Lecture 16 - Gastrointestinal System Part I Flashcards
what are the seven main functions of the gastrointestinal system?
- ingestion
- mechanincal processing
- compaction
- digestion
- secretion
- absorption
- excretion
swirling, mixing, churning, propulsive motions along the entire GI tract
mechanical processing
dehydration of undigested material and converts waste into feces (colon to anus)
compaction
chemical and enzymatic breakdown of sugars, lipids, and proteins into small molecules (mostly occurs in the stomach)
digestion
movement of molecules, electrolytes, vitamins, and water into interstitial fluid (blood vessels –> liver –> heart –> rest of the body)
absorption
elimination of undigested residue and waste products
excretion
what are the main parts of the digestive tract?
oral cavity, pharynx, esophagus, stomach, small intestine, large intestine, and anus
what are the three main parts of the small intestine?
duodenum, jejunum, and ileum
what are the six main parts of the large intestine?
cecum, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum
what are the four main accessory organs/glands associated with the GI tract?
- salivary glands
- liver
- gallbladder
- pancreas
what are the four main layers of the GI tube?
- mucosa
- submucosa
- muscular externis layer
- serosa
made of epithelium (at the ends of the tube), lamina propria, and muscularis layers
mucosa layer
where are glands and immune cells found in the muscosa layer?
lamina proporia (connective tissue)
propels content of glands in the lumen
muscularis mucosa
a conduit for vasculature, nerves, and lymphatics (includes immune cells, some exocrine glands, and submucosal nerve plexus)
submucosa (connective tissue) layer
what is the muscularis externis?
the external muscle layer along the GI tube, contains and inner circular smooth layer and an outer longitudinal smooth layer
at the beginning and end of the GI tube, the muscularis externis is made of
skeletal (somatic) muscle
contains the myenetric plexus which controls GI motility
muscularis externis
layer of the GI tube made of simple squamous epithelium and connective tissue which continually produces watery fluid that lubricates the peritoneal surfaces
serosa layer
two layers of serosa is called the:
mesentery
the esophagus sits behind the:
respiratory system
why cant you swallow and breathe at the same time?
because the esophagus goes through the diaphragm and is pinched closed when the diaphragm contracts
which parts of the GI system are in the right upper quadrant of the abdomen?
liver, gall bladder, duodenum, head of pancreas, transverse colon, and right kidney
which parts of the GI system are in the left upper quadrant of the abdomen?
stomach, spleen, body and tail of pancreas, jejunum, transverse colon, and left kidney
which parts of the GI system are in the right lower quadrant of the abdomen?
ilieum, cecum, appendix, and ascending colon
which parts of the GI system are in the left lower quadrant of the abdomen?
ileum, descending and sigmoid colon
what are the three regions of referred pain in the abdomen?
epigastric region, umbilical region, and hypogastric region
where is the midclavicular plane?
vertical plane between the clavicles
where is the subcostal plane?
horizontal plane below the ribs (L1)
where is the intertubercular plane?
horizontal plane in the tubercles of iliac crests (L5)
runs from the abdominal esophagus to the descending part of the duodenum
the foregut
where does the foregut receive its vasculature and innervation from?
the celiac trunk (artery) and celiac ganglia (T7-T9)
runs from the descending part of the duodenum to the left colic flexure of the transverse colon
the midgut
where does the midgut receive its vasculature and innervation from?
the superior mesenteric artery (SMA) and SMA ganglia (T9-T11)
runs from the left colic flexure of the transverse colon to the rectum
the hindgut
where does the hindgut receive its vasculature and innervation from?
the inferior mesenteric artery (IMA) and IMA ganglia (T11-L1)
the superior mesenteric artery (SMA) supplies blood to the:
pancreas (1/2), duodenum (1/2), jejunum, ileum, cecum, appendix, ascending colon, and transverse colon
the celiac trunk supplies blood to the:
abdominal esophagus, stomach, spleen, liver, gallbladder, pancreas (1/2), and duodenum (1/2)
the renal artery supplies blood to the:
kidneys and adrenal glands
the gonal artery supplies to the:
ovaries and testes
the inferior mesenteric artery (IMA) supplies blood to the:
descending colon, sigmoid colon, and rectum
the splenic vein, SMA, and IMA, all drain into the:
hepatic portal vein
veins from the body wall (renal veins, common iliac veins, gonadal veins) drain directly into the:
inferior vena cava
all vasculature from the Gi tube will end up in the liver to be filtered via the:
hepatic portal vein
serous membrane lining the peritoneal (abdominal) body wall and organs
peritoneum
lines the peritoneal cavity (body wall)
parietal peritoneum
lining of the peritoneal organs
visceral peritoneum
2 layers of peritoneum which serves as a conduit for vessels, nerves, and lymphatics
mesentery (proper)
mesentery from the greater curvature of the stomach to the transverse colon (apron like)
greater omentum
mesentery from the lesser curvature of the stomach to the liver (important structures found here)
lesser omentum
- large pouch of mesentery that forms an apron shape
- has blood, nerves, and lymphoid tissues
- lipid deposition for temperature control
- has immunological function
these are characteristics of:
the greater omentum
which organs are retroperitoneal (behind the peritoneum)?
adrenal glands, kidneys, ureters, abdominal aorta, inferior vena cava, some anchoring organs (abdominal esophagus, most of the duodenum, pancreas, ascending and descending colon, and all pelvic organs
the oral cavity’s mucosal layer is made up of ____ which protects from ____
stratified squamous epithelium, abrasion/stress
what are the four major functions of the oral cavity?
1) sensory analysis of ingested material
2) mechanical digestion (teeth, tongue, palatal surfaces, cheeks)
3) lubrication by mixing ingested material with saliva
4) start of enzymatic digestion (mainly amylase)
name the three sets of tonsils
1) pharyngeal tonsils
2) palatine tonsils
3) lingual tonsils
name the three parts of the pharynx
- nasopharynx
- oropharynx
- laryngopharynx
what is the oral vestibule?
the space between the lips, cheeks, and teeth
is the pharynx part of the oral cavity?
no
name the four main layers of the tooth
1) enamel
2) dentin
3) pulp cavity
4) root canals
glues the tooth to the peridontal ligament
cement layer
fibrous connective tissue that connects the tooth to the maxilla/mandible (gomphosis)
peridontal ligament
what are the four types of teeth?
- incisors
- canines
- premolars (bicuspid)
- molars (multi-cuspid)
the upper dentition in the maxillae are innervated by the:
superior alveolar nerve of the maxillary branch of CN V
the lower dentition in the mandible are innervated by the:
inferior alveolar nerve of the mandibular branch of CN V
how many permanent teeth are there?
32
how many deciduous (baby) teeth are there?
20 (no premolars)
most tongue muscles are innervated by what nerve?
CN XII (hypoglossal nerve)
the intrinsic tongue muscle are responsible for:
the shape of the tongue (speech)
the extrinsic tongue muscles are responsible for:
swallowing (push the tongue superiorly and posteriorly)
where on the tongue are taste receptors found?
throughout all the different types of papillae
the body and root of the tongue are separated by the:
terminal sulcus
what is the function of salivary glands?
serous moistens food (enzymes) and mucus lubricates passage of food
what is saliva made out of?
- amylase (initiates carbohydrate digestion)
- buffers (regulate oral pH)
- antibodies (for immune surveillance)
saliva dissolves chemicals that:
stimulate the taste buds
are the salivary glands stimulated by the somatic or autonomic nervous system?
autonomic
extra salivary gland secretions are stimulated by:
- the presence of food in the mouth
- taste, sight, smell, or thought of food
