Exam 3 Flashcards
Renal and Cardio
1
Q
What are the three functions of the Renal System?
A
- Cleans the Blood
- Regulates many ECF Components
- Endocrine Tissue
2
Q
How Does the kidney Clean the Blood?
A
It removes waste products through filtering and then reabsorbs what it wants. Undesirable components are expelled through the urine.
3
Q
How does the renal system regulate ECF?
A
It receives 25% of cardiac output so it can regulate the levels of blood components especially ions (Na+, K+, and Ca2+) and acid base balance
4
Q
How is the kidney an endocrine tissue?
A
It releases hormones important for regulating BP (renin) and rBC production (EPO and Erythropoietin)
5
Q
How much cardiac out put does the kidney receive?
A
25%
6
Q
where are the kidneys located?
A
Side of spinal column in the dorsal body cavity
7
Q
In humans which kidney is more anterior?
A
Left Kidney/more cranial
8
Q
What color and texture are the kidneys?
A
Red, Brown and smooth
9
Q
How big are the kidneys in humans?
A
10-12 cm long
10
Q
What supplies the kidney with blood?
A
Each kidney has a renal artery
11
Q
What drains the kidney?
A
Each kidney has a renal vein
12
Q
What does the ureter do?
A
Moves urine from each kidney by a peristalsic motion and gravity to bladder
13
Q
Describe the bladder
A
Thin stretchy bag of muscle that stores urine
14
Q
What does the urethra do?
A
Expels urine out of the body from the bladder.
15
Q
What would we see in a sagittal section of the kidney?
A
Cortex(Dark), Medulla and Renal Pelvis(Pale)
16
Q
Why is the cortex of the kidney darker?
A
More vasculature, different cell types
17
Q
What explains the coloration difference between the cortex and medulla?
A
Different cells, more vasculature in the cortex
18
Q
What color is the renal pelvis?
A
pale, creamy yellow
19
Q
What is the renal pelvis?
A
An extension of the ureter that expands to fill out the hollow cavity of the kidney
20
Q
What does the renal pelvis do?
A
collect urine that is formed and emerges from the innermost medulla
21
Q
In what direction does the kidney work?
A
from the outside in
22
Q
Where does blood enter the kidney?
A
blood enters cortex of the kidney from the renal artery
23
Q
What happens to the blood in the cortex in general terms?
A
It gets filtered
24
Q
What fluid emerges from the medulla?
A
Urine
25
What is the boundary called between the cortex and medulla?
Cortico-medullary boundary
26
What is the kidney composed of?
Hundreds of epithelial lined tube structures called nephrons
27
What is the functional unit of the kidney?
The nephron
28
Is there connective tissue in the kidney?
no
29
Where is the Macula Densa?
Cortex
30
What part of the kidney are distal tubules found?
Cortex
31
What part of the kidney do you find loop of Henle?
Medulla
32
Where do you find proximal tubule in the kidney?
Cortex
33
Where do you find collecting duct of the kidney?
Medulla and cortex
34
Where do you find bowmens capsule?
Cortex
35
Where do you find a connecting tubule?
Cortex
36
Where is the renal corpusle?
Cortex
37
What does the renal corpusule do?
filters the blood and generates filterate
38
What does the proximal tubule do?
Selective reabsorbtion
39
What does the proximal tubule reabsorb?
Na, K, glucose, amino acids , bicarbonate
40
Where does the epithelial type change?
at the loop of henle
41
What does the loop of henle do?
Reabsorb water and Sodium Chloride
42
What is another name for the thick ascending limb?
distal straight tubule
43
Where does the distal tubule run?
From the outer medulla to the cortex
44
What does the distal tubule do?
Selective reabsorption but not as powerful as the proximal tubule
45
What does the collecting duct do?
Fine tuning (secretion and reabsorption)
46
Which molecule reabsorbs Na+ at the luminal membrane of the early proximal tubule?
Na-glucose symporter
47
How is Na+ reabsorbed at the basolateral membrane of the early proximal tubule?
Via Active Transport
48
What molecule reabsorbs Na+ at the luminal membrane of the early proximal tubule?
the Na-Glucose symporter
49
Where does the Na-Glucose symporter reabsorb Na+ in the early proximal tubule?
At the luminal membrane
50
What is the number one job of the kidney?
To clean the blood
51
What is the second most important function of the kidney?
regulate many components of the extracellular fluid
52
What are the two parts of the renal corpusle?
1. A bundle of capillaries (glomerulus)
| 2. Bowmans Capsule (surrounds glomerulus)
53
Where does the glomerulus receive blood from?
An Afferant Arteriole
54
Where does blood leave the glomerulus?
An Efferent Arteriole (E for Exit)
55
Where does the blood get filtered?
in the glomeruli
56
As the blood flows through the capillaries of the glomerulus is it under high or low pressure?
High because part of the fluid portion of the blood is squeezed through capillaries into bowmans capsule
57
How much of the fluid portion of the blood is squeezed into bowmens capsule during filtration?
20-25%
58
Where does the filterate go from bowmans capsule?
To the proximal tubule where selective reabsorbtion occurs
59
If a sodium ion wants to enter bowmans capsule from the glomerulus what does it have to do?
Cross the wall of the capillary and then the wall of bowmans capsule
60
What makes up the filteration barrier in the renal corpuscle?
Wall of the capillary in the glomerulus and the lining of bowmans capsule.
61
What can cross the filteration barrier of the renal corpuscle?
Anything super small : Ions (Na,K, Mg)
Anything with a neutral charge or no net charge
Example: glucose, Water, very small proteins
62
What cannot cross the filteration barrier of the renal corpuscle?
Cells (RBCs and WBCs)
antibodies (large blood borne molecules)
Most Protein
63
T/F The blood has lots of protein
True
64
Describe the path of the proximal Tubule in the kidney.
1. Begins in the cortex and winds around
2. Dives into the medulla and turns into the loop of henle
3. goes down the descending limb
4. makes a hairpin loop in the deep medulla
5. Comes back out in the ascending limb
6. Turns into the distal straight tubule
7. distal straight tubule goes back to glomerulus where it touches it at the vascular pole
65
Where is the vascular pole located in the renal corpuscle?
Where the afferent and efferent enter and exits
66
What is the distal tubule associated with?
The renal corpuscle
67
What are the specialized cells are the interface of the distal tubule and glomerulus called?
The macula densa
68
What are the cells of the macula densa important for?
regulation of control of filtration but not filtration itself
69
Why compels something to move out of the bloodstream to cross the glomerulus into bowmans capsule and then into the proximal tubule?
Starlings forces combined (net filtration pressure)
70
Are starlings forces unique to the glomerulus?
no, they function at any capillary bed
71
Define Hydrostatic Pressure
the pressure exerted by the fluid on the container that contains it. Fluid pushing out against cup
72
What are the two categories of starlings forces?
