Chapter 3 Flashcards
Atoms
Elements
Chemical bonds
Molecules
Smallest unit of an element that still retain properties of that element
Substances that cannot be broken down into products with different properties
Forces that hold atoms together
Units of two or more of the same or different elements bonded together
Cells
Organs
The basic structural and functional units of plants and animal life
Discrete structures composed of more than one tissue that perform a specialized function
4 types of tissue
Muscle
Nerve
Epithelial
Connective
Two functions of digestive system
Digestion: the process of breaking down food into components small enough to be absorbed into the body
Absorption: the process of taking substances into the interior of the body
Feces
Body waste; unabsorbed food, bacteria, mucus, and dead cells which is excreted from the GI by passing through the anus
Gastrointestinal tract
A hollow tube consisting of the mouth, pharynx, esophagus, stomach, small intestine, large intestine, and anus, in which digestion and absorption of nutrients occurs
The tube is not inside your body…but food can be absorb less into the body
Transit time
The time between the ingestion of food and the elimination of the solid waste from that food.
24-72 hours in healthy adults
Mucosa
The layer of tissue lining the GI tract and other body cavities.
- protective layer
- absorption of the end products of digestion
- in direct contact with digestive enzymes and churning therefore cells only live 2-5 days
Layers of tissue of GI tract
- mucosa: cells to absorb nutrients
- connective tissue with nerve and blood vessels (support, controls muscles)
- involuntary smooth muscle/peristalsis (breaks up food)
- connective external layer provides support and protection
Mucus
A viscous fluid secreted by glands in the GI tract and other parts of the body, which acts to lubricate, moisten, and protect cells from harsh environments
Enzymes
Protein molecules that accelerate the rate of specific chemical reactions without being changed themselves
- some only affect fat
- some only affect carbs
Salivary amylase
Rennin
Pepsin
Mouth-breaks starch (large carb to smaller carbs molecules)
Stomach-cause the milk protein casein to curdle
Stomach-breaks proteins into polypeptides and amino acids
Trypsin
Chymotrypsin
Carboxypepidase
Pancreas
- breaks proteins and polypeptides into shorter polypeptides
- same as above
- breaks polypeptides into amino acids
Carboxypeptidase
Pancreatic lipase
Pancreatic amylase
Pancreas
- polypeptides into amino acids
- breaks triglycerides into monoglycerides, fatty acids and glycerol
- breaks starch into shorter glucose chains and maltose
Carboxypepidase
Aminopeptidase
Dipeptidase
Small intestine
-breaks polypeptides into amino acids
Lipase
Sucrase
Lactase
Small intestine
- monoglycerides into fatty acids and glycerol
- sucrose into glucose and fructose
- lactose into glucose and galactose
Maltase
Dextrinase
Small intestine enzyme
- breaks maltose into glucose
- breaks short chains of glucose into individual glucose molecules
Hormones
Chemical messengers that are produced in one location, released into the blood, and elicit responses at other locations in the body
Gastrin
Digestive hormone from stomach mucosa that stimulates secretion of HCL and pepsinogen by gastric glands in the stomach and increases gastric motility and emptying
Very important!!!
Somatostatin
Hormone from stomach and duodenal mucosa that inhibits stomach secretion, motility, and emptying, pancreatic secretion, absorption in the small intestine, gallbladder contraction and bile release
Secretin
Hormone released by the duodenum that signals the release of pancreatic juice rich in bicarbonate ions and stimulates the liver to secrete bile into the gallbladder.
Cholecystokinin (CCK)
Hormone released by the duodenum that stimulates the release of pancreatic juice rich in digestive enzymes and causes the gallbladder to contract and release bile into the duodenum
Gastric inhibitory peptide
Hormone from duodenal mucosa that inhibits gastric secretion and motility
Barrier function
The protective role that gastrointestinal cells have in limiting the absorption of harmful substances and disease-causing organisms
The GI tract limits the absorption of toxins and disease-causing organisms
Antigen
Antibody
A foreign substance (almost always has a protein) that, when introduced into the body, stimulates an immune response
Proteins produced by cells of the immune system that destroy or inactivate foreign substances in the body
Allergen
What are allergies
A substance, usually a protein, that stimulates an immune response.
An allergic reaction occurs when the immune system produces antibodies to a substance called an allergen
Saliva
Salivary amylase
A watery-fluid produced and secreted into the mouth by salivary glands. Contains lubricants, salivary amylase and lysozyme (inhibit bacteria growth in mouth).
An enzyme secreted by the salivary glands that breaks down starch (carbohydrates)
Lysozyme
An enzyme in saliva, tears and sweet that is capable of destroying certain types of bacteria
-helps prevent tooth decay
Pharynx
A funnel-shaped opening that connects the nasal passages and mouth to the respiratory passages and esophagus. It is a common passageway for food and air and is responsible for swallowing
Epiglottis
A piece of elastic connective tissue at the back of the throat that covers the opening of the passageway to the lungs during swallowing
Esophagus
What pushed food down???
