Digestive Anatomy - Part 1 Flashcards
Extends through the abdominal pelvic cavity and is open at both ends
Gastrointestinal (GI) tract
(Main organs of digestive system)
T/F
Ingested food material passing through the lumen of the GI tract is outside the internal environment of the body
True
How many tissue layers is the GI tract made of? What are they?
4
Mucosa, submucosa, muscularis, serosa
Wall of GI tract
Inner most, facing lumen (inside)
3 layers
-inner mucosa epithelium
-lamina propria loose CT
-muscularis mucosae thin SM
- Mucosa
Wall of GI tract
Thicker connective tissue (CT) layer contains small glands, blood vessels and parasympathetic nerves
- Submucosa
Wall of GI tract
Thick layer of muscle with an inner circular layer and outer longitudinal layer of smooth muscle (SM)
Contains nerves between the two layers of muscle called myenteric plexus (myenteric = inside/between muscles)
- Muscularis
Wall of GI tract
Outermost layer, a serous membrane
The visceral layer of the peritoneum - serous membrane that covers organs and lines abdominopelvic cavity
Serosa
The lining attached to and covering the walls of the abdominopelvic cavity
Parietal layer
The fold that connects the visceral and parietal layers
Mesentry
Popping in the middle of the tube (GI tract)
Lumen
Covered externally by skin and internally by mucous membrane; the junction between skin and mucous membrane is highly sensitive
Lips
*when lips are closed the line of contact is the oral fissure
Lateral boundaries of the oral cavity, continuous with the lips and lined by mucous membrane; formed in large part by succinct or muscles covered by adipose tissue, contain mucous secreting glands
Cheeks
*buccal muscles
Forms the partition between the mouth and nasopharynx and is made of muscle arranged in an arch
Soft palate
Consists of portions of four bones: two maxillae and two palatines
Hard palate
Where is the uvula situated?
Suspended from the midpoint of the posterior border of the arch
Solid mass of skeletal muscle covered by a mucous membrane; extremely maneuverable
Tongue
What are the 3 parts of the tongue?
Root, tip, body
T/F
4 types of papillae are located on the dorsal and lateral surfaces of the tongue, some has taste buds
True
What anchors the tongue to the floor of the mouth?
Lingual frenulum
*lingual vein is also on underside of tongue
T/F
Intrinsic muscles of the tongue are important for speech and mastication
Extrinsic muscles are important for deglutition (swallowing) and speech
True
How many main pairs of salivary glands are there?
3 (compound tubuloalveolar)
*secrete 1L of saliva each day
T/F
Buccal glands contribute less than 5% of the total salivary volume but provide hygiene and comfort of oral tissues
True
Largest of the paired salivary glands; produce watery serous type of saliva containing enzymes
Parotid glands
Compound glands that contain enzyme and mucous producing elements
Submandibular glands
Smallest of the salivary glands; produce a mucous type of saliva
Sublingual glands
What is the only type of serous gland?
Parotid
Organs of mastication
Teeth
-crown (exposed portion)
-neck (narrow portion that joints crown and root)
-root
See slide 13 for more information
The tube which a food bolus passes when moved from the mouth to the esophagus by the process of deglutition
-from mouth it goes through the faucets into the oropharynx and then laryngopharynx then to esophagus
*aids in speech
Pharynx
-tube that extends from the laryngopharynx to the stomach (25cm)
-first segment of the digestive tube
-lies posterior to the trachea and heart
-normally flattened in a relaxed state
Esophagus
How many parts of the esophagus are there?
3
-cervical
-thoracic
-abdominal
What two sections of the esophagus are lined with stratified squamous epithelium to provide a thick abrasion resistant surface for swallowing
Upper 2/3
Cervical and thoracic
What section of the esophagus is lined with columnar epithelium as a transition to the stomach lining
Lower 1/3
Abdominal
Striated, voluntary
Upper 1/3 - cervical
Striated, smooth
2/3 - middle
Thoracic
Smooth, involuntary
3/3 - lower
Abdominal
A muscular sphincter that acts like a valve to regulate the passage of material
In the cervical part and helps to prevent air from entering the esophagus during respiration
Upper esophageal sphincter
(UES)
*main muscle is called cricopharyngeus
-In the abdominal part of the esophagus and lies at the junction with the stomach
-also called the cardiac sphincter
-thick layer of muscle to help how food in the stomach to help prevent reflux (GERD)
Lower esophageal sphincter (LES)
T/F
When no food is in the stomach it is approx. the size of a large sausage
True
What is the capacity of the stomach in adults?
