Hun 3- Chapter 3: Digestion, Absorption, and Transport
what else can affect a food's flavor
-aroma -appearance -texture -temperature
the chyme travels down the small intestine through its 3 segments: name them
-duodenum -jejunum -ileum *almost 10 feet of tubing coiled within the abdomen
what occurs in the lower portion of the stomach
-juices are added to the bolus and it grinds it to a semiliquid massed called chyme
what 3 types of muscles does the stomach have?
-longitudinal muscles -circular muscles - additional third layer ; diagonal muscles that also alternately contract and relax
what is the role of segmentation
-mix the chyme and promote close contact with the digestive juices and the absorbing cells of the intestinal walls before letting the contents move slowly along
Sphincter contractions are responsible for
-periodically opening and closing -controlling the pace of the movement of the GI tract contents
What does saliva contain and and what nutrient does it digest first
-saliva contains water, salts, mucus, and enzymes that initiate the digestion of carbohydrates
what are the 5 basic
-sweet -sour -bitter -salty -umami
describe how food would go down the esophagus
-the food would now be considered a bolus -During swallowing, the upper esophageal sphincter opens. -The bolus then slides down the esophagus , which passes through a hole in the diaphragm to the stomach -The lower esophagus sphincter at the entrance to the stomach closes behind the bolus so that is proceeds forward and doesn't slip into the esophagus (challenge 3)
Each cell in the body needs a continuous supply of many specific nutrients to maintain itself and carry out its work. Describe how this process works
-the nutrients comes from food we eat -food must be broken down mechanically and chemically -then the body's cells can use the nutrients
The breakdown of food intro nutrients requires secretions from five different organs: what are they?
-the salivary glands -stomach -the pancreas -the liver ( via the gallbladder) -and the small intestine
what is the gastric juice made up of
-water -enzymes -hydrochloric acid (which primarily acts as a protein digestion )
in the process of digestion, the body overcomes many challenges without any conscious effort. what are they? 1st: Multiple tasks of the mouth
1. Human beings breathe, eat, and drink through their mouths. Air must go to the lungs; food and liquid must go to the stomach. The throat must be arranged so that swallowing and breathing don't interfere with each other
`review of sphincter contraction
1. at the top of the esophagus, the upper esophageal sphincter opens in response to swallowing 2. At the bottom of the esophagus, the lower esophageal sphincter (sometimes called the cardiac sphincter because of its proximity to the heart) prevents reflux of the stomach contents. 3. At the bottom of the stomach, the pyloric sphincter, which stays closed most of the time, holds the chyme in the stomach long enough for it to be thoroughly mixed with gastric juice and liquefied. -The pyloric sphincter also prevents the intestinal contents from backing up into the stomach 4. At the end of the small intestine, the ileocecal valve performs a similar function, allowing the contents of the small intestine to empty into the large intestine 5.Finally, the tightness of the rectal muscle acts as a kind of safety device; together with the two sphincters of the anus, it prevents continuous elimination
What is the umami taste?
A savory flavor commonly associated with monosodium glutamate
what is a blind sac about the size of my little finger and houses bacteria and lymph
Appendix
At the beginning of the small intestine, the chyme bypasses the opening from what / also place of lubrication
At the beginning of the small intestine, the chyme bypasses the opening from the common bile duct (challenge 4 : lubrication )
the acidity (pH) of the gastric juice is
Below 2
in the process of digestion, the body overcomes many challenges without any conscious effort. what are they? 2nd: Passage through the diaphragm
Below the lungs lies the diaphragm, a dome of muscle that separates the upper half of the major body cavity from the lower half. The body needs a passageway that will allow food from the mouth to pass through the diaphragm to reach the stomach below
Conducts bile from the gallbladder to the small intestine
Bile duct
the digestive system is finely coordinated and fully integrated with which one of the other systems: A) Circulatory systems B) Nervous system C) Hormonal systems D) All of the above
D) all of the above
Separates the abdomen from the thoracic cavity. what structure is this?
