231 Physiology Term 2 - End of LO4, LO5 and 5 diseases Flashcards
1
Q
Where does most absorption and digestion take place?
A
small intestine
2
Q
What is the path of absorption for glucose and galactose?
A
Via cotransport with Na+
3
Q
Where is aminopeptidase produced?
A
Small intestine from brush border
4
Q
List the enzymes (in correct order) needed to break down glycogen.
A
Salivary amylase, Pancreatic amylase, dextrinase and glucoamylase, maltase
5
Q
After proteins are broken down into amino acids what process is used to absorb them into the cells of the small intestine?
A
cotransport with sodium
6
Q
Does the absorption of amino acids (and sodium) into the cells of the intestine wall require additional energy?
A
No, sodium spontaneously diffuse from high to low concentration transporting the amino acid for free
7
Q
Is the movement of sodium and amino acids from the intracellular fluid, across the cell wall, into the blood, energetically a free process?
A
No. Although the amino acids do not require energy as they are moving from a high to low concentration the sodium potassium pump is required to move the sodium and this does require energy.
8
Q
In terms of enzymes it is quite easy to break lipids down. Why is it difficult to digest them?
A
Because they are hydrophobic
9
Q
What are the two roles of bile in lipid digestion?
A
Emulsification and micelle formation
10
Q
Where do we get most of the protein digesting enzymes from in the small intestine?
A
From the pancreas.
11
Q
True or false: The small intestine produces enzymes to breakdown lipids.
A
False. Enzymes in the small intestine that breakdown lipids come from the pancreas.
12
Q
What groups of enzymes does the small intestine produce that attack nucleic acids?
A
Nucleosidases- Phosphatases
13
Q
What activates trypsinogen and where is it produced?
A
Membrane-bound enteropeptidase activates trypsinogen and it is produced in the brush border of the small intestine.
14
Q
Define bile salts.
A
Primarily salts of cholic and chenodeoxycholic acids, are cholesterol derivatives. They play a crucial role in both the digestion and absorption of fats
15
Q
Define emulsification.
A
Bile salts in the duodenum break large fat globules into smaller fat droplets, increasing the surface area available to lipase enzymes. The non-charged side of bile salts will coat the smaller globules of fat so they can’t stick back together. Lipase then attacks.
16
Q
List the functions of the kidney.
A
- Regulating the total volume of water in the body and the total concentration of solutes in that water (osmolality).
- Regulating the concentrations of the various ions in the extracellular fluids. (Even relatively small changes in some ion concentrations such as K+ can be fatal.)
- Ensuring long-term acid-base balance.
- Excreting metabolic wastes and foreign substances such as drugs or toxins.
- Producing erythropoietin and renin, important molecules for regulating red blood cell production and blood pressure, respectively.
- Converting vitamin D to its active form.
- Carrying out gluconeogenesis during prolonged fasting .
17
Q
What are the main risk factors of emphysema?
A
- Smoking is the major risk factor
- You can also have hereditary factors; gene defective in producing alpha 1 antitrypsine proteins
- Sometimes it is heavily linked to occupations such as welding and mining
18
Q
What are the three key processes of the kidney?
A
- filtration
- secretion
- reabsorption
19
Q
Which substances in the blood should not be filtered?
A
proteins, red blood cells and white blood cells
20
Q
Describe the process of filtration.
A
- It is basically a passive process where substances are moved across the pressure gradient, so they are going from high pressure to low pressure
- The high pressure is caused by the blood pressure and the surrounding glomerular capsule is a fairly low pressure
- Most substances are able to be filtered and this includes things that we would like to keep, including glucose, amino acids, sodium, water
- But substances that shouldn’t be filtered are large substances such as proteins and then your red and your white blood cells
- Once you have formed the filtrate and it has entered the glomerular capsule, then the urine is going to travel through the rest of the nephron
21
Q
Define secretion.
A
Movement of substances from the surrounding capillaries, the blood, back into the urine.
22
Q
Define tubular reabsorption.
A
Movement of substances from the urine into the surrounding capillaries.
