Download Period 2 - Digestive System

Period 2 – Digestive System
1. Oral Cavity, PharynxThe oral cavity is where food is chewed and saliva is produced to help propel food
toward the stomach. The upper portion of the oral cavity is where the hard and soft
palates are located, with the tongue serving as the primary organ in the area.The
Pharynx muscular walls function in the process of swallowing and it serves as a pathway
for the movement of food from the mouth to the esophagus.
o The oral cavity contains the mouth, teeth, gums, hard/soft palate (bony roof),
under the tongue (the floor of the mouth), and cheeks.
o The salivary glands produce saliva, which keeps the mouth and other parts of the
digestive system moist, helps break down carbohydrates, and lubricates the
passage of food.
o The tongue is used for chewing, swallowing food, speech, and taste.
o A bolus is a small rounded mass of a substance, especially of chewed food at the
moment of swallowing.
o They are both found one the roof of the mouth, the hard palate is the front part,
and the soft palate is the back part. The soft palate is moveable, consisting of
muscle fibers sheathed in mucous membrane. It is responsible for closing off the
nasal passages during the act of swallowing, and also for closing off the airway.
The function of the hard palate is both feeding and speech (for example people
with cleft palate can have a hard time speaking).
o Mechanical digestion begins in the mouth as the food is chewed. Chemical
digestion involves breaking down the food into simpler nutrients that can be used
by the cells. Chemical digestion begins in the mouth when food mixes with saliva.
o The epiglottis is located behind the tongue to seal off the windpipe during eating
so that the food isn't accidentally inhaled and stops it from entering the trachea
(prevents choking).
o The normal adult has 32 teeth.
More on the ORAL Cavity:
 Main organs: mouth,pharynx,esophagus,the sphincter,teeth,gums,and tounge
 The function of the oral cavity and its structures is to begin the process of digestion. The
oral cavity receives food, chews and mixes it with saliva and then begins the swallowing
process. The taste buds on the tongue provide the different sensations of taste. The oral
cavity plays an important role in speech.
 Function of the tongue: chewing,swallowing,and talking. It has 5 types of tastes
buds;salty,sour,sweet. The fifth one, results for tasting glutamate.
 Bolus: is a ball-like mixture of food and saliva that forms in the mouth during the process
of chewing, (which is largely an adaptation for plant-eating mammals).
 Soft and hard palate:located of on roof of the mouth
 Soft:It is responsible for closing off the nasal passages during the act of swallowing, and
also for closing off the airway. During sneezing, it protects the nasal passage by putting
some of the mucous down the throat.
 Hard:The hard palate separates the oral and nasal cavities, bordering the oral cavity
superiorly and forming the roof of the mouth and the nasal cavity inferiorly forming its
floor.
 Chemical and mechanical:Mechanical digestion begins in the mouth as the food is
chewed. Chemical digestion involves breaking down the food into simpler nutrients that
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can be used by the cells. Chemical digestion begins in the mouth when food mixes with
saliva. Saliva contains an enzyme that begins the breakdown of carbs.
Teeth: 32 adult teeth
Food not in the windpipe:Epiglottis, The flap that closes over the windpipe so food
doesn't go down. When the flap doesn't close, you choke.
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1. CLF- The function of the teeth is to help food become chewed up so that the food can go
down to your digestive system so that our body can absorb nutrients from the food. The
function of the pharynx is to transfer food from the mouth to the esophagus and it
prevents air from being swallowed. The pharynx is made up of the nasopharynx,
oropharynx and the laryngopharynx.
2. TMM- The oral cavity is the first part of the digestive system. It chews up food and mixes
it with silica to make it easier when it goes down your esophagus. Your oral cavity
contains: mouth, teeth, gums, roof of your mouth, floor of the mouth, and cheeks.
3. TMM- The salivary glands produce saliva which keeps the through mouth and
esophagus moist. their. An also help break down carbohydrates through hydrolysis.
4. TMM- The back of the tongue is anchored to the back of the mouth by the hyoid bone.
The tongue helps you chew, swallow, and speak. The four common taste buds are
sweet, salty, sour, and, bitter.
5. CLF-The bolus is a small rounded mass of a substance, especially chewed food at the
moment of swallowing. There are enzymes in the bolus from the salivary glands.
6.
CLF- The hard palate is located at the front part of the mouth and the soft palate is
located in the back part of the mouth. The hard palate is used to create a vacuum which forces
the liquid into the mouth so that it can be ingested. It also helps with producing certain sounds.
The soft palate helps keep food out of the respiratory tract, it blocks and separates the nasal
cavity and the nasal portion of the pharynx from the mouth and it is composed of muscles and
connective tissue which helps gives it mobility and support. The soft palate is also very flexible.
7.
