Ch 47 Flashcards
heterotrophs
heterotrophs get their nutrients by eating other things, they are organisms that obtain nourishment from the organic molecules manufactured by other organisms
autotrophs
self-nutrients
What are nutrients used for?
Nutrients are used to: run the systems of the body, make compounds for metabolic processes, and grow and repair tissue
What are the four steps of food processing in order?
Ingestion, digestion, absorption, elimination
ingestion
the taking of food into the digestive cavity
digestion
the process of breaking down food mechanically and chemically
absorption
nutrients pass through the lining of the digestive tract and into the blood
egestion/elimination
food that is not digested and absorbed is discharged from the body
How is food processed in simple invertebrate digestive systems?
in simple invertebrates such as cnidarians or flatworms the food is digested in the gastrovascular cavity and the gastrovascular cavity then serves as bout the mouth and anus
How is food processed in more complex invertebrates?
the digestive tract is a complete tube with an opening at each end, the digestion takes place as food passes through the tube
What is the sequence in order of body parts that food passes through?
mouth, pharynx, esophagus, stomach, small intestine, large intestine, and anus
bolus
?
motility
the mixing and propulsive movements of the digestive tract
What do the epiglottis and glottis do when swallowing?
they close of the passageway to the lungs to prevent choking
What are the two types of digestion? Give an example of each.
mechanical: mammalian teeth including incisors for biting, canines for tearing, and premolars and molars for crushing and grinding, chemical: three pairs of salivary glands secrete saliva
What do incisors do? Canines? Premolars/molars?
incisors are for biting, canines are for tearing, and premolars/molars are for crushing and grinding
What happens in the stomach?
food is mechanically digested, proteins are enzymatically digested by pepsin, gastric glands secrete hydrochloric acid and pepsinogen
rugae
stomach folds that expand with food, receptor stretchers
pepsin vs pepsinogen
?
What does HCl activate?
pepsin
chyme
?
What does the pancreas do?
releases enzymes that digest protein, lipid, and carbohydrates, as well as RNA and DNA
What does the large intestine do?
eliminates undigested waste and incubates bacteria that produce Vitamin K and certain B vitamins
What does the liver do?
it produces bile which emulsifies fats (oils), bile is not an enzyme which makes it permeable to water
How are nutrients absorbed in the body?
nutrients are absorbed through the thin walls of the intestinal epithelium, the hepatic portal vein transports amino acids and glucose to the liver (cirrhosis, detoxification)
What are some structural adaptations that increase the surface of the digestive tract?
the surface area of the small intestine is greatly expanded by folds in its walls, intestinal villi, and intestinal microvilli, our gut isn’t smooth, there are folds which increase the chances of absorption
What are lipids used as?
an energy source (fat burned components of cell), and to synthesize steroid hormones and other lipid substances
carbohydrates
most carbohydrates are ingested in the form of complex carbohydrates, fiber is a mixture of cellulose and other indigestible carbohydrates, carbohydrates are used mainly as an energy source
proteins
serve as enzymes, are essential structural components of cells, the best distribution of essential amino acids is found in the complex proteins of animal foods, they can be broken down for energy
vitamins
organic compounds required in small amounts for many biochemical processes, many serve as components of coenzymes
minerals
minerals are inorganic nutrients ingested as salts dissolved in food and water, trace elements are minerals required in amounts less than 100mg per day, not a complex compound
What nutrients are required by our bodies to live?
lipids, carbs, proteins, vitamins, minerals
nutrition
the process of taking in and using food
what does malnutrition result from?
malnutrition results from dietary intake that is either below or above the required need (either too much or too little), undernutrition and obesity
basal metabolic rate (BMR)
the body’s cost of metabolic living, breaking down food
total metabolic rate
BMR plus the energy used to carry on daily activities, some people have higher rates
energy input and output
when energy (kilocalories) input equals energy output, body weight remains constant, when energy input exceeds energy output, body weight increases, when energy output exceeds energy input, body weight decreases
mutant Ob gene
scientists mutated the Ob gene, aka leptin gene, in mice, they discovered that leptin tells a living creature when it should stop eating and when it’s full so when it was broken the mice ate and ate and became obese, when the scientists inject leptin back into the mice they stopped eating as much and didn’t get as fat, scientists also believe the neuropeptite Y (NPY) is the neurotransmitter involved in this