23
Q
Why might you suffer from respiratory alkalosis?
A
Hyperventillation due to stress and pain
24
Q
How and where in the kidneys help solve respiratory alkalosis?
A
Reabsorb hydrogen ions in the collecting duct and secrete bicarbonate ions in the collecting duct
25
What are 3 main hormones that have effect in the kidneys?
- aldosterone
- ADH
- ANP
26
At what stage is the fluid considered urine?
Once it has been filtered in the glomerulus and passed into the proximal convoluted tubule.
27
When sodium ions are reabsorbed in the proximal convoluted tubule, what can they transport with them?
amino acids and glucose
28
Which hormones have an important effect in the collecting duct?
ADH, Aldosterone and ANP
29
When would we want to produce aldosterone?
To reabsorb sodium if you have low blood pressure -water will follow by osmosis. Or to secrete potassium
30
List several substances that are secreted into the kidney tubules.
H+, K+, NH4 +, creatinine, urea, and uric acid are all substances that are secreted into the kidney tubules.
31
Why might you suffer from respiratory alkalosis?
Hyperventilation due to stress and pain
32
How and where in the kidneys help solve the problem of respiratory alkalosis?
Reabsorb hydrogen ions in the collecting duct and secrete bicarbonate ions in the collecting duct primarily (according to Sally, very little secretion of bicarb happens in the PCT)
33
In addition to enzymes, what other pancreatic secretion is important?
Pancreas squirts a lot of bicarb ions; purpose if to reduce the acidity from the stomach
34
Why are protein digesting enzymes inactive most of the time?
So when there is no food, they don't digest your tissues.
35
What will trypsin, chymotrypsin and carboxypeptidase do to proteins?
Trypsin and chymotrypsin are going to break down polypeptide into much shorter chains. Carboxypeptidase will then break down smaller polypeptides into amino acids.
36
From what end of the amino acid will carboxypeptidase chop?
the carboxylic acid end
37
What do you need to deal with hydrophobic fats?
bile salts from the liver
38
Where do bile salts get secreted into?
duodenum
39
What percentage of bile salts are reabsorbed by the ileum?
95%
40
What kind of energy do you need for co-transport?
kinetic energy
41
For carbohydrates, is there an exception in terms of path of absorption from happening via cotransport with sodium?
Yes, fructose passes via facilitated transport. Glucose and galactose both use cotransport with sodium.
42
What is the path of absorption for proteins?
Amino acids are absorbed via cotransport with sodium.
43
What is the path of absorption for fats?
1) fatty acids and monoglycerides enter the intestinal cells via diffusion
2) fatty acids and monoglycerides are recombined with other lipids and proteins within the cells. The resulting chylomicrons are extruded via exocytosis.
3) The chylomicrons enter the lacteals of the villi and are transported to the systemic circulation via the lymph in the thoracic duct.
44
What is the path of absorption for nucleic acids?
- units enter intestinal cells by active transport via membrane carriers
- units are absorbed into capillary blood in the villi and transported to the liver via the hepatic portal vein.
45
What is the importance of the liver to digestion?
Producing bile for fat emulsification
46
What is enterohepatic circulation?
a recycling mechanism for bile salts
47
What is the role of the gallbladder?
stores bile that is not immediately needed for digestion
48
What is the role of the digestive tract in terms of vitamin, electrolyte, and water absorption?
- small intestine absorbs dietary vitamins
- large intestine absorbs K + B vitamins that are created by helpful microflora
- fat soluble vitamins (A, D, E, K) dissolve in dietary fats and become incorporated into the micelles, which move by diffusion
- most ions are actively absorbed along the entire length of the small intestine, but iron and calcium largely in the duodenum
49
What is the role of the large intestine in the digestive process?
- absorb most of the remaining water from indigestible food residues
- store the residues temporarily
- eliminate as stool
50
What are 3 symptoms of asthma?
- shortness of breath
- coughing
- wheezing
51
What is the function of the loop of Henle?
