Lab Exam 4 Flashcards
What are the 8 structures of the GI tract?
mouth
pharynx
esophagus
stomach
duodenum
small intestine
colon
rectum
What are the 6 digestive accessory structures?
teeth
tongue
salivary glands
liver
gall bladder
pancreas
Define ingestion
the process of taking in macronutrients
Where is ingestion accomplished?
in the mouth
Define mastication
chewing
Where is mastication accomplished?
in the mouth
Define deglutition
swallowing
What is the path of deglutition?
mouth to pharynx to esophagus
Define digestion
macromolecules in nutrients are broken down into smaller molecules by enzymatic action
Define absorption
movement of a substance from the lumen to the blood by transport across an epithelium
Define defecation
elimination of waste material following digestion
What enzyme type is most involved in digestion?
hydrolase
Define mechanical digestion
the breakdown of macromolecules into smaller particles to enhance the capabilities of chemical digestion
3 examples of mechanical digestion
chewing in the mouth
churning in the stomach
segmentation in the small intestine
Define chemical digestion
enzyme secretion in the digestive tract causes the breakage of chemical bonds
What enzyme breaks down carbohydrates (starches)?
salivary & pancreatic amylase
What enzyme breaks down proteins?
peptidase
What enzyme breaks down lipids?
lipase
What is the optimum temperature for salivary amylase & starch digestion?
37°C
What is the optimum pH for salivary amylase & starch digestion?
7.0
How does heat affect digestive enzymes?
heat denatures them
How does freezing affect digestive enzymes?
it has no effect
Where does carbohydrate digestion begin?
in the mouth with mastication & the release of salivary amylase from the salivary glands
Amylase breaks down carbohydrates into what?
maltose (sugar)
When you increase amylase activity what results?
increase sugar (maltose)
decrease starch
Pancreatic amylase continues carbohydrate digestion where?
in the small intestine
Reagent IKI detects the presence of what?
starch
When starch is present in a solution, what color does IKI turn?
turns from caramel-colored to BLACK
Benedicts reagent detects the presence of what?
sugars (broken down starch)
With an increasing concentration of maltose (simple sugar), what color does Benedicts reagent turn?
turns from blue to green to orange to red-brown
How does pH affect enzymes?
pH can inhibit enzyme activity when it is lower or higher than optimum
What cells in the stomach release pepsin?
chief cells
What is BAPNA?
a synthetic peptide
In the presence of an active peptidase (or pepsin) what color does a BAPNA solution turn?
turns from colorless to yellow
What does the enzyme lipase do?
catalyzes the break down of triglycerides
What do bile salts do?
break down large lipid globules into smaller lipid globules (emulsification)
increases surface area for lipase enzymes to work
What is the optimal pH for lipase?
7.0
What is the optimal pH for peptidase?
2.0
How does lipid digestion look for a patient with no gallbladder?
the stomach produces bile so they would still be able to digest lipids but that activity would decrease so they would have to monitor their fat intake
Can BAPNA test be used to determine the concentration of a given protein?
no as BAPNA only measures enzyme activity
Define filtration
the movement of fluid across capillary walls of the glomerulus into bowmans capsule
GLOMERULUS to BOWMANS CAPSULE
Define reabsorption
the movement of filtered solutes from the renal tubules into the plasma
RENAL TUBULES to PLASMA
Define secretion
the movement of solutes from the plasma into the renal tubules
PLASMA to RENAL TUBULES
Define excretion
elimination of waste from the body
What 3 layers must a filtrate cross in order to reach the bowmans capsule?
capillary endothelial layer
basement membrane
bowmans capsule epithelial layer
Why is the renal corpuscle favorable to bulk flow of fluid?
fenestrations
large number of slit pores
large surface area
What is the average plasma flow rate per min?
625 ml/min
What is the average glomerular filtration rate (GFR) per min?
125 ml/min
What is the average glomerular filtration rate (GFR) per day?
180 L/day
Which 2 pressures FAVOR filtration?
glomerular capillary hydrostatic pressure (Pgc)
bowmans capsule osmotic pressure (piBC)
Which 2 pressures OPPOSE filtration?
bowmans capsule hydrostatic pressure (Pbc)
glomerular osmotic pressure (piGC)
What is the average glomerular capillary hydrostatic pressure (favors filtration)?
60 mmHg
What is the average bowmans capsule hydrostatic pressure (opposes filtration)?
15 mmHg
What is the average glomerular osmotic pressure (opposes filtration)?
29 mmHg
What is the average bowmans capsule osmotic pressure (factors filtration)?
0 mmHg
How does glomerular capillary hydrostatic pressure favor filtration?
the pressure pushes water & solutes in plasma through the glomerular filter
How does glomerular osmotic pressure oppose filtration?
presence of proteins in the plasma draws filtrate back into the glomerulus
How does bowmans capsule osmotic pressure favor filtration?
presence of proteins in the interstitial fluid draws fluid from capillaries into the capsule
How does decreasing afferent radius affect GFR?
decreases glomerular pressure
decreases GFR
decreases urine volume
How does decreasing efferent radius affect GFR?
increase glomerular pressure
increase GFR
increase urine volume
How does increasing afferent radius affect GFR?
increase glomerular pressure
increase GFR
How does increasing efferent radius affect GFR?
decrease glomerular pressure
decrease GFR
How are AFFERENT radius & glomerular pressure, GFR, urine volume related?
directly related
How are EFFERENT radius & glomerular pressure, GFR, urine volume related?
indirectly related
Where are glucose carriers located?
in proximal convoluted tubule
(tubule closest to bowman’s capsule)
What allows for glucose reabsorption into the plasma?
glucose carriers
The number of glucose carriers is…
constant
If glucose concentration exceed glucose carriers rate, what will happen?
glucose will be secreted in the urine
(seen in diabetes patients)
What does ADH do?
increase water reabsorption
allows water to be reabsorbed from the collecting duct
Low levels of ADH causes what?
an increase in urine output (water is not being reabsorbed)
What does aldosterone do?
increases Na+, K+ and water reabsorption
How does aldosterone increase Na+, K+ & water reabsorption?
increases the number of Na+ and K+ channels
increases the Na/K pumps on the basolateral membrane
How does ADH increase water reabsorption?
it releases aquaporins onto the apical membrane
What are nephrons?
the filtering units of the kidney
How does an increase in blood pressure affect glomerular pressure & GFR?
increases glomerular pressure & GFR
Increasing which arteriole radius has the greater affect?
afferent
How does a closed valve affect GFR?
decreases GFR & produces NO urine volume
What does a closed valve represent?
an obstruction in the renal tubule
Which hormone (ADH or aldosterone) has a greater effect?
ADH
Can reabsorption of solutes influence water reabsorption?
yes, as water follows solutes using osmosis
an increase in solute reabsorption increases water reabsorption
