metabolism and insulin Flashcards
glucose homeostasis: recall the factors regulating blood glucose; explain glucose cellular transport
glucoregulation: hyperglycaemia
when glucose high: insulin release increases; glucagon, catecholamines, somatotrophin and cortisol release decreases
glucoregulation: hypoglycaemia
when glucose low: insulin release decreases; glucagon, catecholamines, somatotrophin and cortisol release increases
what do gap junctions allow
allow small molecules to pass directly between cells (have paracrine effects)
what do tight junctions allow
form small intercellular spaces so high hormone concentrations there
how is glucose selectively reabsorbed
binds to Na (actively pumped out by sodium-potassium ATPase pump) in lumen of primary convoluted tubule and diffuses in through sodium-glucose cotransport proteins (symport); example of facilitated diffusion
how is glucose imported into cells
via GLUT-4 protein channel in membrane
structure of GLUT-4
hydrophilic core, hydrophobic exterior
what tissue is GLUT-4 present in
muscle and adipose tissue
what is the primary source of stored glucose
glycogen in the liver
