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Chap. 13 - The Digestive System
Flash cards about the digestive system
88
Biology
12th Grade
02/08/2011

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Term
Mastication
Definition
Process of chewing
Breaks down food into smaller, more manageable pieces
Term
Digestion
Definition
Food enters bodies through the mouth
It is cut, crushed, and ground into little pieces by teeth
Term
Stomach
Definition
Churns food into smaller bits
Term
Saliva and Tongue
Definition
Food is moistened by saliva
Moved around in mouth by tongue, which also provides taste sensation
Term
Pharynx and Esophagus
Definition
Food is passed from mouth to pharynx, then passed to esophagus
Term
Stomach and Chyme
Definition
From esophagus to stomach
Churned and mixed with gastric juices
New mixture = chyme
Term
Small Intestine
Definition
Chyme sent to small intestine where food molecules are digested and nutrients are absorbed into bloodstream
Term
Liver and Bile
Definition
Nutrient filled blood sent to liver (clears blood and produces bile)
Bile helps digest fats
Term
Gall Bladder and Pancreas
Definition
Bile is stored in gall bladder
Gall bladder releases it into small intestine
Pancreas produces digestive juices, releases into small intestine
Term
Large Intestine and Feces
Definition
Chyme sent into large intestine (by this time most nutrients have been removed)
Water is absorbed from the waste
Waste is turned into feces
Term
Rectum and Anus
Definition
Feces is sent to rectum
Expelled from body through anus
Term
Length of Digestion
Definition
1 min. to chew
2 secs esophagus
2-4 hrs. in stomach
1-4 hrs. in small intestine
6hrs - dys in large intestine
*Food stays in the body for as little to 9 hrs to dys
Term
Appendix
Definition
Worm shaped tube branches off beginning of large intestine
Scientists don't know what it does
Only humans and apes have one
Term
Appendicitis
Definition
Appendix is infected and filled with pus
Pain/cramps near right hip bone
Fever, N&V (nausea and vomiting)
Untreated, can lead to death; bursts and spreads
Term
Incisor Teeth
Definition
Sharp; used to cut food
Term
Canine Teeth
Definition
Tear the food
Term
Premolars and Molars
Definition
Crush and grind food
Term
Saliva
Definition
99% water
Dissolves food
Essential for taste
Term
Mucus
Definition
Lubricates the food so it can travel easily through the body
Term
Amylase
Definition
Digestive enzyme that helps break down starch
Term
Lysosomes and Antibodies
Definition
Lysosomes in saliva kill bacteria
Antibodies provide immune defense against potential invaders
Term
Salivary Glands
Definition
Secrete about 1L of saliva every day (mostly when we eat)
Chewing can stimulate the mouth to secrete saliva
Controlled by ANS (Autonomic Nervous System)
Term
Bolus
Definition
Soft lump of food formed in your mouth after your tongue has moved the food around
Term
Deglutition
Definition
The act of swallowing
One of the most dangerous things to do
Oral cavity leads to the pharynx which leads to the esophagus and larynx. Food must cross the airway to get to the esophagus.
Term
Soft Palate
Definition
Rises up and closes the nasal cavity when you swallow
Larynx rises and epiglottis lowers. This seals the larynx so food can't travel down into the trachea
Term
Stages of Deglutition
Definition
Voluntary Oral - bolus is pushed toward posterior part of the mouth by tongue
Pharyngeal - soft palate lifts up and blocks nasal cavity
Esophageal - muscles contract and relax to push bolus down esophagus
Term
Peristalsis
Definition
Process of contraction and relaxation of circular smooth muscles which pushes food down
Term
Note
Definition
There are 8 cranial nerves involved in swallowing. Nerve damage can impact one's ability to swallow.
