ILA Flashcards
1
Q
what is the first stage of protein synthesis?
A
transcription
2
Q
what is the second stage of protein synthesis?
A
translation
3
Q
where does transcription occur?
A
nucleus
4
Q
which enzyme carries out transcription?
A
RNA polymerase
NOT DNA polymerase
5
Q
what is transcription?
A
DNA sequence is copied to make an RNA molecule
6
Q
function of DNA helicase
A
unzips
breaks hydrogen bonds in the DNA double helix to unzip the DNA double helix and expose nucleotides
7
Q
function of topoisomerase
A
unwinds
relieves the supercoils
8
Q
function of single stranded binding proteins
A
SSBPs
stop DNA strands reannealing
9
Q
where does RNA polymerase bind?
A
at the TATA promoter region
10
Q
what is the promoter region?
A
TATA
11
Q
in what direction does RNA polymerase move?
A
3’ to 5’
12
Q
in what direction does RNA polymerase read?
A
3’ to 5’
13
Q
in what direction does RNA polymerase code?
A
5’ to 3’
14
Q
what are the stop codons?
A
UAA
UAG
UGA
15
Q
for transcription, are one or both strands copied?
A
one
16
Q
how does RNA polymerase work?
A
adds complementary mRNA nucleotides to the template strand to build an RNA chain
17
Q
does the RNA transcript contain the same information as the template or non-template strand?
A
non template strand
this is called the coding strand
18
Q
which nucleotides does RNA contain?
A
AUCG
19
Q
what is the start and end of an mRNA strand?
A
poly-A tail (end) and 5’ cap (start)
20
Q
product of transcription
A
pre mRNA
21
Q
what part of pre-mRNA is removed?
A
introns
22
Q
splicing
A
process of removing introns to form a fully coding strand
23
Q
what part of mRNA remains after splicing?
A
exons
24
Q
where does splicing occur?
A
in the nucleus
25
which enzymes carry out splicing?
spliceosomes
26
how does mRNA leave the nucleus?
nuclear pore
27
what is translation?
protein is synthesised from mRNA
28
where does translation occur?
ribosome in cytoplasm
29
3 bases on tRNA
anticodon
30
what does the tRNA anticodon bind to?
mRNA codon
31
3 DNA bases
triplet
32
describe translation
tRNA anticodons bind to mRNA codons
tRNA carries the correct amino acid
peptide bonds form between the amino acids
stop codon is reached
33
product of translation
polypeptide
34
where is mRNA broken down after translation?
cytosol
35
in which direction does mRNA move?
3' to 5' direction
36
transcriptome
the sum total of all the mRNA molecules
37
what is an SNP?
single nucleotide polymorphism
DNA sequence variation when a single nucleotide is substituted
38
consequences of an SNP
can result in a different codon which generates a different protein and thus disease
can affect recognition/ promoter/ termination sequences to change the length of proteins
most don't (e.g if in an intron)
39
name two diseases caused by an SNP
cystic fibrosis
sickle cell anaemia
40
what is sickle cell haemoglobin?
HbS
41
genetic cause of HbS
SNP of adenine to thymine
GAG becomes GTG on 17th nucleotide
glutamic acid to valine
different primary structure
42
difference between sickle cell anaemia and sickle cell trait
sickle cell anaemia - both genes that code for haemoglobin are abnormal (HbSS)
sickle cell trait - only one chromosome carries the abnormal allele
43
how many of the beta subunits are replaced by HbS in sickle cell disease
just one
44
which subunits does haemoglobin have?
2 alpha
2 beta
45
what is normal adult haemoglobin?
HbA
46
is sickle cell anaemia autosomal dominant or recessive?
recessive
47
functional changes in HbS
red blood cells become sickle shaped
cells don't live as long
lower affinity for oxygen
gets stuck in blood vessels
reduced oxygen delivery to muscles
48
primary structure of a protein
sequence of amino acids
covalently bonded
49
secondary structure of a protein
alpha helices and beta pleated sheets
hydrogen bonds
50
tertiary structure of a protein
3D structure of a single chain of amino acids
- London forces
- hydrogen bonds
- ionic bonds
- disulphide bonds
51
quaternary structure of a protein
the presence of more than one polypeptide chain
52
what fraction of water is in the intracellular fluid compartment?
2/3
53
what fraction of water is in the extracellular fluid compartment?
1/3
54
what volume of water is in the intracellular fluid compartment?
