Module 3 Flashcards
2 main groups of digestive organs
- alimentary canal organs
2. accessory digestive organs
alimentary canal definition and 7 parts
is a continuous muscular digestive tube beginning in the oral cavity. It is open at both ends, winding its way through the body cavity. It is composed of the
oral cavity pharynx esophagus stomach small intestine large intestine anus
6 Accessory digestive organs
teeth tongue gall bladder salivary glands liver pancreas.
mouth and 6 parts
beginning of the gastrointestinal tract. Consists of the
lips tongue cheeks hard and soft palates uvula lingual frenulum.
lips
form the opening to the mouth
tongue
forms the floor of the mouth, grips the food and constantly repositions it between the teeth
cheeks
form the walls of the mouth
hard and soft palates
form the roof of the mouth
uvula
is a process that hangs inferiorly from the attachment to the soft palate. It forms the posterior border of the mouth.
lingual frenulum
vertical mucous membrane by which the body of the tongue is attached to the floor of the mouth.
mastication
process of chewing food. The food is mixed with moistened saliva from the salivary glands.
amylase
an enzyme found in the salivary gland that begins the process of chemical digestion by breaking down starches.
Maxilla
where the upper arch of the teeth is located
mandible
contains the lower arch of teeth
4 different types of teeth:
chisel -shaped incisors for biting
one pointed canine for tearing
two increasingly flat pre-molars for grinding
three flat molars for crushing
3 main parts of the tooth:
crown
neck
root
root
largest portion of each tooth, located within the alveolar process of the jaw bone.
neck
located within the upper portion of the gums (gingiva)
crown
the visible portion of the tooth and lies above the gum line
pulp cavity
at center of each tooth, contains nerves and blood vessels
dentin
bone-like substance composing most of each tooth
enamel
very hard connective tissues that protects the rest of the tooth and is located on the surface of the crown
tongue
forms the floor of the mouth, grips the food and constantly repositions it between the teeth
bolus
forming the food into a compact mass (by the tongue)
papillae
raised bumps on the tongue to help grip food
3 types of papillae:
circumvallate
fungiform
filiform
taste buds
chemical receptors that are stimulated by the chemical composition of food. Found primarily on the tongue as well as on the surface of the mouth and wall of the pharynx.
pharynx
connects the mouth to the esophagus (aka throat)
3 parts of the pharynx:
nasopharynx
oropharynx
laryngopharynx
2 types of skeletal muscle in pharynx
circumferential outer layer
inner longitudinal layer
epiglottis
flap of elastic cartilage that covers the larynx when swallowing food or liquid
aspiration
when food or liquid enter the lungs- can cause aspiration pneumonia
esophagus
extends from pharynx to the stomach, traveling through an opening in the diaphragm on its way to the stomach. Muscular tube containing 4 layers of tissue
4 layers of tissue in esophagus, small and large intestine and stomach:
mucosa
submucosa
muscularis externa
serosa
mucosa
innermost layer of tissue, secretes mucus into the interior gastrointestinal tract.
submucosa
layer contains blood and lymph vessels, lymph nodes, nerves, and mucous glands.
muscularis externa
made of 2 layers of muscle: the outer longitudinal fibers and inner circumferential fibers
serosa
made of cells that make serous fluid
stomach
backward c-shaped organ located along the left side of the abdomen below the diaphragm.
2 curvatures of the stomach:
lesser curvature
greater curvature
lesser curvature
concave, extends inward on the short side of the stomach
greater curvature
convex, extends outward on the longer side of the stomach
peritoneum
a serous membrane covering the stomach, called the lesser omentum and the greater omentum
lesser omentum
attaches the lesser curvature of the stomach to the liver
greater omentum
attaches the greater curvature of the stomach to the posterior wall of the abdomen, covering the transverse colon and antieror surface of the small intestines. Hangs down like an apron.
