digestive system Flashcards
what do plants convert into starch
light
what do animals consume to make ATP
starch and sugar
what do you need to make ATP
sugars from digestion or synthesis(from fats and proteins)
oxygen from ventilation
function of carbohydrates monomers? Function?
sugar; store energy, structural material
function of lipids monomers? functions?
fatty acid; store energy, form membrane, steroids
function of proteins and monomers
amino acids; enzymes, structural material, peptides
function of nucleic acids and monomers
nucleotides; store genetic information
carbohydrates
sugars, starches, polymers, CHO
monosaccharides
Disaccharides
polysaccharides
major source of cellular fule(glucose)
structural molecules
lipids
insoluble in water
triglycerides or neutral fats
phospholipids
steroids
eicosanoids
what are triglycerides(neutral fats) called when they are solid and liquid
fats when solids and oil when liquid
composed of three fatty acids bonded to a glycerol molecule
what are the functions of triglycerides
energy storage
insulation
protection
what kind of bond do saturated fatty acids have
single covalent bonds between C atoms
maximum number of H atoms
what kind of bond do unsaturated fatty acids have
one or more double bonds between C atoms
reduced number of H atoms
proteins
essential for making nucleotides and nucleic acids
needed to build organelles, cells, tissues
proteins are polymers of amino acids
what makes up proteins
amino acids
contain amine group and acid group
all identical except for R group
can act as either acid or base
peptide bonds
what are the essential amino acids for adults
methionine, valine, threonine, phenylalanine, leucine, isoleucine, tryptophan, and lysine
What is true about inorganic essential nutrients
must be obtained from food
help in structure and regulation
act as co-factors
do not contain c
fat-soluble vitamins
vitamin A, D, E, K
water soluble vitamins
b vitamins and vitamin C
function and source of calcium
tooth and bone formation, nerve transmission, muscle contraction,
source: milk, dairy, bean curd, dark green vegetables
function and source of phosphorus
bone development, transfer of energy in cells
source: most foods
function and source of sodium
nerve transmission, muscle contraction
source: meat, dairy, salt
function and source of chlorine
formation of hydrochloric acid
source: salt
function and source of potassium
regulation of heartbeat, maintenance of water balance, nerve transmission
source: fruits(bananas)
function and source of magnesium
a catalyst for ATP formation
source: nuts, grains, dark green vegetables, dried fruits
function and source of iodine
thyroid activity
source: seafood, iodized salt
function and source of iron
hemoglobin formation
source: meat, dark green vegetables, dried fruits
digestion
breakdown of large insoluble food molecules into small water-soluble food molecules
food –> digestive tract–> small molecules
absorption
active transfer of nutrient molecules from the digestive tract to the circulatory and lymphatic vessels
obligate carnivores
rely entirely on animal flesh to obtain their nutrients
facultative carnivores
also eat non-animal food in addition to animal food
digestive tract for invertebrates
gastrovascular cavity
alimentary canal
digestive tract for vertebrates
monogastric
avian
ruminant
invertebrate digestive system(incomplete)
incomplete: single opening for digestion
food enters through the mouth and muscular pharynx, wastes exit through same path, lacks specialized parts
which invertebrates have a gastrovascular cavity
Platyhelminthes-flatworms
Ctenophora- comb jellies
Cnidaria- coral, jellyfish, sea anemones
invertebrate digestive systems (complete)
complete: two openings= alimentary canal
ex: earthworm
food enters through the mouth
stored in crop
ground and digested by gizzard
nutrients absorbed in the intestine
wastes exit through the anus
ex: nematode
mouth–>pharynx–>intestine–> anus
monogastric vertebrate digestive system
one stomach
avian vertebrate digestive systems
two-chambered stomach
crop-stores food
two stomachs- proventriculus- enzymes, gizzard-grinding
cloaca- shared exit for urine and feces
ruminants vertebrate digestive system
four stomachs
cows sheep goats deer giraffes
eat roughage
four stomachs
- rumen and reticulum- contain prokaryotes and protists to digest cellulose fiber
cud is regurgitated chewed and swallowed in the third stomach, the omasum- removes water
cud then passes onto the abomasum- digested by enzymes produced by animals
- homologue of monogastric stomach
psuedo-ruminants digestive system
three-chambered stomach
camels, llamas, alpacas
eat plant and roughage
- food first enters C1- rumen
cud is regurgitated chewed and swallowed again into the C2- omasum
cud then passes onto the C3- abomasum
most digestion happens in the cecum and spiral colon
salivary glands
secret saliva, contains digestive enzyme for carbohydrates
liver
major metabolic organ: processes and stores nutrients: produces bile for emulsification of fats
gallbladder
stores bile from liver; sends it to the small intestine
pancreas
produces pancreatic juice: contains digestive enzymes, and sends it to the small intestine; produces insulin and secretes it into the blood after eating
accessory organs
salivary glands, liver, gallbladder, pancreas
digestive tract organs
mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, anus
mouth
teeth chew food; tongue tastes and pushes food for chewing and swallowing
pharynx
passageway where food is swallowed
esophagus
passageway where peristalsis pushes food to the stomach
stomach
secretes acid and digestive enzyme for protein; churns, mixing food with secretions and sends chyme to the small intestine
a major site of protein digestion
kills microorganism
activates enzymes
pH- 1.5-2.5
HCl acid
small intestine
mixes chyme with digestive enzymes for the final breakdown; absorbs nutrient molecules into the body; secretes digestive hormones into blood
large intestine
absorbs water and salt to form feces
rectum
stores and regulates the elimination of feces
tongue
composed of striated muscle
mixes chewed food with saliva and mixture form into bolus
soft palate
closes off nasopharynx
epiglottis
covers opening into trachea
keeps food from air passages
what does food mixing with gastric juices become
chyme
pyloric sphincter
the junction between the stomach and small intestine
when the sphincter relaxes, a small quantity of chyme passes into the mall intestine
2-6 hours after a meal
what are the 3 part of the small intestine
duodenum, jejunum, lleum
20ft long
duodenum
receives chyme from the stomach, secretions from liver and pancreas
jejunum
responsible for most chemical digestion and nutrient absorption
second part of the small intestine
lleum
bile salts and vitamins absorbed
small intestine absorption
circular folds–>villi–> microvilli
absorption- nutrients cross epithelial cell lining SI tube
- sugars and amino acids- blood capillaries
- lipids-lacteal(lymph vessel
hepatic portal vein
takes nutrients to liver
what does the large intestine include
cecum, colon, rectum, and anal canal
what is the colon subdivided into
asending, transverse, descending, sigmoid colon
what is the colon subdivided into
ascending, transverse, descending, sigmoid colon
bile salts
break up fat into fat droplets via emulsification
four steps of digestive system
ingestion
digestion
absorption
elimination
carbohydrate digestion
starts in mouth
enzymes are added by the pancreas to the chyme as it enters the duodenum of the small intestine
absorption of nutrients across epithelium of duodenum and jejunum of small intestine via active transport
lipid digestion
begin in the stomach
most occurs in the small intestine due to enzymes from the pancreas
bile acids in bile aid in the digestion of lipids–> emulsification
- large fat droplets–> small fat droplets–> triglycerides+enzymes=fatty acids + monoglycerides–>micelles
inside SI epithelial cells
fatty acids+monoglycerides–> triglycerides–>chlymocrons–>exocytosis–> lacteal
protein digestion
break down proteins into peptides
the pancreas releases other enzymes into the duodenum
-larger peptides–> smaller peptides–>free amino acids
amino acids are absorbed into the bloodstream through the small intestines via active transport
vitamin absorption
lipid soluble
water-soluble
- direct absorption across SI epithelium via active transport
elimination
fluid moves into the cecum of large intestine
peristatic waves move it through ascending, transverse and descending colon
- water and mineral absorbed via diffusion, active transport and osmosis
- sodium and chloride first
- water follows by osmosis
remainder compacted into feces
- stored in rectum
peristaltic waves push feces out of anus
digestive system regulation
nervous system
- hunger and satiety
endocrine system
- functions of digestive system
phases of nervous system regulation of digestion
cephalic phase, gastric phase, intestinal phase
cephalic phase
smell, sight, sound of food –> salivation, stomach-churning and secretion
gastric phase
gastric distension, low pH, undigested food–> more HCl and enzymes
intestinal phase
chyme enters duodenum–> secretions from pancreas, liver, gallbladder
endocrine system regulation of digestion
hormones are secreted from digestive organs in response to the presence of food/nutrients
regulate the degree and timing of digestive processes
alimentary canal
tubular digestive system with a mouth and anus
bile
digestive juice produced by the liver for the digestion of lipids
bolus
mass of food resulting from chewing action and wetting my saliva
chyme
mixture of partially digested food and stomach juices
endocrine system
system that controls the response of the various glands in the body and the release of hormones at the appropriate time
esophagus
tubular organ that connects the mouth to the stomach
intestinal phase
third digestive phase
monogastric
digestive system that consists of a single-chambered stomach
mineral
inorganic, elemental molecule that carries out important roles in the body
peristalsis
wave-like movements of muscle tissue
proventriculus
glandular part of a birds stomach
roughage
component of food that is low in energy and high in fiber
salivary amylase
enzyme found in saliva, which converts carbs into maltose
secretin
hormone which stimulates sodium bicarbonate secretion in the small intestine
somatostatin
hormone released to stop acid secretion when the stomach is empty
sphincter
band of muscle that controls movement of material throughout the digestive tract
villi
folds on the inner surface of the small intestine whose role is to increase absorption area