28L
55
what volume of water is in the extracellular fluid compartment?
14L
56
what volume of water is in the plasma fluid compartment?
3L
57
what volume of water is in the interstitial fluid compartment?
11L
58
what percentage of body sodium is exchangeable?
70%
59
what percentage of body sodium is bone crystal?
30%
60
what percentage of the total body sodium is in the ECF?
50%
61
what percentage of body sodium is in the ICF?
5%
62
what percentage of the body weight is water?
60%
63
define osmolality
concentration of a solution expressed as solute particles per kg
64
define osmolarity
concentration of solution expressed as solute particles per L
65
define oncotic pressure
pressure exerted by plasma proteins on capillary wall
force keeping water in a capillary
66
define osmosis
process by which molecules within a solvent pass through a semi-permeable membrane from a high to low concentration
67
what is hydrostatic pressure?
force pushing water out of the capillary
68
what part of the brain detects a low water potential?
osmoreceptors in the hypothalamus
69
what does the hypothalamus trigger?
release of ADH from the posterior pituitary
70
where is ADH released from?
posterior pituitary gland
71
what stimulates the posterior pituitary?
hypothalamus
72
what does ADH act on?
kidney
73
effect of ADH
increased fluid retention
74
is urine diluted or concentrated in the loop of Henle?
diluted
75
where is urine concentrated?
distal tubules and collecting ducts
76
is the descending limb of the loop of Henle permeable to sodium chloride and water?
impermeable to sodium chloride
permeable to water
77
is the ascending limb of the loop of Henle permeable to sodium chloride and water?
permeable to sodium chloride
impermeable to water
78
where is renin released from?
granular cells (juxtaglomerular cells) of the renal juxtaglomerular apparatus
79
what triggers renin release?
1. reduced sodium delivery to DCT detected by macula densa
2. reduced perfusion pressure in the kidney detected by baroreceptors in the afferent arteriole
3. Sympathetic stimulation of the JGA via β1 adrenoreceptors
80
what inhibits renin release?
ANP
atrial natriuretic peptide
81
when is ANP released?
released by stretched atria in response to increases in blood pressure
82
where is angiotensinogen made?
liver
83
what converts angiotensinogen to angiotensin I?
renin
84
what converts angiotensin I to angiotensin II?
ACE
angiotensin converting enzyme
85
effects of angiotensin II
arteriolar vasoconstriction
Na+ reabsorption in the kidneys
triggers the sympathetic nervous system to release noradrenaline
aldosterone release from the adrenal cortex
hypothalamus - increases thirst sensation and stimulates anti-diuretic hormone (ADH) release
increases the volume of ECF and increases blood pressure
86
where is aldosterone released from?
zona glomerulosa of the adrenal cortex of adrenal gland
87
effect of aldosterone
acts on principal cells of the collecting ducts of the nephron
increases absorption of sodium and water into the blood
increases the excretion of potassium
88
where is albumin produced?
liver
89
what is the main plasma protein contributing to oncotic pressure?
albumin
90
what does low albumin cause?
oedema
91
what is low albumin levels called?
hypoalbuminemia
92
why does hypoalbuminemia cause oedema?
fluid moves from capillaries into interstitium
93
key routes of water loss from the body
urine
faeces
sweat
breath
vomiting
94
what are sensible water losses?
can be measured
95
what are insensible water losses?
cannot be measured
96
examples of insensible water losses
breath, sweat, faeces
97
give examples of sensible water loss
urine
98
what is vasopressin also called?
ADH
99
how does ADH/ vasopressin work?
binds to receptors on the collecting duct membrane
causes intracellular production of cAMP which activates protein kinase, which phosphorylates proteins that increase the rate of fusion of vesicles containing aquaporins with the membrane
100
what stimulates thirst?
an increase in plasma osmolarity
decrease in extracellular fluid volume
angiotensin II
101
what happens when renal blood flow is reduced?
juxtaglomerular cells convert prorenin to renin in the kidneys
102
what are the components of the juxtaglomerular apparatus?
1. macula densa - part of DCT
2. juxtaglomerular cells (granular cells) - afferent arterioles
3. extraglomerular mesangial cells
103
where is the macula densa?
DCT
104
function of the macula densa?
sensitive to changes in NaCl
105
where are the juxtaglomerular (granular) cells?
afferent arteriole
106
function of the juxtaglomerular cells
release renin
107
where are mesangial cells?
central stalk of the glomerulus
108
what is the difference between the action of ADH and aldosterone?
