BIO 139 Lecture Quiz 3: Digestive System

Defecation: elimination of ____ substances via ____ in the form of feces

Defecation: elimination of *indigestible* substances via *anus* in the form of feces.

______ and ______ are two hormones that regulate both the secretion and release of bile and pancreatic juice.

*Cholecystokinin* and *secretin* are two hormones that regulate both the secretion and release of bile and pancreatic juice.

The processing of food by the digestive system involves six essential activities:

1. Ingestion 2. Propulsion 3. Mechanical breakdown 4. Digestion 5. Absorption 6. Defecation

All digestive organs have the same four basic layers, or tunics:

1. Mucosa 2. Submucosa 3. Muscularis externa 4. Serosa

Absorption: passage of digested fragments from the _____ of alimentary canal/GI tract into _____ or _____.

Absorption: passage of digested fragments from the *lumen* of alimentary canal/GI tract into *blood* or *lymph*

Accessory organs of the small intestine: Gallbladder ____ and ____ bile by absorbing water and ions. Muscular contractions release bile via the ____ ____, which flows into the bile duct.

Accessory organs of the small intestine: Gallbladder *Stores* and *concentrates* bile by absorbing water and ions. Muscular contractions release bile via the *cystic duct*, which flows into the bile duct.

Accessory organs of the small intestine: Liver _____ bile, which breaks down ____. Liver also: processes blood-borne _____, _____ fat-soluble vitamins ___-___-___-___, and plays important roles in _____. It is the _____ gland in the body. Bile is released via the _____ _____ duct, which fuses with the ____ duct draining the gallbladder to from the bile duct

Accessory organs of the small intestine: Liver *Produces* bile, which breaks down *fat*/*lipids*. Liver also: processes blood-borne *nutrients*, *stores* fat-soluble vitamins *A-D-E-K*, and plays important roles in *detoxification*. It is the largest gland in the body. Bile is released via the *common hepatic* duct, which fuses with the *cystic duct* draining the gallbladder to from the bile duct.

Accessory organs of the small intestine: Pancreas Supplies most of the enzymes that digest ____, as well as _____ that neutralizes stomach acid. Produces _____ _____, which contains the enzymes: ____, ____, ____, and ____ in their inactive form (they are activated in the _____ of the small intestine)

Accessory organs of the small intestine: Pancreas Supplies most of the enzymes that digest *chyme*, as well as *bicarbonate* that neutralizes stomach acid. Produces *pancreatic juice*, which contains enzymes: *protease, amylase, lipase*, and *nuclease* in their inactive form (they are activated in the *duodenum* of the small intestine)

Alimentary canal organs: Esophagus (structure) Esophagus is a flat muscular tube that runs from the _____ to the _____, it ____ when not involved in food _____. - Mucosa contains a _____ _____ _____ epithelium, which changes to _____ _____ epithelium at the esophagus-stomach junction. - Submucosa contains _____-secreting esophageal glands. Muscularis externa contains both _____ and _____ muscle. Instead of a serosa, the esophagus has a fibrous dense CT called the _____.

Alimentary canal organs: Esophagus (structure) Esophagus is a flat muscular tube that runs from the *laryngopharynx* to the *stomach*, it *collapses* when not involved in food *propulsion*. - Mucosa contains a *nonkeratinized stratified squamous* epithelium, which changes to *simple columnar* epithelium at the esophagus-stomach junction. - Submucosa contains *mucus*-secreting esophageal glands. Muscularis externa contains both *skeletal* and *smooth* muscle. Instead of a serosa, the esophagus has a fibrous dense CT called the *adventitia*.

Alimentary canal organs: Large Intestine (function) The major functions of the large intestine is the _____ of feces to the anus and _____. However, the large intestine also functions in: - Digestion: some remaining food residues are digested by _____ _____ (which also produce some ___ and ___ vitamins) - Absorption: absorbs most remaining _____ (main function of colon), _____, and _____ produced by bacteria

Alimentary canal organs: Large Intestine (function) The major functions of the large intestine is the *propulsion* of feces to the anus and *defecation*. However, the large intestine also functions in: - Digestion: some remaining food residues are digested by *gut bacteria* (which also produce some *B* and *K* vitamins) - Absorption: absorbs most remaining *water* (main function of colon), *electrolytes*, and *vitamins* produced by bacteria

Alimentary canal organs: Large Intestine (structure) The large intestine has 5 subdivisions: - _____ : the first part of the large intestine - _____ : masses of lymphoid tissue - _____ : regions include ascending colon, transverse colon, descending colon and sigmoid colon - _____ : three rectal valves stop feces from being passed along with gas. - _____ _____ : last segment that opens to body exterior at anus The large intestine mucosa is _____ _____ epithelium, except at the anal canal where it is _____ _____ epithelium; contains abundant deep crypts with many mucus-producing _____ cells, which ease the passage of feces through the colon.

