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Glossary of sullivan phys last test

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Gastrointestinal system is responsible for
transferring organic molecules, salts, and water from the external environment to the body's internal environment
Processes of the GI track
Digestion
Secretion
Absorption
Motility
Defecation
Digestion
ingested macromolecules dissolved and broken down
Secretion
HCL, bile and enzymes
Absorption
molecules move from lumem of tract into blood or lymph
Motility
contractions of smooth muscles move contents thru tract
Defecation
bacteria and undigested material eliminated from body
Carbohydrate
* 250 - 300 of 800 g food / day
* 2/3 plant starch (polysaccharide)
1/3 sucrose/lactose
Dehydration synthesis
monosaccharide + monosaccharide --> disaccharide + water
Hydrolysis
disaccharide + water --> monosaccharide + monosaccharide
protease
(PROH-tee-ase)
an enxyme capable of breaking peptide bonds in a protein
proteolysis
the process whereby peptides and proteins are cleaved into smaller molecules, by the actions of specific enzymes (proteases)
prothrombin
inactive precursor to thrombin; produced by liver an normally present in plasma
Is Dehydration Synthesis and Hydrolysis reversible?
yes, they are reversible reactions
starch is partially digested by
salivary amylase in mouth and upper stomach
starch digestion continues in
small intestine by pancreatic amylase
starches are broken down to
monosaccharides by enzymes in plasma membranes of small intestine epithelial cells. then transported across epithelial cells into blood
Protein
we ingest/need
ingest 70 - 90 (or 125) g per day
need 40 - 50 g per day
enzyme(s) in the stomach that break(s) down protein
pepsin
enzyme(s) in the small intestines that break down protein
trypsin and chymotrypsin
The major proteases secreted by the pancrease
trypsin and chymotrypsin
amino acid to capillaries
amino acids actively transported (along with Na+) across intestinal wall into capillaries
most protein is digested/absorbed in
the first part of the small intestine
Peptide + Water <===
===> amino acid + amino acid
Protein + enzyme pepsin =
= peptide fragments
(stomach)
protein + typsin /chymotrypsin =
= peptide fragments
(small intestines)
peptide fragments +
carboxypeptidases/
aminopeptidases =
= amino acids
(small intestine)
carboxypeptidase
enzyme secreted in small intestine by exocrine pancreas as precursor, procarboxypeptidase; breaks peptide bond at carboxyl end of protein
aminopeptidase
one of a family of enymes located in the intestinal epithelial membrane; breaks peptide bond at amino end of polypeptide
How do amino acids get absorbed?
amino acids are actively transported (along with Na+) across intestinal wall into capillaries
Most protein is digested/absorbed where?
most protein is digested/absorbed in the first part of the small intestine
give the hydrolysis/dehydration synthesis equation for peptides
peptide + water <==> amino acid + amino acid
NH2 is a what?
an amine
______ace =
enzyme
Name the two common disaccharides in our diets
sucrose and lactose
sucrose
table sugar
lactose
milk sugar
most carbohydrates are digested/absorbed where?
in the first 20% of the small intestine
monosacharide has how many sugars?
one
polysacharide has how many sugars?
1000 or more
fructose gets across by what method?
facilitated diffusion
glucose and galactose get across by what method?
secondary active transport
tripsinogen is the zymogen for
trypsin
zymogen
(ZY-moh-jen)
enzyme precursor requiring some change to become active
Wolffian duct
(WOLF-ee-an)
part of embryonic duct system that, in male, remains and develops into reproductive system ducts, but in female, degenerates
vitamin K
a lipid-soluble substance absorbed from the diet and manufactured by bacteria of the alrge intestine; required for production of numerous factors involved in blood clotting
cellulose is partially broken ...
cellulose partially broken by bacteria in large intestine
How much fat do we have in our diet?
70-100 g per day
most fat we consume is in the form of
triacylglycerols
triacylglycerols are composed of
composed of three FA attached to a glycerol skeleton
fat digestion occurs in
fat digestion is entirely in the small intestine
triacylglycerols are soluble or insoluble?
triacylglycerols are insoluble in water (aggregate in droplets)
bile salts are formed where?
bile salts are formed in the liver
what are bile salts formed from?
cholesterol
are bile salts hydrophilic or hydrophobic?
bile salts are amphipathic
bile salts increase ...
bile salts increase the rate of fat digestion and absorption
what are the two functions of bile salts?