Term
Diaphragm
Definition
Skeletal muscle that helps control breathing
Term
Stomach Acid
Definition
Kills bacteria / microorganisms
Enhances digestion
Term
Regions of Stomach
Definition
Cardiac Region - contains lower esophageal sphincter & entrance to stomach
Fundus - above cardiac region
Body - largest part
Narrow pylorus - "gatekeeper"; joins to small intestine
Term
Layers of stomach
Definition
Serosa - outer layer; thin and slick; AKA visceral peritoneum
Muscularis - 3 layers of smooth muscle by serosa
Submucosa & Mucosa - contains blood vessels and nerves
Term
Gastric Pits
Definition
Openings for gastric glands
Secrete 2 to 3 layers of juice every day
Very acidic
Term
Motor Functions of Stomach
Definition
Storage - as it fills, smooth muscle relaxes
Mixing food - smooth muscles contract; food mixes with gastric juice
Vomiting - stomach compresses and contents come up
Growling - hungry!
Term
Small Intestine
Definition
Nutrients absorbed
Most of digestion takes place here
Chyme travels to small intestine
Approximately 6m/20ft long
Term
Functions of Small Intestine
Definition
Mix and propel the chyme
Digest food
Absorb nutrients
Term
Regions of Small Intestine
Definition
Duedenum - connects small intestine to stomach; 1ft
Jejunum - 8 ft
Ileum - empties into large intestine; 11 ft
Term
Intestinal Villi
Definition
Line intestines
Circular folds
Edges lock like tooth brush bristles - gives more surface area to absorb nutrients
Term
Glands in Small Intestine
Definition
Exocrine - secrete mucus and protect small intestine from acidic chyme
Endocrine - designed to reduce acidity of chyme as well
Term
Cholecystokinin (CCK)
Definition
Hormone secreted by endocrine gland of small intestine
Causes gall bladder to contract, pushing bile into small intestine which promotes digestion of fats
Term
Gastric Inhibitory Peptide (GIP)
Definition
Endocrine hormone of small intestine
Reduces activity of stomach
When too much food goes does s.i., GIP signals stomach to open up and store more food
Term
Major Enzymes
Definition
Maltase
Sucrase
Lactase
Peptidase
Enterokinase
Term
Maltase
Definition
Breaks down maltose
Helps digest carbs (sugar)= glucose + glucose
Term
Sucrase
Definition
Breaks down sucrose
Helps digest table sugar = glucose + fructose
Term
Lactase
Definition
Breaks down lactose
Helps digest milk sugar = glucose + galactose
Term
Peptidase
Definition
Helps digest peptides (protein) into amino acids
Term
Enterokinase
Definition
Doesn't break anything down
Activates entrypsinogen intro trypsin which breaks down proteins, too
Term
Motor Functions of Small Intestine
Definition
Smooth muscles contract and relax to slosh the chyme back and forth
Moves it right on down to the large intestine
Term
Large Intestine (Colon)
Definition
Named because its diameter is bigger than that of the small intestine
Approx. 5 ft
Term
Parts of Large Intestine
Definition
Cecum - connected to small intestine via ileocecal sphincter which regulates the amount of chume leaving s.i. and appendix
Colon - take chyme , form feces, excrete
Rectum - holding container for feces; allows feces to collect
Term
Regions of Colon
Definition
Ascending - chyme goes up
Transverse - chyme moves left to right
Descending - chyme goes down
Term
Feces
Definition
Formed: 1L of water enters colon every day, and only 1/10 of that comes out. The rest is absorbed into bloodstream through large intestine walls
Equals waterless chyme
Term
Flatus
Definition
Gas
Polysaccharides not broken down in small intestine are broken down in colon
Stinky
Term
Bacteria in Colon
Definition
100 trillion of them
Help keep the body healthy
Weight about 3 lbs
Term
When it's time to go...