The mechanical digestion that occurs in the oral cavity is your mouth and teeth
physically chewing the food and breaking it down into smaller pieces. The chemical digestion
that occurs in the oral cavity is when the food is broken down from the mechanical digestion, the
chemical digestion breaks it down even more to the smaller chemicals our body needs to be
used by the cells.
8.
The epiglottis is the mechanism that makes sure the food goes down in the right place.
The epiglottis is a flap that separates the esophagus from the trachea. This helps guide food
and liquids to the right tube so you don't choke.
9.
Adults normally have 32 teeth and that includes their wisdom teeth but around their teen
years they usually chose to get them taken out or have to take them out because they don't
have enough room in their mouths
2. Esophagus and Stomach
What is peristaltic movement and how does it function in the esophagus?
a. It is a wave like movement in the esophagus that transports the food from the
mouth to the stomach by pushing it, it is the reason we can eat in space, and
upside down.
2. Does any digestion of food occur in the esophagus?
No, it just is the way the food gets to the stomach
3. What are the primary functions of the stomach?
.
The main function of the stomach is to break down and digest food in order to extract
necessary nutrients from what you have eaten. In order for this to happen, it is necessary that
the stomach, the digestive glands and the intestines must produce various enzymes, including
pepsin, and acid.
4. What is chyme and how does the stomach mix this material?
.
Chyme is the pulpy acidic fluid that passes from the stomach to the small intestine,
consisting of gastric juices and partly digested food. Chyme results from the mechanical and
chemical breakdown of a bolus and consists of partially digested food, water, hydrochloric acid,
and various digestive enzymes.
5. What role does the stomach play in decontaminating the incoming food matter? The
stomach's action is like contractions of ring-like waves. It produces strong acids that turn
the food into a paste-like substance called chyme. The stomach is a triple muscle, with
the third type of muscle shaped in a spiral to screw the contents down.
6. Why doesn't gastric juice digest in the stomach? The stomach walls have a lining that
contains epithelial cells that secrete a protective layer of mucus and bicarbonate. The
mucous is pretty much the same stuff which lines our throat and nose. It sticks to the
walls of the stomach to provide a physical barrier so the acid doesn’t touch the stomach
itself.
7. What are sphincters and how are they related to the stomach? Sphincters are rings of
muscles surrounding and serving to guard or close an opening or tube, such as the anus
or the openings of the stomach.
8. What mechanical and chemical digestion occurs in the stomach? Mechanical digestion
is the physical division of a mass of food into smaller masses while chemical digestion is
the chemical conversion of larger molecules into smaller molecules.
.
Small Intestine(Function)- the primary function of the small intestine is to absorb nutrients and minerals from
the food that is broken down in the stomach.
What are the three sections of the small intestine and what role does each section play in
digestion or absorption?
1. Duodenum - receives the bile from the stomach and pancreatic juice through the
pancreatic duct. It helps with digestion by breaking down the proteins, also helps
neutralize the acids that come from the stomach. This is also the shortest part of the
small intestine and only measures about 20-30 cm long.
2. Jejunum- is the middle section and is about 2.5 meters long and helps with digestion by
absorbing most the nutrients and minerals that were broken down in the Duodenum.
3. Ileum- is the last part of the small intestine and is about 3 meters long, it helps with
digestion by absorbing mainly vitamin B12 and bile acids and any other nutrients left.
The entire small intestine is about 20ft total in length, in adults.
What is the pH within the small intestine and how is this pH maintained?
The pH level in the pancreas should stay between 5.7-7.4. The duodenum has a pH
level of 6. The terminal ileum has a pH level of 7.4. The caecum has a pH level of 5.7. The
rectum has a pH level of 6.7. That is also the order at which the digestive system moves the
intaken food. The small intestine is considered basic pH level. The pH level in the small intestine
is maintained because of the release of sodium bicarbonate, which is stimulated by the
hormone secretin, from the pancreas.
Where do bile and pancreatic enzymes enter the small intestine?
Bile enters the small intestine at the very beginning in the Duodenum and is absorbed
out by the three parts. All the digestive enzymes which are secreted by the pancreas are
released into the small intestine in the duodenum just like the bile.
How does food move through the intestines?
Food moves through the intestines when the longitudinal muscles contract and then the
circular muscles contract which keeps food moving in a one way path. The muscles are
considered smooth muscles. This is the same way you are able to swallow food, even if you’re
upside down! This is known as peristalsis.
What enzymes act inside the small intestine and what are the functions of these enzymes?
Pancreatic amylase- Completes digestion of carbohydrates which produces glucose.
They also help break down fats, lipids, and proteins. Also to neutralize stomach acid.
Maltase- Converts maltose (disaccharide) into glucose (monosaccharide).
Trypsin- Breaks chemical bonds so that molecules become smaller and easier to
absorb.
Peptidases- Breaks down long protein strands into smaller lengths.
Nuclease- Breaks bonds in nucleotides in nucleic acids.
Nucleotidases- Break down consumed nucleic acids.