1. emulsify fat
2. form part of micelles (keep most insoluble fat products in small aggregates)
micelles
(MY-sell)
soluble cluster of amphipathic molecules in which molecules' polar regions line surface and nonpolar regions orient toward center
what makes up micelles?
formed from fatty acids, monoglycerides and bile salts
micelles are formed when and where?
during fat digestion in small intestine
phosphate + carbon chain =
fatty acid
fatty acid
carbon chain with carboxyl group at one end through which chain can be linked to glycerol to form triglyceride
carboxyl group
(kar-BOX-il)
--COOH; ionizes to carboxyl ion (--COO-)
catabolism
(kuh-TAB-oh-lizm)
cellular breakdown of organic molecules
Epinephrine
(E)
amine hormone secreted by adrenal medulla and involved in regulation of organic metabolism; a biogenic amine (catecholamine)
Norepinephrine
(NE)
biogenic amine (catecholamine) neurotransmitter released at most sympathetic postganglionic endings, from adrenal medulla, and in many CNS regions
Catecholamine
dopamine, epinephrine, or norepinephrine, all of which have similar chemical structures
Thyroxine
(T4)
tetraiodothyronine; iodine-containing amine hormone secreted by thyroid gland
Triiodothyronine
(T3)
iodine-containing amine hormone secreted by thyroid gland
Antidiuretic hormone
(ADH, aka vasopressin)
peptide hormone synthesized in hypothalamus and released from posterior pituitary; increases water permeaility of kidney's collecting ducts and causes vasoconstriction
Oxytocin
(OT)
peptide hormone synthesized in hypothalamus and released from posterior pituitary; stimulates mammary glands to release milk and uterus to contract
Follicle-stimulating hormone
(FSH)
protein hormone secreted by anterior pituitary in males and females that acts on gonads; a gonadotropin
gonadotropic hormone
(gonadotropin)
hormone secreted by anterior pituitary that controls gonadal function; FSH or LH
Luteinizing hormone
(LH)
peptide gonadotropic hormone secreted by anterior pituitary; rapid increase in females at midmenstral cycle initiates ovulation; stimulates Leydig cells in males
Leydig cell
(interstitial cell)
testosterone-secreting endocrine cell that lies between seminiferous tubules of testes
leptin
adipose-derived hormone that acts within the brain to decrease appetite and increase metabolism
lecithin
(LESS-ih-thin)
a phospholipid
lipase
enzyme that hydrolyzes triglyceride to monoglyceride and fatty acids
Growth hormone
(GH)
peptide hormone secreted by anterior pituitary; stimulates insulin-like growth factor I release; enhances body growth by stimulating protein synthesis
growth hormone-releasing hormone
(GHRH)
hypothalamic peptide hormone that stimulates growth hormone secretion by anterior pituitary
anabolism
cellular synthesis of organic molecules
androgen
any hormone with testosterone-like actions
Peptide hormone
any of a family of hormones, like insulin, composed of approximately two to 50 amino acids; generally soluble in acid, unline larger protein hormones which are insoluble
Amine hormone
hormone derived from amino acid tyrosine; includes thyroid hormones, epinephrine, norepinephrine, and dopamine
steroid hormone
any of a family of hormones, like progesterone, whose structure is derived from cholesterol
Thyroid-stimulating hormone
(TSH)
glycoprotein hormone secreted by anterior pituitary; induces secretion of thyroid hormone; also called thyrotropin
thyroid-releasing hormone or
thyroid-releasing factor
(TRH or TRF)
hypophysiotropic hormone that stimulates thyrotropin and prolactin secretion by anterior pituitary
triacylglycerol ----(lipase)--->
monoglyceride + 2 fatty acids
OR
glycerol + 3 fatty acids
What happens to the fatty acids and monoglycerides after lipase breaks them down in the lumen of the SI?
fatty acids and monoglycerides enter the epithelial cells from lumen of SI
Inside the epithelial cells lining the lumen of SI, what happens to FA and monoglycerides?
