Term 4 Digestive System Flashcards
1
Q
What are the two groups of organs in the digestive system?
- _______\_ – alimentary canal, ~5-7 m long, a tube extending from the mouth to the anus through the ventral body cavity
- ________\_ – assist the digestion process e.g. mechanically and enzymatically breaking down food
A
What are the two groups of organs in the digestive system?
- Gastrointestinal (GI) tract – alimentary canal, ~5-7 m long, a tube extending from the mouth to the anus through the ventral body cavity
- Accessory digestive organs – assist the digestion process e.g. mechanically and enzymatically breaking down food
2
Q
Gastrointestial (GI) tract Includes:
- ____\_
- ____\_
- ____\_
- ____\_
- ____\_
- ____\_
A
Gastrointestial (GI) tract Includes:
- Mouth
- Pharynx
- Esophagus
- Stomach
- Small intestine
- Large intestine
3
Q
Accessory organs include:
- _____\_
- _____\_
- _____\_
- _____\_
- _____\_
- _____\_
A
Accessory organs include:
- Teeth
- Tongue
- Salivary glands
- Liver
- Gall bladder
- Pancreas
4
Q
The GI tract is composed of four basic layers:
- _________
- _________
- ________
- ________
A
The GI tract is composed of four basic layers:
- Mucosa (deep)
- Submucosa
- Muscularis
- Serosa or adventitia (superficial)
5
Q
Inner lining of GI tract is a mucous membrane containing:
- ______\_– specialized in absorbing digestive nutrients and contains enteroendocrine cells
- ______\_ – areolar connective, blood and lymphatic vessels and MALT
- ______\_– smooth muscle fibres whose movement increase surface and ensures all absorptive cells are exposed to GI content
A
Inner lining of GI tract is a mucous membrane containing:
- Epithelial cells – specialized in absorbing digestive nutrients and contains enteroendocrine cells
- Lamina propria – areolar connective, blood and lymphatic vessels and MALT
- Muscularis mucosa – smooth muscle fibers whose movement increase surface and ensures all absorptive cells are exposed to GI content
6
Q
- The _______ is:
- Thin meshwork of collagenous fibres, nerves and blood vessels
- Areolar connective tissue binds the mucosa to the middle layer (muscularis)
- Highly vascular
- Contains the submucosal plexus (plexus of Meissner)
A
Submucosa
7
Q
Muscularis:
- Consist of smooth muscle
- Inner sheet of _____\_
- Outer sheet of _____\_
- Contains the ______\_ (plexus of Auerbach)
- Controls _________(movement of chyme)
A
Muscularis:
- Consist of smooth muscle
- Inner sheet of circular fibers
- Outer sheet of longitudinal fibers
- Contains the myenteric plexes (plexus of Auerbach)
- Controls GI tract motility (movement of chyme)
8
Q
Serosa (Adventitia):
- ______\_ layer of the GI tract
- A ______\_ composed of areolar connective tissue and simple squamous epithelium (mesothelium)
- The epithelium is also called the ______\_ as it forms the peritoneum that surrounds organs that are suspended in the peritoneal cavity
- Secretes a ______\_
- Derived from ______\_ of surrounding tissue
A
Serosa (Adventitia):
- Superficial layer of the GI tract
- A serous membrane composed of areolar connective tissue and simple squamous epithelium (mesothelium)
- The epithelium is also called the visceral peritoneum as it forms the peritoneum that surrounds organs that are suspended in the peritoneal cavity
- Secretes a serous fluid
- Derived from interstitial fluid of surrounding tissue
9
Q
-_______\_is a single layer of areolar connective tissue that surround the esophagus and lower aspects of the rectum (these lack serosa)
A
Adentitia is a single layer of areolar connective tissue that surround the esophagus and lower aspects of the rectum (these lack serosa)
10
Q
_______\_ is the largest serous membrane of the body and is divided into 2 portions:
- _______\_ – lines the wall of the peritoneal cavity
- _______\_ (serosa)
-
_______\_ is the space between the parietal and visceral peritonea
- Contains __________fluid
A
Peritoneum is the largest serous membrane of the body and is divided into 2 portions:
- Parietal peritoneum – lines the wall of the peritoneal cavity
- Visceral peritoneum (serosa)
-
Peritoneal cavity is the space between the parietal and visceral peritonea
- Contains serous fluid
11
Q
The Peritoneum contains 7 major fat-filled folds:
Which two can be seen in the attached image:
- ______\_ – largest, drapes over the transverse colon and the coils of the small intestine like a “fatty apron”
- ______\_– attaches liver to the anterior abdominal wall and diaphragm
A
The Peritoneum contains 7 major fat-filled folds:
Which two can be seen in the attached image:
- Greater omentum – largest, drapes over the transverse colon and the coils of the small intestine like a “fatty apron”
- Falciform ligament – attaches liver to the anterior abdominal wall and diaphragm
12
Q
The Peritoneum contains 7 major fat-filled folds:
Which one can be seen in the attached image:
- _____\_ – suspends the stomach and duodenum from the liver
A
- Lesser omentum – suspends the stomach and duodenum from the liver
13
Q
The peritoneum contains 7 major fat-filled folds
Which one can be seen in the attached image?