It creates a concentration gradient between in the interstitial fluid so that water can be reabsorbed as urine passes down the collecting duct
52
What are the main functions of the kidney?
- Regulating the total volume of water in the body and the total concentration of solutes in that water (osmolality)
- Regulating the concentrations of the various ions in the extracellular fluids. (Even relatively small changes in some ion concentrations such as K+ can be fatal.)
- Ensuring long-term acid-base balance
- Excreting metabolic wastes and foreign substances such as drugs or toxins
- Producing erythropoietin and renin, important molecules for regulating red blood cell production and blood pressure, respectively
- Converting vitamin D to its active form
- Carrying out gluconeogenesis during prolonged fasting
53
How do substances move out of the PCT cell, such as glucose and amino acids?
Via facilitate diffusion
54
In the PCT, what things do you need in order to be able to move water?
- concentration gradient
| - aquaporins
55
True or false. In the PCT, movement of water is dependent upon hormones.
False. In the PCT, movement of water is independent of hormones.
56
How is urea reabsorbed? Do we want to? How much do we get rid of?
- reabsorbed via simple diffusion
- no, we don't want to as it is a waste product
- we get rid of 50%, which is enough
57
What substances are being secreted at the PCT? Which one is most important and why?
- hydrogen ions, ammonia, and some drugs
| - hydrogen ions are the most important due to their role in regulating acid-base balance
58
What substances are being reabsorbed in the PCT?
- NA+
- nutrients
- ions
- HCO3-
- H2O
- lipid soluble solutes
- urea
59
When looking at the numbers in the Loop of Henle, what are the numbers?
measures of concentrations
60
What feature of the proximal convoluted tubule increases its surface area for reabsorption?
microvilli
61
Does the concentration of urine increase or decrease in the ascending limb of the Loop of Henle?
concentration of urine decreases as it ascends the ascending limb
62
What is the maximum concentration of urine?
1200
63
How do substances move out of the PCT cell, such as glucose and amino acids?
Via facilitate diffusion
64
In the PCT, what things do you need in order to be able to move water?
- concentration gradient
| - aquaporins
65
What kind of tissue makes up the ascending limb of the Loop of Henle?
simple cuboidal or simple columnar
66
What are two really important features of the ascending limb of the loop of Henle?
1) impermeable to water
2) covered in active transport pumps and pumps sodium, chloride and potassium ions from the urine into the interstitial fluid
67
What are characteristics of the descending limb of the Loop of Henle?
- covered in aquaporins; not dependent on hormones for aquaporins
- permeable to water
- lacking active transport pumps
- going to move water out from the urine to the interstitial fluid
68
What substances are being secretes at the PCT? Which one is most important and why?
- hydrogen ions, ammonia, and some drugs
| - hydrogen ions are the most important due to their role in regulating acid-base balance
69
What substances are being reabsorbed in the PCT?
- NA+
- nutrients
- ions
- HCO3-
- H2O
- lipid soluble solutes
- urea
70
When looking at the numbers in the Loop of Henle, what are the numbers?
measures of concentrations
71
Does the concentration of urine increase or decrease in the descending limb of the Loop of Henle?
concentration of urine increases
72
Does the concentration of urine increase or decrease in the ascending limb of the Loop of Henle?
concentration of urine decreases as it ascends the ascending limb
73
What is the maximum concentration of urine?
1200
74
How is the flow of urine in the Loop of Henle described?
countercurrent flow
75
What kind of tissue makes up the descending limb of the Loop of Henle?
simple squamous
76
What kind of tissue makes up the ascending limb of the Loop of Henle?
simple cuboidal or simple columnar
77
What are two really important features of the ascending limb of the loop of Henle?
1) impermeable to water
| 2) covered in active transport pumps and pumps sodium and chloride from the urine into the interstitial fluid
78
What are characteristics of the descending limb of the Loop of Henle?
- covered in aquaporins; not dependent on hormones for aquaporins
- permeable to water
- lacking active transport pumps
79
In the PCT, what mechanism is used to reabsorb sodium ions?