Hydrostatic and Oncotic Pressure
73
Define Oncotic Pressure
Osmosis generated by proteins in the blood
74
If there was a container with two fluids (one of water and one with sodium chloride) and a semipermeable membrane what way would the water move?
Toward the sodium chloride due to osmosis. (Sodium Chloride generates an osmotic pressure by pulling water across the membrane)
75
What can generate osmotic pressure?
Na+, Cl-, glucose, colloids, proteins
76
What is a colloid?
High molecular weight particle in the ECF
| Usually proteins
77
What are the two hydrostatic pressure?
Glomerular hydrostatic pressure and Bowmans space pressure
78
What is Glomelular (Capillary) Hydrostatic Pressure? (Pc)
As blood runs through the glomerulus it is under pressure and it exerts a pressure pushing out
79
What is bowmans hydrostatic pressure?
The pressure of the filterate in bowmans capsule pushing out. Opposes the glomerular hydrostatic pressure
80
What are the two oncotic pressures?
Glomerular colloid oncotic pressure
| Bowmans space oncotic pressure (should be very small)
81
In the renal corpuscle, where is the protein that exerts oncotic pressure?
It should be in the blood and not in bowmans space
82
What is capillary oncotic pressure? (symbol pi subscript c)
It is the pressure generated by protein in the blood pushing inward in the glomerulus
83
Why is the oncotic pressure small in bowmans space?
There is only a small amount of protein generating that pressure
84
What way does the oncotic pressure in bowmans space pull?
Out
85
What way does the hydrostatic pressure in bowmans space pull?
in
86
How do we calculate the net filteration pressure in the glomerulus?
Glomerular Hydrostatic Pressure - Bowmans capsule pressure (Hydrostatic) - Glomerular oncotic pressure
87
Given the following Starlings forces, what is the net pressure at the glomerulus?
Bowmans space hydrostatic pressure = 24 mmHg
Capillary Oncotic Pressure = 26 mmHg
Bowmans space oncotic pressure = 0 mmHg
Capillary Hydrostatic pressure = 58 mmHg
58 mmHg - 24 mmHg - 26mmHg = 8mmHg
88
How does the kidney regulate the rate at which filtrate is generated? (Glomerular filtration rate)
The capillary hydrostatic pressure determines the glomerular filtration rate. If it increases so does the filtration rate.
89
How does the kidney increase or decrease the capillary hydrostatic pressure to change the glomerular filtration rate?
Constricting or dilating the arterioles controls how much blood can flow in and out of the glomerulus and then change the capillary hydrostatic pressure. (
90
Are arterioles a good conduit of blood alone?
No, they are small
91
What do the arterioles at the vascular pole of the renal corpuscle have that aid in changing the filtration rate?
Smooth muscle in their walls:
If the smooth muscle tightens the arteriole constricts and less blood flows through (Pc decreases and filtration rate decreases)
If the smooth muscle relaxes, the arteriole expands and more blood can go through.
92
What happens when the afferent arteriole constricts?
Pc decreases and GFR decreases
93
What are extra renal triggers?
They tell the kidney to adjust (constrict or dilate the afferent or efferent arterioles)
94
What is autoregulation?
When an organ detects a change and adjusts to correct it
95
How does the kidney autoregulate the GFR?
As systemic blood pressure increases more blood flows through the kidney and GFR increases but there is a range where the GFR and blood flowing in will not change even if the mean arteriole pressure increases or decreases
96
What is mean arterial pressure?
(x axis) systemic blood pressure
97
What is Renal Blood Flow?
(Y axis) How much blood is flowing through the kidneys
98
As Mean Arterial pressure increases blood flow ______ and GFR _________
As Mean Arterial pressure increases blood flow increases and GFR increases
99
As more blood flows into the glomerulus capillary hydrostatic pressure ______ and GFR_______.
increases, increases
100
What is the goal of renal autoregulation?
To keep blood flow and GFR steady even though systemic BP changes dramatically
101
Why does the kidney want to autoregulate?
1. Prevents mechanical damage to glomeruli caused by spiking BP
2. Prevents fluctuations in BP from changing delivery of filtrate to nephron (maintain constant GFR despite changes in BP)
102
What would happen if the nephron became overwhelmed with the amount of filtrate generated?
It could lose some important components in the urine rather than reabsorbing them
103
What happens to blood pressure and renal blood flow during anesthesia?
BP fluctuates while renal blood flow stays steady (autoregulation)
104
What are the two mechanisms that the kidney autoregulates?
Myogenic mechanism
| Tubuloglomerular feedback
105
Describe the Myogenic mechanism
The afferant arteriole can sense if it should constrict or dialate based on if its smooth muscle is streched or relaxed and this adjusts the GFR
106
What happens when smooth muscle is stretched?
It contracts
107
T/F when smooth muscle is not stretched it is contracting
False, it is relaxed
108
If BP is high, the smooth muscle in the afferent arteriole will ________ , intracellular Ca+ will ______, vascular resistance will _________ and the arteriole will ______. Renal Blood flow will _____, _______GFR.
If BP is high, the smooth muscle in the afferent arteriole will stretch, intracellular Ca+ will increase, vascular resistance will increase and the arteriole will constrict. Therefore renal blood flow will decrease, decreasing GFR.
109
If BP is low, the afferent arteriole will ________ , intracellular Ca+ will ______, vascular resistance will _________ and the arteriole will ______. Renal Blood flow will _____, _______GFR.
If BP is low, the afferent arteriole will relax and dilate, intracellular Ca+ will decrease, vascular resistance will decrease . Renal Blood flow will increase, increasing GFR.
110
What is the response time of the myogenic mechanism?
1-2 seconds
111
What is the myogenic response to increased BP?
Afferant arteriole constricts
112
What is the trigger for Tubuloglomerular Feedback?
changing distal tubule fluid compositon
113
What is the response time for Tubuloglomerular Feedback to occur?
10-12 seconds (many more steps than the myogenic mechanism)
114
How does the Tubuloglomerular mechanism work?
The macula densa senses changes in the distal tubule fluid caused by fluctuations in the GFR and responds by changing the resistance of arterioles to correct the GFR by regulate the amount of blood
115
In the tubuloglomerular feedback mechanism of autoregulation what happens when the BP increases?
Normally a BP increase will increase Pc and GFR would then increase, due to the increase there is more filtrate. The macula densa senses the higher concentration of ions in the distal tubular fluid and transmit a signal to the wall of the afferent arteriole tell the smooth muscle to constrict and thus reduce the GFR
116
What does it mean when we say the GFR is increased?
More filterate is being dumped into the system.
117
In the tubuloglomerular feedback mechanism of autoregulation what happens when blood pressure is low?
GFR decreases normally due to lower capillary hydrostatic pressure. In the fluid at the distal tubule thereare less ions and the macula densa senses this. It then needs to increase GFR. The efferant arteriole constricts in the presence of angiotensin II released by renin and the afferent arteriole dilates when prostaglandin E2 is sensed and GFR increases
118
What is the tubuloglomerular response to lower than expected solute concentration in the distal tubule?