- ______ – fan-shaped; binds the jejunum and ileum to the posterior abdominal wall
A
Mesentery – fan-shaped; binds the jejunum and ileum to the posterior abdominal wall
14
Q
What are the 3 pairs of major salivary glands?
-
______\_
* Parotid (Stensen’s) duct opens into the ______\_opposite the ______\_ tooth -
______\_ – located beneath the tongue
* Submandibular (Wharton’s) ducts opens into the ______\_on either side of the ______\_ -
______\_ - located in the floor of the mouth, superior to the submandibular glands
* Lesser sublingual (Rivinus’) ducts open into the ______\_
A
What are the 3 pairs of major salivary glands?
-
Parotid glands
* Parotid (Stensen’s) duct opens into the vestibule opposite the second maxillary molar tooth -
Submandibular glands – located beneath the tongue
* Submandibular (Wharton’s) ducts opens into the oral cavity on either side of the lingual frenulum -
Sublingual glands - located in the floor of the mouth, superior to the submandibular glands
* Lesser sublingual (Rivinus’) ducts open into the floor of the mouth
15
Q
The tongue is an accessory digestive organ composed of _____\_muscle covered with _____\_
A
The tongue is an accessory digestive organ composed of skeletal muscle covered with mucous membrane
16
Q
______\_ is a fold of mucous membrane that connects the tongue to the floor of the mouth
A
Lingual frenulum – fold of mucous membrane that connects the tongue to the floor of the mouth
17
Q
The tongue is divided into lateral halves by a ____ _____ ______
- inferiorly, this attaches to the _______
A
The tongue is divided into lateral halves by a median fibrous septum
- inferiorly, this attaches to the hyoid bone
18
Q
Tongue muscles are of two types:
- _______\_ - originate outside the tongue and insert into it, moving the entire tongue in various directions
-
_______\_ - originate and insert within the tongue, altering the tongue’s shape
- Named by the direction of the muscle fibres – anterior longitudinal, posterior longitudinal, transverse and lateral
A
Tongue muscles are of two types:
- Extrinsic tongue muscles - originate outside the tongue and insert into it, moving the entire tongue in various directions
-
Intrinsic tongue muscles - originate and insert within the tongue, altering the tongue’s shape
- Named by the direction of the muscle fibres – anterior longitudinal, posterior longitudinal, transverse and lateral
19
Q
Extrinsic muscles that move the tongue
- _______\_ – depress and protracts (stick out) tongue
- _______\_ – elevates and retracts tongue
- _______\_ – depresses tongue and draws down its sides
- _______\_ – elevates posterior portion of the tongue
A
Extrinsic muscles that move the tongue
- Genioglossus – depress and protracts (stick out) tongue
- Styloglossus – elevates and retracts tongue
- Hyoglossus – depresses tongue and draws down its sides
- Palatoglossus – elevates posterior portion of the tongue
20
Q
The teeth:
- sit in sockets of ______\_ of the ______ (bone) and ______ (bone)
- Alveolar processes are covered by _____\_(gums) that extend slightly to form the _____\_
- Sockets are lined by _____\_ ligament that anchors teeth and absorbs shock when chewing
A
The teeth:
- sit in sockets of alveolar processes of the mandible and maxillae
- Alveolar processes are covered by gingivae (gums) that extend slightly to form the gingival sulcus
- Sockets are lined by periodontal ligament that anchors teeth and absorbs shock when chewing
21
Q
Teeth consist of three major regions:
- visible portion above the gum line
- 1 to 3 embedded in the socket
- junction between crown and root, near gum line
A
Teeth consist of three major regions:
- Crown- visible portion above the gum line
- Roots - 1 to 3 embedded in the socket
- Neck - junction between crown and root, near gum line
22
Q
Most of the tooth is ______.