- primary active transport via basolateral Na-K pump; crosses apical membrane through channels
80
In the PCT, what mechanism is used to reabsorb glucose, amino acids, vitamins, some ions)?
Secondary active transport with Na+ (co-transport)
81
In the PCT, what mechanism is used to reabsorb water?
osmosis
82
In the PCT, what mechanism is used to reabsorb lipid-soluble solutes?
passive diffusion driven by the concentration gradient created by the reabsorption of water.
83
In the PCT, what mechanism is used to reabsorb urea?
primarily passive paracellular diffusion driven by chemical gradient.
84
What is weird about the active transport pumps in the ascending limb of the Loop of Henle?
They pump three ions: sodium, chloride and potassium
85
What is the concentration of urine when it enters the loop of Henle?
300
86
What concentration characteristic happens in the descending limb of the Loop of Henle when you can no longer move any water?
The concentration in and out are the same.
87
True or false. The concentration in the interstitial fluid is the same as the concentration in the descending limb.
True
88
What is the purpose of the vasa recta in the kidney?
To preserve the concentration gradient in the Loop of Henle.
89
What contributes to the preservation of the concentration gradient in the Loop of Henle?
- the vasa recta
| - blood vessel that loop around the Loop of Henle and also has a concentration gradient (countercurrent loop)
90
What substances get reabsorbed in the Loop of Henle?
- sodium, chloride and potassium
- water
- calcium and magnesium
91
How do the kidneys regulate urine concentration and volume?
They use the counter current mechanism in the Loop of Henle to create a concentration gradient, which will allow the body to control its urine concentration and volume.
92
What do you need hormones for in the nephron?
To create aquaporins to put in the cell membrane to reabsorb water.
93
What would be the difference between the anatomy of a kangaroo rat and a human in terms of the nephron if you knew the maximum concentration of their urine was 5000 instead of 1200 like humans?
Their Loops of Henle would be much longer.
94
If you want to reabsorb calcium in the DCT, what hormone do you need?
parathyroid hormone
95
True or false. Hormones have an effect on the DCT and the collecting duct.
True
96
What is the main substance secreted in the DCT?
potassium
97
What hormone is required to secrete potassium in the DCT?
aldosterone
98
Why doesn't the concentration gradient get all mixed up in the Loop of Henle?
Because of the vasa recta that surrounds it. It is a blood vessel that also has a counter current mechanism and this helps to preserve the concentration gradient.
99
Why is the concentration gradient in the collecting duct so important?
So we can absorb as much or as little water as we need in the collecting duct.
100
What 2 things can happen to make the blood in the vasa recta the same as the interstitial fluid as the concentration in the interstitial fluid changes?
1) Could move sodium and chloride ions into the blood
2) move water out
(this reflects near the descending limb; opposite near the ascending limb)
101
What two proteins does aldosterone enable to be created?
sodium channel proteins and sodium-potassium pumps
102
What process is required to create aldosterone (briefly)
renin-angiotensin- aldosterone complex
103
Why is calcium reabsorption so important?
- Needed for skeletal and cardiac muscle contraction
- Needed for the secretion of hormones and enzymes
- Needed for action potentials in the heart
- Needed for releasing neurotransmitters
104
What is arguably the most important ion?
potassium. Should have this in high concentration in your cells.
105
What is one of the most important functions in the DCT?
Secreting potassium ions.
106
What hormone controls the secretion of potassium in the DCT?
aldosterone
107
True or false, High concentrations of potassium in the blood will directly trigger the adrenal glands to produce aldosterone. The renin-angiotensin-aldosterone complex is not required.
True
108
What is the typical concentration of urine at the DCT and the collecting duct?
300
109
In the collecting duct, which substances will be reabsorbed if needed?
- sodium (requires aldosterone)
| - water; one of the most important places (required ADH)
110
Where does most sodium reabsorption happen?
DCT and collecting duct (both require hormone aldosterone)
111
What hormone is required to reabsorb water in the collecting duct?
ADH
112
The collecting duct is impermeable to water unless you have which hormone? What does the hormone do?