Diaphragm
Allow passage from mouth to esophagus and from esophagus to stomach; prevent backflow from stomach to esophagus and from esophagus to mouth. what is this structure
Esophageal sphincters
in the process of digestion, the body overcomes many challenges without any conscious effort. what are they? 5th: Digestive enzyme functions
For digestive enzymes to work, foods must be broken down into small particles and suspended in enough liquid to that every particle is accessible. Once digestion is complete and nutrients have been absorbed from the GI tract into the body, the remaining waste must be excreted. Excreting all the water along with the solid residue, however, would be both wasteful and messy. some must be withdrawn , leaving a solid waste product that is easy to pass
Allows passage from small to large intestine; prevents backflow from large intestine. what is the structure?
Ileocecal valve (sphincter)
in the process of digestion, the body overcomes many challenges without any conscious effort. what are they? 7th: Excretion of waste
Once waste matter has reached the end of the GI tract, it must be excreted, but it would be inconvenient and embarrassing if this function occurred continuously. Evacuation needs to occur periodically
when a mouthful of food is swallowed , it passes through what structure?
Pharynx
what is the function of the rectum?
Stores waste prior to elimination
in the process of digestion, the body overcomes many challenges without any conscious effort. what are they? 3rd: Steady movement
The contents of the digestive tract should be kept moving forward, slowly but steadily, at pace that permits all reactions to reach completion
in the process of digestion, the body overcomes many challenges without any conscious effort. what are they? 6th: Protection
The digestive enzymes are designed to digest carbohydrate, fat, and protein. The cells of the GI tract are also made of carbohydrate, fat, and protein. The cells must be protected against the power
in the process of digestion, the body overcomes many challenges without any conscious effort. what are they? 4th: Lubrication of food
To move through the system, the food must be lubricated with fluids. Too much would form a liquid that would flow too rapidly; too little would form a paste too dry and compact to move at all. The amount of fluids must be regulated to keep the intestinal contents at the right consistency to move along smoothly
the hydrochloric acid is so strong that is would destroy the cells of the stomach as well; however, what is used to protect the stomach from damage from the acid
To protect themselves from gastric juice, the cells of the stomach wall (in fact, of the entire gastrointestinal lining) secrete mucus
when stimulated, the taste buds detect one or a combination of the five basic taste sensation. True or False
True
what is the function of the trachea
allows air to pass from the mouth to the lungs
what do all these by organs provide that allows for the breakdown of food intro nutrients
an abundance of water and variety of enzymes
does the waves of contraction normally ripple along the GI tract at varying rates or the same rate?
at varying rates and intensities depending on the part of the GI tract and on whether food is present
what is a mouthful of food called when it has been chewed and swallowed
bolus
when the ring relax and the long muscles tighten, the tube
bulges
what is the function of the epiglottis
bypass the entrance to the lungs; closes off the airway so that coking doesn't occur when swallowing; thus resolving the first challenge
a compound that facilitates chemical reactions without itself being changed in the process.
catalyst
what is peristalsis
circular/ring muscles and longitudinal muscles surrounding the GI tract working together continuously to push intestinal contents along
the large intestine is also known as
colon
The Muscular Action of Digestion such as chewing, addition of saliva, the action of the tongue transform food into a coarse mash that can be swallowed all occur without
concerted effort on your part
when the rings tighten and longitudinal muscles relax, the tube is
constricted
proteins found in digestive juices that act on food substances, causing them to break down into simpler compounds are known as
digestive enzymes
the function of the pharynx
directs food from mouth to esophagus
an is a protein that facilitates a chemical reaction- making a molecule, breaking a molecule apart, changing the arrangement of a molecule, or exchanging parts of molecules
enzyme
the word ending -ase denotes an
enzyme
The gastrointestinal (GI) tract is a flexible muscular tube that extends from the what to what?
extends from the mouth, through the esophagus, stomach, small intestine, large intestine, and rectum to the anus
When is the only time the tongue can taste
fluids must be involved so that the tongue can test it; only particles that are involved in solution can react with taste buds
Stores bile until needed; what structure is this
gallbladder
what does the gastric gland secrete
gastric juice
The enzymes involved in digestion facilitate a chemical reaction known as
hydrolysis - the addition of water (hydro) to break (lysis) a molecule into smaller pieces
having traveled the length of the small intestine, in the large intestine the remaining contents arrive at another sphincter called
ileocecal valve
what is located at the beginning of the large intestine (colon) in the lower right side of the abdomen and receives the arrival of the chyme after it leavings the small intestine
ileocecal valve
Where does the process of digestion begins ?