Label ^ along with the following structures that make up the tooth:
- Pulp cavity
- Root Canals and their openings:
- Apical foramen
- Enamel
- Cementum
A
23
Q
The_______ (milk teeth) begin to erupt at ~6 months old
- One pair appears every month until 20 teeth present (~2 yrs old)
A
The Deciduous teeth (milk teeth) begin to erupt at ~6 months old
- One pair appears every month until 20 teeth present (~2 yrs old)
24
Q
There are 32 _______\_ that appear between age 6 and adulthood (~21 yrs old)
A
There are 32 permanent teeth that appear between age 6 and adulthood (~21 yrs old)
25
The _____ (throat) extends from the internal nares to the esophagus posteriorly and the larynx anteriorly.
It is composed of ______ muscle and lined by \_\_\_\_\_\_\_\_
The _pharynx_ (throat) extends from the internal nares to the esophagus posteriorly and the larynx anteriorly.
It is composed of _skeletal_ muscle and lined by _mucous_
26
Which of the following structures only function in respiration?
* Nasopharynx - only respiration
* Oropharynx - digestive and respiratory functions
* Laryngopharynx
* **Nasopharynx - only respiration**
* Oropharynx - digestive and respiratory functions
* Laryngopharynx - digestive and respiration
27
What is deglutition?
Term for swallowing:
mechanism that moves food (bolus) from the mouth, through the pharynx and to the stomach
28
The _____ is a muscular, collapsible tube from the laryngopharynx to the stomach
Esophagus
29
The esophagus lies in the _______ (anterior to the _____ and posterior to the \_\_\_\_\_\_) and passes through the ________ in the diaphragm
The esophagus lies in the _mediastinum_ (anterior to the _spine_ and posterior to the _trachea_) and passes through the _esophageal hiatus_ in the diaphragm
30
The wall of the esophagus is composed of the following 4 layers:
1. ______ - contains glands near stomach
2. ______ - contains glands and elastic fibres
3. ______ - skeletal and smooth muscle
4. ______ - areolar connective tissue but not covered by epithelium
The wall of the esophagus is composed of the following 4 layers:
1. _Mucosa_ - contains glands near stomach
2. _Submucosa_ - contains glands and elastic fibres
3. _Muscularis_ - skeletal and smooth muscle
4. _Adventitia_ - areolar connective tissue but not covered by epithelium
31
The esophagus has two functions:
1. secrete \_\_\_\_
2. transport \_\_\_\_\_-
The esophagus has two functions:
1. secrete _mucus_
2. transport _food into the stomach_
32
The ________ sphincter (pharyngeosophageal sphincter) controls entry of food into the esophagus
The _Upper esophageal_ sphincter (pharyngeosophageal sphincter) controls entry of food into the esophagus
33
Elevation of the _____ during swallowing causes the UES (\_\_\_\_\_\_\_\_) to relax and bolus enters the esophagus
Elevation of the _larynx_ during swallowing causes the UES (_upper esophageal spincter_) to relax and bolus enters the esophagus
34
The _______ sphincter (aka gastroesophageal or cardiac sphincter) controls entry of food into the stomach
The _lower esophageal_ sphincter (aka gastroesophageal or cardiac sphincter) controls entry of food into the stomach
35
Esophageal glands secrete ____ to reduce friction
mucus
36
The stomach lies inferior to the \_\_\_\_\_\_in the left ______ region of the abdominal cavity
The stomach lies inferior to the _diaphragm_ in the left _hypochondriac_ region of the abdominal cavity
37
The stomach connects the _____ to the \_\_\_\_\_\_
The stomach connects the _esophagus_ to the _duodenum_
38
What are the four main areas of the stomach?
1. \_\_\_\_\_\_
2. ______ - storage of food
3. \_\_\_\_\_\_
4. ______ - contains 3 regions:
1. ______ - connects to the stomach body
2. ______ - leads to pylorus
3. ______ - opening of the pyloric sphincter
What are the four main areas of the stomach?