A portion of the GI tract that extends from the pharynx to the stomach
Peristalsis: coordinated muscular contractions that move food through the GI tract
Sphincter
A muscular valve that helps control the flow of materials in the GI tract
Chyme
A mixture of partially digested food and stomach secretions
How many smooth muscle layers does the stomach have?
3
Parietal cells
Cells in the stomach lining that make HCL and intrinsic factor (needed for absorption of B12) in response to nervous or hormonal stimulation
Pepsinogen
An inactive protein-digesting enzyme produce by gastric glands and activated to pepsin by acid in the stomach
Pepsin
A protein-digesting enzyme produced by gastric glands. It is secreted in the gastric juice in an inactive form and activated by acid in the stomach
Peptic ulcer
An open sore in the lining of the stomach, esophagus or smaller intestine
How much stomach churning and how much gastric juice is released is regulated by signals from both ______ and ______. These signals originate from 3 sites:
Nerves and hormones
Brain, stomach and small intestine
Gastrin
A hormone secretion by the stomach mucosa that stimulates the secretion of gastric juice
Villi
Microvilli
Finger-like projections of the lining of the small intestine that participate in the digestion and absorption of nutrients
Or brush border minute, brush-like projections on the mucosal cell membrane that increase the absorptive surface area in the small intestine (are on villi)
Lacteal
A tubular component of the lymphatic system that Carrie’s fluid away from body tissues. Lymph vessels in the intestine are known as lacteals and can transport large particles such as the products of fat digestion
(Each villus contains a blood vessel and a lymph vessel (Lacteal)
Segmentation
Rhythmic local constructions of the intestine that lix food with digestive juicers and speed absorption by repeatedly moving the food mass over the intestinal wall
Pancreas
An organ that secretes digestive enzymes and bicarbonate ions into the small intestine during digestion(neutralize acid to make small intestine less acidic)
Gallbladder
Bile
An organ of the digestive system that stores bile which is produced by the liver
A substance made in the liver and stored in the gallbladder, which is released into the small intestine to aid in fat digestion and absorption (emulsifies fat)
Lipases
Fat digesting enzymes from pancreas
The release of bile and pancreatic juice into the small intestine is controlled by which two hormones
Secretin
Cholecystokinin
Simple diffusion
Osmosis
The movement of substances from an area of higher concentration to an area of lower concentration (no energy required)
The passive movement of water across a semipermeable membrane in a direction that will equalize the concentration of dissolved substances on both sides
Facilitated diffusion
The movement of substances across a cell membrane from an area of higher concentration to an area of lower concentration with the aid of a carrier molecule. No energy required
Active transport
The transport of substances across a cell membrane with the aid of a carrier molecule and the expenditure of energy. This may occur against the concentration gradient
Colon
Rectum
The largest portion of the large intestine
The portion of the large intestine that connects the colon and anus
Intestinal micro flora or microbiota
Micro-organisms that inhibit the large intestine
Probiotics
Prebiotics
Specific types of live bacteria found in foods that are believed to have beneficial effects on human health (new in health world)
Indigestible carbohydrates that pass into the colon, where they serve as a food supply for bacteria, stimulating the growth or activity of certain types of beneficial bacteria
The amount of water in the feces is affected by ____
Fibre and fluid intake
Fibre retains water, so when adequate fibre and fluid are consumed, feces have a higher water content and are easily passed
Dysbiosis
An imbalance in the microbiota that results in detrimental effects such as inflammation and impaired immune function
Diseases associated with dysbiosis
IBS Inflammatory bowel disease (crohns, ulcerative colitis) Celiac disease Obesity Cardiovascular disease Diabetes Asthma
Heartburn
One of the most common digestive complaints. Cashed by acidic stomach content leaking back into the esophagus, causing a burning sensation in the chest or throat
GERD
Gastroesphageal reflux disease
A chronic condition in which acidic stomach contents leak back into the esophagus, causing pain and damaging the esophagus
-gastroesophageal sphincter not closing
-can lead to bleeding, cancer, ulcers
Peptic Ulcers
Can arise in both esophagus, duodenal and stomach. They occur when the mucosa is eroded away, exposing the underlying tissue to the gastric juices. If the damage reaches the nerve layer, it causes pain and bleeding which can be fatal
Can be caused by GERD, stress, medications-pain killers (NSAIDS), or
More often caused by Helicobacter pylori bacteria.
Can treat with antibiotics
Gallstones
Clumps of solid material that form in the gallbladder or bile duct and can cause pain when the gallbladder contracts in response to fat in the intestine. (Blocks bile!)
- symptom: pain
- after gall bladder removal, bile drips into the small intestine rather than being secreted when fat is consumed so fat content of meals needs to be reduced.
Diarrhea
Frequent watery stools
Material moves through the colon too quickly for sufficient water to be absorbed or when water is drawn into the lumen from the cells lining the intestinal tract.
