L29 Digestion and Metabolism Flashcards
what are the basic building blocks in the body?
nutrients
what are the 4 classes of nutrients?
essential and non essential amino acids, vitamins and minerals
what is vitamin B3?
a vitamin and a cofactor
what is iron?
a mineral and a cofactor
what is linoleic acid?
an essential amino acid
what is the GI tract?
gastrointestinal system = digestive system
what is the GI tract?
external way of interacting with enviornment in a nutritional/waste point of view
what does mucus consist of?
viscous water, amylase and glycoproteins
why can we not stop swallowing half way through?
it is a reflex - epiglottis prevents re-entry to mouth
what is coughing?
an involuntary reflex when swallowing reflex fails
what regulates movement in digestive system walls?
sphincters
what sphincter do we have voluntary control over?
anal sphincter
food is processed into a liquid called?
chyme
what is the pH of gastric juice?
2
what enzyme breaks protein bonds?
pepsin protease
where does HCl come from?
priorital cells secreted into stomach
where does HCl form?
lumen of stomach
when does pepsin form?
in acidic conditions in presence of HCl
what causes gastric ulcers?
bacteria called Heliobacter pylori
where does most chemical digestion occur?
intestine
how are fats partly digested?
bile salts
what is life cycle of red blood cells?
120 days - bile kills them and recycles them via liver
what does the hepatic artery do?
brings oxygen to liver, comes from GI tract and funnels nutrients to liver
what is a lacteal?
part of lymphatic vessel that absorbs fat
what are chylomicrons?
a droplet of fat present in the blood or lymph after absorption from the small intestine
what minor role does appendix play?
immune response
where is faeces stored?
rectum
what regulates the digestive system/ GI tract?
endocrine and nervous system
what happens when we eat food?
medulla recieves a signal and autonomic nervous system causes secretion of saliva
conditioned reflex?
associating a certain stimulus with a certain response
what functions keep us alive?
vegetative functions - nutritional, metabolic, and endocrine functions
how is energy stored?
first in liver and then in glycogen, excess energy in adipose cells
when the body requires energy what occurs?
glycogen storage is used first followed by muscle glycogen and then fat stores
what is the absorptive state?
the body has been fed - glucose is plentiful - insulin regulates this state
what is the postabsorptive state?
this is fasting - energy stores are mobilised for energy, glucagon hormone is a major regulator
what is metabolic syndrome?
cluster of risk factors including insulin resistance, hypertension and high fat content
what is a central mechanism in insulin resistance?
chronic state of inflammation
what does obesity contribute to?
type 2 diabetes, cancer of colon and breat, heart attacks and strokes
how do hormones regulate appetite?
satiety centre in brain, ghrelin hormone triggers hunger
what secretes ghrelin?
stomach walls
what hormone suppresses appetite?
insulin and PYY - small intestine
Leptin - adipose tissue
what is an important concept in disease and health?
each individual has a unique microbiota/ bacterial fingerprint
