Lab 14 Flashcards
The digestive system can be separated into two main components:
Digestive tract
Various accessory organs.
The digestive tract is a continuous tube that begins at the ______ and ends at the _______
Mouth; anus
The accessory digestive organs include (6):
Teeth, tongue, salivary glands, liver, gall bladder, and pancreas
The ________, are located in the mouth and surrounded by a delicate mucosa, the __________.
Teeth; gingiva (or gums)
The roof of the mouth is formed by the ______ palate anteriorly and the _______ palate posteriorly.
Hard; soft
Most of the mouth cavity is filled by the _______, an accessory organ which functions in food manipulation, taste and speech.
Tongue
Solid food must be reduced to small particles before it can effectively undergo chemical changes in the digestive tract. The teeth accomplish this function by the process of _________.
Mastication
Each type of tooth is adapted for its:
Function
Chisel-shaped _______ are used for cutting and shearing food.
Incisors
______________ have a single cusp, a high point used for tearing the food.
Canines (cuspids)
______________ which have two cusps, are adapted for crushing and cracking food
Premolars (bicuspids)
______________, with multiple cusps, are well adapted for grinding food into fine pieces.
Molars (tricuspids)
Humans and all other mammals develop ___ sets of teeth during their lifetimes,
2
The first set consists of the ______ (primary or baby) teeth
Deciduous
The second set, the ________ (secondary)
teeth
Permanent
Teeth begin to erupt in babies at about _ months of age.
6
By the time a child is six years old, a full
set of deciduous teeth (consisting of __ teeth) is usually present
20
Each HALF of each jaw (right and left.
halves of upper and lower jaws) contains (counting the teeth from the centre to the sides):
Two incisors, one canine and two molars.
two incisors, one canine and two molars. This count is represented by a:
Dental formula
In the dental formula: I incisors, C = canines, P = premolars, M = molars. The numbers above the lines represent the teeth in HALF of the _______ jaw and the lower numbers represent the teeth in HALF of the ______ jaw.
Upper; lower
In the adult, there are 16 teeth in each jaw, ____ teeth altogether.
32
It is not unusual for the third molar (the ________ tooth) never to develop or erupt.
“Wisdom”
Extra teeth (_____________ teeth) occur frequently as well.
Supernumerary
All teeth are constructed on a basic plan, consisting of two principal parts:
Crown
Root
which is the exposed portion of the tooth
Crown
which is the portion of the tooth imbedded in the alveolus (the bony socket) of the maxilla or mandible.
Root
Accessory organs that are found in association with the mouth include the ____ pairs of primary
salivary glands.
Three
The largest of the salivary glands; lie anterior to the ear. These glands have an irregular shape and overlap the large masseter muscle
Parotid glands
Inferior to the parotid glands are the _________ glands. These glands are situated along the inner surfaces of the mandible.
Submandibular
The small ________ glands are anterior and deep to the submandibular glands.
Sublingual
The salivary glands all secrete a watery fluid, ______, into thin ducts which open into the mouth.
Saliva
Saliva has a variety of functions, including:
Mouth lubrication
Moistening food
Dissolving chemicals in food (taste)
As well, saliva contains the enzyme - _____________ that begins the digestion of CARBOHYDRATES
Salivary amylase
A muscular tube that functions in the transport of food to the stomach.
Esophagus
The esophagus descends through the thoracic cavity, just posterior to the trachea, and then enters the abdominal cavity through an opening in the ___________.
Diaphragm
As food and liquids pass from the laryngopharynx
into the esophagus, the opening to the larynx is closed off by the __________.
This action ensures that food and fluids do not enter the respiratory tract.
Epiglottis
Large, crescent shaped organ located in the abdominal cavity, a temporary storage area for food.
Stomach
Is the primary digestive organ of the human body.
Small intestine
It is the part of the digestive tract in which the chemical digestion of food is completed and the absorption of nutrients occurs.
Small intestine
The small intestine is a convoluted tube that consists of three regions:
Duodenum, jejunum, and ileum (in order)
This region receives the partially digested food from the stomach and secretions from the liver, the gallbladder and the pancreas.
Duodenum
The middle portion of the small intestine is the _______ and the last portion is the _____
Jejunum; ileum
Extends from the ileum to the anus. The major function of this region is the absorption of water from the undigested food material
Large intestine
The ileum opens into a short, sac-like ________,
which is the first part of the large intestine.
Cecum
Attached to the cecum is a small worm-like structure, the
________________
Vermiform appendix
From the cecum, the ascending colon travels along the right side of the abdominal cavity up to the inferior edge of the liver where it makes a right-angle turn and becomes the:
Transverse colon
The transverse colon crosses the abdomen, from right to left, and makes a sharp downward-turn to become the
Descending colon
The descending colon travels down the left side of the abdominal cavity where; at the brim of the pelvis, it forms an S-shaped curve, called the ______________ and then continues to the rectum.
Sigmoid colon
The rectum opens to the exterior of the body through the:
Anus
Located in the upper right quadrant of the abdominal cavity, immediately beneath the diaphragm. The digestive function is in the production and secretion of bile
Liver
Performs many other vital metabolic functions such as: removing nutrients from the blood; storing glucose, liver glycogen, and vitamins; detoxification of metabolic wastes; and synthesis of blood-clotting factors.
Liver
The liver organ is divided into two main lobes:
Right lobe and smaller left lobe
The lobes of the liver are made up of many functional units called __________.
Lobules
Is a roughly hexagonal structure consisting of plates of liver cells or hepatocytes, that radiate outward from a central vein
Each lobule
__________ manufacture bile, a fat emulsifier, which is secreted into tiny channels, bile canaliculi, between the cells
Hepatocytes
At the corners of the lobule is a _____________ - consisting of a branch of the hepatic artery (supplying oxygen rich blood to the liver), a branch of the hepatic portal vein (carrying venous blood rich in nutrients from the intestines), and a bile duct.