1. _Cardia_
2. _Fundus -_ storage of food
3. _Body_
4. _Pylorus_ - contains 3 regions:
1. _Pyloric antrum_ - connects to the stomach body
2. _Pyloric canal_ - leads to pylorus
3. _Pylorus_ - opening of the pyloric sphincter
39
Large mucosa folds of the stomach are called \_\_\_\_\_
rugae
40
The concave medial border of the of the stomach is called the \_\_\_\_\_\_\_
lesser curvature
41
The convex lateral border of the stomach is called the \_\_\_\_\_\_\_\_
Greater curvature
42
What are the four layers of the stomach?
1. ________ - contains mucus-secreting surface mucous cells (where rugae is found)
2. ________ - Composed of areolar CT
3. ________ - Has 3 layers of smooth muscle:
1. \_\_\_\_\_\_\_
2. \_\_\_\_\_\_\_
3. \_\_\_\_\_\_\_
4. ______ - composed of simple squamous epithelium
What are the four layers of the stomach?
1. _Mucosa_ - contains mucus-secreting surface mucous cells (where rugae is found)
2. _Submucosa_ - Composed of areolar CT
3. _Muscularis_ - Has 3 layers of smooth muscle:
1. _Outer Longitudinal layer_
2. _Middle Circular layer_
3. _Inner Oblique layer_
4. _Serosa_ - composed of simple squamous epithelium
43
Name the cells of the gastric glands based on the description:
* _________ - secrete mucus
* _________ - secrete enzymes
* pepsinogen
* gastric lipase
* ________ - Secrete HCl (activates pepsinogen into pepsin and creates acidic pH (2.3) for pepsin)
* __________ - secrete hormone gastrin into the blood; gastrin stimulates the _____ cells
Name the cells of the gastric glands based on the description:
* _mucous neck cells_ - secrete mucus
* _Chief (zymogenic) cells_ - secrete enzymes
* pepsinogen
* gastric lipase
* _Parietal cells_ - Secrete HCl (activates pepsinogen into pepsin and creates acidic pH (2.3) for pepsin)
* _G Cells_ - secrete hormone gastrin into the blood; gastrin stimulates the _parietal_ cells
44
What organ is located posterior to the greater curvature of the stomach?
Pancreas
45
The pancreas has a major ______ function - secretes pancreatic juice
The pancreas has a major exocrine function - secretes pancreatic juice
46
Pancreatic juice contains:
* _______ - neutralizes gastric pH in chyme, inactivates pepsin, provides optimal pH for digestive enzymes in the small intestine
* Digestive enzymes:
* _______ - digest carbs
* ______ - trypsin, chymotrypsis, carboxypeptidase, elastase
* ______ - digests triglycerides (lipids)
* ______ - digests RNA
* ______ - digests DNA
Pancreatic juice contains:
* _Bicarbonate_ - neutralizes gastric pH in chyme, inactivates pepsin, provides optimal pH for digestive enzymes in the small intestine
* Digestive enzymes:
* _Pancreatic amylase_ - digest carbs
* _Proteases_ - trypsin, chymotrypsis, carboxypeptidase, elastase
* _Pancreatic lipase_ - digests triglycerides (lipids)
* _Ribonuclease_ - digests RNA
* _deoxyribonuclease_ - digests DNA
47
The pancreas consists of 3 major regions:
1. _____ - located near the curve of the duodenum, from which the _______ projects
2. \_\_\_\_
3. _____ - lateral, tapered
The pancreas consists of 3 major regions:
1. _Head_ - located near the curve of the duodenum, from which the _uncinate process_ projects
2. _Body_
3. _tail_ - lateral, tapered
48
The pancreatic duct joins the common bile duct to form the \_\_\_\_\_\_\_\_\_\_
The pancreatic duct joins the common bile duct to form the _hepatopancreatic ampulla (ampulla of vater)_
49
The two ducts that empty pancreatic juice into the _____ are the:
1. ________ duct
2. \_\_\_\_\_\_\_\_\_
The two ducts that empty pancreatic juice into the _duodenum_ are the:
1. _pancreatic_ duct
2. _accessory duct_
50
Hepatic blood flow:
51
what is the path of bile flow from the liver to the duodenum
52
There are three ways that the liver can be organized into anatomical and functional units: label the italicized structures
1. \_\_\_\_\_\_\_\_\_\_
2. \_\_\_\_\_\_\_\_\_\_
3. \_\_\_\_\_\_\_\_\_\_
1. Hepatic Lobule
2. Portal Lobule
3. Hepatic acinus
53
The Hepatic Lobule is a hexagonal-shaped structure consisting of _\_\_\_\_\_\_\__organized into _\_\_\_\_\_\_\__ along _\_\_\_\_\_\_\_\_\__ that radiate from a central vein
The Hepatic Lobule is a hexagonal-shaped structure consisting of _hepatocytes_ organized into _hepatic laminae_ along _hepatic sinusoids_ that radiate from a central vein
54
The portal lobule organization emphasizes the _______ function of the liver - bile secretion and thus has the _____ duct at the center of the portal lobule
The portal lobule organization emphasizes the _______ function of the liver - bile secretion and thus has the _____ duct at the center of the portal lobule
55
The hepatic acinus includes two neighbouring hepatic lobules:
Zone 1: is closest to the ________ containing blood vessels and bile duct - cells here are last to die and first to regenerate if circulation is impaired
