human nutrition Flashcards
what are the 5 main steps of digestion
ingestion digestion absorption assimilation egestion
what is ingestion
intake of food by an organism
what is digestion
break down of large components of food to smaller components
what is absorption
sucking of digestive component of food into the blood
what is assimilation
transport of absorbed food to each and every part of the body
what is egestion
removal of undigested from the body by stools (potty 😭)
what are the food groups that are needed in a diet for it to be balanced
carbs proteins lipids/fats vitamins minerals dietary fibre water
what are the function of carbs
source of energy, energy store
sources of carbs
bread, cereals, pasta, rice, potatoes
what are the functions of protien
growth and repair in the body
makes anti bodies in the body
source of energy
transport and storage of molecules
what are some sources of protiens
meat, fish, eggs, pulses, nuts
functions of fats/lipids
insulation layer
highest energy store
helps make cell membrane
what stores the most energy in the body
fats
sources of fats
butter, oil, nuts
function of dietary fibre
provides bulk (roughage) for the intestine to push food through
sources of dietary fibre
vegetables, whole grain
function of vitamins
helps heal wounds
bolsters immune system
converts food to energy, repairs cellular damage
function of minerals
helps in making enzymes and hormones
sources of vitamins
fruits and vegetables
sources of minerals
fruits, vegetables, meats and dairy products
function of calcium in the body
needed for strong teeth and bones, helps clot blood
what can a deficiency of calcium lead to
osteoparosis
what is vitamin c’s function in the body
forms an essential part of collagen protein, which makes up skin, hair, gum and bones
what is vitmain D’s function
helps the body to absorb calcium and required for strong teeth and bones
what does vitamin D deficiency cause
rickets, bones become soft and deformed
what does iron deficiency cause
anemia, tissues don’t receive enough oxygen
what does vitamin C deficiency cause
scurvy, bleeding of gums
which people need more protein in their body
young people to help them grow
which people need more calcium and iron in their body
pregnant women to help build the bones, teeth and give the baby a supply of healthy blood
what is the function of the mouth/salivary gland
site of mechanical digestion, teeth chew food to break it into smaller pieces and increase its surface are to volume ratio
amylase enzymes in the saliva start digesting starch into maltose
what is the function of the oesophagus
tube that connects the mouth to the stomach where the food bolus goes after being swallowed
wave-like contractions take place to push the food bolus down without needing help of gravity
what is the function of the stomach
food is mechanically digested by churning actions while protease enzymes start to chemically digest proteins
HCL is present to kill bacteria in the food and provide optimum pH for protease to work (pH 2)
mucus is secreted by the stomach to prevent inner lining of the stomach from affects of acidic HCL
what is the function of the small intestine
what happens in which part of the small intestine
duodenum:- is where the food coming out of the stomach finishes being digested by enzymes produced in the duodenum and pancreas
pH of the small intestine is alkaline (8-9)
Ileum:- absorption of digested food molecules takes place, lined with villi to increase the surface area over which absorption takes place
what is the function of the large intestine
what happens in which part of the large intestine
water is absorbed from the remaining material in the colon to produce feces
feces are stored in the rectum and removed through the anus
what is the function of the pancreas
produces all 3 types of digestive enzymes (amylase, protease, lipase) can also secrete hormones and enzymes
secretes enzymes in an alkaline solution into the duodenum for digestion, to raise pH of fluid coming out of the stomach
explain the role of mechanical digestion
breaks up food into smaller pieces without chemical change by teeth
increases surface area for enzyme action helps speed up chemical digestion
what is the function of the liver
produces bile to emulsify fats
amino acids not used to make proteins are broken down in the liver which produces urea
urea used in the metabolism of nitrogen
what is the function of the gallbladder
used to store bile and releases it into the duodenum
what is glucagon
where is it produced
when the body has a low blood sugar level the pancreas secretes glucagon into the liver, and the liver then secretes it into the blood. this helps maintain the blood sugar level in the body
what is insulin
where is it produced
when the body has a high blood sugar level, insulin is released from the pancreas and the fat cells take in the glucose from the blood and the body’s blood sugar level is restored back to normal
where does glucose convert to glycogen
the liver
where does absorption of digested products occur
small intestine
which type of protease does the stomach release
pepsin
What type of protease does the pancreas secrete
