Bio: Ch 9, 5 Flashcards
intracellular digestion
oxidation of glucose and fatty acids to make energy
extracellular digestion occurs in…
lumen of alimentary canal
mechanical digestion
physical breakdown of large food particles into smaller food particles
chemical digestion
enzymatic cleavage of chemical bonds, such as the peptide bonds of proteins or the glycosidic bonds of starches
digestive tract pathway
oral cavity > pharynx > esophagus > stomach > small intestine >large intestine > rectum
accessory organs of digestion
salivary glands, pancreas, liver, gallbladder
enteric nervous system
wall of alimentary canal
controls peristalsis
function independently of brain and spinal cord
enteric nervous system
upregulated/downregulated by…
upregulated by parasympathetic nervous system
downregulated by sympathetic nervous system
extracellular digestion
nutrients are obtained fro mfood
digestive system
ADH
promotes thirst
digestive system
aldosterone
promotes thirst
digestive system
glucagon
promote hunger
digestive system
ghrelin
promote hunger
digestive system
leptin
promote satiety
digestive system
cholecystokinin (CCK)
promote satiety
which hormones promote thirst
ADH and aldosterone
which hormones promote hunger
glucagon and ghrelin
which hormones promote satiety
leptin and CCK
digestive system
what happens in oral cavity
- mastication starts mechanical digestion
- salivary amylase and lipase start chemical digestion
- food formed into bolus and swallowed
what/where does mechanical digestion start?
oral cavity
mastication
what/where does chemical digestion start?
oral cavity
salivary amylase and lipase
digestive system
esophagus
propels food to the stomach using peristalsis
what does food enter the stomach through?
lower esophogeal (cardiac) sphincter
salivary amylase
hydrolyzes starch into smaller sugar
lipase
catlyzes hydrolysis of lipids
digestive system
3 main sources of energy
carbs, fats, proteins
parts of stomach
fundus and body - mostly gastric glands
antrum and pylorus - mostly pyloric glands

lesser curvature
internal curvature of the stomach
greater curvature
external curvature of stomach
rugae
folds that line the stomach
mucous cells
produce bicarbonate rich mucus to protect the stomach
chief cells
secrete pepsinogen
pepsinogen
protease activated by the acidic environment of the stomach
parietal cells
secrete HCl and intrinsic factor
intrinsic factor
needed for vitamin b12 absorption
G-cells
secrete gastrin
gastrin
peptide hormone
increases HCl secretion and gastric motility
gastric glands respond to signals from…
vagus nerve of parasympathetic nervous system
stomach secretes 6 products:
- HCl - kills microbes, denature proteins, converts pepsinogen into pepsin
- pepsinogen - partially digests proteins
- mucus - protects mucosa
- bicarbonate - protects mucuosa
- water
- intrinsic factor
chyme
food particles after mechanical and chemical digestion in stomach
food passes into duodenum through…
pyloric sphincter
duodenum
first part of small intesting
primarily involved in chemical digestion
parts of small intestin:
duodenum, jejunum, ileium
hormones and enzymes in duodenum/small intestine
disaccharidases, peptidases (aminopeptidase, dipeptidase), enteropeptidase, secretin, CCK
disaccaharidases
brush border enzymes that break down maltose, isomaltose, lactose, and sucrose into monosaccharides
brush border peptidases
includes
break down proteins
aminopeptidase, dipeptidase
brush border enzymes
present on the luminal surface of cells lining the duodenum
break down dimers and trimers of biomeolcules into absorbable monomers
enteropeptidase
activates trypsinogen and procarboxypeptidases
initiating an activation cascade
secretin
stimulates release of pancreatic juices into digestive tract
slows motility
CCK
stimulates bile release from gallbladder, release of pancreatic juices, and satiety
bile
fluid composed of bile salts, pigments, and cholesterol
emulsifiers fats, making them soluble and increasing their surface area
bile salts
facilitate chemical digestion of lipids
acinar cells
in pancreas
produce pancreatic juices that contain bicarbonate, pancreatic amylase, pancreatic peptidases, pancreatic lipase
liver
- produces bile, nutrients, urea
- detoxifies chemicals
- activates or inactivates medications
- synthesizes albumin and clotting factors
bile is stored in
gallbladder
gallbladder
stores and concentrates bile
jejunum and ilium
small intestine
absorption
small intestine structure
lined with villi, which are covered with microvilli
increases surface area available for absorption
villi structure
contain capillary bed and lacteal
lacteal
vessel of lymphatic system
small intestine
water soluble compounds such as… enter the…
monosaccharides, amino acids, water soluble vitamins, small fatty acids, water
enter capillary bed
small intestine
fat soluble compounds such as… enter the…
fats, cholesterol, fat soluble vitamins
enter the lacteal
large intestine
absorbs water ad salts, forming semisolid feces
cecum
outpocketing that accepts fluid from the small intestine through the iceocecal valve
site of attachment of the appendix
colon parts
ascending, transverse, descending, sigmoid
rectum
stores feces that are then excreted through anus
gut bacteria produce…
vitamin K and biotin (vitamin B7)
Compare the secretion of parietal cells versus chief cells.