Zone 2: cells here show intermediate structural and functional characteristics
Zone 3: is furthest away from _______ - last to show effects of bile obstruction, first to show effects of fat accumulation
The hepatic acinus includes two neighbouring hepatic lobules:
Zone 1: is closest to the _portal triad_ containing blood vessels and bile duct - cells here are last to die and first to regenerate if circulation is impaired
Zone 2: cells here show intermediate structural and functional characteristics
Zone 3: is furthest away from _the portal triad_ - last to show effects of bile obstruction, first to show effects of fat accumulation
56
The small intestine extends from the _____ to the _____ and consists of three regions:
1. \_\_\_\_\_\_\_
2. \_\_\_\_\_\_\_
3. \_\_\_\_\_\_\_-meets the large intestine at the ileocecal sphincter (valve)
The small intestine extends from the _pyloric sphincter_ to the _large intestine_ and consists of three regions:
1. _Duodenum_
2. _Jejunum_
3. _Ileum_-meets the large intestine at the ileocecal sphincter (valve)
57
The small intestine receives blood from the _______ artery and ________ artery and then this blood drains into the ______ vein
The small intestine receives blood from the _superior mesenteric_ artery and _gastroduodenal_ artery and then this blood drains into the _superior mesenteric_ vein
58
Remember, the GI tract has 4 major layers. In the small intestine, these layers are modified to ensure optimal digestion and absorption:
1. Mucosa - has numerous ______ to increase surface area
2. Submucosa - together with the mucosa forms the \_\_\_\_\_\_\_
3. Muscularis - has _____ muscle
4. Serosa - visceral peritoneum that surrounds ll except the majority of the \_\_\_\_\_\_
Remember, the GI tract has 4 major layers. In the small intestine, these layers are modified to ensure optimal digestion and absorption:
1. Mucosa - has numerous _villi_ to increase surface area
2. Submucosa - together with the mucosa forms the _circular folds_
3. Muscularis - has _smooth_ muscle
4. Serosa - visceral peritoneum that surrounds all except the majority of the _majority of the duodenum_
59
The mucosa of the small intestine is composed of \_\_\_\_\_\_, _______ and \_\_\_\_\_\_
* Specialized cells line the epithelium –
1. \_\_\_\_\_\_\_cell,
2. \_\_\_\_\_\_\_cell,
3. _______ cell and
4. _______ cell
* _______ cells line intestinal glands (crypts of Lieberkuhn)
* Lamina propria contains \_\_\_\_\_\_
The mucosa of the small intestine is composed of _epithelium_, _lamina propria_ and _muscularis mucosae_
* Specialized cells line the epithelium –
1. _Absorptive_ cell,
2. _Goblet_ cell,
3. _Enteroendocrine_ cell and
4. _Paneth_ cell
* _Secretly_ cells line intestinal glands (crypts of Lieberkuhn)
* Lamina propria contains _MALT_
60
The Submucosa of the small intestine is composed of Connective tissue containing _____ and _____ vessels and \_\_\_\_\_
* At the duodenum, _\_\_\_\_\_\_\_\__glands secrete _\_\_\_\_\_\__ to neutralize gastric acid in chyme
The Submucosa of the small intestine is composed of Connective tissue containing _blood_ and _lymphatic_ vessels and _nerves_
* At the duodenum, _duodenal (Brunner’s)_ glands secrete _alkaline mucus_ to neutralize gastric acid in chyme
61
The muscularis of the small intestine is composed of an outer thinner layer of _______ muscle and an inner thicker layer of _______ muscle
The muscularis of the small intestine is composed of an outer thinner layer of _longitudinal smooth_ muscle and an inner thicker layer of _circular smooth_ muscle
62
The serosa of the small intestine is composed of ________ that completely covers the small intestine with the exception of the majority of the \_\_\_\_\_\_\_
The serosa of the small intestine is composed of _visceral peritoneum_ that completely covers the small intestine with the exception of the majority of the _duodenum_
63
The large intestine extends from the ____ of the small intestine to the \_\_\_\_\_
The large intestine extends from the ____ of the small intestine to the \_\_\_\_\_
64
The *ascending* and *descending colon* are \_\_\_\_\_\_\_\_
The *ascending* and *descending colon* are _retroperitoneal_
65
Colon structures (excluding the ascending and descending colon) are attached to the posterior abdominal wall by _______ which is a double layer of ______ connecting the _______ peritoneum to the _____ peritoneum
Colon structures (excluding the ascending and descending colon) are attached to the posterior abdominal wall by _mesocolon_ which is a double layer of _peritoneum_ connecting the _parietal_ peritoneum to the _visceral_ peritoneum
66
What are the four principal regions of the large intestine?
