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125 Cards in this Set
- Front
- Back
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adenosine triphosphate (ATP) |
cellular processes and chemical reactions, which occur constantly in every living cell, require a continuous supply of energy in the form of dietary carbohydrate, protein, and fat.
Almost all cells need oxygen to transform the energy in nutrients into the form the body can use - ATP
The chemical that supplies energy for many cellular processes and reactions |
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Tissue |
made up of similar groups of similar cells working together to perform a specific task. |
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4 tissues that humans are made up of |
1. Epithelial 2. Connective 3. Muscle 4. Nervous |
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Epithelial Tissue |
is composed of cells that cover surfaces outside and inside the body. The skin and lining of the gastrointestinal (GI) tract are examples. Epithelial cells absorb nutrients, secrete important substances, excrete waste, and protect underlying tissues. |
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Connective tissue |
supports and protects the body by holding structures ( cells and cell parts) together, store fat, and produce blood cells. Tendons, cartilage, and parts of bone, arteries, and veins are made up of connective tissue |
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Muscle Tissue |
Can contract and relax and permit movement |
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Nervous tissue |
found in the brain and spinal cord, transmits nerve impulses from one part of the body to another |
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Organs |
tissues combine in a specific way to form structures which perform specific functions. |
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Organ system |
This is formed when several organs work together to perform a specific function.
ex: digestive system includes the GI tract ( mouth, esophagus, stomach, small intestine, and large intestine, which terminates with the rectum and anus), liver, pancreas, and gallbladder |
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Digestive system |
Major components: Mouth, esophagus, stomach, intestines, and accessory organs (liver, gallbladder and pancreas)
Functions: perform the mechanical and chemical processes of digestion of food, absorption of nutrients, and elimination of wastes. |
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Nervous system |
Major components: Brain, Spinal cord, nerves, and sensory receptors
Functions: detects and interprets sensations, controls movements and physiological and intellectual functions |
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Cardiovascular System |
Major components: Heart, blood vessels, and blood
Functions: carries blood and regulates blood supply, transports nutrients, waste products, hormones, and gases ( oxygen and carbon dioxide) throughout the body, and regulates blood pressure |
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Integumentary System |
Major components: skin, hair, nails, and sweat glands
Functions: protects the body, regulates body temperature, prevents water loss, and produces vitamin D |
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skeletal system |
Major components: bones, cartilage, ligaments, and joints
Functions: protects organs, support body weight, allows body movement, produces blood cells, and stores minerals |
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Endocrine System |
Major components: endocrine glands, such as the pituitary, thyroid, and adrenal glands, hy
Functions: regulates metabolism, growth, reproduction, and many other functions by producing and releasing hormones |
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Lymphatic and Immune Systems |
Major Lymphatic components: lymph, lymphocytes, lymphatic vessels, and lymph nodes
Lymphatic Functions: aids in fluid balance, fat absorption and transport, and immune funtions
Major Immune components: mechanical (skin), chemical (lysozye), and cellular ( white blood cells
Immune Functions: protects against microorganisms and other forgien substances |
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Urinary System |
Major components: kidneys, urinary, bladder, and the ducts that carry urine
Functions: removes waste products from the blood and forms urine; regulates blood acid-base (pH) balance, overall chemical balance, and water balance |
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Respiratory System |
Major components: lungs and respiratory passages
Functions: exchanges gases (oxygen and carbon dioxide) between the blood and the air; regulates blood acid-base (pH) balance |
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Reproductive System |
Major components: gonads (ovaries and testes) and genitals
Functions: performs the process of sexual maturation and reproduction; influences sexual functions and behavior |
