Physiology E2- Fitch Flashcards
1
Q
Isoosmotic
A
- Having an osmolarity of normal ECF
- 300 mOsmol/L
- ECF = plasma and interstitial fluid = 300 mOsmol/L
2
Q
Hyperomotic
A
Having an osmolarity more than normal ECF
Greater than 300 mOsmol/L
3
Q
Hypoosmotic
A
Having an osmolarity less than normal ECF
Less than 300 mOsmol/L
4
Q
Kidneys produce a small volume of _______ urine when ADH secretion rate is high
A
Hyperosmotic
Why? ADH removes the water from the urine and puts it back into the body. Therefore, concentrating the urine
5
Q
The osmolarity of urine cannot exceed
A
1300 mOsmol/L
6
Q
What is the obligatory water loss?
A
How much volume of urine that we have to lose a day: 0.46L/day
7
Q
Where are sodium and chloride ions actively being pumped out?
A
Ascending limbs fo the loop of Henle into the interstitial fluid that surrounds the loop
8
Q
T/F the ascending limbs of the loop of Henle are permeable to water
A
False. They are impermeable to water. This allows for the creation of hyperosmotic urine in the medullary
9
Q
T/F the renal medullary interstitial fluid becomes more hyperosmotic as you move deeper into the renal medulla
A
True because of countercurrent multiplication
10
Q
What contains a countercurrent that prevents the washing out of the hyperosmolarity of the interstitial fluid?
A
Vasa recta: The blood supply of the renal medulla
It will take in water and solute, but it will excrete solute as well
11
Q
If blood ADH levels are high,
A
Water diffuses out of the medullary collecting ducts into the renal medullary interstitial fluids (Diffusion because of the hyperosmolartiy)
The water then moves from the interstial fluid into the capillaries of the renal medulla to be carried away by venous blood
12
Q
If ADH levels are low,
A
Because both the cortical and the medullary’s COLLECTING DUCTS are impermeable to water, water is not reabsorbed as the filtrate flows through the CD and a large of HYPO osmotic urine is formed
Water stays in the urine
Osmolarity is less than 300 mOsmol/L
13
Q
Sodium excreted =
A
Sodium filtered - sodium reabsorbed
14
Q
What are the reflex controls of sodium?
A
Baroreceptors in the cardiovascular system and the sensors in the kidneys
15
Q
How does low total body sodium affect:
ECF volume
Plasma volume
Blood Pressure
A
Low total body sodium –> low ECF volume –> Low plasma volume –> low blood pressure
If there is less sodium, then there is less water being reabsorbed
16
Q
Low blood pressure will result in what actions by the kidneys?
A
Control of GFR
(How much sodium is filtered out of the blood)
(Remember that GFR is controlled by pressures)
17
Q
Low blood pressure will result in what actions by the cardiovascular system?
A
Determining the pressure that is needed for filtration in order to control Mean arterial pressure (MAP)
18
Q
What are the three things needed for GFR
A
Blood pressure, osmotic pressure, and interstitial pressure
19
Q
If BP is low, then GFR is
A
low
20
Q
If BP is high, then GFR is
A
high
21
Q
Which is more important in the control of low blood plasma volume?
Constriction of afferent renal arterioles or decreed net glomerular filtration pressure
A
Constriction of afferent renal arterioles
22
Q
Low blood pressure can induce two things in regards to GFR. What are those two things?
A
Decreased net glomerular filtration pressure directly
or
indirectly via increased activity in sympathetic nerves to the kidneys (Leads to constriction of afferent renal arterioles
23
Q
How will decreasing GFR help blood pressure?
A
Decrease in GFR will decrease the amount of sodium and water being excreted. Therefore retaining fluid and plasma volume which will increase BP
24
Q
T/F Controlling sodium reabsorption is more important than controlling filtration
A
True
25
What are the steps of hormonal release of aldosterone?