GFR will be increased
119
T/F Oxygenated blood from the upper body is returned to the heart via the superior vena cava
F-oxygen poor blood is returned
120
What vessel is blood returned to the heart from the upper body?
The superior vena cava
121
What is the normal resting heart rate for a human?
70 bpm
122
What is the normal arterial pressure for a human?
120/80 mmHg
123
What are the normal hemocrit values for a human male and female?
```
F = 38-46%
M = 40-54%
```
124
What is the top number in BP readings?
Systolic
125
What is the bottom number in BP readings?
Diastolic
126
What is hemacrit?
The total number of blood cells in the total blood volume
127
A normal heart shape and size = what?
A normal cardiac cycle
128
What does dialated cardiomyopathy cause?
Congestive heart failure (backflow of blood)
129
What are the three CV system components?
1. Heart
2. Blood Vessels
3. Blood
130
What does persistant high blood pressure cause?
High blood pressure damages the endothelium in the artery causing inflammation. The inflammation causes a plaque formation in the artery. The plaque causes a turbulant blood flow
131
What is atheroscleric plaque consist of?
Lipids, Calcium, Cellular Debris
132
What is a myocardial infarcation caused by?
The fibrous cap in the artery when there is plaque formation breaks and blood flow is hindered causing a heart attack.
133
What does the plasma contain?
WBCs and Platelets
134
What does coagulation of the blood lead to?
Thrombus formation leading to myocardial ischemia or infarcation (zero blood flow)
135
What is ischemia?
Decrease in Blood Flow
136
Define Hemorrhage
You lose the entire RBC including its membrane from the body
137
Hemolysis
RBC membrane ruptures
138
What can cause Hemorrhage or hemolysis?
Trauma, Major Surgery, Hemolytic Anemia or Hemophilia
139
How is cardiac muscle different than skeletal muscle in a histological sample?
Branching of fibers and intercalcated discs (At the tissue level)
140
What does it mean when we say cardiac muscle is a syncytium?
Many cells joined together allowing for fast conduction of action potentials from cell to cell
141
What does the distinct features of cardiac muscle allow for?
Resist fatigue and contract in a corrdinated fashion
142
What feature of cardiac muscle is important for pumping blood throughout the entire CV system?
Rapid, involuntary contraction and relaxion
143
What is responsible for providing low electrical resistance in cardiac muscle?
Intercalcated discs
144
Describe the pathway of blood to and from the heart
1.Low oxygenated blood
-superior vena cava
from upper limbs
-inferior vena cava from lower limbs into the right atrium
2. right atrium
3. tricuspid valve
4. right ventricle.
5. pulmonary valve
6. pulmonary artery
7. Lungs
Blood Picks up Oxygen
145
Where does the blood go after gaining oxygen in the lungs?
The pulmonary veins into the left atrium of the heart
146
Describe blood flow through the heart from the left atrium
1. Left atrium
2. Mitral Valve (Bicuspid)
3. Left Ventricle
4. Aortic Valve
5. Aorta
6. Circulation
147
Define cardiac cycle
The sequence of events that occur during systole and diastole
148
Define Systole
Cardiac muscle contracts and pumps blood from the ventricles into the arteries (Blood leaves the heart)
1st phase
149
Define Diastole
(Ventricle)Muscle relaxes and chambers fill
Blood returns to the heart
2nd phase
150
Where is the heart located?
Slightly left and center
151
what do the coronary arteries supply?
Oxygenated blood
152
Where do electrical impulse begin in the heart?
At the Sinus Node
153
What does the conduction system of the heart do?
Keeps your heart pumping in a normal rhythum
154
On the posterior side of the heart what does low oxygenated blood enter?
The coronary sinus
155
How is the heart able to contract without any extrinic stimulation?
Through the intrinsic conduction system
156
Define the hearts intrinsic conduction system
It can be described as a group of specialized cardiac muscle cells in the walls of the heart that sends signals to the heart muscle causing it to contract.
157
Describe the path of the hearts internal conduction system
1. SA node
2. Internodal pathways
3. AV node
4. AV bundle
5. Left and Right bundle branches
6. Purkinje fibers to ventricle
158
What happens at the AV node
1. Impulse is delayed
| 2. The delay allows atria to contract before ventricles
159
Where does the AV bundle take the electrical impulse?
Into the Ventricles
160
Where are the left and right bundle branches located?
Interventricular Septum
161
What is the other name for the sinus node
pacemaker node
162
What is the function of the SA node?
Signals the atria to contract
163
What is the primary function of the AV node?
To cause the ventricles to contract
164
What is the pacemaker potential?
Rhythmic discharge of Sinus Atrial nodal fiber
165
How many discharges are there in a minute at the SA node?
70-80
166
Which has a higher action potential in millivolts, the Sinus nodal fiber or ventricular muscle fiber?
Ventricular
167
What does the AV node do to the impulse conduction?
Slows it considerably to allow sufficient time for the atrial depolarization and contraction (systole) before the ventricle
168
Why don't the purkinje fibers need to discharge as frequently as the AV node?
They are located very close to the muscle
169
What is depolarization?
Membrane potential increases
| Phase 0 -->Fast Na+ channels open, then slow Ca++ open
170
Describe phase zero of ventricular muscle action potential
It is the phase where depolarization occurs and the fast sodium ion channels open and then the slow Calcium ion channels open. There is a sharp increase in membrane potential from negative to positive
171
Descibe what happens at phase 1 of ventricular muscle action potential
Slight repolarization
- apex of the graph
- K+ channels open
172
What happens in phase 2 of Ventricular AP?
There is a plateau
- slower Ca++ channels open,
- decreased permeability to K+
- Membrane potential decreases but it is still postive
173
What happens in phase 3 of ventricular AP?
Repolarization
- more K+ channels open
- Membrane potential decreases to about -50
174
What happens in phase 4 of ventricular ap?
Resting membrane potential is acheived
| -85-95 mV
175
How long does an action potential take in the ventrcle?
about 1.75 second
176
What does calcium flowing into the cell cause?
Coordinated contraction
177
What does a S-T Segment elevation mean?
possible myocardial infarcation
178
What does the P wave of the ECG coorospond to?
Atrial depolarization
179
What does the QRS complex of the ECG corrospond to?
Ventricles depolarizing
180
What segments of the ECG does an R-R interval include?
RSTPQR -a full cycle
181
What is the Q-T interval on the ECG?
QRST
182
How long is a P-R interval
0.16 seconds
183
What does a T wave on an ECG indicate?
When the heart is being primed to relax
184
How does the heart speed up?
The sympathetic nervous system....
1. Norepinephrine is released at the synapse
2. Sinus node discharge increases
3. Impulse conduction rate increases
4. Force of contraction into atria and ventricles increases
185
What system is responsible for the heart rate to slow down?
Parasympathetic (Vagus cranial nerve X)
186
What is released to slow the heart rate?