Definition
REctum distends which triggers defecation reflex causes internal anal sphincter to relax. External anal sphincter (EAS) we control and we go when we are able
Term
Liver
Definition
Most complicated organ of digestive sys
Body's largest internal organ
2 Major and Minor Lobes: Left & Right lobes; Caudate & Quadrate
Term
Functions of Liver
Definition
Bile production - helps digest fats
Storage - stores fat; converts glucose to glycogen
Synthesis
Detoxification
Term
Gall Bladder
Definition
Concentrates the bile produced by liver
Secretes bile into small intestine when needed
Term
Hepatic Artery
Definition
Brings oxygen to the liver through oxygenated blood
Term
Hepatic Portal Vein
Definition
Brings deoxygenated blood into the liver from the small intestine, stomach, spleen, and liver
Term
Liver Tissue
Definition
Divided into lobules
Hexagonal in shape with portal triad at each corner, bile duct, central vein, and hepatic veins
Term
Hepatocytes
Definition
Functional cells of liver
Radiate outward from central vein
Look like spokes in a wheel
Term
Bile
Definition
Travels in bile canaliculi
Flows in the opposite direction of blood
Flows into the lobule then out
Helps neutralize gastric juice acid
Emulsifies fats - separates large drops of lipids into smaller drops
Term
Nutrient Interconversion
Definition
Liver converts nutrients into other types of nutrients
Term
Synthesis
Definition
One of the body's main chemical manufacturing facilities
Liver produces prothrombin, fibrinogen, and blood coagulation
Term
Phagocytosis
Definition
Cells in liver are phagocytic
Helps spleen take up worn out RBCs (red blood cells), WBCs (white blood cells), bacteria, and other blood debris
Term
Detoxification
Definition
Liver detoxifies body
e.g. Ammonia is a byproduct of amino acids. If it built up in the body, it would die. The liver converts ammonia into urea, which isn't toxic.
Term
Gall Bladder
Definition
Bile from liver enters via cystic duct
Can live without it
Usually removed because it's full of gallstones = mostly cholesterol
Term
Pancreas
Definition
Joins with common bile duct and empties pancreatic juice into the duodenum
Secretes more than 1L of juice every day
Juice contains enzymes
Helps break down jumbo nucleic acids
Term
Macronutrients
Definition
Nutrients the body needs in large amounts
e.g. carbs, fats, protein (out body's source of energy)
Term
Micronutrients
Definition
Nutrients the body needs in small amounts
e.g. vitamins, minerals
Term
Complex Carbs
Definition
Large polysacchardies
Amlyase helps digest
Term
Cholesterol
Definition
Lipid
Good because it gives cells their rigidity
In excess, bad
Term
Essential Fatty Acids
Definition
Body must have
Linoleic acid (Omega 6) - common in salad oils
Linolenic acid (Omega 3) - found in plant oil (soy oil, pumpkin seeds)
Term
Proteins
Definition
Body burns amino acids for energy
Used to make the body's own proteins
Term
Vitamin A
Definition
Helps eyes detect light
Maintains skin cells
Term
Vitamin D
Definition
Allows calcium being eating and drunk to be absorbed for the bones
Term
Vitamin E
Definition
Antioxidant
Helps protect important chemicals in the body from being destroyed by oxidation
Term
B Vitamins
Definition
1,2,3,5,6,12
Helps body's cellular metabolism
Does a lot of things
Term
Vitamin C
Definition
Helps build collagen in bones and teeth
Helps fight disease
Term
Vitamin K
Definition
Helps blood clot
Term
Iron
Definition
Important for hemoglobin in RBCs (red blood cells) to carryout oxygen to tissues
Anemia - lack of iron
Term
Iodine
Definition
Needed in small amounts for thyroid
Term
Sodium and Chloride
Definition
Essential for nerve conduction and water balance
Chloride necessary for pH balance of blood and gastric juice production
Excess sodium causes high blood pressure
Term
Zinc
Definition
Used in many enzymes
Essential for carbon dioxide transport
Term
Sulfur
Definition
Component of many hormones, vitamins, and proteins the body makes
Term
Copper
Definition
Essential part of hemoglobin production
Term
Potassium
Definition
Important for proper muscle function
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