1. Liver releases Angiotensin
2. Renin from the kidneys will convert Angiotensin into Angiotensin I
3. Angiotensin 1 will flow through the lungs where ACE will convert it into Angiotensin II
4. Angiotensin II wills stimulate the adrenal cortex to secrete aldosterone
5. Aldosterone will make the collecting ducts more permeable to sodium
6. Sodium reabsorption is increased
26
In the absence of aldosterone, where is absorption of sodium occurring?
65% in the proximal tubules
30-32% in the Loop of Henle and the distal tubules
Totaling to 95-97% being reabsorbed without the help of aldosterone
27
What does aldosterone act upon for the reabsorption of sodium?
collecting ducts
28
What are the three inputs that increase renin secretion?
- Sympathetic nerves (activated by baroreceptor reflex will constrict the juxtaglomerular )
- Baroreceptors in the kidneys (Stretch: BP down = less stretch = more renin)
- Paracrine factors from the macula densa (Response from a decreased volume and/or concentration of sodium in the tubular fluid flowing past the manual densa cells)
29
Increase sodium in the body causes water to be _____ due to _____
reabsorbed; osmotic considerations
This water increases the ECF to help regulate arterial blood pressure in the long term
30
What is the mechanism is used to help with long term BP?
Angiotensin --> Aldosterone mechanism
31
What are the effects of angiotensin II?
Will tell the adrenal cortex to secrete aldosterone
Will also act as as vasoconstrictor to increase total peripheral resistance
Increase in Cardiac Output via aldosterone (increase in volume)
32
What is the ANP pathway?
1. High plasma volume will lead to distention of atria in the heart
2. ANP will be released due to the stretch
3. ANP will be placed into the blood as a hormone
4. ANP will act on the kidneys to decrease sodium reabsorption
AND
It will increase GFR by dilating the afferent arteriole and constricting the efferent (increasing pressure)
5. Increase in sodium excretion (Which will lead to lower plasma volume and decreased blood pressure)
33
What is the purpose of ANP
To increase sodium excretion to control cardiac output and blood pressure
Also inhibits the secretion of aldosterone (preventing the reabsorption of sodium)
34
T/F we can change water excretion rates without changing sodium excretion rates
True
35
Compared to sodium, where is water found?
Sodium is mainly found in the ECF, but water is found everhwere
36
T/F Baroreceptors are the main contributor in regulating water excretion
False: Because water is everywhere from interstitial fluids to within our cells, it has little affect on our baroreceptors compared to other mechanics of regulation
37
What are the main receptors that will affect water regulation of the body?
Osmoreceptors in the hypothalamus
They only detect ECF Osmolarity
38
What do osmoreceptors control? Via what?
Water retention
via the posterior pituitary'r release of ADH (vasopressin)
39
What happens to osmoreceptors when there is a decrease in water?
They would shrink and they would increase their frequency
Because mechanical gated ion channels in neurons will open
Which will stimulate the release of ADH by the posterior pituitary
40
What happens to osmoreceptor shine there is excess water?
They swell up and the mechanical gates will close: decreasing the frequency of firing/action potential
Which will decrease the stimulation on the posterior pituitary. Thus, leading to less ADH secretion
41
Name an example in which arterial baroreceptors and cardiovascular baroreceptors are involved in influencing ADH secretion
Hemorrhages
42
What are the three factors needed in order to keep water excretion separate from sodium excretion?
1. A way to detect changes in osmolarity (osmoreceptors)
2. A way to create concentrated urine (countercurrent system and ADH)
3. A way to create dilute urine (Absence of ADH)
43
Congestive Heart Failure:
- A failing heart will have ____
- Which leads to a ____ in BP
- Which leads to an increase in plasma _____
And ____ Sodium excretion
- sodium excretion is also ___ by _____ via hormonal pathway
- Which leads to ____ Water reabsorption/retention
- Excess water will _____
- All of this leads to ______
Congestive Heart Failure:
- A failing heart will have "Reduce Cardiac Output"
- Which leads to a "Decrease" in BP
- Which leads to an increase in plasma "Renin --> Angiotensin II"
And "Decrease" Sodium excretion
- sodium excretion is also "Decreased" by Aldosterone" via hormonal pathway
- Which leads to "Increased" Water reabsorption/retention
- Excess water will "move into interstitial spaces"
- All of this leads to "edema"
44
What is the hormonal component of congestive heart failure?
