exam 3 class 19 Flashcards
Heme iron is absorbed by?
an apical transporter on the enterocyte
ionized iron is actively absorbed by?
apical cotransport with on a protein called the divalent metal transporter 1
(DMT1)
Inside the cell, enzymes convert heme
iron to and both pools of ionized iron
leave the cell on a transporter called?
ferroportin
iron uptake by the body is regulated by a
peptide hormone called
hepcidin
When body stores of iron are high, the
liver secretes ________, which binds to ________
hepcidin, ferroportin
Hepcidin binding causes the
enterocyte
to destroy the ferroportin transporter,
which results in decreased iron uptake
across the intestine
Most absorption of Ca2+ in the gut occurs by?
passive paracellular
pathways
Calcium enters the enterocyte through apical channels and is actively transported across the basolateral membrane by either
(1) Ca2+ -ATPase
(2) Na+- Ca2+ antiporter
Most water absorption takes place in?
small intestine
Na+ and Cl- are absorbed via various transporters in __________ and cells of
colon
enterocytes
Large intestine concentrates
waste
chyme enters the large intestine through the ____________, continues to
be mixed by segmental contractions
ileocecal valve
____ liters of unabsorbed chyme enters, most of this is absorbed and
_____liter of water is lost daily in feces
1.5
0.1
Bacteria inhabiting colon break down undigested complex carbohydrates
and proteins through?
fermentation
removes undigested feces from the body
The defecation reflex (spinal reflex)
Stress may increase intestinal motility and cause?
psychosomatic diarrhea
decrease motility in digestive system ?
constipation
is a pathological state in which intestinal secretion of
fluid is not balanced by absorption, resulting in watery stools
Osmotic diarrhea
occur when bacterial toxins enhance Cl- and fluid
secretion
Secretory diarrheas
Food intake is based on
two hypothalamic
centers, behaviors and create sensations of
hunger and fullness.
-Feeding center
-Satiety center
receives input
from different organs
Hypothalamus
has both psychological
and physiological
components
Eating disorder
anorexia nervosa
chemical signals secreted by adipose tissue
called adipocytokines (or adipokines
leptin is an?
adipokine
As fat stores increase, adipose cells secrete more
leptin, and?
food intake decreases (negative
feedback control)
a brain neurotransmitter that seems to
be the stimulus for food intake
neuropeptide Y (NPY)
Ingested food is used for
(1) Energy production, (2) Synthesis, and (3) Storage