1. \_\_\_\_\_\_
2. \_\_\_\_\_\_
3. \_\_\_\_\_\_
4. \_\_\_\_\_\_
1. _Cecum_
2. _Colon_
3. _Rectum_
4. _Anal Canal_
67
The ____ is the blind pouch in the lower right of the abdominal cavity;
Chyme from the ileum passes through the _______ sphincter
The appendix contains _______ and is attached to the ileum by the \_\_\_\_\_\_\_
The _Cecum_ is the blind pouch in the lower right of the abdominal cavity;
Chyme from the ileum passes through the _ileocecal_ sphincter
The appendix contains _lymphatic nodules_ and is attached to the ileum by the _mesoappendix_
68
The colon consists 4 segments:
1. _\_\_\_\_\_\_\__
2. _\_\_\_\_\_\_\__
3. _\_\_\_\_\_\_\__
4. _\_\_\_\_\_\_\__
* _\_\_\_\_\_\__ are condensed longitudinal muscle
* Runs the length of the colon
* Cause bunching of pouch-like structures (_\_\_\_\_\_\__)
* _\_\_\_\_\_\__ are small fat-filled pouches of visceral peritoneum that lines the teniae coli
The colon consists 4 segments:
1. _Ascending colon_
2. _Transverse colon_
3. _Descending colon_
4. _Sigmoid colon_
* _Teniae coli_ are condensed longitudinal muscle
* Runs the length of the colon
* Cause bunching of pouch-like structures (_Haustra_)
* _Omental appendices_ are small fat-filled pouches of visceral peritoneum that lines the teniae coli
69
The _____ of the large intestine is located anterior to the sacrum and coccyx
Rectum
70
The ____ is the last 2-3cm of the large intestine
* Has mucous membrane arranged in longitudinal folds (\_\_\_\_\_\_\_) that contain blood vessels
The _anal canal_ is the last 2-3cm of the large intestine
* Has mucous membrane arranged in longitudinal folds (_anal columns_) that contain blood vessels
71
The large intestine contains the same 4 layers of the GI tract but with functional differences:
1. Mucosa - simple columnar epithelium, lamina propria, muscularis mucosa
* Absorptive cells ______ and goblet cells secrete \_\_\_\_\_
* No _____ secreted
2. Submucosa - areolar CT
* Contains ___ and ____ vessels and nerves
3. Muscularis - 2 layers of smooth muscle tissue
* inner circular layer
* outer longitudinal layer with 3 thickened bands \_\_\_\_\_\_
* Topic contractions create a series of pouches in the colon (\_\_\_\_\_)
4. Serosa - Visceral peritoneum
The large intestine contains the same 4 layers of the GI tract but with functional differences:
1. Mucosa - simple columnar epithelium, lamina propria, muscularis mucosa
* Absorptive cells _reabsorb water_ and goblet cells secrete _mucus_
* No _enzymes_ secreted
2. Submucosa - areolar CT
* Contains _blood_ and _lymphatic_ vessels and nerves
3. Muscularis - 2 layers of smooth muscle tissue
* inner circular layer
* outer longitudinal layer with 3 thickened bands _teniae coli_
* Topic contractions create a series of pouches in the colon (_haustra_)
4. Serosa - Visceral peritoneum
72