Acetylcholine
187
What is the SA node and AV junctional fibers innervated by to slow the heart rate?
The vagus nerve (X)
188
When Ach is relased at the SA and AV junctional fibers what occurs?
Increased permeability of K+ causing hyperpolarization
- rate of conduction impulse decreases
- Decrease in force of contraction in atria and ventricles
189
What do we measure on the Y axis of the cardiac cycle?
Volume and pressure (Ventricular and Atrial volume and pressure)
190
What is the lub sound corrospond to?
Systole
191
What does the Dub sound corrospond to?
Diastole
192
Contraction ______ the pressure within a chamber
Increases
193
Blood Flows from ____ to ______ pressure.
Higher to Lower
194
Semilunar valves open when ______
Ventricular pressures are higher than aortic pressure
195
AV valves _____ when atrial pressures are ______ than ventricular pressure.
Open, higher
196
What is the first heart sound?
S1
197
What is each cardiac cycle initiated in?
The SA Node
198
How do you find the duration of the cardiac cycle?
Take the reciprocal of heart rate
199
What phase is ventricular systole?
Phase 1
200
How long does ventricular systole last?
0.3 seconds
201
What happens during phase 1: Ventricular Systole?
1. Isovolumic contraction
| 2. Ventricular ejection
202
Define ventricular systole
Contraction in the ventricular myocardium
203
What happens during phase 2 of the cardiac cycle?
Diastole
204
What is diastole?
Relaxtion of the ventricular myocardium
205
How long is diastole?
0.4 sec
206
What are the steps in diastole?
3. Isovolumeric relaxation
4. Rapid inflow
5. Diastasis
6. Atrial Systole
207
What is atrial systole?
Contraction of the myocardium (rt. and left atria)
208
How long does atrial systole last?
0.1 sec
209
Why does atrial systole occur during diastole?
Some blood volume is being deposited into the ventricles prior to ventricular systole
210
What happens during isovolumic contraction?
First step of Sytole- 1.The ventricular pressure rises rapidly without a change in volume
2. All valves are closed
211
What do you hear during isovolumeric contraction?
The AV valves snap shut and you hear the lubb sound (S1)
212
What is reabsorption?
The movement of molecules in the tubular fluid accross the epithelial lining of the nephron back into the bloodstream via the peritubular capillary network
213
After going through the peritubular capillary network in the kidney where does the blood go?
Dumps into the renal vein to exit the kidney
214
What is the oppostite of reabsoption when talking about the kidney?
Secretion
215
What is the opposite of reabsoption when talking about the kidney?
Secretion
216
In the kidney, what is the luminal membrane>
Seperates tubular cell from tubular fluid
217
In the kidney, what is the basolateral membrane?
The other side of the cell, seperates the cell from the peritubuler interstitium
218
What is the goal of reabsorption?
To move stuff from the lumen of the tubular cells to the blood
219
What part of the cell directly interacts with the filterate produced in the kidney?
The luminal membrane
220
what are the pathways from the luminal membrane to the blood in kidney reabsorption?
Transcellular route and paracellular route
221
Describe the transcellular route in reabsorption
Reabsorption through the cytoplasm of tubular cells (Through cells)
222
Describe the paracellular route of reabsorption in the kidney
Reabsorption between tubular cells across tight junctions (Between Cells)
223
What pathway is used for the majority of reabsorption in the kidneys?
Transcellular
224
Define passive transport
- no energy required
| - moves down an electrochemical gradient (alot of molecules to less molecules)
225
What are the types of passive transport?
Diffusion and facilitated diffusion
226
What types of things move using facilitated diffusion?
molecules that don't easily cross biological membranes (Charge, polar (inbalance of charge) (Na, K, Mg, glucose)
227
What does facilitated diffusion require?
a transporter
228
What is a polar molecule?
A molecule with an uneven distribution of charge (Glucose)
229
What is active transport?
- Energy required
| - Moves against an electrochemical gradient (low to high)
230
What are the types of active transport?
Primary and Secondary
231
What is all reabsorbtion linked in some way to?
NaK+ ATPase
232
Where is Na K+ATPase located?
Basolateral membrane
233
Where is NaK+ATPase not located in the basolateral membrane in the kidney?
Loop of henle
234
Is there a difference in concentration of molecules that are found in the filterate vs. the molecules in the interstiticial fluid?
No there is no gradient
235
What makes the nephron tick?
The energy in NaKATPase
236
How many sodium and potassium molecules does NaK+ATPase move?
3 Na+ ions out and 2 K+ ions in
237
Does ATPase require energy?
Yes
238
What is the Na K+ATPase mechanism in the basolateral membrane in the kidney?
To pump 3 Na+ out energy is required because it is moving against its electrochemical gradient
239
What is the Na K+ATPase mechanism in the basolateral membrane in the kidney?
To pump 3 Na+ out energy is required because it is moving against its electrochemical gradient but since Na is going out an electrochemical gradient is generasted
240
What is the function of NaKATPase in tubular reabsorption?
Maintains low intracellular Na+ to establish the electrochemical gradient up which all reabsorption depends
241
```
Which of the following statements about Na+K+ATPase is correct?
A
It transports Na+ and K+ at the luminal membrane of nephron epithelia
B
It moves 3 Na+ into the cells in exchange for 2 K+ out of the cell
C
Na+ movement is by facilitated diffusion
Correct
D
It requires energy in the form of ATP
E
It moves K+ paracellularly
```
D
242
What does the proximal tubule reabsorb?
```
67% of filtered water
Na
Solutes
99% of filtered glucose
Amino Acids
90% bicarbonate
```
243
What reabsorbs most water?
Proximal tubule
244
What can get secreted from the proximal tubule?
Bases, protons, organic acids
245
What special features do you find in the cells of the proximal tubule that tell you its function?
Brush Border-microvilli-increases surface area realitive to volume
Mitochondria-generates ATP
246
What part of the membrane has the brush border in the proximal tubule?
Lumen
247
What type of transport goes on in the proximal tubule?
Active-Mitochondria indicate that ATP is being made
248
Where is the Na K ATPase located in the cells at the proximal tubule?
Basolateral membrane
249
Describe the mechanism of action in the cells of the proximal tubule by where Na is reabsorbed
1. NaKATPase pumps 3 Na ions out which creates a concentration gradient at the lumen membrane of the cell.
2. This allows Na to enter the cell via facilitated diffusion at the lumenal membrane
3. Sodium goes in and then is pumped out by NaKATPase (reabsorbed)
250
How does glucose enter the cell in the proximal tubule ?
- Secondary active transport by using the ATP (potential energy) that was generated by NaKATPase moving sodium out of the cell
- Glucose transporters move glucose
251
Where do transporters move glucose and amino acids into the cell?
At the basolateral membrane
252
How to amino acids enter the cell at the proximal tubule?
Secondary active transport
253
What are Na proton exhangers?
a secondary transporter
254
How does water enter the cell at the proximal tubule?