Alimentary canal organs: Large Intestine (structure) The large intestine has 5 subdivisions: - *cecum*: the first part of the large intestine - *appendix* : masses of lymphoid tissue - *colon* : regions include ascending colon, transverse colon, descending colon and sigmoid colon - *rectum* : three rectal valves stop feces from being passed along with gas. - *anal canal* : last segment that opens to body exterior at anus The large intestine mucosa is *simple columnar* epithelium, except at the anal canal where it is *stratified squamous* epithelium; contains abundant deep crypts with many mucus-producing *goblet* cells, which ease the passage of feces through the colon.

Alimentary canal organs: Mouth/oral cavity (structure) - Walls of mouth are lined with ____ ____ epithelium. - Boundaries are ____ anteriorly, ____ laterally, ____ superiorly, and ____ inferiorly.

Alimentary canal organs: Mouth/oral cavity (structure) Walls of mouth are lined with *stratified squamous* epithelium. Boundaries are *lips* anteriorly, *cheeks* laterally, *palate* superiorly, and *tongue* inferiorly.

Alimentary canal organs: Pharynx (structure) Divided into three sections: the ____ (has no digestive role), ____, and ____. From the mouth food passes posteriorly into the ____ and then the ____. The mucosa of the pharyngeal wall is ____ ____ epithelium with _____-producing glands. External muscle layer consists of two ____ muscle layers; contractions of these muscles propel food into the _____ below.

Alimentary canal organs: Pharynx (structure) Divided into three sections: the *nasopharynx* (has no digestive role), *oropharynx*, and *laryngopharynx*. From the mouth food passes posteriorly into the *oropharynx* and then the *laryngopharynx*. The mucosa of the pharyngeal wall is *stratified squamous* epithelium with *mucus*-producing glands. External muscle layer consists of two *skeletal* muscle layers; contractions of these muscles propel food into the *esophagus* below.

Alimentary canal organs: Pharynx and Esophagus (function) The single digestive function of the pharynx and the esophagus is food _____, accomplished by _____ (aka. swallowing).

Alimentary canal organs: Pharynx and Esophagus (function) The single digestive function of the pharynx and the esophagus is food *propulsion*, accomplished by *deglutition* (aka. swallowing).

Alimentary canal organs: Small Intestine (function) ______ is completed within the small intestine and almost all _____ occurs here. The small intestine also functions in _____ _____ and _____.

Alimentary canal organs: Small Intestine (function) *Digestion* is completed within the small intestine and almost all *absorption* occurs here. The small intestine also functions in *mechanical breakdown* and *propulsion*.

Alimentary canal organs: Small Intestine (structure) The longest part of the alimentary canal, the small intestine has three subdivisions: the _____ (first part), the _____, and the _____ (joins the large intestine). Small intestine is highly adapted for absorbing nutrients: - _____ _____: slows the movement of ____ increasing nutrient absorption, - _____ : contains dense capillary bed, and lymphatic capillary called a ____: for lipid absorption, - _____ : contains brush border enzymes, used for final _____ and _____ digestion.

Alimentary canal organs: Small Intestine (structure) The longest part of the alimentary canal, the small intestine has three subdivisions: the *duodenum* (first part), the *jejunum*, and the *ileum* (joins the large intestine). Small intestine is highly adapted for absorbing nutrients: - *circular folds*: slows the movement of *chyme* increasing nutrient absorption, - *villi*: contains dense capillary bed, and lymphatic capillary called a *lacteal*: for lipid absorption, - *microvilli*: contains brush border enzymes, used for final *carbohydrate* and *protein* digestion.

Alimentary canal organs: Stomach (function) - Carries out _____ _____ of food; and serves as a ____ ____ for food - Propulsion: delivers _____ to small intestine - Digestion: Chief cells secrete inactive form of _____, which when activated carries out digestion of proteins (casein is broken down by _____ in infants); denatures proteins by _____. - Absorption: absorbs a few ____-soluble substances: _____, _____, some _____. - Secretes ____ ____ for ____ absorption of vitamin B12 (needed for red blood cells to mature).

Alimentary canal organs: Stomach (function) - Carries out *mechanical breakdown* of food; and serves as a *holding area* for food - Propulsion: delivers *chyme* to small intestine - Digestion: Chief cells secrete inactive form of *pepsin*, which when activated carries out digestion of proteins (casein is broken down by *rennin* in infants); denatures proteins by *HCl* - Absorption: absorbs a few fat-soluble substances: aspirin, alcohol, some drugs; secretes *intrinsic factor* for *intestinal* absorption of vitamin B12 (needed for red blood cells to mature).