Lipase- Breaks down dietary fats into smaller molecules such as fatty acids and glycerol.
Large IntestineThe large intestine absorbs water from indigestible food and then transmits the useless
waste from the body.
It removes the food from the body that will not be needed and finishes absorbing
nutrients from the materials the stomach already broke down into the nutrients it
needed.
The cecum receives undigested food from the small intestine; aids in formation of
feces, chyme is mixed with bacteria by contractions in walls of cecum and then is
pushed up into the ascending colon. The colon (ascending, transverse, descending,
sigmoid) ; first two sections of the colon absorb salts and fluids from the indigestible
foods. The colon also produces mucus that helps move feces to the rectum, which is
the third part of the large intestines. The rectum is where feces waits to exit the body
through the anus.
The large intestine maintains a water balance in the body by absorbing water from
food.
Pancreas
1)What is the size and the location of the pancreas?
The Pancreas is roughly 6 inches long, and sits across the back of the abdomen, behind
the stomach.
2) What are different functions of the pancreas, and how is the pancreas directly related to
digestion?
In digestion the Pancreas has an exocrine function that releases juices that help to break
down food after is has left the stomach before it enters the bloodstream, it releases these juices
into the bloodstream.
The Pancreas also has a endocrine function which regulates blood sugar.
3) How does the pancreas connect to the rest of the digestive system?
The Pancreas is physically connected to the rest of the digestive system by a small
connection into your small intestine, but your pancreas is also connected to the gall bladder.
The pancreas also produces digestive enzymes and it produces them in the duodenum.
The name of the categories of these enzymes are pancreatic lipase,
4) What enzymes are produced by the pancreas and what are their Functions?
 Pancreatic proteases (such as trypsin and chymotrypsin) - which help to digest proteins.
 Pancreatic amylase - which helps to digest sugars (carbohydrates).
 Pancreatic lipase - which helps to digest fat.
5) How is insulin related to the digestive system?
Insulin helps to regulate the amount of sugar in the blood.
Liver and gallbladder
Introduction:
The liver is both a gland and an organ. It is one of the largest gland/organs in your body. Your
liver is on the right side of your body. The liver has more than 400 jobs! It does things such as
getting rid of toxins, fighting infections, helps regulate blood sugar, and digests fats. It's also the
only organ that can grow back. The gallbladder is a pouch right beneath the liver. It stores bile
which helps break down or digest food. Humans can live without their gallbladder. Your
gallbladder produces 400 ml to 800 ml of bile each day.
1. What is the size of the liver and where is it located?
. The adult liver weighs somewhere between 2.6lb and 3.3lb. It is located in the
right upper quadrant of your abdomen. The gallbladder is 8 cm in length and 4
cm in diameter.
2. How does the liver function in relation to digestion?
It processes the nutrients absorbed from the small intestine and produces bile that helps
in digesting fat.
3. What are other functions of the liver in the body?
The liver makes the proteins that can help in blood clotting. It helps your body process
some chemicals or toxins like drugs or alcohol. It can clean some of these out before they enter
the bloodstream to other important areas because blood from the intestines goes to the liver
first. Then it sends the toxins out of your body.
4. What is the relationship between the liver and the gallbladder?
The gallbladder stores the bile that the liver produces. After a meal the gallbladder
releases the bile into the duodenum(small intestine) to help break the food down.
5.
What is the function of bile and where does it enter the digestive tract?
Bile increases the absorption of fats in your small intestine. And it helps to break down
food. It's stored inside the gallbladder. It enters the digestive tract in the duodenum(small
intestine).
More about the Liver and Gallbladder;
1. IntroductionThe liver is meaty organ that detoxifies chemicals and metabolizes drug. It also makes proteins
that aids in blood clotting. The Gallbladder is hollow structure that stores and concentrates bile
and drains waste products from the liver.
2. What is the size of the liver and where is it located?
The liver is the largest internal organ. It is about the size of a football. It is located mainly in the
upper right portion of the abdomen beneath the diaphragm and above your stomach.
3. How does the Liver function in relation to digestion?
It’s the chemical “factory”. The liver processes the nutrients from the small intestines so we can
get things like glucose and other things into our bloodstream and eventually use them. The liver
also aids in fat digestion by secreting bile into the small intestines.
4. What are other functions of the liver in body?
The liver metabolizes drugs in the body making it easier for the body to use. It also creates bile
which helps carry away waste. It creates proteins important for blood clotting.
5. What is the relationship between the liver and the gallbladder?
The gallbladder drains waste from the liver as well as stores the bile that the liver produces and
stores it for digestion. The bile that the gallbladder stores will help break down all the food we
eat, which the liver will eventually process the nutrients from what we ate.
6. What is the function of bile and where does it enter the digestive tract?
The function of bile is to carry away waste products and it ends up in the intestines. Bile ducts
carry bile from the liver and then get released into the small intestine duodenum.