It is pulled with sodium by osmosis by NaKATPase
255
In the first half of the proximal tubule, why does chloride concentration build up?
Water is leaving and chloride is staying in the tubular fluid
256
What happens to chloride concentration in the second half of the proximal tubule?
Since it built up in the first half, there is now a concentration gradient for chloride and so chloride can move between cells by simple diffusion paracellularly into the blood. This only happens because Water was reabsorbed and water can move because of Na ion reabsorbtion
257
What happens in the last part of the proximal tubule?
Cl- attracts Na+ paracellularly and more sodium is reabsorbed
258
What does the loop of henly reabsorb?
25% of filtered NaCl and 15% of filtered water
259
Where does water reabsorption occur in the loop of henle?
descending limb
260
In the loop of henly is NaCl reabsorption passive or active?
passive
261
Where is NacL reabsorped in the loop of henle?
ascending limb
262
Where does the descending limb of the loop of henle go?
to the medulla
263
Where does the ascending limb of the loop of henle go?
To the cortex
264
What part of the loop of henle is permeable to water?
Descending Limb
265
What part of the loop of henle is permeable to sodium and chloride?
Ascending
266
What type of reabsorption occurs at the loop of henle?
passive
267
What type of cells line the proximal tubule epithelium?
Low cuboidal
268
What type if cells line the loop of henle epithelialum?
Simple squamous Epitheilium
269
Is there mitochondria in the cells of the loop of henle?
not many as no energy is needed
270
Is Cl- absorbed paracellularly or transcellularly in the proximal tubule?
both-paracellularly at the proximal tubule and transcellularly at the loop of henle
271
How much water is reabsorbed at the distal tubule and collecting duct?
9-15%
272
How much NaCl is reabsorbed at the distal tubule and collecting ducts?
7%
273
What does water permeability depend on at the distal tubule and collecting duct?
ADH must be present
274
What cell type is found in the distal tubule?
cuboidal
275
What is the job of the nephron at the distal tubule and collecting duct?
Fine tuning
276
What is reabsorbed at the distal tubule?
Na, K, Cl, ions
277
What is secreted at the distal tubule?
protons
278
In the distal tubule what are features of the cell?
Smaller brush border, some mitochondria
279
What happens in the early part of the distal tubule (straight tubule)?
There is a very strong lumen postitve potential difference (fluid that runs is positively charged paracellularly) That repels other positively charged ions and they move paracellularly
280
In the straight distal tubule (early) what is the transcellular method of reabsorbtion at the Lumenal membrane?
NaKATPase moves Na out but there is another molecule called NaKCC2 that can move 1 ion of Na, 1 ions K and 2 ions of chloride into the cell. This is based on the movement of Na.
281
How is Cl- moved into the cell at the basolateral membrane?
Cl- channels
282
What happens in the convoluted distal tubule(late)?
NaKATPase works at the basolateral membrane and a sodium chloride symporter works at the luminal membrane moving sodium and chloride in and chloride is then reabsorbed via chloride channels at the basolateral membrane
283
What transports Na+ at the luminal membrane of the late distal tubule?
Na-Cl symporter
284
What type of cells are found in the collecting duct in the cortex?
Principal cells and intercalcated cells
285
What do principal cells absorb?
Na, K+ and some Cl-
286
What is the function of intercalcted cells found in the collecting duct
Move protons and Bicarbonate (regulate pH)
287
In the medullarly collecting duct what type of cells are found?
Only principal cells
288
What do principal cells look like?
Lighter in color cuboidal
289
Where do you find larger collecting ducts?
In the medulla
290
What is the major mechanism for reabsorbtion in the collecting duct?
Ions moved basically via channels at the luminal membrane along with NaK ATPase at work in the basolateral membrane
291
How is tubular reabsorption regulated?
1. Glomerulotubular balance
2. Starlings forces at the peritubular capillary bed
3. Hormones
292
How does Glomerulotubular balance work?
The more filterate dumped into proximal tubule, the more reabsorbed so as GFR increases, so does reabsorption
293
How do starlings forces at the peritubular capillary bed regulate reabsoption?
Normally promote reabsorption in the proximal tubule
| Changes in the capilarry pressure and osmotic capillary pressure will change reabsorbtion
294
How can hormones regulate reabsorption?
1. Increase activity
| 2. Increase the number of transporter molecules
295
Define Osmolarity
It is the concentration of osmotically active atoms per L of solvent.
296
What way does water move in the presence of a high osmolarity substance such as NaCl?
Toward the higher osmolarity substance
297
In the loop of henle where is it permeable to Na+ and impermeable to water?
ascending limb
298
In terms of osmolarity, what is the fluid leaving the proximal tubule defined as?
isoosmotic (300 MOsm/kg)
299
What creates an osmotic gradient in the distal straight tubule?
The active reabsorbtion of Na+. Water follows the Na+ as it is being reabsorbed leaving the descending limb passively (without the use of energy) of the loop of henle
300
Where does osmolality increase in the loop of henle?
The Medullary interstitium-Na+ leaves the ascending limb contributing to osmolality. It leaves passively
301
What happens in the hairpin loop in the loop of henle?
Water reabsorption has concentrated Na+ above interstitial concentration so now there is a Na+ gradient
302
In terms of osmolarity, how do you describe the fluid going into the distal tubules at the end of the loop of henle?
Hypoosmotic
303
Where are osmoreceptors located?
Hypothalamus
304
What do osmoreceptors do?
Shrink and swell to detect changes in osmolality
305
What do baroreceptors do?
Detect changes in plasma volume or pressure
306
What happens when ADH is low?
A high volume of dilute urine is produced
307
What happens when ADH is high?
Antidiuresis, where there is a low volume of concentrated urine produced
308
What preserves medulla hypeosmolarity?
The vasa Recta
309
What is an effective osmole?
It can generate osmotic pressure
310
In the descending limb of the loop of henle what is the osmolarity in side the limb when compared to the intersticial fluid?
It is lower inside the limb so water moves out to the intersticial fluid
311
What is countercurrent multiplication?
The thing in the loop of henle in the descending limb causes the opposite effect in the ascending limb
312
Which statement about physiology at the loop of Henle is true?
Na+ is reabsorbed passively at the descending limb
B
Water is reabsorbed down an osmolarity gradient (low to high osmolarity)
C
Interstitial osmolarity decreases as you move deeper into the medulla
D
Distal tubule fluid is hypertonic to insterstitium
B
| Water is reabsorbed down an osmolarity gradient (low to high osmolarity)
313
What are the triggers to produce ADH?
Low volume (Osmoreceptors detect shrinking) and Low pressure (Baroreceptors detect Pressure)
314
what is the PRIMARY determinent of the release ADH?
Osmoreceptor response
315
What is the response in the late distal tubule and collecting duct to ADH release?
1. Increase expression of aquaporins in the luminal membrane of the late distal tubule and entire collecting duct so water can be reabsorbed.