Because of a decrease in BP, there will be an increase of renin which lead to more angiotensin II for more aldosterone secretion
All of this leads to decrease water excretion and more water retention
45
Is sweat hypo osmotic or hyperosmotic?
Hypoosmotic: You lose more water than you do salt
46
Describe the steps when there is an increase in plasma osmolarity
1. Plasma osmolarity increase = it is saltier
2. Osmoreceptors will shrink
3. Increase in signal for post. pituitary to secrete ADH
4. Increase in ADH
5. Decrease in Water excretion and increase in water retention
47
Describe the steps when there is a decrease in plasma volume
1. Decrease in plasma volume = decrease in plasma sodium and a decrease pressure
2. This will decrease GFR
Increase the renin angiotensin pathway
And increase Plasma ADH
3. This all increases sodium and water retention
***NOTE the main mode of action that this takes is the hormonal path of Renin angiotensin for sodium retention
48
What does excessive sweating do?
Decrease plasma volume and increase plasma osmolarity
| detected by baroreceptors and osmoreceptors respectively
49
What is the most abundant intracellular ion?
Potassium
50
Most of the potassium that is filtered is ____
Reabsorbed
51
Some of the potassium can be ____ by the ______
secreted by the cortical collecting duct and is regulated according to need
52
How is potassium secreted ?
Sodium potassium pump will take the sodium back in while secreting the potassium into the interstitial fluid and moves through diffusion
53
How does aldosterone affect potassium in renal physiology?
It increases potassium secretion
| Makes sense: it increases sodium reabsorption, therefore increases potassium secretion via the sodium potassium pump
54
What are two things that can affect potassium secretion?
Aldosterone and potassium levels
55
Higher than normal potassium in the ECF
Hyperkalemia: Cells can be excited easily
56
Lower than normal potassium in the ECF
Hypokalemia: Cells are less likely to be excited
57
What all is calcium involved in?
```
Cell division
Function of many enzymes
Heart electrical activity
Neurotransmitter secretion
Hormone secretion
Oocyte activation
Removal of inhibition of muscle contraction
Blood clotting
Formation of bones and teeth
```
58
Higher than normal Calcium in the ECF
Hypercalcemia
Depresses nervous system and muscle activity
(Less of a gradient to make an action potential)
59
Lower than normal calcium in the ECF
Hypocalcemia
Causes nervous system excitement and tetany
(Takes very little to get something started because who know when calcium will come by again)
60
Where is calcium found in the body?
0.1% in the ECF
1% in the cell's organelles
98.9% in the bones
61
Of the ECF calcium, where is calcium found and filterable?
50% ionized
9% combined with other ions
41% bound to proteins
Proteins cannot be filtered by the kidneys therefore only 59% of the 0.1% of calcium is filterable
62
How calcium stored in the bones?
As a crystalline salt called hydroxyapatite
| Ca10(PO4)6(OH)2
63
What is the organic matrix of bone?
Collagen fibers plus ground substance
64
Osteoclats will
breakdown down and add calcium and phosphate to the ECF
65
What two things are needed for osteoclasts to be fully activated
PTH and vitamin D
| Low vitamin D = low reabsorption of calcium into the blood
66
What dissolves the organic matrix in bone
proteolytic enzymes from osteoclasts
67
What dissolves the inorganic matrix in bone
acids released from osteoclasts
68
What is the role of osteoblasts
To take calcium out of the blood and add it to bone
69
How does PTH affect osteoclasts?