ADH increases the nephron's permeability to water whereas aldosterone increases the reabsorption of both sodium and water
109
effect of sodium on ECF volume, blood volume and blood pressure
an increase in Na+ in ECF =
- increased ECF volume
- increase in blood plasma volume
- increased blood pressure
a decrease in Na+ in ECF
- ECF decrease
- blood volume decreases
- blood pressure decreases
110
where is the thirst centre?
hypothalamus
111
normal homeostatic response to excess fluid
decrease in ECF osmolality detected by osmoreceptors
- water moves into ICF from ECF
- stops the stimulation of the thirst centre in the hypothalamus
- inhibits ADH in the posterior pituitary, leading to an increased urine volume
112
where are osmoreceptors found?
hypothalamus
113
consequence of excess water consumption
hyponatremia
114
normal homeostatic response to dehydration
increase in ECF osmolality detected by osmoreceptors
- water moves from ICF to ECF
- stimulates thirst centre of hypothalamus
- ADH released from posterior pituitary to decrease urine volume
115
state how much water a 70kg man has, and how much of this is intracellular, interstitial and intravascular
42L in total
28L is intracellular
11L is interstitial
3L is intravascular
116
estimated plasma osmolality
2[Na] + 2[K] + urea + glucose mol/L
117
normal range for plasma osmolality
270-310
118
where is ADH made?
hypothalamus
119
where is ADH stored?
posterior pituitary
120
where does ADH act?
kidney
121
where is aldosterone produced?
adrenal cortex of adrenal gland
122
where is aldosterone secreted from?
adrenal cortex
123
where is renin produced and secreted from?
juxtaglomerular cells of the kidney
124
equation for cardiac output
stroke volume x heart rate
125
what is cardiac output?
volume of blood pumped by the heart per minute
126
unit of cardiac output
L/ minute
127
what factors affect heart rate?
autonomic innervation, hormones, fitness levels, age
128
equation for stroke volume
SV = EDV - ESV
stroke volume = end diastolic volume - end systolic volume
129
what factors affect stroke volume?
contractility, preload, after load, heart size, fitness level, gender, duration of contraction
130
what is contractility?
how hard/ fast muscles flex
131
what is preload?
degree of myocardial distension prior to shortening
132
what is afterload?
force against which ventricle must act in order to eject blood
133
what does the LAD supply?
anterior 2/3 of interventricular septum, lateral wall of left ventricles and anterolateral papillary muscle
134
what does the right coronary artery supply?
SAN and AVN
right ventricle, right atrium
135
equation for blood pressure
blood pressure = cardiac output x total peripheral resistance
BP = CO x TPR
136
equation for pulse pressure
PP = SP - DP
pulse pressure = systolic pressure - diastolic pressure
137
equation for mean arterial pressure
MAP = DP + 1/3PP
mean arterial pressure = diastolic pressure + 1/3pulse pressure
138
what is pulse pressure?
difference between systolic and diastolic pressure
139
what is mean arterial pressure?
average arterial pressure throughout one cardiac cycle, systole, and diastole
140
what is stroke volume?
volume of blood pumped out of the left ventricle of the heart during each systolic cardiac contraction
141
which factors affect blood pressure?
vasopressin (ADH), aldosterone, ANP, haemorrhage, sweating, stressors, hydration, weight, muscular activity, posture
142
average cardiac output
5L/min
143
what is Frank Starling's Law?
the greater the stretch of myocardium before systole, the stronger the ventricular contraction
stroke volume of the heart increases in response to increased volume of blood in ventricles before contraction
stroke volume increases with EDV
144
what is the physiology behind the Frank-Starling Law?
increased force because actin and myosin filaments are brought to more optimal degree of overlap for force generation
145
normal range of EDV
110-120ml
146
when is the cardiac cycle initiated?
SAN fires
147
what does firing of the SAN cause?
atrial depolarisation
148
how is atrial depolarisation represented on an ECG?
p wave
149
when does atrial contraction start?
shortly after the p wave
150
consequence of atrial contraction
blood enters ventricles
151
why doesn't ventricular volume start at zero?
there is a passive movement of blood from the atria to the ventricles as the AV valves are open due to the pressure gradient
152
why do the AV valves shut?
ventricular pressure rises above atrial pressure
153
what causes the first heart sound?
closing of AV valve
154
how is ventricular depolarisation represented on an ECG?