2. Increase number of urea transporters in the luminal membrane of the medullary collecting duct so urea it is permeable to urea
316
What is the other word for ADH?
Vasopressin
317
Does ADH affect filteration in the nephron?
no
318
What happens when there is low ADH?
Diuresis and water is trapped in the distal tubule and collecting duct. A high volume of dilute urine is produced
319
What happens when ADH is high?
Antidiuresis-Water is reabsorbed and urine is concentrated
320
What is urea?
By product of protein metalbolism
321
Is urea an effective osmole in the collecting duct?
no just in the loop of henle
322
During diuresis, which of the following is true?
A
Urea reabsorption in medullary collecting duct is high
B
Collecting duct permeability to water is low
C
Water reabsorption at loop is increased
D
A small volume of urine is produced
B
| Collecting duct permeability to water is low
323
What is the vasa recta?
A group of capillaries around the late distal tubule and collecting duct
324
What is the function of the vasa recta?
To preserve medullary hyperosmolarity by keeping solutes
325
What is the main ECF ion?
Na+
326
What is changed by changing the amount of Na+?
ECF volume
327
What is changed by changing the concentration of Na+?
ECF osmolarity
328
What needs to be regulated to control the osmolarity and volume of the extracellular fluid?
ECF Na+
329
Where is most of the Na+ located in the body?
Extracellular (ECF)
330
Where does most of the K+ live in the body?
intracellularly
331
What do you find in the cell
Mg++,K+ , PO4, protein
332
Where do you find most Cl- in the body?
Extracellularly
333
Where do you find most bicarbonate?
Extracellularly
334
What is the derterminant of ECF osmolarity?
Na+ concentration
335
High ECF Concentration is called
Hypernatremia
336
What are the signs of hypernatremia?
Rupture of cerebral vessels
Muscle weakness
Ataxia,behavioral change
Coma to death
337
What is low Na+ ECF Concentration called?
Hyponatremia
338
What are the signs of Hyponatremia?
Incoordination and seizures
339
What is concentration?
The amount of a specified substance (Na+) in a unit amount of another substance (water)
340
What detects change in ECF osmolarity
osmoreceptors in the pituitary gland
341
When there is high ECF osmolarity what do the osmoreceptors do?
Shrink
342
What are the effects of osmoreceptor shrinkage
ADH release and Thirst Body, ADH is released and aquaporins are made thus reabsorption of water takes place and ECF osmolarity decreases
343
What occurs when there is more ECF in volume?
Hypervolemia (ascites and pulmonary edema)
344
What happens when ECF volume is too low?
Hypovolemia-Hypovolemic shock, organ damage
345
What can cause a volume change in ECF?
Na+, Blood loss, vomiting, liver failure
346
What do kidneys do to when it detects a volume change of ECF.
Regardless of cause, they change the amount of ECF Na+ to correct the volume
347
Does the kidney regulate protein?
no, the liver
348
```
What will be the effect of increasing extracellular fluid sodium concentration?
A
ECF volume will go down
B
ECF volume will go up
C
ECF osmolarity will go down
D
ECF osmolarity will go up
```
D
| ECF osmolarity will go up
349
Where is the thirst center in the brain?
Hypothalamus
350
Which statement about hyponatremia is most accurate?
A
A hyponatremic individual will have high ECF Na+ concentration
B
There will likely be translocation of fluid from ECF into ICF
C
Osmoreceptors in hypothalamus will shrink
D
ADH release will be increased
E
The individual will feel thirsty
B
| There will likely be translocation of fluid from ECF into ICF
351
What is more serious hypervolemia or hypovolemia?
Hypovolemia
352
How does the kidney detect volume change in the ECF?
1. Baroreceptors
| 2. Juxtaglomerular Apparatus
353
Where are baroreceptors located?
Heart (mostly right side), aorta, carotid sinus
354
What do baroreceptors sense?
Stretch (increase in volume)
355
When the baroreceptors stretch what is the response?
Sympathetic nervous system and natriuretic peptide release(decreases a high ECF volume)
356
How does the juxtaglomerular Apparatus regulate ECF volume?
It has stretch receptors that stretch when ECF volume goes up.
357
Where is the juxtoglomerular apparatus located?
By the afferant arterioles
358
How does the juxtoglomerular apparatus increase a low ECF fluid?
The Renin-Angiotensin system
359
How do we increase ECF volume?
When low ecf is detected the 1. sympathetic nervous system increases Na+ reabsorption ECF volume
2. Increases GFR and Pic and Pc is reduced of the peritubular capillaries of the proximal tubule to increase rebsorbtion
360
What does the sympathetic nervous system specifically do in when ecf volume is low?
norepinephrine constricts the efferant arteriole which builds capilary hydrostatic pressure within the glomerulus and the GFR increases promoting the movement of sodium back into the bloodstream
361
What triggers the renin -angiotensin mechanism?
The afferant arteriole detects stretch and Low ECF volume triggers the release of renin from the juxtaglomerular cells
362
What happens when renin is released?
Angiotensin II is increased and Na+ reabsorbtion is increased
363
Describe the renin angiotensin mechanism
1. Angiotensinogen is produced in the liver and enters the blood stream
2. When it encounters renin, renin cleaves angiotensenogen to angiotensin I
3. Angiotensin I sits in the blood stream until it encounters Angiotensen converting enzyme
4. This enzyme cleaves it to angiotensin II
364
Where is angiotensin converting enzyme produced?
In the lungs
365
What does angiotensin II do?
1. Potent vasoconstrictor that changes starlings forces in peritubular capillaries
2. Stimulate Aldosterone which increases Na+ reabsorbtion via NaK+Atpase
366
Where is aldosterone found?
Adrenal gland
367
How is ECF Volume decreased?
Natriuretic peptides inhibit the ways sodium can be reabsorbed and it promotes Na excretion through the urine
368
What is the mechanism of natriuretic peptide release?
it inhibits renin-angiotensin II, aldosterone and Na+ channels in the collecting duct all decreasing renal Na+ reabsorption
369
Which statement about hypovolemia is accurate?
A
It is defined as high ECF volume
B
It is caused by low ECF Na+ concentration
C
In response, sympathetic flow to the kidneys is increased
D
To correct it, the Renin-Angiotensin system will be inhibited
Submit
In response, sympathetic flow to the kidneys is increased
370
An increase in afterload causes stroke volume to
Decrease
371
What does the cardiac cycle refer to?
The sequence of events that occur with every heartbeat
372
What are the two major phases of the cardiac cycle?
Systole and Diastole
373
What does Systole refer to?
Ventricular contraction
374
What does diastole refer to?
Ventricular relaxation
375
Valves open and close according to _______
pressure gradients
376
Contraction ________the pressure
Increases
377
Blood flows from ____ to ______ pressure
Higher to lower
378
Semilunar valves open when Ventricular pressures are _____ than aortic pulmonary pressures
Higher
379
AV valves ______when atrial pressures are ____ than ventricular pressure.