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alimentary canal |
The GI tract it is a long, hollow, muscular tube that extends almost 15 feet from mouth to anus. Nutrients must pass through the wall of this tube to be absorbed into the body,. |
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4 layers of GI tract |
1. Muscosa 2. Submucosa 3. Muscle 4. Serosa
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Mucosa |
the innermost layer of the alimentary canal. It is lined with epithelial cells and glands. The mucosa is not smooth and in some areas has tiny, fingerlike structures that project into the hollow low interior of the tube known as the lumen. These projections increase the surface area of the mucosa. |
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Lumen |
The mucosa is not smooth and in some areas has tiny, fingerlike structures that project into the hollow low interior of the tube known as the lumen |
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Submucosa |
The second layer of the alimentary , consists of loose connective tissue, gland, blood vessels, and nerves. The blood vessels carry substances, including nutrients, both to and from the GI tract |
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Muscle |
the next layer of the alimentary, occurs as double layers in most parts of the GI tract: an inner layer of circular smooth muscle that encircles the tube and an outer layer of longitudinal muscle fiber that runs up and down the tube. These muscles move food forward through the GI tract. The stomach has a third layer of muscle fiber running diagonally around it. |
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Serosa |
The outermost layer of the alimentary canal (GI) which protects it. The serosa secretes fluid that cushions the GI tract and reduces friction as it and other organs move. |
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Sphincters |
They are located along the GI tract and they are ringlike muscles that open and close like valves to control the flow of the contents. The sphincters prevent food from moving through the GI tract too quickly. This allows food in the GI tract to be mixed thoroughly with digestive system secretions. The sphincters also help propel food through the GI tract. |
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GI motility: peristalsis |
Food is mized with digestive secretions and propelled down the GI tract by a process called peristalsis. Peristalsis consists of a coordinated wave of contraction (squeezing and shortening) and relaxation of these muscles. This process begins in the esophagus as 2 waves of muscle action closely follow each other. The thickest and strongest muscles of the GI tract are in the stomach, where the conctraction of 3 opposing muscle layers promote complete mixing of food and gastric jucies. This can occur as often as 3 times per minute after a meal
The mos frequent peristalsis takes place in the small intestine, where contractions occur about every 4-5 seconds. |
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Segementation |
these are contractions that move the intestinal contents back and foth, causing the contents to break apart and mix with idigestive moements |
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peristalsis |
Peristalsis consists of a coordinated wave of contraction (squeezing and shortening) and relaxation of these muscles. This process begins in the esophagus as 2 waves of muscle action closely follow each other. The thickest and strongest muscles of the GI tract are in the stomach, where the conctraction of 3 opposing muscle layers promote complete mixing of food and gastric jucies. This can occur as often as 3 times per minute after a meal |
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Vomiting |
Reverses the normal digestive tract flow. It is controlled by the vomiting center of the brian, is triggered by toxins in the gastrointestinal tract, rapidly changes body position, and stomach distension
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Digestive Enzymes |
compounds that aid in the breakdown of carbohydrates, fats, and proteins.
they are protein molecules that speed up digestion by catalyzing chemical reactions.
They are produced in mouth, stomach, small intestine and pancreas
The pancreas adjusts its enzyme production to match the macronutrient content of the diet.
They are stored in an inactive state and released by tightly controlled by nerves and hormones
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Saliva |
from salivary glands in the mouth, moistens food and begins the process of digestion.
the salivary gland produce about 4 cups
It is a dilute, watery fluid that contains several substances including mucus to lubricate the bolus and hold it together - Lysozyme and amylase
It also prevents tooth decay because it contains antibacterial agents, minerals to repair teeth, and substances that neutralize acid |
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Mucus |
it is a thick fluild that protects body cells and lubricates digestive foods to help it move smoothly along the GI tract.