4 parts of the stomach:
cardia
fundus
body
pyloric region
cardia
where the food enters from the esophagus
fundus
dome-shaped top of the stomach just under the diaphram
body
wider midportion located between the fundus and the pyloric region.
pyloric region
last part in the stomach, funnel-shaped
2 purposes of stomach
temporary storage area for food
mechanical food breakdown
rugae
folds within the stomach wall which allow the stomach to expand when it is full
oblique layer
extra muscle layer that allows stomach to mix food more efficiently with the gastric juices.
ulcer
open sore in the wall caused by gradual disintegration of tissues
H. pylori
helicobacter pylori caused duodenal ulcers by eating away at the mucosal lining.
chyme
stomach contents- thick, soupy consistency.
pyloric sphincter
valve that controls the narrow opening of the base of the stomach.
ileocecal valve
controls the entrance to the large intestine
small intestine 3 sections
duodenum
jejunum
ileum
duodenum
shortest section of the small intestine- where enzymes from the pancreas and bile from the liver enter the small intestine.
jejunum
second section of the small intestine
ileum
third section of the small intestine, longest region of small intestine
circular folds
increase the surface area of the small intestines wall’s mucous membrane. they have villi and microvilli on them.
villi
small, finger-like projections that increase surface area of intestine
microvilli
smaller projections on villi that increase the surface area of small intestine
lacteal
lymphatic vessels found in villus (villi)
large intestine
extends from ileocecal valve to the anus. Chyme move through the large intestine to be excreted as feces.
8 parts of large intestine:
cecum appendix ascending colon transverse colon descending colon sigmoid colon rectum anal canal
cecum
entrance to the large intestine through the ileocecal valve
appendix
hangs from the cecum and is usually twisted.
Appendicitis
occurs when bacteria accumulates and causes inflammation of the appendix.
ascending colon
runs along the right side of the abdomen superiorly.
transverse colon
runs across the abdomen
descending colon
runs along the left side of abdomen superiorly to the sigmoid colon
sigmoid colon
travels through the pelvis connecting with the rectum
anal canal
where feces are expelled through the anus- the end of the gastrointestinal tract.
the right colic flexure
hepatic- connects ascending colon to transverse colon
the left colic flexure
splenic - connects the transverse colon to the descending colon
internal sphincter
involuntary smooth muscle in anal canal
external sphincter
voluntary skeletal muscle in the anal canal
rectum
last 20 cm of the large intestine which terminates at the anus, connects to the anal canal
feces
digestive wastes
main function of large intestine
reabsorb any remaining water and propel waste
3 important accessory glands
liver
pancreas
gallbladder
pancreas
lies deep in the abdominal wall. Sends pancreatic juice into the duodenum by way of the pancreatic duct.
sodium bicarbonate
in pancreatic juice, neutralizes the chyme and makes the pH of the small intestine slightly basic.
3 main liver functions in digestion
produce bile
store glucose
produces urea
bile
produced by the liver, stored in the gallbladder before entering the small intestine, where it emulsifies fats - looks green
gallbladder
stores bile before it enters the small intestine
glycogen
stored in the liver, breaks it down to glucose between meals to maintain a constant glucose concentration in the blood.
Urea
produced by the liver from amino groups that are removed from excess amino acids.
satiety
the sensation of being full
hunger
internal drive to find and eat food often experienced as a negative sensation such as churning, growling, or a painful sensation in the stomach.
hypothalmus
region of the brain that plays a role in hunger, satiety and the feeling of “being full”
hormones
compounds secreted into the bloodstream by one type of cell that acts to control the function of another type of cell
3 hormones that increase hunger
ghrelin
endorphins
neuropeptide- Y
3 hormones that cause satiety
leptin
serotonin
cholecystokinin (CCK)
2 key hormones:
leptin
ghrelin
leptin
produced by adipose tissue (fat cells) and alerts the brain to turn off the hunger center in the brain and activate the satiety center when consuming a meal
Ghrelin
produce by stomach and has the opposite role as leptin. It travels to the brain and stimulates the hunger center as it deactivates the satiety center.
3 categories of lipids:
saturated fat
unsaturated fat
cholesterol
carbohydrates
classified as starches and sugars
3 biochemical categories of food the body needs in large amounts:
carbohydrates
proteins
lipids
saturated fat
butter and meat and dairy products
unsaturated fats
vegetables oils like olive oil and nuts
cholesteral
made by our bodies but can be ingested by eating animal products.
2 types of proteins:
complete
imcomplete
complete proteins
are meat, poultry, eggs, milk, dairy products, and soybeans
incomplete proteins
grains, legumes, seeds and nuts
essential amino acids
9 of them.(10 required in an infants diet) called essential amino acids because the body is unable to make these amino acids. Complete proteins contain all nine but incomplete do not.