fatty acids and monoglycerides are resynthesized into triacylglycerols on smooth ER, coated with protein in Golgi and packaged in vesicles
What happens to triacylglycerols once they are coated on ER and packaged at Golgi into vesicles?
the vesicles are released on the other side into interstitial fluid as cyhlomicrons
chylomicrons
small droplet of triacylglycerol coated with protein
what happens to chylomicrons released into interstitial fluid?
chylomicrons absorbed into lacteals then entr venous circulation
monoglyceride
glycerol linked to one fatty acid side chain
triglyceride or triacylglycerol
subclass of lipids composed of glycerol and three fatty acids
What type of control mechanisms are there for digestion?
neural and hormonal
gastrointestinal reflexes are initiated by ...
1. distension of wall
2. chyme osmolarity
3. chyme acidity
4. concentration of products
where are the receptors for the gastrointestinal reflex triggers of distension, osmolarity, acidity, and concentration, and what do they do?
these stimuli receptors are in the wall of the tract and they trigger reflexes that influence muscles and glands
how many nerve networks are in the enteric nervous system and what are their names?
1. myenteric plexus
2. submucosus plexus
facts re enteric nervous system
* local NS
* neurons synapse with other neurons in plexes or innervate smooth muscle or glands
* plexes influence eachother
* both plexes receive ANS fibers
* stimulation conducted up and down tract
what are the types of reflex arcs?
1. short reflexes
2. long reflexes
where are the hormones secreted from that regulate digestion?
hormones secreted by endocrine cells scattered thru epithelium of stomach and small intestine
what are the major hormones of the digestive tract?
1. secretin
2. cholecystokinin (CCK)
3. gastrin
4. glucose insulinotropic peptide (GIP)
effector cells of the GI tract contain receptors for ...
more than one hormone
potentiation
one hormone in the presence of another hormone produces an exaggerated effect
secretin
(SEEK-reh-tin)
peptide hormone secreted by upper small intestine; stimulates pancreas to secrete bicarbonate into small intestine
cholecystokinin
(CCK)
peptide hormone secreted by duodenum that regulates gastric motility and secretion, gallbladder contraction, and pancreatic enzyme secretion; possible satiety signal
gastrin
peptide hormone secreted by antral region of stomach; stimulates gastric acid secretion
glucose insulinotropic peptide
OR
glucose-dependent insulinotropic peptide
(GIP)
intestinal hormone; stimulates insulin secretion in response to glucose and fat in small intestine
What are the phases of neural and hormonal control of the GI system?
Cephalic phase
gastric phase and
intestinal phase
Cephalic phase -
receptors in HEAD stimulated by ...
1. sight, smell, taste and chewing
2. emotional states
gastric response during cephalic phase is mediated by ...
parasympathetic (vagus) and sympathetic fibers to plexuses which cause secretion and contraction
Gastric phase -
receptors in STOMACH stimulated by ...
1. distension
2. acidity
3. presence of amino acids
4. presence of peptides
gastric response during gastric phase is mediated by ...
short/long reflexes and release of gastrin
Intestinal phase -
receptors in INTESTINE stimulated by ...
1. distension
2. acidity
3. osmolarity
4. digestive products in the chyme
gastric response during intestinal phase is mediated by ...
short and long reflexes; secretin, CCK and
GIP
the GASTROINTESTINAL TRACT consists of
Mouth
Stomach
Pancreas
Liver
Small Intestine
Large Intestine
pressure of food in the mouth activates what?
mechanoreceptors
chewing is controlled by what?
somatic nerves to skeletal muscles
name the salivary glands;
parotid
submandibular
sublingual
saliva
watery solution of salts and proteins, including mucins and amylase, secreted by salivary glands
which autonomic stimulation influences saliva?
both sympathetic and parasympathetic
name the gland cells secreting in the stomach
parietal cells
chief cells
goblet cells
enterochromaffin-like cells
G cells
parietal cells
gastric gland cell that secretes hydrochloric acid and intrinsic factor
chief cells
gastric gland cells that secrete pepsinogen, precursor of pepsin
goblet cells
secrete mucus
enterochromaffin-like cells
(ECL)
histamine-secreting cell of the stomach
(serotonin?)