Mucus are secreted in the mouth, stomach, small and larege intestines |
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Hydrolysis Reactions |
Digestive enzymes catalyze these enzymes
In these reactions, water (hydro-) breaks apart (-lysis) molecules that are too large to pass through the GI tract wall. Hydrolysis reactions eventually yield simple molecules that are small enough to be absorbed through the intestinal wall. |
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Acid |
Produced in the stomach
It promotes digestion of protein, destroys microorganisms, and increases solubility of minerals |
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Bile |
Produced in the liver (Stored in the gallbladder)
It aids in fat digestion (emulsifies fat) |
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Bicarbonate |
Produced in Pancreas, small intestine
It neutralizes stomach acid when it reaches the small intestine |
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Hormones |
produced in stomach, small intestine, and pancreas
It regulates digestion and absorption |
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Four hormones that aid in digestion |
1. Gastrin 2. Secretin 3. Cholecystokinin (CCK) 4. gastric inhibitory peptide |
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Cooking |
softens the tough connective tissues in meats and fibrous tissue of plants whcih makes the food easier to chew, swallow, and break down during digestion
starch granules in food swell as they soak up water during cooking, making them much easier to digest. |
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Bolus |
When digestion begins in the mouth and he teeth tear and grind solid food into smaller pieces exposing it to salvia while the tongue presses morsels of food against the hard palate which helps mix the food with saliva. The food is now called a bolus |
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Lysozyme |
this substance is in saliva and kills bacteria by rupturing cell membranes |
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Amylase |
This is in saliva and is used to break down starch into simple sugars. |
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Taste buds |
they are found on the papillae of the tongue and soft palate, contain specialized taste-receptor cells that can detect taste compounds in food |
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5 Basic tates |
1. Salt 2. Sour 3. Sweet 4. Bitter 5. Umami |
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Olfactory cells |
they are located in the nose and are related to our sense of smell they are stimulated when we chew |
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Swallowing |
Swallowing moves the food from the mouth into the esophagus
1. epiglottis- prevents food from entering the trachea 2. When food is swallowed the epiglottis closes over the larynx 3. The bolus drops into the epiglottis and the esophagus relaxes and opens ( involuntary response) 4. with the use of peristalsis of the esophagus ad gravity, the food travels down the esophagus, not the trachea. |
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Epiglottis |
Flap that folds down over the trachea during swallowing |
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Trachea |
Airway leading from the larynx to the lungs |
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Larynx |
Structure located between the pharynx and trachea; contains the vocal cords |
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Lower esophageal sphincter |
located between the esophagus and the stomach prevents backflow (reflux) of the highly acidic stomach contents into the esophagus. If it malfunctions hearburn occurs |
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Stomach |
it is essentially a holding and mixing tank
The average adult stomach holds about 2 ounces when empty and expands to 4-6 cups after a typical meal however it can expand to 16 cup ( 4 liters)
Little digestion occurs in the stomach only water, a few forms of fat, and about 20% of any alcohol consumed can be absorbed there |
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Gastric Jucies |
the stomach secrets about 8 cups of gastric jucies that aids i the digestive process. They are released when we see, smell, taste, or even think about food. They include the very strong acid (HCl) |
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Parietal Cells |
Gastric gland cells that secretes hydrochloric acid and intrinsic factor |
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Pepsinogen |
Inactive precursor to the protein-digesting enzyme pepin; produced in the stomach |
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Chief Cells |
Gastric gland cells that secrete pepsinogen |
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Gastrin |
a hormone made in the stomach, controls the release of HCl and pepsinogen. Gastrin secretion is highest at the beginning of a meal and declines as the meal progresses. The decline in gastrin secretion causes the release of HCl and pepsinogen to tapper off. |
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HCl importance |
it inactivates the bilogical activity of ingested proteins, such as certain plant and animal hormones. THis pervents them from affecting human fucntion. HCl also destroys most harmful bacteria and viruses in foods, dissolves dietary minerals, so that they can be more easily absorbed; and converts pepsinogen into the active protein-digesting enzyme pepsin |
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postaglandins |
potent compounds that are synthesized from polyunsaturated fatty acids and produce diverse effects in the body |
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nonsteroidal anti-infammatory drugs (NSAIDS) |
class of medications that reduce inflammation, fever and pain but are not steroids>
ex: aspirin, ibuprofen (advil) , Aleve etc. |
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Chyme |
Liquid mixture of stomach secretions and partially digested foods |
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Gastric inhibitory peptide |
Hormone that slows gastric motility and stimulates insulin release from pancreas. It helps slow the relase of chyme into the small intestine, givien the small intestine time to neutralize the acid and digest the nutrients |
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Pyloric Sphincter |
Located between the stomach and the duodenum(first part of the small intestine), controls the flow of chyme into the small intestine.