trypsin
why do fats need to be emulsified
increases surface area for enzyme action (lipase)
how does insulin affect the concentration of glucose in the blood
decreases
how does insulin affect the uptake of glucose cells in the liver
increases it
how does glucagon affect the uptake of glucose cells in the liver
decreases it
how does glucagon affect the concentration of glucose in the blood
increases
why is the control of the concentration of glucose in the blood an example of negative feedback
glucose concentration is kept within narrow limits, any change to this concentration is detected as a stimulus
glucose concentration will increase or decrease depending on the change to the normal concentration by using insulin or glucagon so as to bring the blood concentration level back to normal
how is food moved along the small intestine
peristalsis
how is food moved along the esophagus
peristalsis
what are some structures of the villi (outermost to inward)
epithelial cell
blood capilary
lacteal
what is the vein that takes blood away from the small intestine
hepatic portal vein
why are microvilli advantageous
increase surface area
increase absorption by diffusion/active transport
what are the differences between chemical digestion and mechanical digestion
chemical digestion breaks down molecules by breaking their bonds, using enzymes, and converts molecules from insoluble to soluble
mechanical digestion breaks down molecule to increase the surface area to mix/churn
where is most soluble food absorbed into the blood
illeum
how can gallstones affect the digestion of fat
less bile is secreted into the small intestine, less emulsification of fats, surface area of fats is not decreased, takes longer for lipase to break it down
how is the ileum adapted to its function
long and hollow contains many villi
to increase surface area, increase the rate of absorption
microvilli on the surface of the villi further increase the rate of absorption
wall of villi is 1cm thick allowing for short-distance for diffusion and active transport
what are some features of the microvilli that help it in its job
well supplied with a network of blood capillaries that transport glucose and amino acids away from the small intestine into the blood
Lacteal runs through the centre of the villus to transport fatty acids and glycerol away from the small intestine in the lymph
the hardest part of the teeth in order
Enamel
dentine
what are some unique characteristics of dentine
dentine have channels with living cytoplasms in them
what is the dental formula for permanent teeth
upper - 2 insicors + 1 canine + 2 premolar + 3 molar
lower - 2 insicors + 1 canine + 2 premolar + 3 molar
total teeth (4+2+4+6)x2 = 32
what is the function of incisors
chisel-shaped, for biting off pieces of food and cutting them, 8 present in the mouth (4 upper, 4 lower)
what is the function of the canines
used for biting of pieces of food and cutting
only in carnivores 4 in mouth (2 upper, 2 lower)
what is the function of premolars
wide surfaces
used for grinding food
8 present in the mouth (4 upper, 4 lower)
what is the function of molars
used for grinding, 8 present in the mouth (4 upper, 4 lower)
dental formula for milk teeth
upper- incisors 2, canine 1, premolars 2, molars 0
lower- incisors 2, canine 1, premolars 2, molars 0
total = (4+2+4)x2 = 20
what are heterodont teeth
the 4 main types of teeth, premolars, molars, canines, incisors
what are diphydont teeth
the 2 sets of teeth
milk and permanent
what are thecodont teeth
teeth are completely embedded in jaw bone of buccal cavity
dental decay
acidic conditions dissolve tooth enamel which is the main cause for dental decay
what are the positions of the circular and longitudinal muscles during peristalsis
circular muscles are contracted
longitudinal muscles are relaxed
Explain the effect of cholera bacteria on the digestive system
cholera bacteria produce a toxin
toxin causes the secretion of chloride ions into the small intestine
lowers water potential
results in diarrhoea
aerobic resp eq
c6h12o6 + 6o2 —> 6co2 + 6h2o
chemical digestion definition
the breakdown of large, insoluble molecules into small, soluble molecules
mechanical digestion definition
the breakdown of food into smaller pieces without chemical change to the food molecules
structures of tooth from outward to in
enamel
dentine
cement
pulp
function of cement
resist bite pressure produced by the teeth and jawbones.
how do chloride ions move in and out of diffusion
active transport
against conc gradient
using respiration
through protein
what does amylase work on and what products does it form
starch
forms maltose
what does maltase break maltose down into
glucose
describe the process of tooth decay in humans
sugar left on teeth
aerobic respiration of bacteria
produces lactic acid and dissolves tooth enamel
State the exact location of maltase in the small intestine
membrane of epithelium
what does hepatic portal vein do
carries deoxygenated blood from the intestine to liver
where is maltase secreted
epithelial lining of the small intestine
what does amylase break starch down into
starch to maltose
maltase—> maltose to glucose
