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78 Cards in this Set
- Front
- Back
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Metabolism is...
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extracting energy from the environment and using it to fuel your processes. Energy extraction is the basic feature of life, the two most basic are metabolism and reproduction
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Where does the human digestive system begin?
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The mouth. Our oral cavity where our tounge and teeth are.
The tounge is skeletal muscle that manipulate food into a BOLUS, a spit covered ball that will slide down. |
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Divide upper and lower teeth into quadrants. What kinds of teeth do you usually have in one quadrants?
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in one quarter you usually have 2 incisors, 1 canine, 2 premolars, and three molars.
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What are teeth composed of?
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Enamel (calcium), and dentin (hard but not as hard as enamel). We have a pulp cavity where nerves and vessels run. Root of the tooth extends into jawbone.
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What are the functions of our different kind of teeth?
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Incisors- broad and flat for grasping & peeling fruits and veggies.
Premolars are for grinding. Canines- unimpressive. In other primates not used for dietary but rather threat displays. |
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Salivary Glands
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Provide lubrication for food we eat.
Stimulated by site and smell and feel of food in mouth. Stimulated by the parasympathetic nervous system. We have the Parotid(dumps saliva into mouth), Submandibular, & under tounge is sub-lingual gland. |
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Where does most of our saliva come from?
How much do we produce each day? |
Submandibular 70%
Parotid 25% Sublingual 5% We produce one liter each day. We swallow it and reabsorb the water with our large intestine (large function of Lg intestine) |
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Amylase
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An enzyme that breaks down the nutrient, STARCH.
Starch is a complex sugar. Mechanical and Chemical digestion begins in the mouth. |
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The digestive tube.
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Extends from esophagus to the anus.
It's modified depending on functions of different areas, secretion of juices or absorbtion of nutrients or water. |
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What does the Digestive tube consist of from the inside out?
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Inside of tube where material passes is called the LUMEN, surrounding the lumen are the MUCOSA, under the mucosa you have SUBMUCOSA. Then we have MUSCULARIS, and on top of it all we have the SEROSA aka visceral perotineum.
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What tissue does the Mucosa consist of?
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Epithelial tissue underlying by a thin layer of connective tissue called lamina propria.
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What tissue makes up most of the digestive tract from the stomach to the large intestine?
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Simple Columnar
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What type of tissue is the esophagus lined with? also parts of the rectum and anus?
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Stratified squamous epithelial tissue.
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What type of tissue does the submucosa consist of?
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smooth muscle and connective tissue
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Enteric Nervous System
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The part of the nervous system associated with digestive tract.
The digestive system has a nervous system that has as many neurons as the spinal cord. A lot of the same neurotransmitters are released like serotonin. (Gut feelings) |
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What is the muscularis?
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Two layers of muscle tissue, one longitudinal and the other circular so you can both shorten and lengthen the digestive tube.
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What is the Serosa aka Visceral peritoneum made of?
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It's a surrounding connective tissue layer with a small layer of epithelial tissue that covers the tube.
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The Esophagus
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Connects the throat and the stomach. It conducts food through gravity and the process of peristalsis
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What is the process of Peristalsis?
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it's the contraction of smooth muscle. You squeeze the circular part and contract the longitudinal part.
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Why is the mucosa in the esophagus stratified epithelial tissue?
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because it gets scraped off as we eat food. We can easily replace it just as we do on the surface of the skin.
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What is the role of the stomach?
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Stores food
Fixes food Produces enymes that chemically digests the food Produces gastric juices that help with digestion. |
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What is the entrance from the esophagus to the stomach called?
What is heartburn? |
the cardiac orifice aka cardiac sphincter. Food is dumped through process of gravity. It doesn't come back up usually because there is a bit of smooth muscle that helps to constrict the openning.
Heartburn is when the contents of the stomach comes back into the esophagus. |
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Why is the muscularis, (the wall of the stomach) thickened?
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Because the stomach has a lot of smooth muscle that grinds the food after we eat it. The muscularis is arranged in waves called Rugae
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What is the MUCOSA of the stomach and what important purpose does it serve?
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it consists of simple columnar epithelial tissue sprinkled throughout with goblet cells.
Goblet cells produce mucus. There is a thick layer of mucous on the surface of the stomach that protects it from being eroded by Hydrochloric acid |
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Parietal Cells
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the cells in mucosa that produce hydrocloric acid.
strong enough to digest iron nails. really acidic envionment |
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What is the PH of your stomach?
