ANIMAL NUTRITION Flashcards
function of digestive system
is responsible for breaking down complex molecules into their simplest forms to be absorbed into the body to sustain life
what the digestive system made up of
- alimentary canal(tube from mouth to anus)
2. accessory organs(aid in digestive process)
5 stages of nutrition
- ingestion
- digestion
- absorption
- assimilation
- egestion
ingestion
process of taking food into digestive system/ mouth
function of ingestion
ensures the intake of energy(cell respiration)and vitamins and minerals
digestion
where food is broken down from large insoluble molecules into smaller soluble molecules to be absorbed into the bloodstream
function of digestion
to release necessary nutrients found in food
absorption
nutrients pass through the villi of small intestine(diffusion and active absorption) into the bloodstream
function of absorption
to absorb the necessary nutrients needed for body functions
assimilation
soluble nutrients diffuses from blood into cells and are used to make new cells or cellular structures and release energy (ATP) in the nutrients like glucose
function of assimilation
to ensure metabolic processes
egestion
to remove faeces(undigested food)
function of egestion
to remove undigested food from the body to prevent toxicity
difference between egestion and excretion
excretion is the act of getting rid of metabolic waste products whereas egestion is the process of getting rid of undigested food
2 types of digestion
- mechanical digestion
2. chemical digestion
mechanical digestion
is the physical breakdown of large food particles into smaller particles, by chewing in the mouth and by churning movements in stomach
chemical digestion
the breaking down of large food compounds into smaller food compounds using digestive enzymes
enzymes
molecules that act as a catalyst
3 kinds of enzymes
- carbohydrases
- proteases
- lipases
where carbohydrases are produced
- saliva
- pancreatic juices
- intestinal juices
where proteases are produced
- stomach
- pancreatic juices
- intestinal juices
where lipases are produced
- pancreatic juices
2. intestinal juices
substrate of carbohydrases
carbohydrates only(starch)
substrate of proteases
proteins only
substrate of lipases
lipids only(fats and oil)
preferred pH of carbohydrases
slightly alkaline
preferred pH of proteases
- acidic in stomach
2. alkaline in small intestine
preferred pH of lipases
slightly alkaline
end product of carbohydrases
glucose
end product of proteases
amino acids
end product of lipases
glycerol and fatty acids
what’s amylase
secreted in saliva and breaks down carbohydrates
function of tongue
- mixes food with saliva
- aids in taste
- aids in swallowing
function of teeth
where food is broken down into smaller pieces
function of salivary glands
- pH of 7.2
- is antiseptic to prevent the growth of micro-organisms
- lubricates the food bolus
- amylase breaks down carbs
function of oesophagus
transports food to stomach by means of peristalsis
function of stomach
produces hydrochloric acid which activates enzymes like pepsin to break down proteins to peptides
function of liver
- produces bile
- stores glucose in the form of glycogen
- deamination of amino acids occurs
- detoxifies alcohol
- stores iron, vit A and D
function of pancreas
- endocrine function: SECRETES HORMONES like insulin and glucagon
- exocrine function: EXCRETES ENZYEMES like amylase and lipase
function of gallbladder
stores bile
functions of hepatic portal vein
is the blood vessel that carries blood from the gastrointestinal tract, gallbladder, pancreas and spleen to the liver
function of the colon
reabsorbs water and nutrients
function of small intestine
breaking down of enzymes
bile functions
- emulsifies large fat globules into small fat droplets which aids digestion
- neutralises the acidic fluid(chyme) which comes from the stomach
- promotes peristalsis in small intestine
- acts as an antiseptic, preventing the decay of food particles in the small intestine
what’s peristalsis
process where food is moved through the digestive system by the rythmic contraction and relaxation of circular muscles along the alimentary canal
what triggers peristalsis(reflex action) to occur?
the presence of the food in the alimentary canal
how is the small intestine adapted for its function?
- many folds and villi create a large SA for max absorption
- epithelium is one cell layer thick for easy diffusion
- beaker and columnar epithelium cells secrete mucous to ensure moisture
- thin blood capillaries and lacteal vessels ensure transportation
- columnar epithelium cells have lots of mitochondria to provide energy for active absorption of larger molecules
function of epithelium cells in villi
- one cell layer thick to increase the rate of diffusion.
2. has micro-villi to increase SA for absorption
function of goblet cells in villi
produces mucous
function of blood capillaries in villi
- absorbs glucose and amino acids(active); vitamins and minerals(active and passive); water(passive/osmosis)
oxygenated blood enters
arteriole
deoxygenated blood leaves
venule
function of lacteal
transports fat: absorbs fatty acids and glycerol, transported by lymph system to left subclavian vein
function of lymphatic vessel
lymphatic vessels forms part of the lymphatic system
function of lymphatic system
absorbs fats from the digestive tract: lymph includes fluids from the intestines that contains fats and transports it to the bloodstream