Alimentary canal organs: Stomach (structure) Stomach mucosa epithelium is _____ _____, composed entirely of ____ cells. Empty stomach has volume of about ___ ml, but can distend to ___ L. Innervated by both _____ and _____ fibers. Most digestion occurs in the stomach ____ and ____; the ____ ____ protects the stomach from acidic ____ ____ produced by gastric glands in the mucosa.

Alimentary canal organs: Stomach (structure) Stomach mucosa epithelium is *simple columnar*, composed entirely of *mucus* cells. Empty stomach has volume of about *50 ml*, but can distend to *4 L*. Innervated by both *sympathetic* and *parasympathetic* fibers. Most digestion occurs in the stomach *fundus* and *body*; the *mucosal barrier* protects the stomach from acidic *gastric juice* produced by gastric glands in the mucosa.

Digestion: series of _____ steps that involves _____ which break down complex food molecules into ____ building blocks

Digestion: series of *catabolic* steps that involves *enzymes* which break down complex food molecules into *chemical* building blocks

Functions of: the mouth; and teeth, tongue, salivary glands (associated accessory organs) - Ingestion: food is voluntarily placed into _____ _____ - Propulsion: the voluntary phase of _____ (swallowing) is initiated by the _____; propels food into _____ - Mechanical breakdown: _____ (chewing) by teeth and mixing movements by the _____ act in formation of the _____ (a mixture of food and saliva to be swallowed). - Digestion: the enzyme _____ in saliva, produced by _____ _____, begins digestion of _____.

Functions of: the mouth; and teeth, tongue, salivary glands (associated accessory organs) - Ingestion: food is voluntarily placed into *oral cavity* - Propulsion: the voluntary phase of *deglutition* (swallowing) is initiated by the *tongue*; propels food into *pharynx* - Mechanical breakdown: *mastication* (chewing) by teeth and mixing movements by the *tongue* act in formation of the *bolus* (a mixture of food and saliva to be swallowed). - Digestion: the enzyme *amylase* in saliva, produced by *salivary glands*, begins digestion of *starch*.

Gastrin, a hormone secreted by secretory (enteroendocrine) cells in the stomach mucosa, has an essential role in the regulation of stomach _____ (of HCl) and _____ (peristalsis).

Gastrin, a hormone secreted by secretory (enteroendocrine) cells in the stomach mucosa, has an essential role in the regulation of stomach *secretion* (of HCl) and *motility* (peristalsis).

Ingestion: taking food into the digestive tract, aka. ____.

Ingestion: taking food into the digestive tract, aka. *eating*.

Mechanical breakdown: includes _____, mixing food with _____, churning food in the _____, and _____ (for mixing and breakdown).

Mechanical breakdown: includes *chewing*, mixing food with *saliva*, churning food in the *stomach*, and *segmentation* (for mixing and breakdown).

Mucosa: lines the alimentary canal ____. Functions to: secrete ____, digestive ____ and ____, ____ end products of digestion into the blood, and protect against _____ ____. It is made up of 3 sublayers: - epithelium: ____ _____ (except for mouth, pharynx, esophagus, and anus where it is ____ ____), - lamina propria: ____ ____ connective tissue - muscularis mucosae: _____ muscle.

Mucosa: lines the alimentary canal *lumen*. Functions to: secrete *mucus*, digestive *enzymes* and *hormones*, *absorb* end products of digestion into the blood, and protect against *infectious diseases*. It is made up of 3 sublayers: - epithelium: *simple columnar* (except for mouth, pharynx, esophagus, and anus where it is *stratified squamous*), - lamina propria: *loose areolar* connective tissue - muscularis mucosae: *smooth* muscle.

Muscularis externa: ____ ____ layer, responsible for _____ and _____, ie. motility.

Muscularis externa: *smooth muscle* layer, responsible for *segmentation* and *peristalsis*, ie. motility.

Overview of digestive system functions: Mouth (and teeth, tongue, salivary glands): _____, _____, _____ _____, _____ Pharynx + Esophagus: _____ Stomach: _____, _____ _____, _____, _____ Small Intestine: _____ (of _____); also _____, _____ _____, _____. Liver: _____ bile Gallbladder: _____ and _____ bile Pancreas: supplies _____ Large Intestine: (mainly) _____ + _____; also _____, _____ - colon: ______ ______

Overview of digestive system functions: Mouth (and teeth, tongue, salivary glands): *ingestion*, *propulsion*, *mechanical breakdown*, *digestion* Pharynx + Esophagus: *propulsion* Stomach: *propulsion*, *mechanical breakdown*, *digestion*, *absorption* Small Intestine: *absorption* (*of nutrients*); also *propulsion*, *mechanical breakdown*, *digestion* Liver: *produces* bile Gallbladder: *stores* and *concentrates* bile Pancreas: supplies *enzymes* Large Intestine: (mainly) *propulsion + defecation*; also *digestion*, *absorption* - colon: *water absorption*

Overview of digestive system mucosa epitheliums: Mouth: _____ _____ epithelium Pharynx: _____ _____ epithelium Esophagus: _____ _____ _____ epithelium, then_____ _____ at esophageal-stomach junction Stomach: _____ _____ epithelium Small Intestine: _____ _____ epithelium Large Intestine: _____ _____ epithelium, then _____ _____ at anal canal.