It also prevents the bakflow of bile into the stomach |
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intrinsic factor |
this substance is required for the absorption of vitamin B-12 in the small intestine ` |
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3 sections of the small intestine |
1. Duodenum 2. Jejunum 3. Ileum |
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Duodenum |
The first part of the small intestine
t is about 10 inches long |
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Jejunum |
The middle part of the small intestine
it is about 4 ft long |
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Ileum |
the last section of the small intestine
It is about 5 ft long
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Villi and MicroVilli |
the interior of the small intestine which contains these circular folds and fingerlike projection which increase its surface area. The large surface area cntributes to the thoroughness and efficiency of digestion and absorption
They are lined with goblet cells that make mucus, endocrine cells that produce hormones and hormonelike substances, and cells that produce digestive enzymes and absorb nutrients |
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Circular fold in the small intestine |
They make the chyme flow slowly, following a spiral path as it travels through the small intestine. The slow spiraling completely mixes the chyme with digestive jucies and brings it in contact with the villi that extend into the lumen . |
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enterocytes |
specialized absorption cells in the villi of the small intestine |
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glycocalyx |
projections of proteins on microvilli. They contain enzymes to digest protein and carbohydrate |
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Liver |
Produces bile, a cholesterol-containing, yellow-green fludi that aids in fat digestion and absorption |
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Bil e |
a cholesterol-containing, yellow-green fluid that aids in fat digestion and absorption. Bile emulsifies fat- it breaks the large fat globules into micelles, tiny fat droplets that are suspended in the watery chyme.
Bile released into the duodenum in reabsorbed in the ileum and returend to the liver. |
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Enterohepatic cirulation |
continual recycling of compounds between the small intestine and the liver. Bile is one example of a recycled compound |
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Pancreas |
produces about 5 to 6 cups of pancreatic juice per day. This juice is an alkaline (basic) mixture of sodium bicarbonate and enzymes. The sodium bicarbonate neutralizes the acidic chyme arriving from the stomach thereby protecting the small intestine from damage by acid. Digestive enzymes from the pancrease include pancreatic amylase (to digest starch), pancreatic lipase (to digest fat), and several proteases ( to digest protein). |
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Cholecystokinin |
Released by: small intestine in response to dietary fat in chyme
Functions: simulates release of pancreatic enzymes and bile from the gallbladder |
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Secretin |
Released by: small intestine in response to acidic chyme. Small intestine as digestion progresses
Functions: stimulates release of pancreatic bicarbonate |
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Motilin |
Released by: small intestine in response to gastric distension and dietary fat
Functions: regulates motility of gastrointestinal tract |
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Gastric inhibitory peptide |
Released by: Ileum and large intestinein response to fat in the large intestine
Functions: signals the stomach to limit the release of gastric jucies and slows gastic motility |
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Peptide YY
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Released by: Ileum and large intestine in response to fat in the large intestine
Functions: Inhibis gastric and pancreatic secretions |
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Somatostatin |
Released by: stomach, small intestine, and pancreas
Functions: Inhibits release of GI hormones, slows gastric emptying, GI motility, and blood flow to the intestine |
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Passive diffusion |
when the concentration of a nutrient is higher in the lumen of the small intestine than in the absorptive cells, the difference in concentration, known as the concentration gradient, forces the nutrient into the absorptive cells. Fats, water, and some minerals are absorbed by passive diffusion |
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Facilitated diffusion |
A higher concentration of a nutrient in the lumen than in the absorptive cells is not enough to move some nutrients into the absorptive cells. THey need carrier proteins to shuttle them from the lumen into absorptive cells. For instance, the sugar fructose is absorbed by facilitated diffusion. |
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Active absorption |
In addition to the need for a carrier protein, some nutrients also require energy (ATP) for absorption. Active absorption, also known as active transport, allows the cell to concentrate nutrients on either side of the cell membrane. Amino acids and some sugars, such as glucose, are actively absorbed. |