Portal triad
Blood from both the hepatic portal vein and hepatic artery flows from the triad region, into liver ___________, capillary channels located between the hepatocytes.
Sinusoids
Blood then empties into the central vein, eventually entering the hepatic veins which carry blood to the
Inferior vena cava
The pancreas is composed of two distinct types of glandular tissue:
Exocrine glands (98%) Endocrine glands (2%)
98% of the pancreas
Exocrine glands
2% of the pancreas
Endocrine tissue
Ductless endocrine glands that consist of a group of cells of pancreas which release hormones into the blood.
Islets of Langerhans
The serous membrane that lines the abdominopelvic cavity and covers most of the abdominal organs is called the:
Peritoneum
The peritoneum can be divided into two portions: the _________ peritoneum that covers the external surface of most of the digestive organs and the ___________ peritoneum which lines the walls of the abdominopelvic cavity.
Visceral; parietal
The visceral and parietal portions of the peritoneum are __________ with one another.
Continuous
There are several membranes, made up of folds of the peritoneum, which hold the digestive organs in place and contain blood vessels, lymphatic vessels and nerves.
Mesenteries
A mesentery which hangs free in the abdominal cavity or connects organs to each other is called an __________.
Omentum
The _________________ is a double walled peritoneal sac that extends from the inferior border (greater curvature) of the stomach over the small and large intestines.
Greater omentum
Attached to the left side of the greater omentum at the lateral border of the stomach is another organ, the ________.
Spleen
This reddish organ plays an important role in the removal of aged and defective blood cells, but is not involved in digestion.
Spleen
Joins the superior border (lesser curvature) of the stomach to the liver.
Lesser omentum
The ______________ suspends the liver from the diaphragm and anterior abdominal wall.
Falciform ligament
The mesentery that connects the different parts of the small intestine to each other is called the:
Mesentery proper
The most distinctive aspect of the esophagus is the presence of a _________________ epithelium in the mucosa
Stratified squamous
The epithelial layer of the mucosa of the stomach is composed of a __________________, these surface cells are mucus-producing cells.
Simple columnar epithelium
In the stomach, the gastric pits lead into deep:
Gastric glands
Specialized ______________ line the gastric glands, some of these cells produce mucous, others pepsinogen (a precursor of the enzyme pepsin) and some cells produce hydrochloric acid.
Epithelial cells
When the stomach is empty, the mucosa lies in large folds called:
Rugae
The submucosa of the stomach resembles that of the esophagus and the ____________ contains the inner circular and outer longitudinal layers of smooth muscle
Muscularis
Composed of simple columnar cells (3 regions):
Stomach
Small intestine
Large intestine
In the small intestine, tiny extensions of the plasma membrane of the epithelia cell, _________, not visible with the light microscope, will increase surface area.
Microvilli
in the core of each villus is a dense capillary bed and wide lymph capillary called:
Lacteal
Between the villi are deep indentations, the:
Intestinal glands or crypts
You may also see larger folds present in your section, these are the:
Circular folds or plicae circulares
These deep permanent folds (circular folds or plicae circulares) of the mucosa and submucosa force chyme to spiral through the intestine, ________ it and slowing its progress
Mixing
The characteristics which distinguish the large intestine from the small intestine are:
Absence of villi
Presence of enormous numbers of goblet cells in the simple columnar epithelium
The intestinal glands of the mucosa are:
Deep and straight
Special proteins, the ____________, which are secreted by various accessory glands, catalyze these chemical reactions.
Digestive enzymes
By binding with the food molecules, the enzymes speed up the digestive reactions, allowing them to occur at ____________ body temperature and pH.
Normal
Protein digestion begins in the _______ with the action of pepsin.
Stomach
Is a proteolytic (protein-breaking) enzyme secreted by the chief cells of the stomach in the inactive form, pepsinogen
Pepsin
Pepsin functions most effectively in an ______ pH of 1.5 to 2.0.
Acidic
The parietal cells of the stomach secrete ______________ which maintains the optimum pH for protein digestion by pepsin.
Hydrochloric acid
Many of the lipids in the human diet are
Triglycerides
These lipid molecules are insoluble in water and must be treated with _______ to emulsify them before digestion can occur.
Bile salts
The enzyme, ____________ is responsible for the digestion of lipids into free fatty acids and glycerol.
Pancreatic lipase
Pancreatic lipase is produced by the __________ and secreted into the duodenum of the small intestine.
Pancreas
Bile salts are a component of the bile, which is produced by the _______ and released into the duodenum.
Liver
Visceral smooth muscle exhibits automaticity the ability to contract without:
Nervous stimulation
The fibers (cells) of smooth muscle are capable of stimulating __________
Each other
Impulses travel from cell to cell via specialized membrane junctions called
Gap junctions
Visceral smooth muscle also exhibits _________: a regular pattern of repeated contractions.
This pattern results from the presence of specialized fibers which generate spontaneous impulses into the surrounding muscle tissue.
Rhythmicity
These two characteristics of visceral smooth muscle are responsible for the wave-like contractions called ___________ that occur in the digestive tract.
Peristalsis
The role of the __________ nervous system in visceral smooth muscle function is to regulate the rate and the relative strength of contraction.
Autonomic
Hydochloric acid is required for protein digestion by pepsin becuase pepsin requires an _____ pH
Acidic
Pancreas secretory cells produce ______________ which contains many important digestive enzymes. These enzymes enter a system of ducts, eventually reaching the duodenum.
Pancreatic juice
Stomach, the epithelium forms indentations called
Gastric pits