Parietal cells and chief cells are both found in the stomach.
Parietal Cells release HCl, whereas Chief Cells release pepsinogen.
Which of the following produce a protective coating that prevents the stomach from digesting itself?
(A) Chief Cells
(B) Mucous Cells
(C) Parietal Cells
(D) Beta Cells
(B) Mucous Cells
Mucous Cells release mucin, which coats the stomach to prevent pepsin or HCl from degrading the stomach lining.
What converts trypsinogen and chymotrypsinogen into their active forms?
Enteropeptidase converts trypsinogen and chymotrypsinogen into their active forms.
Describe how pancreatic lipase and bile work together to break down fats.
Bile emulsifies fats, organizing them into smaller droplets that can be acted on by pancreatic lipase.
The duodenum is receiving a lot of chyme from the stomach that is being digested by gastric juice/hydrochloric acid. To neutralize all that acid, the exocrine pancreas secretes which of the following?
(A) H2O
(B) H2SO4-
(C) Cl-
(D) HCO3-
(D) HCO3-
The exocrine pancreas releases bicarbonate, a base, to neutralize the gastric acid.
The exocrine pancreas releases many enzymes to aid in digestion. Match the following enzymes to their function.
(1) Amylase
(2) Lipase
(3) Trypsin/chymotrypsin
(A) Break down triglycerides into free fatty acids/ monoglycerides/ diglycerides/ glycerol
(B) Break down starches into smaller carbohydrates
(C) Break down protein into amino acids
(1) Amylase ->
(B) Break down starches into smaller carbohydrates
(2) Lipase -> (A) Break down triglycerides into free fatty acids/ monoglycerides/ diglycerides/ glycerol
(3) Trypsin/chymotrypsin -> (C) Break down protein into amino acids
The large intestine’s primary responsibility is to absorb:
(A) nutrients
(B) proteins
(C) fatty acids
(D) water
(D) water
The large intestine’s primary responsibility is to absorb water.
Gastrin will also increase or decrease stomach motility? What does that mean?
Gastrin increases stomach motility, which increases the churning of food by the stomach.
When chyme enters the duodenum, the production of which of the following hormones is triggered?
I. Ghrelin
II. Secretin
III. Cholecystokinen
(A) I Only
(B) I and III Only
(C) II and III Only
(D) I, II, and III
(C) II and III Only
When chyme enters the duodenum, the production of secretin and cholecystokinen is triggered.
What is the primary role of secretin versus cholecystokinen?
The primary role of secretin is to increase the pH of the chyme as it enters the duodenum.
The primary role of cholecystokinen is to promote digestion in the duodenum.
peptide hormones are composed of
amino acids
peptide hormones are derived from
larger precursor proteins that are cleaved during posttranslational modification
peptide hormones
membranes
polar
cannot pass through plasma membrane
peptide hormones
location of receptor
extracellular (cell membrane)
peptide hormones
mechanism of action
- stimulates a receptor (usually GPCR)
- affecting levels of second messengers (usually cAMP)
- initiates signal cascade –> can induce amplification of signal

peptide hormones
speed of onset
quick
peptide hormones
duration of action
short lived
peptide hormones
method of travel in bloodstream
water soluble –> dissolves and travels freely
steroid hormones are derived from
cholesterol
steroid hormones are produced by
gonads and adrenal cortex
steroid hormones
location of receptor
intracellular or intranuclear
steroid hormones
mechanism of action
- binds to a receptor
- induces conformational change
- regulates transcription at the level of the DNA
steroid hormones
method of travel in bloodstream
lipid soluble –> cannot dissolve in blood stream –> binds to carrier protein
steroid hormones
speed of onset
slow
steroid hormones
duration of action
long lived
steroid hormones
membrane
minimally polar –> can pass through membrane
amino acid hormones are derived from
amino acids
amino acid hormones
features
variable
amino acid hormones
exs
epinephrine, norepinephrine, triiodothyronine, thyroxine
catecholamines
mechanism of action
duration and speed of onset
bind to GPCR
usually fast and shortlived
catecholamines exs
epinephrine, norepinephrine
thyroid hormones
mechanism of action
bind intracellularly
direct hormones
secreted then act directly on a target tissue
have major effects on nonendocrine tissues
tropic hormones
require intermediary to act
have major effects on other endocrine tissues
peptide and amino acid derivative hormone
end in
-in or -ine
steroid hormones
end in
-one, -ol, -oid
anterior pituitary releases hormones in response to stimulation from
hypothalamus
anterior pituitary
hormones
FLAT PEG
- 4 tropic hormones (FLAT)
- FSH, LH, ACTH, TSH
- 3 direct hormones (PEG)
- prolactin, endorphins, growth hormone
follicle stimulating hormone (FSH)
released by anterior pituitary
promotes the development of ovarian follicles in females and spermatogenesis in males
lutenizing hormone (LH)
released by anterior pituitary
promotes ovulation in females and testosterone production in males
adrenocorticotropic hormone (ACTH)
released by anterior pituitary