1-1.5L
Where is the stomach located?
Upper part of the abdominal cavity, under liver and diaphragm
Mostly to the left of midline in epigastrium and left hypochondrium regions of the abdomen
Collar like region of the stomach at junction of esophagus
Cardia
Enlarged portion of the stomach to the left and above the opening of the esophagus into the stomach
Fundus
Central portion of the stomach
Body
Lower part of the stomach
Pylorus
Where will the air be situated in stomach if the patient is erect?
Fundus
Upper curve of the stomach
Lesser curve
Lower left curve of the stomach
Greater curvature
Circular muscles arranged so an opening is in the center when relaxed and no opening is present when contracted
Sphincter muscles
Controls the outlet of the pyloric portion of the stomach into the duodenum
Pyloric sphincter
What are the 3 major secretory cells found in the gastric mucosa?
Chief cells, parietal cells, endocrine cells
Where are the gastric glands found?
Below the level of the gastric pits, the secrete most gastric juices
Secretory cells found in the gastric glands; secrete the enzymes of gastric juice
Chief cells
Secretory cells found in the gastric glands; secrete hydrochloride acid; thought to produce intrinsic factor needed for vitamin B12 absorption
Parietal cells
Secrets gastrin (influences gastric functions) and ghrelin, a hormone to increase appetite
Endocrine cells
Thick layer of muscle with 3 distinct sublayers of smooth muscle tissue
-longitudinal
-circular
-oblique*
*arranged in crisscross pattern
Gastric muscularis
What allows the stomach to contract strongly at many angles and to be very efficient at the mixing action
Muscles arranged in crisscross pattern
What is the digestive organ that needs an extra layer of muscle?
Stomach
*oblique layer
-2.5cm in diameter
-6m long
-coiled loops fill most of abdominal cavity
-smooth appearance
Small bowl
-Uppermost division of small bowl
-approx. 25cm long
-āCā shaped (sometimes)
Duodenum
-starts where tube takes abrupt turn forward and down
-approx. 2.5m long
-part of small bowel
Jejunum
Part of small bowel Approx. 3.5m long
Ileum
-6 cm diameter
-1.5-1.8m long
Large intestine
-first 5-8m of large intestine
-blind pouch located in the lower right quadrant of the abdomen
-appendix is attached to the
Cecum
-starts at cecum
-vertical position on right side of abdomen up to liver
Ascending colon
Where the ileum enters the cecum and then becomes the ascending colon, prevents material from passing from large intestine back into the ileum
Ileocecal valve
Where ascending colon turns into liver horizontally and becomes transverse colon
Hepatic flexure
Passes horizontally across the abdomen above small intestine, below liver, stomach and spleen; extends from hepatic flexure to splenic flexure
Transverse colon
Where transverse colon turns downward and becomes descending colon
Splenic flexure
Vertical position on left side of abdomen from the splenic flexure down, below the stomach and spleen to the level of the iliac crest
Descending colon
Joins the descending colon below iliac crest, is S shaped and bends to the left to join the rectum
Sigmoid colon
Gaping of large bowel (not smooth) caused by taeniae coli (like elastic in waist band)
Haustra
-last 20cm of the intestinal tube
-terminal inch is the anal canal
Rectum
T/F
In the anal canal the mucus lining is in vertical folds called anal columns
True
T/F
At the anus there are 2 sphincters
1. Internal - smooth muscle layer
2. External - striated muscle layer
True
What direction is the anus positioned?
Directed posterior at almost a right angle to the rectum
-accessory organ of digestive system
-8-10cm long
-communicates with cecum 3cm below ileocecal value
-right side
Veriform appendix
What is the function of the appendix?
-function not fully understood
-may breed intestinal bacteria to aid in digestion and absorption of nutrients
