Digestive System Review Saladin Chapter 25

Components of bile important for fat digestion and absorption

Bile acids Lecithin

List in order the passage of bile from its point of secretion in the liver to the duodenum

Bile canaliculi Bile ductules Hepatic ducts Common hepatic duct Bile duct

Enzymes found on absorptive cell surfaces that carry out the final stages of enzymatic digestion

Brush border enzymes

Tubular glands that open into the gastric pits of the initial region of the stomach

Cardiac glands

Gastric secretion in response to sight, smell, taste, or thought of food occurs during the ____ phase of gastric function

Cephalic

Examples of how digestive system mechanically digests materials

Chewing Churning of stomach Segmentation (Swallowing is not considered part of mechanical digestion)

Incisors

Chisel-like edges

Chyme stimulates enteroendocrine cells to secrete secretin and ____, a hormone that has strong stimulatory effects on the gallbladder; causing it to contract

Cholecystokinin

3 layers of muscularis externa of the stomach

Circular Longitudinal Oblique

Longitudinal ridges within the mucosa of the anal canal are called anal ____

Columns

2 Effects of defecation reflex

Contraction of rectum Relaxation of internal anal sphincter

Bile drains from gallbladder via the ____ duct

Cystic

Functions of stomach acid

Denature proteins in food Destroy pathogens Activate pepsin and lingual lipase

Collectively, the teeth are known as

Dentition

The ____ of the pancreas secrete sodium bicarbonate, while the ____ of the pancreas secrete digestive enzymes

Duct cells Acinar cells

In order to improve fat digestion, large fat globules must first be dispersed into smaller droplets in a process called ____

Emulsification

The pancreatic islets are the ____ portion of the pancreas, while the majority of the pancreas is an ____ gland secreting enzymes and sodium bicarbonate

Endocrine; Exocrine

The term ____ means pertaining to intestines

Enteric

Bile acids are recycled from the liver to the small intestine and back via ____ circulation

Enterohepatic

The upper ____ ____ is formed by the inferior pharyngeal constrictors

Esophageal Sphincter

Straight muscular tube conveying food from pharynx to stomach is ____

Esophagus

Location of cystic duct

Gallbladder

Phase of gastric regulation that occurs in response to food in the stomach

Gastric phase

Hormone produced by enteroendocrine G cells that stimulates stomach HCl and enzyme activty

Gastrin G (cells) > Gastrin

Hormone secretions of gastric glands

Gastrin Histamine Somatostatin

Examples of processes involving digestion

HCl mixing with bolus of food Chemical breakdown of food Mechanical breakdown of food

Blood vessels that carry blood to liver

Hepatic artery Hepatic portal vein

Valve at junction of small and large intestine

Ileocecal valve

Connective tissue extending from liver to lesser curvature of stomach

Lesser omentum

Enzyme that digests lipids

Lipase Lingual, gastric, and pancreatic forms

Substances absorbed in stomach

Lipid-soluble drugs Aspirin

Structures that work together to retain food and push it between the teeth for chewing

Lips Tongue Cheeks

The hormone ____ is released in response to acidity in the small intestines and stimulates the pancreas to secrete sodium bicarbonate (to neutralize the acidity)

Secretin

Dipeptidase

Splits a molecule of 2 amino acids

Stimulus for defecation reflex

Stretching of sigmoid colon Stretching of rectum

Salivary glands located on the floor of the mouth just under the tongue

Sublingual glands

Salivary gland located halfway along the body of the mandible

Submandibular glands

The enteric nervous system is comprised of

Submucosal plexus Myenteric plexus

Cheeks and Lips

Sucking action Speech articulation Push food between teeth

True or false: After digestion and absorption into absorptive cells, fatty acids and monoglycerides are reassembled into triglycerides before moving into the lymph

True

True or false: Partial digestion of both protein and fat can occur in the stomach

True

Pancreatic zymogens

Trypsinogen Chymotrypsinogen Procarboxypeptidase

Class of nutrients absorbed without being digested

Vitamins and minerals

4 Components of gastric juice

Water Lipase Pepsin HCl

The hormone ____ is released in response to fats in the small intestine, and has the effect of stimulating gallbladder contraction (discharging the bile needed to digest fats)

Cholecystokinin

The hormone ____ is secreted by the small intestine in response to the presence of fats in the small intestine

Cholecystokinin

3 Hormones produced by digestive tract

Cholecystokinin Gastrin Secretin (Pepsin is an enzyme, not a hormone)

Particles that transport fat in lymph and blood

Chylomicrons

True or false. A typical meal is emptied from the stomach in 1-2 hours.

