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The Human Body: Digestive System
Digestive System
carries out digestion which is the process of breaking down food in the body
into a form which can be absorbed and used or excreted
Mouth
point of entry for food into the digestive system; first site of the reduction of
food size; adds the first bodily fluids to the bolus; composed of the teeth
and tongue
Saliva
functions to moisten food, making it easier to chew, and begins chemical
digestion through hydrolysis
Hydrolysis
decomposes food by placing water molecules between chemical bonds
Amylase
enzyme in saliva which catalyzes the hydrolysis of starch into smaller
carbohydrate molecules
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Lysozyme
enzyme in saliva which breaks down the polysaccharide walls of many kinds of
bacteria thus providing protection against infection
Teeth
break down larger particles of food into smaller pieces through mechanical
digestion
Incisors
used for cutting food
Canines
used for cutting and tearing food
Premolars
used for grinding food
Molars
used for grinding food
Accompanies: The Human Body: Digestive System
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The Human Body: Digestive System
Tongue
muscle organ used to maneuver food within the mouth by collecting food and
moving it to the back of the mouth when swallowing
Pharynx
connects the mouth and esophagus; contains a flap of connective tissue which
closes over the trachea when food is swallowed to prevent choking or
aspiration
Epiglottis
protective flap which closes over the trachea when food is swallowed
Esophagus
muscular tube connecting the pharynx and the stomach; moves food from the
pharynx to the stomach by a process called peristalsis
Peristalsis
waves of involuntary muscle contractions moving food through a tube-shaped
organ
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Stomach
J-shaped hollow muscular organ which stores food which has been eaten,
breaks down food into a liquid mixture through mechanical digestion, and
empties the liquid into the small intestine
Chyme
mixture of gastric juices and food
Cardia (Gastroesophageal Region)
entrance into the stomach
Fundus
blind portion of the stomach
Body
location of the gastric pits and secretory cells
Pylorus
area around the pyloric sphincter leading into the small intestine
Accompanies: The Human Body: Digestive System
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The Human Body: Digestive System
Mucosa
innermost layer of the stomach which consists of epithelium and a thin layer of
smooth muscle
Submucosa
layer of the stomach made of fibrous connective tissue and the Meissner’s
plexus
Muscularis externa
layer of the stomach which consists of three layers of smooth muscle
Serosa
outermost layer of the stomach made up of layers of connective tissue
Mucus
lubricates and protects the stomach from harsh acidic conditions
Hydrochloric Acid
functions to make food in the stomach acidic and activates pepsin
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Pepsin
works with hydrochloric acid to break down proteins
Pancreas
produces hormones which regulate blood sugars; creates enzymes which aid
in the breakdown of carbohydrates, lipids and proteins in the small intestines;
aids in the neutralizing the acidity of the chime entering the small intestine
Liver
produces bile which is essential for the digestion and absorption of fats in the
small intestine; receives the nutrients which have been absorbed in the small
intestine
Bile
yellow-brown liquid mixture of salts and lipids which breaks down the lipids in
the digestive system into a fluid mixture
Gallbladder
stores bile until the body needs it for digestion
Accompanies: The Human Body: Digestive System
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The Human Body: Digestive System
Small Intestine
breaks down the chyme to absorb vitamins, minerals, proteins, carbohydrates
and fats
Duodenum
begins the small intestine and is where most chemical digestion takes place
Jejunum
absorbs carbohydrates and proteins and is covered in villi
Villi
small finger like projections which aid in absorption
Ileum
absorbs lipids and bile and is covered in villi and microvilli
Jejunum
absorbs carbohydrates and proteins and is covered in villi
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Villi
small finger like projections which aid in absorption
Ileum
absorbs lipids and bile and is covered in villi and microvilli
Large Intestine
removes water from the chyme and houses many bacteria
Appendix
tubular organ connected to the large intestine which has no known purpose
Cecum
big pouch which receives waste material from the small intestine
Colon
largest portion of the large intestine; extracts water from feces
Rectum
acts as a temporary storage facility for feces
Anus
used to expel feces from the body
Accompanies: The Human Body: Digestive System
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The Human Body: Digestive System
Appendicitis
inflammation of the appendix due to a blockage in the appendix
Cirrhosis
scarring of the liver
Colorectal cancer
colon cancer or bowel cancer
Gallstones
crystalline bodies formed by normal or abnormal bile components
Hepatitis
inflammation of the liver
Obesity
condition where the natural energy reserve is increased to a point where it is
associated with certain health conditions or increased mortality
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Ulcers
areas of the gastrointestinal tract which are acidic
Accompanies: The Human Body: Digestive System
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