- caused by infections, irritants, medications and diseases
- symptoms: pain, dehydration, malnutrition
Risks and decreased risks to digestive system cancers
- red meat
- alcohol
- body fatness
- salt
- sugar
- whole grains
- fibre rich foods
- calcium supplements
- dairy products
- citrus fruit
Enteral or tube feeding
A method of feeding by providing a liquid diet directly to the stomach or intestine through a tube placed down the throat or through the wall of the GI tract
Total parenteral nutrition (TPN)
A technique for nourishing an individual by providing all needed nutrients directly into the circulatory system
Atrophic gastritis
An inflammation of the stomach lining that causes a reduction in stomach acid and allows bacterial overgrowth
Common in elderly
Hepatic Portal circulation
The system of blood vessels that collects nutrient-laden blood from the digestive organs and delivers it to the liver which than transfers nutrients to body systems
Lymphatic system
The system of vessels, organs, and tissues that drains excess fluid from the spaces between cells, transports fat-soluble substances from the digestive tract, and contributes to immune function
Nutrients absorbed into the mucosal cells of the intestine enter the blood circulation by either
Hepatic portal circulation
Lympathtic system
Hepatic portal vein
The vein that transports blood from the GI tract to the liver
Metabolic pathway
a series of chemical reactions inside of a living organism that result in the transformation of one molecule into another
Catabolic
Anabolic
The process by which substances are broken down into simpler molecules, releasing energy
The process requiring energy in which simpler molecules are combined to form more complex substances
Cellular respiration and stages
The reactions that break down carbohydrates, fats, and proteins in the presence of oxygen to produce carbon dioxide, water and energy in the form of ATP
-when oxygen is present, glucose, fatty acids and amino acids are broken down to a 2-carbon molecule that units to form a molecule called acetyl-COA. To form this, glucose must be broken down by glycolysis, amino acids go through deamination and fatty acids must go through beta-oxidation. Acetyl-COA is broken down inside mitochondria in citric acid cycle. Here the two carbons are removed which generates small amount of ATP by releasing electrons. Electrons move into electron transport chain and passed to oxygen to form water and produce ATP.
Oxidized
Reduced
Refers to a compound that has lost an electron or has undergone a chemical reaction with oxygen
Refers to a compound that has gained an electron
Glomerulus
A hall of capillaries in the nephron that filters blood during urine formation
Are you what you eat???
No you are what you absorb!!!
Small intestine function
Completes digestion, absorbs nutrients into blood and lymph
- main source of digestion and absorption
- 6M ling
- 3 sections: duodenum (most digestion), jejunum, ileum
- contains secretions from pancreas, gall bladder, liver and small intestine
Large intestine function
Absorbs water and some vitamins and minerals. Home to intestinal bacteria; passes waste material.
- 1.5 M long
- colon and recurring to anus
- no digestion
- some absorption of water, vitamins and minerals
- stores food waste prior to excretion
- can stay here for 24 hours
- propelled by peristalsis
- growth of intestinal microbiota: prebiotics and probiotics
Some cells of the immune system are present in the GI tract include:
Phagocytes: macrophages engulf harmful organisms
Lymphocytes: B cells and T cells
Antibodies
What is the importance of chewing
Chewing breaks down food to increase surface area for digestive enzymes
Regulation of stomach motility and secretion
- Thought, smell, sight and taste of food stimulates gastric secretions and stomach motility
- Good entering stomach increases gastric secretions and motility
- Food entering the small intestine triggers hormonal and nervous system signalling
The only way to have high quality and stable mental health isssss to have a
Healthy gut
Neurotransmitters responsible for mood and motivation are made in your gut!!!!!!!!!!!!!!
Healthy gut environment vs altered gut environment
Healthy:
- healthy level of inflammation
- healthy immune function
- healthy epithelial barrier
Altered gut environment: (Villi don’t have tight junctions=leaky gut, microvilli not starting tall) -excess inflammation -altered immune function -damaged epithelial barrier
Celiac disease
- inherited disease:autoimmune disease not an allergy
- gluten in wheat, barely, rye, oats, spelt etc. act as an antigen
- immune response damages or destroys villi which stops proper absorption and looks like nutrition deficiencies
- symptoms: abdominal pain, diarrhea, fatigue, malnutrition, weight loss, anemia, osteoporosis, brain fog, joint pain, iron deficiency, intestinal cancer
1/100 is truly intolerant
1/30 have lesser intolerance
Disorders of the lower GI tract-colon
Irratible bowel syndrome
Inflammatory bowel disease
- abdominal cramps
- bloating
- constipation and diarrhea
- caused by stress, nervous system miscommunication, certain foods, and hormones
- inflammation
- diarrhea, abdominal pain, blood in stool, mouth sores, weight loss, reduced appetite
- two forms: crohns and ulcerative colitis
Digestive cancers are the most _____ form of cancer
Preventable
Transport of carbohydrates to body cells
Fructose-facilitated diffusion-blood capillary
Glucose, galactose-active transport-blood capillary
Transport of proteins to body cells
Proteins-enzymes-amino acids-active transport-diffusion-blood capillary
Fat transport to body cells
Fat droplets- bile-Miceles-monoglycerides an fatty acids-triglycerides-chylomicrons-exocytosis-Lacteal (lymph vessel)
Metabolism-waste generation based on -digestive system
- integumentary system
- respiratory system
- urinary system
- takes in nutrients, removes unabsorbed waste
- perspiration: water and minerals
- takes in oxygen, removes carbon dioxide
- removes urine and nitrogen products