False. Can take up to 4 hours

True or false: Blood enters the liver via the hepatic vein and hepatic artery.

False. Hepatic artery and hepatic PORTAL vein

Functions of saliva

Inhibits bacterial growth Aids in swallowing Dissolves molecules so they can be tasted

Tubular glands within the mucosa and submucosa of the small intestine are called ____ ____

Intestinal crypts

Produced in the stomach, ____ ____ is essential for the absorption of vitamin B12 by the small intestine

Intrinsic factor

In order to absorb the mineral ____, transferrin is required to transport it

Iron

Phagocytic cells found within the sinusoids of the liver are called hepatic macrophages or ____ cells

Kupffer

Lymphatic capillary within the core of intestinal villus, necessary for the absorption of lipids

Lacteal

Bacterial flora refers to the many species of bacteria residing in our _____

Large intestine

Describe the type of motility called segmentation

Non-migrating constrictions at several places along intestine

Glucose and galactose are moved into absorptive cells via ____ while fructose is absorbed by ____

Transporters Facilitated diffusion

Gastroileal reflex

Triggered by food in stomach; causes ileal segmentation

Long reflexes that aid in regulation of digestive tract involve the ____ nerve and ____

Vagus; Brainstem

Space between teeth and lips

Vestibule

The term ____ refers to the small finger-like projections of the lining of the small intestine

Villi

Primary ligament separating right and left lobes of liver

Falciform ligament

True or false: The stomach is innervated by parasympathetic, but not sympathetic, fibers

False

True or false: Secretin and cholecystokinin are gastric hormones

False Both secreted by duodenal enteroendocrine cells

Components of bile

Bile pigments Cholesterol Bile acids Phospholipids

Tongue muscles originating outside of the tongue but act upon it are ____ muscles

Extrinsic

The vitamins _, _, _, and _, are fat-soluble and are absorbed along with dietary fats , while other vitamins are absorbed by simple diffusion

A D E K

Process of uptake of nutrient molecules

Absorption

The vagus and enteric nerves release the neurotransmitter called ____ which signals pancreatic acini to secrete their enzymes

Acetylcholine

Goal of intestinal phase of gastric regulation

Adjust gastric activity so as to not overload the duodenum

Receptive-Relaxation response of the stomach

As smooth muscle is stretched, it first resists stretching, then relaxes

Segment of digestive tract on right side of abdomen is the ____ colon

Ascending

Vitamin that is so large it can only be absorbed if it binds to intrinsic factor

B-12

Location of bile canaliculi

Between plates of hepatocytes in lobules

The pancreas secretes ____ into the duodenum in order to neutralize acid arriving from stomach

Bicarbonate

Primary bile pigment

Bilirubin

Components of pulp found within teeth

Blood and lymphatic vessels Nerves Loose connective tissue

Vitamin C and B are absorbed into ____, while vitamins A, D, E, and K are absorbed into ____

Blood; lymph

The portion of the stomach between the fundus and pyloric region is known as the ____

Body

Premolars and molars

Broad-surfaces

The fringe of the microvilli on the apical surface of an epithelial cell which serves to increase surface area for absorption is also known as the ____ ____

Brush border

The ____ phase of swallowing is voluntary

Buccal

Large intestine begins with a pouch inferior to the ileocecal valve known as the ____

Cecum

Branch of aorta supplying blood to stomach

Celiac trunk

Another name for swallowing

Deglutition

Yellowish tissue forming bulk of tooth

Dentin

The glands that secrete bicarbonate rich mucus into the duodenum are called ____

Duodenal Glands (or Brunner glands)