PTH binds to osteoblasts which then induces an autocrine signal that will allow it to become an osteoclast
70
Calcitonin
Acts mainly on bones to decrease ECF calcium concentrations
| of very litter importance
71
How much of filtered calcium reabsorbed?
99% of it (80% of it is unregulated)
72
What does PTH do on the DT/CD?
Increase Calcium reabsorption
73
How is PTH connected to vitamin D?
PTH will cleave and activate an enzyme that will, in turn, activate the enzyme necessary to make vitamin D (1,25 dihydroxyvitamin D) usable
74
Which vitamin D is dietary and which is made within the body?
Vitamin D2 is dietary
| Vitamin D3 is made from the our skin via UV radiation
75
Where does inactive vitamin D go to be activated?
First modification in the liver, then final activation in the kidneys by PTH
76
What is the 1,25 dihydroxyvitamin D's hormonal abilities?
It is carried by the blood to the intestine where it will increase the absorption of calcium and phosphate from our diets
77
T/F Vitamin D increases PTH activity in osteoblast/clasts
True: Makes them more useful in calcium reabsorption
78
How much calcium in the diet is actually absorbed?
35%
the rest is excreted in the feces
79
T/F all the dietary, reabsorption, and excretion of calcium equals out to 0%
True: Therefore, it is set around a set point
80
What two forms do phosphates exist in?
HPO4 2- and P2PO4-
81
Where can phosphates be found in our bodies?
Bone matrix, Buffer system, ATP, ADP, cAMP, GTP, cGMP, DNA, RNA, and proteins
82
How much of plasma phosphate is filterable?
50%
83
Where are phosphates reabsorbed?
Proximal tubules
84
What is the role of PTH in the reabsorption of phosphate
it decreases it
| it increases calcium
85
What is the pathway of digestion?
```
Mouth
pharynx
esophagus
stomach
small intestine
large intestine anus
```
86
What is the purpose of accessory organs in the GI tract?
To secrete things that will help with digestion
87
What are the accessory organs in the GI tract?
Salivary glands, liver, gallbladder, exocrine glands of the pancreas
88
Define Digestion in the GI tract
Breaking down of food into smaller particles (macromolecules that can be absorbed)
Mechanically (chewing) and by actions of digestive enzymes, acid, and bile
89
Define secretion in the GI tract
Release of enzymes, acid, and bile into the lumen of the GI tract
90
Define Absorption in the GI tract
Movement of molecules resulting from digestion from the GI tract across a lay of epithelial cells and into the blood or lymph
91
Define motility in terms of the GI tract
Contraction of smooth muscles in the GI tract wall that mix the luminal contents and propel them forward from the mouth to the anus
92
What is the purpose of saliva?
Antibacterial
Contains mucus for lubricating food particles before swallowing
Contains amylase that will begin the breakdown of polysaccharides
dissolves molecules so that they can interact with chemoreceptors (gives the sense of taste)
93
What provides a pathway from the oral cavity to the stomach?
Pharynx and esophagus
94
T/F digestion is actively occurring in the pharynx and esophagus
False
95
What organ stores food?
The stomach
96
What produces gastrin?
The stomach
97
What dissolves the particulate matter in food, kills bacteria, and activates pepsinogens into pepsin?
Hydrochloric acid
98
Where is pepsin first found and its function?
The stomach
| Begins the digestion of proteins
99
What is the purpose of mucus in the stomach?
Lubrication and protection
| Protection from acid, pepsin, and mechanical strain
100
Where can intrinsic factor be found and its purpose?
The stomach and is used to absorb vitamin B12
101
What can the stomach absorb?
Ethanol, aspirin, and a little bit of water
102
What does the stomach regulate?
The rate at which things are entering the small intestine
103
What is chyme?
Solution of partially digested protein and polysaccharide fragments, fat droplets, salt, water, and other small molecules int the stomach, SI, and LI
104
How is the small intestine divided up?
Duodenum, Jejunum, and ileum
105
Where do most digestion and absorption occur?
