Digestive system Flashcards
2 components in digestion and describe them briefly
mechanical ( broken down using physical forces)
chemicals( broken down using chemical reactions )
what’s the purpose go the digestive system?
supply the body with raw materials needed to grow, and maintain homeostasis.
where does digestion begin?
in the mouth
what is the mouth bound by and what do those allow you to do?
bound by cheeks and lips which allow expansion and sealing while food is being consumed
what kind(s) of digestion occur inside the mouth?
mechanical - chewing
chemical - salivary amylase
chewed is aka?
masticated
the food ball we create after chewing is called?
bolus
what’s responsible for the movement of food inside the mouth?
tongue
what’s responsible for the tasting of food inside the mouth?
tongue
what type of muscle is the tongue composed of?
skeletal muscle
what type of reception is taste?
chemoreception (sensing chemicals)
chemoreception is done by what?
taste buds
what do taste buds do?
absorb molecules from the food and send signals to the brain identifying the chemicals it senses
how many taste buds does the human tongue have and how often is it replaced?
8,000
replaced every 10 days
what kind breakdown is teeth responsible for? an where?
mechanical breakdown in the mouth
what’s the hardest substance in. the human body?
teeth
what does teeth do?
break down food in increase it’s surface area to aid digestion
human children have how many teeth?
20
human adults have how many teeth?
32
how are the teeth anchored to the gums?
by long root extension s layered with enamel, dentin, and pulp
enamel, dentin, and pulp house what in the centre?
blood vessels
what are the 4 different types of teeth
incisors
canines
molars
pre molars
what are incisors used for?
cutting and plucking plant matter
what are canines used for?
used for tearing ( usually meat)
what are molars/pre molars used for?
used for crushing and grinding plant matter
what’s commonly referred to as the roof of the mouth?
the palate
what’s the purpose of the palate ?
separated the mouth cavity from the nasal cavity
the hard palate is made up of _____, and the soft palate os made up of____
bone
muscles
children born without a full formation of a palate is called?
cleft palate
what can being born with a cleft palate effect?
breathing
speech
eating & hearing
what kids of tissue are salivary glands?
epithelial tissue
how many glands of epithelial tissue secrete saliva?
3
what does saliva aid in?
to assist in chemical digestion
what is saliva mostly made up of?
98% water
what are the other substances in saliva except water?
epithilial tissue
white blood cells
anti-microbial agents
electrolytes
mucus & enzymes
what’s the most important enzyme in saliva and what does it break down?
salivary amylase
breaks down starch into maltose using hydrolysis.
what/where is the pharynx
the region between the mouth and the oesophagus where digestive and respiratory systems intersect
what’s the use of the pharynx?
acts as a gate to allow appropriate material to passage into the proper tube.
how does the pharynx control what goes where?
using flaps of tissue that closes off the one system when the other is in use.
what 2 body parts, prevents food from entering the nasal cavity?
soft palate
uvula
how does the uvula and soft palate prevents food from entering the nasal cavity?
by contracting and blocking the nasopharynx
the entry to the trachea is called?
glottis
use if the epiglottis ?
blocks the entry to the trachea to prevent food from entering the lungs
what rises and uses the epiglottis like an umbrella to prevent food form entering the lungs??
trachea
2 steps that take place when food is being swallowed
sort palate and ulna closes off the nasopharynx and the trachea rises to cover itself with the epiglottis.
1 step that take place when air is being breathed.
nasopharynx is open and the glottis is uncovered, allowing air inside the lungs.
where does the oesophagus start and end?
start at the pharynx and end at the stomach.
where is the stomach located?
at the abdomen
what region is considered the thorax region?
The area of the body between the neck and the abdomen.
does the oesophagus perform any digestion?
no
the oesophagus is ____ until it receives food
collapsed
describe peristalsis
rhythmic muscular contractions that occur thought the digestive process to move the food along
can peristalsis move food the in the correct direction even if we’re hanging upside down?
yes
what prevents back flow inside the tubes of our body?
valves
what are valves composed of?
muscle that contracts to close the area off
where does the oesophagus really end? (both terms )
the lower oesophageal sphincter or the cardiac sphincter
describe the cardiac sphincter
a ring shaped muscle capable of contracting to seal off a tube.
when will the cardiac sphincter be closed? and why?
when food is being digested to prevent the acidic chyme from entering the oesophagus.
is stomach the main organ for digestion?
no, its a myth
the folds in the stomach are called?
rugae
use if rugae?
to allow the stomach to expand and increase the surface area
what type of muscle make up the stomach and a use of it?
smooth muscle which assists in the mechanical digestion
3 ways the stomach digests food mechanically?
contraction of the stomach’s muscular portion
churning the food
increasing surface area by expanding the rugae
what’s the acidic solution responsible for chemical digestion in the stomach?
gastric juice
what secretes mucus in the stomach?
the mucus cells in lumen
what is gastric juice composed of?
hydrochloric acid
electrolytes ( Na, K, Ca, S etc.)
organic molecules ( gastrin, pepsin, etc)
ph of hydrochloric acid?
2
function of hydrochloric acid?
break down connective tissues in food
kill bacteria
enables the absorption of vitamin B
what is pepsinigin? and it’s use?
the unactivated from of pepsin, which is activated y hydrochloric acid. converts proteins into smaller polypeptide chains
what the hormone secreted due to stretching of the stomach walls?
gastrin
what secretes gastrin and what absorbs it?
secreted and absorbed by the stomach
what does gastrin trigger?
the production and secretion of gastric juice
how much time does food usually spend in the stomach?
2-6 h
the valve at the bottom of the stomach?
pyloric sphincter. `
the purpose of the pyloric sphincter?
repeatedly open and close to let small amounts of chyme out.
how long is the small intestine and what’s it’s main objective?
6 meters
main objective is to absorb nutrients
why is small intestine called that and not the long intestine?
because the small intestine’s DIAMETER is smaller than the long intestines.
why is the intestine so long?
to ensure the food spends a long time in the stomach, enabling it to absorb the maximum amount of nutrients
what can we achieve by increasing or decreasing the surface area?
we can control the rate an action take place.
what structures increase the surface area in the stomach? (2 terms)
villi and micro villi
where exactly are the villi located?
in the lumen of the small intestine
what kind of tissue make up the villi’s?
epithelial tissue ( as it secretes hormones and stuff)
what does the villi do in the process of digestion?
directly absorb the digested nutrients into the blood and the lymphatic system
each villas has a capillary for ____ and a capillary for______
blood and lymphatic fluid ( lacteal)
another name for lymphatic fluid?
lacteal
what kinds of molecules directly enter the blood capillaries?
sugar and amino acids
what kinds of molecules directly enter the lymphatic fluid capillaries?
glycerol and fatty acids packaged together as a lipoprotein.
3 different sections in the small intestine in order?
duodenum
jejunum
ilium
how long is the duodenum?
25 cm
what’s considered the site of the common bile duct?
duodenum
what kind of tissue does the ilium have and what’s its purpose?
lymphoid tissue called Peyer’s patches which regulate the presence of pathogenic bacteria in the lumen