What is the PH of your blood? |
stomach is about 2
blood is about 7.3 the ph in the stomach is acidic enough to kill bacteria |
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What are chief cells?
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Cells in the stomach that produce an enzyme called pepsinogen.
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What is the role of pepsinogen?
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Pepsinogen is an enzyme that becomes activated in the presence of hydrochloric acid.
In the presence of Hydrocloric acid, pepsinogen is converted to pepsin. Pepsin begins protein digestion. it breaks down proteins into polypeptide chains. Most proteins we eat are big molecules that are amino acid chains. |
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What are the three portions of the small intestine, their size, and function?
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Duodenum- 10 inches long, where ALL the chemical digestion of nutrients takes place.
Jejunum- 8 feet long Ileum- 12 ft long In all, it's about 21 feet long in humans. |
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Chyme
What is it and what does it do? |
After food is mixed with gastric juices it's called chyme. It's liquid like a smoothie.
Chyme squirts from stomach to duodenum one skirt at a time through the pyloric sphincter. |
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The role of the Pancreas.
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Chemical digestion is partly accomplished through pancratic juices.
The Pancreas secrets enzymes that travel through the pancreatic duct and dump into the duodenum to help you digest fats, proteins, carbs. |
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Facts about Bile
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-Bile is a liquid, amazing, green stuff.
-Produced in the liver and enters the duodenum through the common bile duct. -Stored in the Gallbladder -Helps with fat digestion |
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What ensures the breakdown of fats, carbs, and proteins by the time you reach the end of the duodenum?
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The mixture from the gall bladder, pancreas, and small intestine.
The cells of the duodenum produce intestinal juices chock full of enzymes that help break down nutrients. |
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The role of the Jujunem and the Ileum
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to absorb nutrients. Lots of surface area, nutrients cross the membrane of the simple columnar cells into blood vessels so it can be carried to the liver.
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What helps to increase the surface area for absorbtion in the small intestine?
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Pilcae (infoldings of the tube)
Villi (looks like a shag rug) Micro Villus (on each villus is a micro villus) |
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Explain Micro Villus &
ENTEROCYTES |
Micro Villus are covered with simple columnar cells. These are absorbative cells called enterocytes. Each Micro villi are pierced by capillaries so nutrients can be absorbed ito the blood. They are also pierced by a lymph vessel called a lacteal.
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Lacteal
How is fat absorbed? |
A lymph vessel that pierces a micro villi.
Looks milky cause the lacteal absorbs fat. Fat is not absorbed in the blood but rather through the lymph vessel. The lymph vessels converge and dump into the blood in the subclavian vein. This is why you can get high levels of fat in the blood right after eatting a high fat meal. |
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Where does chemical digestion occur?
How is chemical digestion accomplished? |
The Duodenum
Pancreatic juices, bile, and juices produced by epithelial cells in the duodenum itself. |
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Where are nutrients absorbed?
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Jejunum and Ileum
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What are the folds of the small intestine called that help to increase curface area?
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Plica
On Plicae there are Villi that sticks out like velvet. |
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Nutrients move from the Lumen to underlying capillaries. What do these capillaries absorb?
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Glucose and the amino acids that you produce from the breakdown of proteins.
They do NOT absorb Fat. |
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What is the structure of the Lymph vessels?
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Less tightly joined epithelial cells on there walls so stuff can move back and forth easily.
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Cecum
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The first part of the large intestine.
Humans do not have an impressive one. Some animals have elaborate ones to process plant food more readily. |
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After the Cecum, what are the parts of the large intestine?
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The ascending colon
transverse colon descending colon a sigmoid colon and then it dumps to the rectum |
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What is the Rectum?
What is the anus? |
Rectum is a muscular canal that stores feces.
The Anus is the openning to the outside of the body that feces comes out of. |
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What are Houstra
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The folds of the large intestine. They are pouched created by ribbons of smooth muscle called Taeniae Coli
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What are Taeniae Coli?
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The ribbons of smooth muscle on the Houstra (folds of large intestine)
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What are Epiploic Appendages?
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Fingers of fat that hang off the large intestine
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What is a main job of the large intestine?
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To reabsorb water. We ingest and secrete about 9 liters of water a day.
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What is a cause of Diarrhea?
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If our large intestine does not reabsorb water efficiently.
Diarrhea is stil a leading cause of death of infants partly due to lack of clean water. |
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What is the worm like structure called that hangs off the Ceacum?
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The Appendix.
It's a hangover from evolutionary past. |
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What is the purpose of the Appendix?