The small intestine via hydrolytic enzymes
106
T/F Enzymes for carbs, fats, and proteins are secreted by accessory organs for the digestion of nutrients
False: Enzymes for carbs, fats, and proteins are embedded in the luminal surfaces of cells lining the SI or are secreted into the lumen by the pancreas
107
What does the SI secrete?
Water, salts, and mucus
108
What does the gallbladder and liver secrete?
bile into the small intestine
109
Where is the main hub for all absorption and digestion?
SI: absorbs monosaccharides, fatty acids, amino acids, vitamins, minerals, and water
110
What is the purpose of the motility in the SI?
Mixes the contents with various secretions
Brings the contents closer to the epithelial wall for absorption
Slowly propels the chyme to the large intestine
111
What does the pancreas secrete?
Pancreatic juices:
Bicarbonate (Buffer against stomach acid)
Enzymes necessary for digesting carbs, proteins, fats, and nucleic acids
112
What does the liver secrete?
```
Bile salts (not an enzyme, but breaks down fat)
Bicarbonate (neutralization)
```
113
What organic waste product along with some trace metals is placed into the feces by the liver?
Bilirubin via bile secretion
114
What is the purpose of the gallbladder?
To store bile between meals
(bile comes from the liver)
Secretes the bile into the duodenum
115
What is the purpose of the large intestine?
Secrete mucus
Concentrates and temporarily stores undigested matter
Mixes and propels its contents
Sends it to the rectum for defection
116
What aspect of the luminal surface increases its surface area?
The fact that it is convoluted
117
From the stomach on, the luminal surface secrete what?
Exocrine: mucus into the lumen
Endocrine: hormones into the blood
118
Exocrine glands of the lumen secretes:
```
Water
Acid
Enzymes
mucus
ions
into the lumen
```
119
What are the four tunics of the GI wall?
Mucosa
Submucosa
Muscularis Externus
Serosa
120
Which tunic is a single layer of epithelial cells that contain blood and lymphatic vessels and nerve fibers and a thin layer of smooth muscles?
Mucosa tunic
121
Which tunic is made of connective tissue that contains the submucosal plexus and some blood and lymphatic vessels?
Submucosa tunic
122
What tunic is made of two layers of smooth muscles and are separated by neurons? Those neurons combine to be called the___
Muscularis externus tunic
| Myenteric plexus
123
The myenteric plexus gets its innervation from the ____
Autonomic nervous system
124
What are the two types of muscles in the muscularis externus tunic?
Circular Muscles: Which narrow the tube
| Longitudinal Muscles: Which shorten the tube
125
What organ in the GI system has a three-layered muscularis externus?
Stomach
126
What tunic covers the outer surface of the GI tube?
Serosa Tunic
127
Where is the serosa not present, but instead has an adventitia?
Esophagus
128
What is a mesentery?
Sheets of connective tissue that connects the serosa to the abdominal cavity
- Fused double layer of peritoneal membrane
- Holds organs in place
- Allows a route for blood vessels, lymphatics, and nerves
129
Villi can be found in
the small intestine
130
Brush border is a part of the
Villis that contain microvilli
131
A lacteal is
the center of each villus that contains capillaries and a single, blind-ended lymphatic vessel that absorbs fats and allows them to enter the lymphatic system
132
What veins drain the SI, LI, pancreas, and parts of the stomach?
Hepatic Portal
133
Where does the hepatic porta vein circulate to?
They give rise to secondary capillary network that will supply the liver
134
What does the liver receive and do with it from the hepatic portal?
The things that have been digested
It will process it: Metabolize, detoxify, store, etc. (everything but fats)
135
What is the peritoneum?