Open, higher
380
How is the cardiac cycle initiated?
When the SA node fires(p wave)
381
What happens to the pressure when contraction begins?
Pressure increases in the atrium and blood flows through the AV valve to the ventricle
382
T/F atrial contraction is responsible for filling the entire ventricle
False-it only accounts for a fraction of the filling as the ventricles already have some blood in them.
383
What causes the AV valves to close?
A decrease in atrial pressure
384
What marks the beginning of systole?
Closing of the AV valves (S1 heart sound)
385
At the beginning of ventricular contraction, are the semilunar valves open?
No they are closed and the ventricle contracts in a closed space
386
What is isovolumetric contraction?
Semilunar valves are closed while ventricle contracts, no blood is ejected and pressure in the ventricle is unchanged
387
When does ventricular ejection start?
When ventricular pressures exceed the pressures within the aorta and pulmonary artery
388
what valves open to allow ejection from the ventricles?
pulmonary and aortic
389
What produces the second heart sound?
Closing of the semilunar valves
390
Where is each cardiac cycle initiated?
SA Node
391
What is phase 1 of the cardiac cycle called?
Ventricular Systole
392
What steps occur during ventricular systole?
1. Isovolumic contraction
| 2. Ventricular ejection
393
What is phase 2 of the cardiac cycle called?
Diastole
394
What steps occur during diastole?
3. Isovolumic relaxation
4. Rapid inflow
5. Diastasis
6. Atrial Systole
395
What happens during atrial systole?
More blood is being deposited into the ventricles
396
What happens to ventricular pressure during step 1 of the cardiac cycle isovolumeric contraction?
It rises rapidly without a change in volume
397
Are the valves open or closed during isovolumic contraction?
All 4 are closed
398
Which heart sound is the loudest?
S1 because the pressure is going to be the highest
399
When the bicuspid valve is closed what is the chordae tendiae and papillary muscles doing?
Paillary muscle is contracted and chordae tendinae are taut
400
What happens to ventricular pressure in step 2 of phase 1 (Ventricular Ejection)?
Left ventricular pressure is greater than aortic pressure and the right ventricular pressure is greater than the pulmonary trunk pressure
401
What valves open during step 2 of phase 1 ,Ventricular Ejection?
Semilunar
402
On the ECG What is happening during the T wave?
Ventricular ejection
403
What is end systolic volume (ESV)
The amount of blood remaining in the ventricle after systole (50 ml)
404
How do you calculate stroke volume?
SV = EDV-ESV
405
What is the stroke volume output into the aorta and pulmonary trunk?
70 mL
406
What happens to aortic pressure during ventricular ejection?
It starts increasing during systole after the aortic valve opens
407
When does aortic pressure decrease during ventricular ejection?
Toward the end of the ejection phase
408
What happens to atrial pressure during ventricular ejection?
C wave- there is a slight backflow of blood into the atria
409
What happens to ventricular volume during isovolumic relaxion?
Stays the same
410
What do the valves do during isovolumic relaxation ?
They close (all 4)
411
What sound do you hear when isovolumic relaxation occurs?
S2-the Dupp sound
412
What is happening when you hear the Dupp sound?
Semilunar valves are closing (pressure in the ventricle decreases and blood flows back to the ventricles which closes the semilunar valves
413
What happens to ventricular volume during the rapid inflow phase of diastole?
Increases
414
What happens to ventricular pressure during the rapid inflow phase of diastole?
it is low due to the AV valves being open and rapid ventricular filling and blood flowing continually from the great veins in the atria
415
How much blood flows directly through the atria into ventricles before atrial systole?
80%
416
What happens to atrial pressure during the rapid inflow phase of Diastole?
There is a slow venous return of blood into atria from veins while AV valves are closed
417
What is a V wave?
It is the end of ventricular contraction
418
What happens to aortic pressure during the rapid inflow phase of diastole?
Decreases slowly due to elasticity of the aorta and blood flow to the periphery.
419
What will you see on the graph during rapid inflow during diastole?
An incisura on the aortic pressure due to the sudden cessation of back flow toward the left ventricle
420
What happens during the diastasis stage of diastole?
A small amount of blood passively flows into the ventricles
421
On an ECG what occurs during diastasis?
A P wave
422
What do you see on an ECG during atrial systole?
QRS complex
423
What happens to ventricular volume during atrial s during atrial systole?
Increases by 20% and the end diastolic volume of each ventricle is 120 ml
424
What is the end diastolic volume of each ventricle?
120 ml
425
What happens to ventricular pressure during atrial systole?
It increases slightly
426
What do you see on the atrial pressure graph during atrial systole?
A small wave occurs on the graph due to atrial contraction
427
During atrial systole that occurs during diastole what is happening?
Atria contract and this accounts for 20% of ventricle filling during the cardiac cycle.
428
What do atria function as during atrial systole?
A primer pump or kick that increases ventricular pumping effectiveness by 20%
429
What happens to aortic pressure during atrial systole?
It decreases slightly
430
During the Ventricular Systole in the isovolumic contraction step, What do the valves do?
AV valves close and semilunar valves close
431
During the Ventricular Systole in the isovolumic contraction step, What do you hear?
S1 heart sound (Lubb)
| Closure of AV valves
432
During the Ventricular Systole in the isovolumic contraction step, What is the ventricular volume?
120ml
433
During the Ventricular Systole in the isovolumic contraction step, What is ventricular pressure?
Rapid increase from 0-90 mmhg
434
During the Ventricular Systole in the isovolumic contraction step, What is the aortic pressure?
80 mmhg
435
During the Ventricular Systole during Ventricular ejection What do the valves do?
AV valves close and semilunar valves open
436
During the Ventricular Systole during Ventricular ejection What do you see on a ECG?
A T wave
437
During the Ventricular Systole during Ventricular ejection, what is the ventricular volume?
ESV=50 mL
| SV=70 ml
438
During the Ventricular Systole during Ventricular ejection What is the ventricular pressure?
Increases from 90-120 mmhg
439
During the Ventricular Systole during Ventricular ejection What do the valves do?
120 mmhg
440
During Diastole, During isovolumeric relaxation (Phase 3) What do the valves do?
AV valves close and semilunar valves close.
441
During Diastole, During isovolumeric relaxation (Phase 3) What heart sound do you hear?
S2-(Dupp)-semilunar valves closing
442
During Diastole, During isovolumeric relaxation (Phase 3) What is the ventricular volume?
Decreased from previous stage to 50 ml
443
During Diastole, During isovolumeric relaxation (Phase 3) What is the ventricular pressure?
Rapid decrease from 90-0mmhg
444
During Diastole, During isovolumeric relaxation (Phase 3) What is the aortic pressure?
You will see an incisura on the graph and it is 100 mmhg
445
During Diastole, During Rapid inflow (Phase 4) What do the valves do?