G cells
secrete gastrin
pepsinogen --(HCl) -->
pepsin
protein --(pepsin)-->
peptides
protein --(trypsin) -->
peptides
protein --(chymotrypsin)-->
peptides
peptides --(carboxypeptidases) -->
amino acids
pepsin
family of several protein-digesting enzymes formed in the stomach; breaks protein down to peptide fragments
pepsinogen
inactive precursor of pepsin; secreted by chief cells of gastric mucosa
chymotrypsin
enzyme secreted by exocrine pancreas; breaks certain peptide bonds in proteins and polypeptides
trypsin
enzyme secreted into small intestine by exocrine pancreas as precursor trypsinogen; breaks certain peptide bonds in proteins and polypeptides
serotonin=
vasoconstrictor
histamine =
vasodialator
gastric juice =
HCl + pepsin
HCO3-
bicarbonate
amylase
enzyme that partially breaks down polysaccharides
ribonuclease
enzyme that breaks down RNA
deoxyribonuclease
enzyme that breaks down DNA
exocrine portion of pancreas secretes
HCO3-
trypsin
chymotrypsin
carboxypeptidase
lipase
amylase
ribonuclease
deoxyribonuclease
pancreatic enzymes secreted in inactive form then activated in ...
duodenum by proteolytic enzyme enterokinase
proteolytic
breaks down protein
pancreatic secretion increases during ...
a meal
secretin stimulates
HCO3- secretion
CCK stimulates
secretion of digestive enzymes
largest gland in the body
liver
functions of liver
1. metabolize hormones
2. secrete angiotensin
3. produce clotting factors
4. synthesize albumin
5. convert glucose to glycogen
6. convert amino acids to fatty acids
7. produce urea/uric acid
8. synthesize cholesterol
9. detoxify blood
10. secrete bilirubin/bile pigments
11. produce bile
angiotensin I
small polypeptide generated in plasma by renin's action on angiotensinogen
angiotensin II
hormone formed by action of angiotensin-converting enzyme on angiotensin I; stimulates aldosterone secretion from adrenal cortex, vascular smooth-muscle contraction, and thirst
angiotensin-converting enzyme
(ACE)
enzyme on capillary endothelial cells that catalyzes removal of two amino acids from angiotensin I to form angiotensin II
angiotensinogen
plasma protein precursor of angiotensin I; produced by liver
renin
(REE-nin)
peptide hormone secreted by kidneys; acts as an enzyme that catalyzes splitting off of angiotensin I from angiotensinogen in plasma
bile is secreted by
the liver
what does the gall bladder do?
stores and concentrates bile
what are the components of bile?
1. bile salts
2. cholesterol
3. lecithin
4. bicarbonate
5. bile pigments
6. trace metals
name the parts of the small intestine
duodenum
jejunum
ileum
net absorption of chyme and water happens where?
small intestine
brush border
small projections (microvilli) of epithelial cells covering the villi of the small intestine; major absorptive surface of the small intestine
name the brush border enzymes
1. sucrase
2. maltase
3. lactase
4. aminopeptidase
5. enterokinase
6. alkaline phosphatase
sucrase
enzyme involved in the hydrolysis of sucrose to fructose and glucose
maltase
one enzyme produced by the cells lining the small intestine to break down disaccharides. It comes under the enzyme category carbohydrase (which is a subcategory of hydrolase), and the disaccharide it hydrolyses is maltose
lactase
small intestine enzyme that breaks down lactose (milk sugar) into glucose and galactose
enterokinase
enzyme in luminal plasma membrane of intestinal epithelial cells; converts pancreatic trypsinogen to trypsin
alkaline phosphatase
a hydrolase enzyme responsible for removing phosphate groups in the 5- and 3- positions from many types of molecules, including nucleotides, proteins, and alkaloids. The process of removing the phosphate group is called dephosphorylation. As the name suggests, alkaline phosphatases are most effective in an alkaline environment
name the parts of the large intestine
1. cecum
2. colon
3. rectum
4. anal canal
5. anus
what is the name of the little thingie attached to the cecum?
(appendix)
name the parts of the colon
1. ascending
2. transverse
3. descending
4. sigmoid
surface area of large intestine
less than small intestine
what does the large intestine actively absorb?