- A serous membrane similar to the pleural cavity and pericardial membranes
o Covers the external surface of many digestive organs and also lines the inner surface of the abdominopelvic cavity wall
o Encloses the peritoneal cavity
Filled with a thin layer of lubricating serous fluids
136
Carbs are ingested as:
Starch
Sucrose
Lactose
Galactose
137
Cellulose is metabolized by
bacteria in the cecum
138
Digestion of carbs is done by
amylase (from saliva and the pancreas)
*** Mainly happens in the small intestine
Results in a mix of maltose and short chains of glucose molecules
139
What enzymes are embedded in the luminal membranes that break down carbs?
* Lactase: Breaks down lactose
* Sucrase: Breaks down sucrose
* Maltase: breaks down maltose
* Alpha-dextrinase
140
What are the water-soluble monosaccharides?
Fructose
Galactose
Glucose
141
Glucose and galactose enter the epithelial cells via
SGLT-1 via secondary transport
| Coupled with sodium
142
Fructose enters the epithelial cells via
GLUT-5
143
T/F Glucose, Galactose, and Fructose exit the epithelial cells into the interstitial fluid via GLUT-2
True: Through diffusion
144
T/F essential amino acids are the ones that we make ourselves
False: Essential AA's are the AA's that we cannot produce
145
What is the waste product of breaking down AA?
The nitrogens from AA breakdowns end up in urea
146
Pepsin from the stomach will
Break down proteins into fragments
147
Trypsin and Chymotrypsin from the pancreas
produces peptide fragments
148
What will break down peptide fragments into free AA?
Carboxypeptidase and aminopeptidase which are embedded int he SI mucosal epithelial cell membrane (brush border)
149
Free amino acids are absorbed by
sodium co-transport
| requires ATP: secondary active transport
150
Chains of 2 or 3 amino acids move into the cells by
Secondary active transport with hydrogen
| *** They are then hydrolyzed into free AA within the cell
151
T/F All proteins have to be digested in order to be absorbed
False: Some proteins can be absorbed whole via endocytosis
| i.e. Antibodies from mother's milk
152
Lipids are ingested as
triglycerides
153
What breaks down triglycerides and what are they broken into?
Lipases
| 2 free fatty acids and 1 monoglyceride
154
Emulsification
Speeds up digestion of fat by breaking down fat droplets into smaller droplets
155
Emulsification is achieved by
Mechanical disruption via churning activity
| Emulsifying agents: bile salts, and lecithin (phospholipid)
156
Micelles
Bile salts surround the small fat droplets that open and close and speeds up their movement towards the epithelial cells for absorption
157
T/F Fats use secondary transport to be absorbed
False: Fats freely diffuse through the plasma membrane
158
What happens to fats inside of the cell?
They are reassembled into triglycerides again in the smooth ER and form a fat droplet that will move through the Golgi and the plasma membrane to be placed into the interstitial fluid
159
What are micelle like droplets called in the interstitial fluid?
Chylomicrons
160
T/F Chylomicrons move through the basement membrane of capillaries and travel through the blood
False: Chylomicrons are prevented from entering the blood capillaries because of the basement membrane. They instead enter the lacteal and enter the lymphatic system to eventually be placed into the venous blood
161
What vitamins are fat-soluble?
Vitamins A, D, E, and K
162
What vitamins are water-soluble?
Vitamins B and C
163
What vitamin needs help from which protein to be absorbed?
Vitamin B12 uses assistance from Intrinsic Factor
164
How is Vitamin B and C absorbed?
Diffusion or carrier-mediated transport
165
How are vitamins A, D, E, and K absorbed?
Same pathway as fats
166
Where is water mainly absorbed in the GI system?
Small amounts in the stomach, but the main absorption is in the small intestine
167
How is water absorbed?
Diffusion through the small intestine epithelial membranes following a gradient
168
How is sodium absorbed?
Sodium is absorbed by creating a gradient with a sodium-potassium pump, then it moves in either through an ion channel or through co-transport with another molecule
169
What is the exception in terms of trying to absorb as much as possible?
Potassium and calcium and Iron
| They are both under physiological regulations
170
T/F some ions are secreted and absorbed through the SI and LI
True: Ions like bicarbonate are secreted and then absorbed again
