acid protection
which cells have acidic mucus?
mucous cells
which cells secrete hydrochloric acid to create highly acidic environment in the stomach?
parietal cells
which cells produce enzymes and pepsin (active enzyme that plays a crucial role in the digestion of proteins)?
chief cells
what are gastric pits?
-depressions in the mucosal lining of the stomach
-openings of glands
-mucous neck cells, parietal cells, chief cells
what happens in cell type distribution?
-all cell types in body and fundus
-only mucous secreting cells in pylorus and cardia
function of mucosa
reduces acidity of chyme
erosion of the protective mucus lining by acids
peptic ulcer
type of digestion that occurs in small intestine
complete chemical digestion
features of the small intestine
-absorb 90% of all nutrients and water
-20 ft long
-thing walled tube
where does the small intestine begin and end?
starts at pylorus and ends at cecum
3 regions of small intestine
-duodenum
-jejunum
-ileum
-first and shortest segment of the small intestine 10-12 in long
- further digestion of food and the neutralization of stomach acid
-brunner glands (submucosal glands)
-alkaline mucus
duodenum (major duodenal)
-middle section of the small intestine and is approximately 8-9 ft long
-this is where the majority of nutrient absorption takes place
jejunum
-final and longest portion of the small intestine, extending for about 12-15 feet
-further absorb any remaining nutrients and to reabsorb bile salts; immune response to gut pathogens
-Peyer’s patches (collections of lymphoid tissue that play a role in the immune system)
ileum (ileocecal valve)
features of mucosa of small intestine
-circular folds
-intestinal crypts
covering of circular folds
villi covering
tissue type of circular folds
simple columnar epithelium w/ microvilli
appearance of circular folds
only color change visible under light microscope
function of circular folds
increase surface area
features of intestinal crypts
-b/t villi
-goblet cells, unicellular glands, enteroendocrine cells
-secrete hormones regulating digestion, mucus, enzymes
features of large intestine
-5 ft long
-larger diameter
-perimeter of abdominal cavity
functions of large intestine
-absorbs water & ions
-absorbs some nutrients
-stores feces
parts of large intestine
-cecum
-ascending colon
-right colic flexure
-transverse colon
-left colic flexure
-descending colon
-sigmoid colon
-rectum
-anal canal
where is the vermiform appendix located?
cecum
features of vermiform appendix of large intestine
-walls full of lymphatic tissues (lymphocytes)
-appendicitis
what happens to someone with appendicitis?
-inflammation of appendix
-risks bursting - worse infection
-blockage by fecal matter
-pain localized to lower right quadrant
-antibiotic treatment (appendectomy if persistent)
mucosa of large intestine
-simple columnar epithelium
-intestinal glands
-no villi
muscularis of large intestine
-2 layers
-teniae coli
-haustra
-omental appendices
features of teniae coli
-outer longitudinal layer
-three ribbons
feature of haustra
-bunches large intestine into sacs
feature of omental appendices
-lobules of fat
movement of large intestine
-haustral churning
-mass movements
what happens during haustral churning?
-stimulated by distention
-mixes material & moves it to next haustran
what happens during mass movements?
-tenea coli contract & propel fecal matter towards rectum
-3 times a day
-gastrocolic flexure
features of rectum
-straight retroperitoneal distal portion
-expands to store fecal matter
-rectal valves
functions of rectal valves
-transverse folds
-retain fecal matter as gas is passed
parts of anal canal
-terminal few centimeters
-anal sinuses
-internal anal sphincter
-external anal sphincter
what type of tissue is the anal canal?
stratified squamous epithelium
features of anal sinuses
-depressions in anal canal
-release mucin when compressed
-lubricate feces
what type of muscle is the internal anal sphincter?
involuntary muscle
what type of muscle is the external anal sphincter?
voluntary muscle
general parts of the liver
-right upper quadrant
-largest internal organ
-4 lobes
left lobe of liver
-separated from right by falciform ligament
-round ligament of liver (fetal remnant)
right lobe of liver
-caudate lobe
-quadrate lobe
functions of liver
-produces bile
-detoxifies active molecules (drugs, poisons)
-store excess nutrients & vitamins
-synthesize blood plasma proteins (clotting factors)
-recycle old red blood cells
features of liver
-hepatic portal vein
-hepatic artery proper
-blood through hepatocytes to hepatic veins
what happens during cirrhosis?
-degenerative loss of hepatocytes
-hepatic portal hypertension
-liver failure
-liver transplant
what happens during degenerative loss of hepatocytes?
-chronic injury to hepatocytes
-scar tissue
-irreversible
features of the gall bladder
-inferior surface of liver
-sac stores bile (released during digestion)
-bile-green fluid helps break down fats
features of bile ducts
-common hepatic duct
-cystic duct
-common bile duct
where does the common hepatic duct come from?
comes from the liver
where does the cystic duct come from?
-comes from gall bladder
-biles flows into gallbladder and out
what happens in the common bile duct?
-joining of the two (common hepatic duct and cystic duct)
-goes to the duodenum (major duodenal papilla)
features of the pancreas
-retroperotineal organ
-medial duodenum to the spleen
mixed gland (both exocrine and endocrine functions)
pancreas exocrine function
-exocrine
-pancreatic juice
-pancreatic duct
cells in the pancreas exocrine and type of tissue
-acinar cells
-simple cuboidal epithelium
parts of pancreatic juice
-mucin
-digestive enzymes
-bicarbonate
where does neutralizing stomach acid happen?
bicarbonate
where is the major duodenal papilla located?
pancreatic duct
pancreas endocrine function
-pancreatic islets
-diabetes mellitus
features of pancreatic islets
-1% of pancreas
-hormones (glucagon, insulin)
features of diabetes mellitus
-insufficient glucose uptake from blood
-excess is urinated
-Insulin-dependent and independent forms