Na+ and K+ ions and water
what does the large intestine absorb other than ions and water?
vitamins synthesized by bacteria
what does the large intestine lack?
digestive enzymes
what does the large intestine secrete?
mucus
what does the large intestine do?
stores and concentrates fecal material
what are the functional states of organic metabolism?
absorptive state and
postabsorptive state
absorptive state
ingested materials entering blood from GI tract
postabsorptive state
GI tract empty and energy must be derived from body stores
absorptive state:
what specifically enters blood?
glucose, amino acids and triacylglycerol
ABSORPTIVE STATE:
glucose absorbed...
1. by liver for storage or conversion to VLDL which enter the circulation and are carried to adipose tissue for storage
2. by body cells and catabolized for energy
3. by skeletal muscle for catabolism and stored as glycogen
4. by adipose tissue for catabolism (but most transformed to triacylglycerols and stored)
ABSORPTIVE STATE:
amino acids absorbed...
1. by liver for protein synthesis or converted to keto acids
2. by muscle for protein synthesis
3. by liver and converted to fatty acids
4. by body cells for protein synthesis
ABSORPTIVE STATE:
triacylglycerols absorbed ...
1. as fatty acids (released from chylomicrons) which leave the blood and enter adipose tissue (in fat cells reassembled into triacylglycerols and stored)
POSTABSORPTIVE STATE:
what must be done?
plasma glucose concentration must be maintained
POSTABSORPTIVE STATE:
how is plasma glucose concentrations maintained?
1. increase sources of glucose
2. glucose sparing occurs
POSTABSORPTIVE STATE:
what stops and starts?
1. net synthesis ceases
2. net catabolism begins
POSTABSORPTIVE STATE:
sources of glucose
1. glycogenolysis in liver
2. glycogenolysis in muscle
3. catabolism of triacylglycerols
4. catabolism of protein in muscle and other tissue
POSTABSORPTIVE STATE:
glucose sparing -- what do most organs do?
most organs greatly reduce their glucose catabolism (sparing glucose for the nervous system)
POSTABSORPTIVE STATE:
glucose sparing
1. glycogen, fat and protein synthesis is curtailed
2. gluconeogenesis by liver and kidneys
3. glycogenolysis
4. lipolysis
5. NS still uses glucose
Hormones involved in control of metabolism
1. Insulin
2. glucagon
3. epinephrine
4. cortisol
5. Growth Hormone
where is Insulin made?
beta cells in the islets of langerhans (in the pancreas)
what is the most important hormone controller of metabolism
insulin
what does insulin do to plasma glucose?
lowers plasma concentration of glucose
insulin causes ...
1. increased target cell membrane's capacity to transport glucose and amino acids into cells
2. increased activity of enzymes for glycogen synthesis
3. inhibition of enzyme of glycogen catabolism
where is glucagon made?
alpha cells and lining of GI tract
(alpha cells of pancreatic islets of Langerhans
what does glucagon do to plasma glucose?
(opposite effect of insulin)
increases plasma concentrations of glucose, fatty acids, glycerol and ketones
glucagon causes ...
1. increased glycogen breakdown in liver
2. increased lipolysis
3. increased gluconeogenesis by liver
4. synthesis of ketones by liver
HORMONAL CONTROL OF METABOLISM:
What secretes epinephrine?
epinephrine is secreted by the adrenal medulla
HORMONAL CONTROL OF METABOLISM:
What controlls the release of epinephrine?
release controlled by sympathetic preganglionic fibers in adrenal medulla
HORMONAL CONTROL OF METABOLISM:
Epinephrine causes ...
1. inhibition of insulin
2. stimulation of glucagon
3. glycogenolysis
4. gluconeogenesis
5. lipolysis
6. inhibition of glucose uptake by skeletal muscle
HORMONAL CONTROL OF METABOLISM:
Cortisol is a ...
glucocorticoid produced by adrenal cortex
HORMONAL CONTROL OF METABOLISM:
Cortisol's presence in small levels maintains ...
presence in small levels maintains required enzyme levels for gluconeogenesis and lipolysis
HORMONAL CONTROL OF METABOLISM:
Cortisol during stress ...
during stress can oppose insulin
HORMONAL CONTROL OF METABOLISM:
Growth Hormone stimulates ...
stimulates growth and protein anabolism
HORMONAL CONTROL OF METABOLISM:
Growth hormone effects are like ...
effects like cortisol (opposite insulin)
HORMONAL CONTROL OF METABOLISM:
Growth hormone causes ...