Vitamins
organic compounds that are not consumed in metabolic reaction but help enzymes carry out the metabolic reactions, which converts nutrients to materials needed by the body
2 classifications of vitamins
water soluble
fat soluble
water soluble vitamins
not able to be stored in the body and are excreted in the urine
fat soluble vitamins
stored in body fat.
minerals
inorganic compounds that, like vitamins, are not used as fuel in metabolic reactions but combine with other nutrients to form necessary body substances.
7 minerals needed in human diet:
calcium chloride magnesium phosphorus potassium sodium sulfur
Metabolism
set of chemical reactions that are essential for the body to sustain life
Anabolism
set of reactions in which smaller molecules are combined to make larger, more complex molecules
Catabolism
set of reactions in which larger molecules are broken down to be used as energy sources for the body
adenosine triphosphate or ATP
most widely used form of energy in the cell
ADP
adenosine diphosphate- if a phosphate group is removed. So ATP has energy to donate and ADP can accept energy to become ATP.
Cellular respiration
the process by which cells generate ATP.
aerobic respiration
requires oxygen and a fuel (glucose, for example) and releases carbon dioxide, water, and ATP.
Carbohydrates
main source of energy for cells with the body digesting carbohydrates into glucose
Glycolysis
begins with the breakdown of a single molecule of glucose into two pyruvate molecules
Cellular respiration
an aerobic process (oxygen must be present) used by cells to produce energy
mitochondria
Respiration takes place inside and around the double membrane-enclosed organelle
Fermentation
takes place in the absence of oxygen.
tricarboxylic acid (TCA) cycle
the central pathway of respiration also known as the Krebs Cycle or the citric acid cycle. In the TCA cycle, the pyruvic acid (product of glycolysis) is converted to carbon dioxide forming some additional ATP
The electron transport system
also referred to as the electron transport chain, is a continuation of cellular respiration and can proceed either aerobically (with oxygen) or anaerobically (without oxygen).
proton motive force
drives H+ back through the ATP synthase complex, also located in the membrane, resulting in the production of up to 34 molecules of ATP.
Lipid metabolism
occurs in the liver by a process known as beta-oxidation. Lipids are used by the body primarily during low energy activities. Lipid metabolism yields twice the amount of ATP than when a carbohydrate or protein is broken down.
Protein metabolism
only takes place when carbohydrates and fats are unavailable to the body. Proteins are the building blocks for the cells and saved as a last resort.
ammonia
is formed when proteins must be used to form ATP, the amino group is removed from the protein
urea
made when ammonia is combined with carbon dioxide in the liver
3 transitions in complete catabolism of a single molecule of glucose
Glycolysis
Cellular respiration
The electron transport system
Pancreatic enzymes
pancreatic amylase
trypsin
lipase
pancreatic amylase
breaks down startch
trypsin
breaks down protein
lipase
breaks down fat droplets to glycerol and fatty acids
4 types of digestion
ingestion
digestion
absorption
defication
Ingestion
when food enters the mouth
digestion
food breakdown occurs when food is moved, mixed, and exposed to enzymes along the gastrointestinal tract
Mechanical digestion
when food is physically broken down into smaller pieces. This occurs when the teeth chew food, when the stomach churns and mixes food, and as food is moved and squeezed along the gastrointestinal tract
Chemical digestion
is the chemical breakdown of food by enzymes into smaller nutrients
Absorption
is the process of moving digested food into the bloodstream
Defecation
is the excretion of indigestible food from the anus.
salivary amylase
contained in the saliva begins the chemical breakdown of starches
Peristalsis
(rhythmic muscular contractions) moves the food along the esophagus to the stomach
parietal cells
(located in the wall of the stomach body) secrete hydrochloric acid, generating a pH of 1.3-3.5. This very acidic pH kills many of the bacteria ingested along with food. In addition, the low pH stops the activity of salivary amylase
Pepsinogen
(a pre-enzyme) is secreted by the chief cells in the stomach.
Peptides
result from the first step in protein digestion, are digested by peptidases to amino acids
Maltose
results from the first step in starch digestion, is digested by maltase to glucose
small intestine secretes two hormones:
cholecystokinin
secretin
Cholecystokinin
causes the gallbladder to secrete bile
Secretin
causes the liver to secrete bile
bile
breaks down fat into smaller pieces and is needed for the absorption of fats.