Overview of digestive system mucosa epitheliums: Mouth: *stratified squamous* epithelium Pharynx: *stratified squamous* epithelium Esophagus: *nonkeratinized stratified squamous* epithelium, then *simple columnar* at esophageal-stomach junction Stomach: *simple columnar* epithelium Small Intestine: *simple columnar* epithelium Large Intestine: *simple columnar* epithelium, then *stratified squamous* at anal canal.

Peristalsis: food is moved ____ along the ____ ____; primarily ____. Involves alternating waves of _____ and _____ in the organ walls.

Peristalsis: food is moved *distally* along the *GI tract*; primarily *propulsive*. Involves alternating waves of *contraction* and *relaxation* in the organ walls.

Propulsion: movement of food through the _____ _____; includes: voluntary _____ and involuntary _____ (the major means of propulsion of food)

Propulsion: movement of food through the *alimentary canal*; includes voluntary *swallowing* and involuntary *peristalsis* (the major means of propulsion of food).

Salivary Glands are composed of two types of ____ cells: 1. _____ cells: produce a watery secretion containing enzymes, ions, and tiny bit of mucin, 2. ____ cells: produce mucus.

Salivary Glands are composed of two types of *secretory* cells: 1. *serous* cells: produce a watery secretion containing enzymes, ions, and tiny bit of mucin, 2. *mucous* cells: produce mucus.

Segmentation: food is moved ____, then ____; primarily for ____ and ____ ____ of food. Involves local constrictions of the _____ intestine that mixes food with _____ _____.

Segmentation: food is moved *forward*, then *backward*; primarily for *mixing* and *mechanical breakdown* of food. Involves local constrictions of the *small intestine* that mixes food with *digestive juices*.

Serosa (visceral peritoneum): ____ connective tissue covered with a single layer of ____ epithelial cells (mesothelium). Covers the ____ surfaces of most digestive organs, reducing _____ between the organs and the _____ cavity. - Replaced by _____, dense CT in the esophagus, which binds structures together.

Serosa (aka. visceral peritoneum): *areolar* connective tissue covered with a single layer of *squamous* epithelial cells (mesothelium). Covers the *external* surfaces of most digestive organs, reducing *friction* between the organs and the *abdominal* cavity. - Replaced by *adventitia*, dense CT in the esophagus, which binds structures together.

Submucosa: consists of ____ connective tissue, which contains a rich supply of blood and ____ vessels, ____ follicles and ____ fibers that supply surrounding tissues of the GI tract. Also abundant in ____ fibers, which help organs to ____ their shape.

Submucosa: consists of *areolar* connective tissue, which contains a rich supply of blood and *lymphatic* vessels, *lymphoid* follicles and *nerve* fibers that supply surrounding tissues of the GI tract. Also abundant in *elastic* fibers, which help organs to *retain* their shape.

The 6 accessory organs are:

The 6 accessory organs are: 1. teeth 2. tongue 3. gallbladder - digestive glands, that produce secretions which help break down foodstuffs, include: 4. salivary glands 5. liver 6. pancreas

The 6 alimentary canal (GI tract or gut) organs are:

The 6 alimentary canal (GI tract or gut) organs are: 1. mouth/oral cavity 2. pharynx 3. esophagus 4. stomach 5. small intestine 6. large intestine

The alimentary canal (GI tract or gut) is a continuous muscular tube that runs from the ____ to the ____. It ____ food, and ____ the digested fragments through its lining into the ____.

The alimentary canal (GI tract or gut) is a continuous muscular tube that runs from the *mouth* to the *anus*. It *digests* food, and *absorbs* the digested fragments through its lining into the *blood*.

The enzyme amylase digests _____.

The enzyme amylase digests *starch*/*carbs*.

The enzyme lipase digests _____.

The enzyme lipase digests *fats*/*lipids*.

The enzyme nuclease digests _____.

The enzyme nuclease digests *nucleic acid*.

The enzyme protease digests _____. - _____ is an example of protease.

The enzyme protease digests *protein*. - *Pepsin* is an example of protease.

Tongue: composed of interlacing bundles of _____ muscle.

Tongue: composed of interlacing bundles of *skeletal* muscle.