promotes the synthesis and release glucocorticoids from the adrenal cortex
thyroid stimulating hormone (TSH)
released by anterior pituitary
promotes the synthesis and release of triiodothyronine and thyroxine from the thyroid
prolactin
released by anterior pituitary
promotes milk production
endorphins
released by anterior pituitary
decrease perception of pain and can produce euphoria
growth hormone (GH)
released by anterior pituitary
promotes growth of bone and muscle and shunts glucose to these tissues
raises blood glucose concentrations
posterior pituitary releases ___ hormones produced in the ____
2
hypothalamus
posterior pituitary
hormones
ADH and oxytocin
antidiuretic hormone (ADH or vasopressin)
released by posterior pituitary
secreted in response to low blood volume or increased blood osmolarity
increases reabsorption of water in collecting duct of nephron, increasing blood volume, and decreasing blood osmolarity
oxytocin
released by posterior pituitary
secreted during childbirth and promotes uterine contractions
positive feedback loop
negative feedback
hormone later in pathway inhibits hormones earlier in the pathway
hypophyseal portal system
blood vessel system that directly connects the hypothalamus with anterior pituitary
thyroid
hormones
triiodothyronine (T3) and thyroxine (T4)
calcatonin
T3 and T4 produced by
follicular cells
T3 and T4
released by thyroid
- contain iodine
- increase basal metabolic rate and alter the utilization of glucose and fatty acids
- required for proper neurological and physical development in children
calcitonin
released by thyroid
- decreases plasma calcium concentration by promoting calcium excretion in the kidneys
- decreases calcium absorption in the gut
- promotes calcium storage in bone
parathyroid glands release
parathyroid hormone
parathyroid hormone
released by parathyroid glands
- decreases excretion of calcium by the kidneys
- increases bone resorption directly to increase blood calcium conc
- activates vitamin D
- promotes resorption of phosphate from bone
- reduces reabsorption of phosphate in the kidney
- vitamin D promotes absorption of phosphate from gut - cancel out
vitamin D
necessary for calcium and phosphate absorption from the gut
adrenal cortex
hormones
- glucocorticoids (cortisol and cortisone)
- mineralocoriticoids (aldosterone)
- cortical sex hormones (androgens and estrogens)
glucocorticoids
(cortisol and cortisone)
released from adrenal cortex
- increase blood glucose concentration
- reduce protein synthesis
- inhibit immune system
- participate in stress reponse
glucocorticoid (cortisol and cortisone) release stimulated by
ACTH
mineralocorticoids (aldosterone)
produced by adrenal cortex
promote sodium readsorption in distal convoluted tubule and collecting duct –> increases water reabsorption
aldosterone
produced by adrenal cortex
increases potassium and hydrogen ion excretion
aldosterone activity is regulated by
renin-angiotensin-aldosterone-system
adrenal medulla
hormones
catecholamines (epinephrine, norephinephrine)
catecholamines
secreted by adrenal medulla
- promote glycogenolysis
- increase the basal metabolic rate
- increase heart rate
- dilate bronchi
- alter blood flow
pancreas
hormones
regulate glucose homeostasis
glucagon, insulin, somatostatin
glucagon produced by
alpha cells in pancreas
insulin produced by
beta cells in pancreas
somatostatin produced by
delta cells in pancreas
glucagon
hormone
produced by pancreas
raises blood glucose levels by stimulating protein and fat degradation, glycogenolysis, and gluconeogensis
insulin
hormone
produced by pancreas
lowers blood glucose levels by stimulating glucose uptake by cells and promoting anabolic processes like glycogen, fat, and protein synthesis
somatostatin
hormone
produced by pancreas
inhibits insulin and glucagon secretion
testes secrete
testosterone
ocaries secrete
estrogen and progesterone
pineal gland releases
melatonin
melatonin
regulates circadian rhythms
stomach and intestine produces
secretin, gastrin, CCK
kidneys secrete
erythropoitin
erythropoietin
secreted by kidneys
stimulates bone marrow to produce erythrocytes in response to low oxygen levels in the blood
heart’s artria secrete
atrial natriuretic peptide (ANP)
atrial natriuretic peptide (ANP)
secreted by atria
promotes excretion of salt and water in kidneys in response to stretching of atria (high blood volume)
thymus secretes
thymosin
thymosin
secreted by thymus
important for proper t-cell development and differentiation
GnRH causes __hormone__ to be released
FSH and LH
GHRH causes __hormone__ to be released
GH
TRH causes __hormone__ to be released
TSH
corticotropin-releasing factor causes __hormone__ to be released
ACTH
gigantism
excess of GH
dwarfism
deficit of GH
hypothyroidism
deficiency of iodine
hyperthyroidism
excess of thyroid hormone
glucagon is released when glucose levels are ___
low
insulin is secreted when glucose levels are ___
high
hypoglycemia
excess insulin
low blood glucose concentration
hyperglycemia
excess blood glucose concentration
polyuria
increased frequency of urination
polydipsia
increased thirst