ADH. ADH sticks aquaporins in the membrane of the collecting duct.
113
Even if you have aquaporins in your membrane due to the ADH, what else do you need to have in place to move water?
concentration gradient in the interstitial fluid
114
Why do we need ADH in the collecting duct and not the PCT?
- due to membrane structure
- the PCT always has aquaporins
- collecting duct needs ADH to create aquaporins
115
If you have too much sodium in the interstitial fluid at the DCT or the collecting duct, what do you need?
ANP; it will enable you to secrete sodium
116
True or false. You can secrete potassium at the collecting duct.
True
117
Are lungs or kidneys faster at regulating acid-base balance?
lungs (can only deal with metabolic acid base problems)
118
What kinds of acid-base problems do the kidneys help with?
Both metabolic and respiratory
119
In respiratory acidosis, which way is the equation being driven?
CO2 + H2O ----> H2CO3 ------> HCO3- + H+
Causing me to produce too many hydrogen ions
120
How many more bicarb ions are there in mammals than hydrogen ions?
600,000 times more
121
Why might you have respiratory acidosis?
- not able to breathe off CO2 like we should
- pneumonia, severe bronchitis, emphysema (anything that will trap CO2 in the lungs)
- lungs are malfunctioning
122
What can the kidney do to help with respiratory acidosis?
1) secrete more hydrogen into the urine
| 2) reabsorb more bicarb
123
Where does the kidney secrete more hydrogen or reabsorb more bicarb when trying to resolve respiratory acidosis?
PCT and collecting duct (secreting hydrogen)
| PCT and collecting duct (reabsorb bicarb)
124
How long will it take for the kidneys to help resolve respiratory acid-base balance problems?
hours to 24 hours to sort the problem out
125
In respiratory alkalosis, which way is the equation being driven?
HCO3- + H+ -------> H2CO3 ----------> CO2 + H20
126
How does the kidney help resolve respiratory alkalosis?
1) reabsorb more hydrogen in collecting duct
| 2) secrete more bicarb in collecting ducts
127
What are the functions of the liver?
The liver regulates most chemical levels in the blood and excretes a product called bile. This helps carry away waste products from the liver. All the blood leaving the stomach and intestines passes through the liver. The liver processes this blood and breaks down, balances, and creates the nutrients and also metabolizes drugs into forms that are easier to use for the rest of the body or that are nontoxic.
The primary functions of the liver are:
Bile production and excretion.
Excretion of bilirubin, cholesterol, hormones, and drugs.
Metabolism of fats, proteins, and carbohydrates.
Enzyme activation.
Storage of glycogen, vitamins, and minerals.
Synthesis of plasma proteins, such as albumin, and clotting factors.
128
List the enzymes and other main substances secreted by the pancreas.
- trypsinogen
- chymotrypsinogen
- procarboxypeptidase
- lipase
- amylase
- bicarb
- ribonuclease
- deoxyribonuclease
129
What does lipase do to triglycerides?
Chops off two fatty acids which leaves two free fatty acids and a monoglyceride (glycerol + fatty acid)
130
Is the process for absorbing glucose and galactose considered active or passive?
Active. B/c you need ATP to get sodium out of the cell that was used for co-transport.
131
Is the process for absorbing fructose considered active or passive?
Passive. Does not use co-transport; can get in and out using facilitated diffusion.
132
Is the process for absorbing amino acids considered active or passive?
Active. Use co-transport and need ATP to get the sodium out of the cell.
133
Is the process for absorbing the individual elements of a nucleotide (phosphate, sugar, base) considered active or passive?
Active. In via active processes, out via diffusion.
134
List in correct order the enzymes required for protein breakdown.
- pepsin (stomach)
- membrane bound enteropeptidase
- trypsinogen - converted to trypsin (by the enteropeptidase)
- chymotrypsinogen --> converted to chymotrypsin
- procarboxypeptidase --> converted to carboxypeptidase
- aminopeptidase
135
True or false. Bicarb is reabsorbed in the PCT.
True