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It;s full of lympathic tissue that probably acts as a tonsil to trap foreign substances that might make us ill.
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What is appendicitis?
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When the appendix accumulates hardened material from the large intestine and the material becomes infected, inflammed. It then needs to be removed or it can rupture and contents spew into peritoneal cavity. Bad! bacteria! a person can become septic and die
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The importance of the Liver
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It's a PROTEIN FACTORY
It creates proteins. proteins that you will find in the blood for example. |
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What is the roll of the liver in digestion?
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It receives all the blood from the small intestine via the Hepatic Portal Vein. The blood is processed by liver cells called hepatocytes.
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What does the Hepatic Portal Vein do?
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It transports blood from the small intestine to the liver
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What are Hepatocytes and what do they do?
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Liver cells that process the blood from the small intestine.
They have machinery to access the level of glucose in the the blood. If there is too much blood glucose, hepatocytes will manufacture glycogen from glucose. Hepatocytes also produce bile |
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More functions of the Liver
pertaining to cholesterol |
The liver processes some lipids, particularly cholesterol. Not all lipis get absorbed into the lacteals. Cholesterol is so small it can get absorbed in the blood.
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How is cholesterol processed?
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It goes from the small intestine through the hepatic portal vein and the liver will process it.
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Another function of the liver
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Extracts toxins from the blood.
A lot of oral medication processed in the digestive tract, absorbed across the small intestine and processed by the liver. |
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What is in Bile and why is it green?
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Bile has cholesterol in it and phospholipids and acts as a soap in many ways.
It's green because it accumulates the bi-products of red blood cell breakdown. After the liver produces bile it's stored in the gallbladder. |
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What is the purpose of the Appendix?
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It;s full of lympathic tissue that probably acts as a tonsil to trap foreign substances that might make us ill.
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What is appendicitis?
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When the appendix accumulates hardened material from the large intestine and the material becomes infected, inflammed. It then needs to be removed or it can rupture and contents spew into peritoneal cavity. Bad! bacteria! a person can become septic and die
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The importance of the Liver
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It's a PROTEIN FACTORY
It creates proteins. proteins that you will find in the blood for example. |
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What is the roll of the liver in digestion?
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It receives all the blood from the small intestine via the Hepatic Portal Vein. The blood is processed by liver cells called hepatocytes.
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What does the Hepatic Portal Vein do?
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It transports blood from the small intestine to the liver
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The PANCREAS has an exocrine function and an endocrine function. What is the EXOCRINE function?
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produces digestive enzymes that break down fats, proteins, and carbs.
produces an alkaline fluid the digestive enzymes and alkaline fluid are dumped into a pancreatic duct that goes into the duodenum |
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What is the ENDOCRINE function of the PANCREAS?
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it produces insulin and glucagon that helps to regulate blood sugar.
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What is the ENDOCRINE function of the PANCREAS?
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it produces insulin and glucagon that helps to regulate blood sugar.
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What organs does the celiac artery supply?
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it gives blood to the stomach but also supplie the pancreas.
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Where does chemical digestion occur?
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it starts in the mouth with Amylase. Amylase is in saliva and it is an enzyme that breaks down starch.
In the stomach you find Pepsin that breaks down amino acid chains. But most of chemical gigestion occurs in the duodenum |
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What is the mechanical digestion of food?
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Chewing food with the mouth
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What is Lactase?
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an enzyme that works to break apart lactose. Lactose is milk sugar.
Most mammals pass juvenile stage do not produce lactase. Some humans don't (lactose intollerant). Some human pop have adapted to using cattle milk so they retained lactase. Most mammels don't drink milk beyond infancy. |
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What is pancreatic juice?
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-it's basic rather than acidic
- in counter acts chime from the stomach. -it has bunches of enzymes including amylase which we also find in saliva. -also has Trypsin (breaks down proteins, chops off amino acids) -Lipases (facilitates fat digestion, breaks apart triglicerides into fatty acid chains) |
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List some enzymes present in pancreatic juice.
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Lactose
Amylase (also in saliva) Trypsin Lipases |
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Is Pancreatic Juice acidic or alkaline and why?
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Alkaline in nature
It counter acts the acid that comes from the stomach witth the chyme |
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What is a pancreatic juice enzyme that breaks down protein?
and how does it work? |
Trypsin
It chops off amino acids |
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What pancreatic juice enzyme facitilitates fat digestion?
and how? |
Lipases break apart triglycerides into fatty acid chains for example.
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