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Endocytosis |
In this type of active absorption absorptive cells engulf compounds (phagocytosis) or liquids (pinocytosis). In both of these processes, an absorptive cell forms an invagination in its cell membrane that engulfs the particles or fluid to form a vesicle. The vesicle is finally pinched off from the cell membrane and taken into the cell. This process allows immune substances (large protein particle) in human breast milk to be absorbed by infants. |
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Cardiovascular System |
This includes the heart, blood vessels (arteries,capillaries,veins), and blood
he short/medium chain fatty acids are transported by the cardiovascular system. These are absorbed directly into the bloodstream in the capillary beds inside the villi. Blood flows from the capillary beds into the hepatic portal vein system and collects in the large hepatic portal vein, which leads directly to the liver. The liver metabolizes or stores a portion of the absorbed nutrients, especially proteins, lipids, glucose, and several vitamins and minerals. Nutrients not utilized or stored in the liver enter the general circulation. This nutrient-rich blood circulates throughout the body delivering nutrients to all cells, where they are used for energy, growth, development, maintenance of tissues, and regulation of body processes. |
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short-chain fatty acids |
fatty acids that contain less than 6 carbon atoms
Transported by the cardiovascular system |
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Medium chain fatty acids |
fatty acid that contains 6-10 carbon atoms
Transported by the cardiovascular system |
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Capillary |
Smallest blood vessel; the major site for the exchange of substances between the blood and tissues |
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Hepatic Portal Vein System |
Veins leaving from the stomach, intestine, spleen, and pancreas that drain into the hepatic portal vein, which flows into the liver |
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Lymphatic system |
Contains lymph, which flows throughout the body in lympthatic vessels, whcih are similar to veins. Unlike blood, lymph is not pumped through the vessel. It instead flows as muscles contract and squeeze the lymphatic vessels.
Lymphatic system provides an alternative route into the bloodstream for large molecules that cannot be absorbed by the capillary beds. Fat-solube nutrients and other substances such as proteins, are transported in lymph. |
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Lacteals |
Tiny vessels in the small intestine villus that absorb dietary fat
They transport nutrient to larger lympthatic vessels that connect to the thoracic duct. The |
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Circulatory Systems |
Nutrients absorbed in the small intestine are delivered to one of the body's 2 circulatory systems
1. Cardiovascular (Blood) 2. Lymphatic |
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Large intestine |
After digestion and absorption in the small intestine, normally only water, some minerals, and undgiested food fibers and starches are left.
3 main parts
1. colon 2. rectum 3. anus
3 functions: it houses bacterial flora that keep the GI tract healthy, absorbs water and electrolytes, such as sodium and potassium; and it forms and expels feces
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bacterial Flora |
the large intestine is home to many species of bacteria. Some is beneficial and others are pathogenic. The ileocecal valve prevents these bacteria from migrating into the small intestine.
Benefital bacterial keep the growth of pathogenic bacterial under control. They also synthesized vitamins, most notably vitamin K and the B-vitamin biotin, both of whcih can be absorbed in the colon. |
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The ileocecal valve |
prevents bacteria from the large intestine from migrating into the small intestine where it could disrupt normal functions and compete with the body for nutrients |
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Fermentation |
Breakdown of large organic compounds into smaller compounds, especially organic acids. The breakdown is often by anaerobic bacteria.
it creates short-chain fatty acids that can be absorbed and used as an energy source in the colon. |
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Probiotic |
they are live microorganisms that, when consumed in sufficient amounts, colonize the large intestine and provide health benefits. They are found in fermented foods (yogurt). |
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Prebiotics |
they are food ingredients that promote the growth of benefical bacterial in the lare intestine. |
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inulin |
a carbohydrate known as a fructan because it is made of several units of the sugar fructose.
It is found in many foods, including chicory, wheat, onions, garlic, asparagus, and bananas.
It is also added to some processed foods to add texture, bulk, and potential health benefits |
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Resistant Starch |
this is found in unprocessed whole grains, seeds, legumes, unripe frut, and cooked and chilled pasta, potatoes, and rice, while also functioning as a prebiotic.