The source of secretin and cholecystokinin

Duodenal enteroendocrine cells

____ is an enzyme that converts trypsinogen into trypsin

Enterokinase

The ____ anal sphinter is under voluntary control and the ____ is under involuntary control

External; Internal

Pouches that form walls of large intestine

Haustra

Form of segmentation that occurs in the large intestine is called ____ contractions

Haustral

Contractions of the segments of large intestine that promote mixing of residue, water and salt absorption, and passing of the residue distally

Haustral contractions

Microscopic structural subunits of liver

Hepatic lobules

Function of brush border

Increase surface area for absorption

Fold of tissue at the termination of the hepatopancreatic ampulla

Major duodenal papilla

Digestion of starch by amylase results in the production of ____

Maltose

Strong contractions within the large intestine that occur 1-3 times a day are called ____ ____ and function to move residue several centimeters at a time

Mass movements

Describe the lesser curvature of the stomach

Medial superior margin from esophagus to duodenum

Mesentery that runs from transverse colon to posterior abdominal wall

Mesocolon

Transport fats in the intestine to the surface of the enterocytes

Micelles

Mechanisms of stomach protection

Mucous coat Epithelial cell replacement Tight junctions between epithelial cells

Primary secretion of glands in large intestine

Mucus

Components of saliva

Mucus Amylase and lipase Water Lysozyme

List components of intestinal juice secreted by intestinal crypts

Mucus Water

Messages are carried to adjacent regions of the GI tract by short reflexes via the ____ nerve plexus

Myenteric

Enzymes that hydrolyzes nucleic acids into nucleotides

Nucleases

Two enzymes that decompose nucleotides into phosphate ions, pentose sugars, and nitrogenous bases

Nucleosidase Phosphatase

How water is absorbed

Osmosis

Bile duct empties into

Pancreas

The accessory organ of the digestive system that is an endocrine and exocrine gland

Pancreas

Duct that runs lengthwise through pancreas, joining the bile duct at the hepatopancreatic ampulla

Pancreatic duct

Within the glands of the stomach, ____ cells secrete HCl and ____ cells secrete pepsinogen

Parietal Chief

Salivary gland located anterior to the earlobe

Parotid salivary gland

The enzyme ____ begins digestion of protein in stomach

Pepsin

Inactive form of pepsin

Pepsinogen

The predominant type of involuntary muscle contraction occurring in the stomach is called ____

Peristalsis

Wave-like contraction of smooth muscle in digestive tract

Peristalsis

Canines

Pointed

Group of enzymes that digest proteins

Protease

Pepsin

Protein digestion in stomach

Muscular band that regulates the passage of chyme from stomach to duodenum

Pyloric sphincter

Portions of large intestine located in pelvic cavity are the ____ and anal canal

Rectum

Carboxypeptidase

Removes amino acids from -COOH end of amino acid chain

Aminopeptidase

Removes amino acids from the -NH2 end of amino acid chain

Structure located against posterior wall and only covered with peritoneum on its anterior side

Retroperitoneal

4 Lobes of liver

Right Left Quadrate Caudate

Lingual lipase is produced by the _____, but not activated until it reaches the acidic stomach

Salivary glands

Parietal cells

Secrete HCl

Enteroendocrine Cells

Secrete paracrine compounds

Chief cells

Secrete pepsinogen

Muscular contractions called ______ involve alternating ring-like constrictions at several places along the intestine

Segmentation

S-shaped portion of large intestine, located in lower left quadrant

Sigmoid colon

Mucosa of colon is primarily lined with ____ ____ epithelium

Simple columnar

The blood-filled channels between the layers of hepatocytes in the liver are called hepatic ____

Sinusoids

Pancreatic secretion needed to neutralize acid in chyme arriving in duodenum

Sodium bicarbonate

The hormone secretin stimulates the pancreas to secrete a solution high in ____ ____

Sodium bicarbonate

Duodenalcolic reflex

Stretching of duodenal wall leads to altered colic motility

Gastrocolic reflex

Stretching of stomach triggers colic motility

Enzymes that are secreted as inactive proteins

Zymogens