1. stimulates lipolysis
2. increases liver gluconeogenesis
3. decreases glucose uptake in peripheral tissues
Kidneys and regulation of water -
regulation of the extracellular (plasma/tissue fluid) environment
1. regulate the volume of blood plasma
2. regulate the concentration of waste products in the blood
3. regulate the concentration of electrolytes
Kidneys and regulation of water -
system consists of:
* kidney
* ureters
* urinary bladder
* urethra
Functional unit of kidney:
nephron
nephron conmposed of:
1. renal corpuscle
2. tubule
renal corpuscle composed of:
glomerulus
bowman's capsule
name the two types of nephrons
juxtamedullary
cortical
juxtamedullary nephrons:
where do they originate?
originate in inner 1/3 of cortex
cortical nephrons:
where do they originate?
originate in outer 2/3 of cortex
juxtamedullary nephrons:
describe their loops
longer loops
cortical nephrons:
describe their loops
shorter loops
glomerular capillaries have large pores called
fenestrae
bowman's capsules have slits called
filtration slits
what does not filter?
protein, RBC, WBC
water and solutes pass from
plasma into glomerulus to capsule and into lumen of tubule
filtrate passes thru fenestra and then
a basement membrane and a layer of cells called podocytes
podocyte
epithelial cells lining bowman's capsule, whose foot processes form filtration slits
filtered molecules pass thru slits between cytoplasmic extensions on podocytes called
pedicels
fluid entering caplsule from glomerulus is called
ultrafiltrate
what is glomerular filtration rate measuring?
volume of filtrate produced by both kidneys per minute
what percentage of plasma volume flowing into renal artery is filtered ?
20% of plasma volume that flows into renal artery is filtered
what is the term to describe the 20% plasma volume that flows into renal artery that is filtered?
filtered fraction
if the kidney receives 1580 L / day, and the hematocrit is 45%, what is the renal plasma flow?
renal plasma flow = 870 L/day
if the kidney receives 1580 L / day, and the hematocrit is 45%, what is the filtered fraction?
174 L/ day
if the kidney receives 1580 L / day, and the hematocrit is 45%, what is the hourly amount filtered?
7.25 L/hr
What is the typical hydrostatic force in glomerular capillaries?
45 mmHg
What is the typical hydrostatic force in capsule?
10 mmHg
if your glomerular capillaries hydrostatic force is 45 mmHg, and your capsule hydrostatic force is 10 mmHg, what is the net hydrostatic driving force?
35 mHg OUT
what is the osmotic pressure in clomerular capillaries from?
negative charged proteins that don't filter
What is the typical osmotic pressure in the glomerular capillaries
25 mmHg
What is the typical osmotic pressure in the capsule
0 mmHg
if your glomerular capillaries osmotic pressure is 25 mmHg, and your capsule osmotic pressure is 0 mmHg, what is the net osmotic pressure?
25 mmHg IN
If you Hydrostatic pressure is 35 mmHg OUT, and your osmotic pressure is 25 mmHg IN, what is your net filtration force?
10 mmHg net filtration OUT
Alterations in filtration rate occur when:
1. filtration increases when glomerular hydrostatic capillary pressure rises
2. filtration increases when osmotic pressure is reduced in glomerulus
3. filtration decreases if hydrostatic pressure in capsule rises (ureters occluded)
4. filtration increases if proteins escape into capsule
5. filtration decreases when sypathetic stimulation causes afferent arteriolar constriction
What can cause glomerular hydrostatic capillary pressure to rise?
* due to afferent arteriole dilation
* due to efferent arteriole constriction
what happens to filtration when glomerular hydrostatic capillary pressure rises?
filtration increases when glomerular hydrostatic capillary pressure rises
what happens to filtration when osmotic pressure is reduced in glomerulus?
filtration increases when osmotic pressure is reduced in glomerulus
what happens to filtration if hydrostatic pressure in capsule rises, and what can cause this?
filtration decreases if hydrostatic pressure in capsule rises (ureters occluded)
What happens to filtration if proteins escape into capsule?
filtration increases if proteins escape into capsule

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