Resistant starch is not digested in the small intestine; thus, bacteria in the large intestine |
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Absorption of Water and Electrolytes |
the small intestine absorbs about 90% of the water and teh large intestine completes the job. Just less than 1% of the water in the GI tract remains in excreted feces. The large intestine is also the main site where electrolytes, especially sodium and potassium, are absorbed. |
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Defecation of Feces |
it take 12-24 hours for the residue of a meal to tracel through the large intestine. By the time the contents have passed through the first 2/3 of its length, a semisoldi mass has been formed. the mass remains inthe large intestine until peristaltic waves and mass movements, usually greatest following the consumption of a meal, push it into the rectum.
The expulsion of feces.
This process involves muscular reflexes in the sigmoid colon and rectum. as well as relaxation of the internal and external anal sphincter.
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External Sphincter |
The voluntary control for defecation of feces |
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Heartburn |
stomach acid backs up into the esophagus, causing a burning sensation or sour taste in the back of the mouth. |
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GERD |
this occurs when the lower esophageal sphincter relaxes and lets stomach contents backflow into the esophagus.
weight loss, ulceration, bleedin in the esophagus, anemia etc. |
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Hiatal hernia |
Protrusion of the part of the stomach upward through the diaphragm into the chest activity |
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anemia |
decreased oxygen-carrying capacity of the blood. It occurs for many reasons including blood loss |
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treatment for GERD |
1. antacids 2. H2 blockers 3. proton pump inhibitors 4. prkinetic drugs 5. surgury |
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Peptic Ulcers |
a very small erosion of the top layer of cells in the stomach or duodenum. |
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Causes of a peptic ulcer |
1. Bacteria Helicobacter pylori 2. Heavy use of NSAID drugs |
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Gallstones |
The stones develop in the gallbladder when substances in the bile - mainly choleserol and bile pigments - form crystal- like particles
they can block ducts and stop the free flow of bile |
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Food intolerances |
They are caused by an individual's inability to digest certain food components, usually due to low amounts of specific enzymes.
1. deficiencies in digestive enzymes 2. sensitivities to food components 3. certain synthetic components added to food 4. Residues of medication 5. Toxic contaminants
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Food Allergies |
cause an immune response as a result of exposure to certain food products |
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Intestinal gas |
we produce about 1-4 pints of gas each day and pass gas about 14 times a day. It comes from swallowed air and the breakdown of undigested carbohydrates by bacteria in the large intestine
Gas is eliminated by burping and passing it through the rectum.
the sulfur is responsible for the smell
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Constipation |
defined as difficult or infrequent (fewer than 3 times per week) bowel movements. Slow movement of fecal material through the large intestine causes constipation. As fluid is increasingly absorbed during the extended time the feces stay in the large intestine, they become dry and hard. |
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Treatment for Constipation |
1. bulk-forming laxatives- contain different types of fiber whihc draw water into the intestine and increase fecal volume 2. Osmotic laxatives - keep fluid in the intestine 3. stimulant laxative - afitate intesinal nerves to stimulate peristaltic muscels 4. lubricant laxative - are not recommended because they may block absorption of fat-soluble vitamins |
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Diarrhea |
it is loose watery stools occuring more than 3 times per day.
Most cases of diarrhea result from bacterial or viral infection, often from contaminated food or water. |
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Irritable Bowel Syndrome |
This is more common in women than men
It invovles irregular bowel function, abdominal pain, and abdominal distension.
The cause is unknown |
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Inflammatory Bowel Disease |
it is a group of serious chronic intestinal disease that afflict many people.
The most common forms are ulcerative colitis and Crohn's disease.
no cause is known |
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Colitis |
Inflammation of the colon that can lead to ulcers |
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Crohn's disease |
inflammatory disease of the GI tract that often reduces the absorptive capacity of the small intestine. Family history is a major risk factor |
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Hemorrhoids |
they are swollen veins of the rectum and anus. They are subject to intense pressure and this may add stress to the vessels. They may cause itching pain or bleeding. |