AV valves open
| Semilunar valves close
446
During Diastole, During Rapid inflow (Phase 4) What is the ventricular volume?
50-90 ml
447
During Diastole, During Rapid inflow (Phase 4) What is the aortic pressure?
Decreases from 100-90 mmhg
448
During Diastole, During Diastasis (Phase 5) What do the valves do?
AV Valves open and Semilunar valves close
449
During Diastole, During Diastasis (Phase 5) What do you see on a ECG?
A p wave
450
During Diastole, During Diastatis(Phase 5) What is the ventricular volume?
90-96 ml
451
During Diastole, During Diastasis(Phase 5) What is the aortic pressure?
Decreases 90-85 mmhg
452
During Diastole, During Atrial systole(Phase 6) What do the valves do?
AV valves open and semilunar valves close
453
During Diastole, During Atrial systole (Phase 6) What do you see on an ECG?
QRS complex
454
During Diastole, During Atrial systole(Phase 6) What is the ventricular volume?
Adds 24 ml so EDV = 120 ml
455
During Diastole, During Atrial systole(Phase 6) What is the ventricular pressure?
0 mmhg
456
During Diastole, During Atrial systole(Phase 6) What is the aortic pressure?
Decreases 85 to 80mmhg
457
What is stroke volume?
The amount of blood pumped from each ventricle
458
What is cardiac output?
The amount of blood pumped from each ventricle per minute
459
What is ejection fraction?
How well the heart is pumping, what is the percentage of blood ejected by the ventricles each contraction.
460
What number does the American heart association use for staging heart failure?
Ejection fraction
| Normal is 55-60%
461
What are three factors that regulate stroke volume?
1. Preload
2. Afterload
3. Contractility
462
What volume do we want to regulate so there are equal amounts?
Ventricular volume
463
What is the external work of the heart?
The work required for normal stroke volume
464
What is preload?
the degree of tension (amt. of stretch) on the myocardium when it begins to contract
465
What does the frank starling mechanism refer to?
Greater stretch on cardiac muscle fibers prior to contraction increases force of contraction (stretching and releasing a rubber band)
466
What is preload measured as?
Measured as End diastolic pressure when ventricle is filled with blood = (EDV)
467
What is the cause of increased pre-load?
Increased stroke volume caused by hypervolemia, Aortic valve stenosis and regurgitation or pulmonary valve stenosis
468
What are some causes of decreased pre-load (decreased sV)?
Atrial Fib
| Hemorrhage
469
What is afterload?
The pressure that must be overcome before a semilunar valve can open
470
During Afterload pressure in the ventricle needs to be ______pressure in the aorta
greater
471
What causes increased afterload?
Decreased stroke volume such as atherosclerosis, hypertension, aortic stenosis
472
What causes decreased afterload?
increased stroke volume such as mitral valve regurgitation (endocarditis)
473
What does an increased afterload do to the frank starling curve?
shifts it down and to the right, which decreases SV (y axis) but increases left ventricular end diastolic pressure (x axis) (LVEDP)
474
An increase in afterload ____the velocity of fiber shortening
decreases
475
What does the decrease in fiber velocity shortening do to the rate of volume ejection in the ventricle?
reduces it so that more blood is left within the ventricle at the end of systole
476
What are positive inotropic agents?
Substances that increase contraction by enhancing Ca2+ inflow during cardiac action potential
477
What do positive inotropic agents stimulate?
The sympathetic nervous system (epinephrine and norepinephrine)
478
What does digitalis do?
Enhances Ca2+ inflow during cardiac action potential for dilated cardiomyopathy
479
What are negative inotropic agents?
substances that decrease contraction by blocking Ca2+ inflow during cardiac action potential
480
What do inotropic agents inhibit?
Sympathetic nervous system (anoxia, acidosis, increased K+ in intersticial fluid)
481
What does diltiazem do?
It is an enhanced Ca2+ blocker for hypertrophic cardiomyopathy
482
What is dilated cardiomyopathy?
Heart cannot contract as well
483
What is ventricular myopathy?
Increase in the size and mass of the right or left ventricle
484
Is ventricular myopathy always bad?
No, in athletes it enables the heart to pump more effectively. It is physiological and not abnormal. It is reversible
485
What are causes of pathogenic ventricular hypertrophy?
```
Ventricle adapting to increased stress either increased volume load (preload) or increased pressure load (afterload)
-valve disease
-cardiomyopathies
-genetic abnormalities
coronary heart disease
```
486
What is concentric hypertrophy?
Increase in afterload = chronic pressure overload due to chronic hypertension or aortic valve stenosis
487
Does the ventricular radius always change in concentric hypertrophy?
it may not
488
What happens to the heart wall in the ventricle in concentric hypertrophy?
wall thickness increases and the ventricle is capable of generating greater forces and higher pressures
489
why is ventricle filling compromised in ventricular hypertrophy?
compliance is reduced because ventricle is stiffer
490
what is eccentric hypertrophy?
there is an increase in preload (a volume increase) and afterload (increase in pressure) which leads to a volume and pressure overload
491
What happens to the ventricular chamber in eccentric hypertrophy?
Ventricular chamber radius is increased and wall thickness may increase
492
What is right sided heart failure?
A small amount of blood transfers from the pulmonary circulation to the systemic circulation
493
what increases as a result of right sided heart failure.
small increase in atrial pressure and a small increase in cardiac output.
494
What happens to systemic circulation in right heart failure?
large volume and capitance
495
What are some symptoms of right sided heart failure?
Congested liver leading to ascites
Jugular vein distension
peripheral distension (sweilling in feet and ankles)
496
What is pulmonary circulation?
Only in the lungs-it cannot store a lot of blood. it only has small volume and capitance
497
Why is there jugular distention in right heart failure
Blood backs up in the superior and inferior vena cava due to the increased volume and pressure but due to gravity it will be mostly towards the inferior vena cava
498
What happens when there is left sided heart failure
A large amount of blood transfers from the systemic circulation into the pulmonary circulation and causes a big increase in left atrial pressure
499
Why is there pulmonary edema in left heart failure?
due to the pressure increase in the left atria there will be a backup of blood into the bicuspid valve and then into lungs
500
How could we evaluate for heart failure?
Could hear it in the lungs, more shallow
radiography
increase in radioopacity will see fluid (cloudy)
501
What would we see in a echocardiogram in left heart failure?
Encarditis-inflammation of the endocardium
| lines the valve
502
What causes inflammation of the endocardium?
Bacteria enter the bloodstream during dental procedures, sx, iv drug use
Bacteria attach to heart valve and there are growths holes and scarring
valves get leaky
leaky valves can become fibrotic and calcified causing stiffness
if they are stiff papillary muscles can stretch or tear
503
How are we able to measure the electrical activity in the heart through electrodes?
when heart depolarizes and repolarizes electrical currents spread through the body
504
How many leads in bipolar leads?
3
505
What is an ECG?
A recording of the electrical difference between 2 leads
506
In lead 1 the right arm is
positive