in the mouth
where is the gastric gland located
in the stomach
what are the role of salivary gland in digestion
it allows for the food the be swallowed with ease by secreting saliva
what is the function of the tongue
it provide taste sensation and moves food around the mouth facilitating chewing and swallowing
little by little, the stomach transfers the food to its
lower portion
what is the inner space within the GI tract that is continuous from one end to the other
lumen
what is a thick, slippery, white substance that coats the cells, protecting them from the acid, enzymes, and disease causing bacteria that might otherwise harm
mucus
does ALL material that pass through the GI tract get digested and absorbed
no many material don't get digested or absorbed
when does a nutrient or substance enter the body proper?
only when a nutrient/substance finally penetrates the GI tract's wall does it enter the body proper
what is the pyloric sphincter responsible for?
opens into the small intestine and then closes behind the chyme
Manufactures enzymes to digest all energy-yielding nutrients and releases bicarbonate to neutralize acid chyme that enters the small intestine. what structure is this?
pancreas
Conducts pancreatic juice from the pancreas to the small intestine. what structure is this?
pancreatic duct
what is the function of the esophagus
passes food from the mouth to the stomach
The entire GI tract is ringed with
peristalsis
what structure is known to be a short tube that is shared by both the digestive system and the respiratory system
pharynx
then, bit by bit, the stomach release the chyme through the
pyloric sphincter
Allows passage from stomach to small intestine; prevents backflow from small intestine. what structure does this?
pyloric structure
what is the protective role that saliva plays
saliva protects the teeth and the lining of the mouth, esophagus, and stomach from substances that might cause damage
what is it called when circular muscles of the intestines rhythmically contract and squeeze their content
segmentation
what type of muscle does the esophagus have at each end
sphincter muscle
Role of salivary gland
squirt just enough saliva to moisten each mouthful of food so that pass easily doen the esophagus
3 factors that interferes with normal GI tract contractions
stress, medicines, and medical conditions
negative of hydrochloric acid
the acid is so strong that it causes the sensation of heartburn if it happens to reflux into the esophagus
if the content does take that opening to the colon, where will it end up?
the appendix
What is digestion?
the body's ingenious way of breaking down foods intro nutrients in preparation for absorption
as the intestinal content pass to the rectum, what is the function of the colon
the colon withdraws water, leaving semisolid waste (challenge 5)
the common bile duct drips fluids into the small intestine from which two organs outside the GI tract?
the gallbladder and the pancrease
enzymes are often identified by
the organ they come from and the compound they work on. Gastric lipase, for example, is a stomach enzyme that acts on lipids, whereas pancreatic lipase comes from the pancreas (and also works on lipids).
how does waste ultimately release?
the rectal muscles relax and the two sphincter of the anus opens to allow passage of the waste
the content normally avoids going through the opening that leads to the colon and instead travel through the large intestine; when this happens, the content goes to what struture
the rectum
Churns, mixes, and grinds food to a liquid mass; adds acid, enzymes, and fluid. what structure does this?
the stomach
out of all of the GI tract organs, which has the thickest walls and strongest muscles
the stomach
positive of hydrochloric acid
the strong acidity of the stomach prevents bacterial growth and kills most bacteria that enters the body with food
how does the waste get hold back until it's time to defecate
the strong muscles of the rectum and anal canal
the 3 sets of muscles in the stomach work to force what? what ultimately happens?
timing the release of chyme/ force the chyme downward; however, what ultimately happens is the chyme does go down at first; the pyloric sphincter remain tightly closed until the stomach wall releases a gastric juice to liquefied the chyme and allow to flow through little by little . at this point, the chyme no longer represents food
what is the function of the mouth
to chew and mixes food with with saliva
True/False the human body surrounds the GI tract
true
in the process of digestion, the body overcomes many challenges without any conscious effort. what are they?
try to list them by yourself
as a catalyst, the enzyme itself remains
unchanged
Two sphincter muscles control movement
upper esophageal sphincter and lower esophageal sphincter
The stomach retain the bolus for a while in its
upper portion
does the content pass through ANOTHER opening after entering the colon
yes