QRS complex
155
why does the ventricular volume initially not change?
semilunar valves are shut
156
what is isovolumetric contraction?
ventricles contract when the semilunar valves are shut, so the volume does not change
157
what is the rapid ejection phase?
ventricular pressure exceeds pressure in the aorta and pulmonary artery
semilunar valves open and blood is ejected out of the ventricles
158
how is ventricular repolarisation represented on an ECG?
T wave
159
what is the second heart sound?
ventricular pressure falls below aortic pressure
semilunar valves shut
160
what is isovolumic relaxation?
ventricles start to relax with all valves closed
161
what increases ventricular pressure on the graph?
contraction
filling with blood
162
when is most myocardium perfused and why?
diastole
subendocardial coronary vessels are compressed during ventricular systole which results in momentary retrograde blood flow
however, the epicardial coronary vessels remain open
163
blood supply to the heart muscles
coronary arteries
164
where does venous blood from the heart muscle go?
cardiac veins drain into coronary sinus, which drains into right atrium
165
what does the right coronary artery supply?
right ventricle, right atrium, SAN, AVN
septum
166
which is the largest coronary artery?
LAD
167
where does the LAD run?
anterior ventricular groove
168
what is the most common coronary artery occlusion?
LAD
169
how is the LAD occluded?
plaque from cholesterol
atherosclerosis
170
territory supplied by the LAD
anterior 2/3 interventricular septum
lateral wall of left ventricle
anterolateral papillary muscle
171
consequence of occlusion of LAD
block impulse conduction between atria and ventricles
left/ right heart block
172
symptoms of occlusion of LAD
infarction of conducting system, atheroma production, ST elevation, heart block and arrhythmia, (impulses cannot travel down left and right ventricle branches simultaneously), or heart failure, prolonged PR (type 1 heart block), nausea, shortness of breath, pain in head, jaws, arms
173
which type of coronary occlusion is called a widowmaker, and why?
LAD
high mortality rate
174
consequence of occlusion of right coronary artery
conduction of nodes affected, contractions become out of rhythm or slower, inefficient blood flow (ischaemia) and potential backflow
175
symptoms of occlusion of right coronary artery
chest pain, if complete block then heart muscle dies and MI results, pain radiating in arms, shoulders, jaw, neck or back, shortness of breath, weakness and fatigue
176
ways to reduce risk of heart problems
cut down alcohol intake
stop smoking
be more physically active
vaccination
177
how many units of alcohol per week?
14 units
178
effect of sympathetic stimulation on peripheral blood vessels
vasoconstriction to increase blood pressure
179
are peripheral blood vessels innervated by parasympathetic fibres?
no
180
the occlusion of which coronary artery is most likely to result in a fatal heart attack?
left main coronary artery
181
the occlusion of which coronary artery is most likely to result in a fatal heart attack and why?
left main coronary artery
supplies the largest area of heart muscle
182
which nerve supplies the pericardium?
phrenic
phrenic supplies the 3 p's
pericardium, pleura, peritoneum
183
what is end diastolic volume?
total amount of blood in the ventricle just before systole
184
average stroke volume?
70ml
185
mitral valve stenosis
narrowing of the mitral valve
left atrium has to contract with more force to generate more pressure to overcome the valve stenosis
increase in left atrium pressure
186
what is the embryological ductus arteriosus?
connects the pulmonary artery to the aorta
187
what does the embryological ductus arteriosus become?
ligamentum arteriosum
188
what is the foramen ovale?
hole between the right and left atrium
189
what type of heart failure causes pulmonary oedema and why?
left heart failure
blood backs up in the pulmonary system
190
what type of heart failure causes peripheral oedema?
right heart failure
191
failure of both sides of the heart
biventricular failure
192
movement of oxygen and carbon dioxide in and out of the respiratory system
oxygen rich air from environment - nasal cavities - pharynx - trachea - bronchi - bronchioles - alveoli - oxygen and carbon dioxide exchange at alveoli - bronchioles - bronchi - trachea - pharynx - nasal cavities - carbon dioxide rich air to the environment
193
how is physiological dead space calculated?
anatomical (conducting) dead space + alveolar dead space
194
what is conducting/ anatomical dead space?
volume of the conducting airways
from the nose, mouth and trachea to the terminal bronchioles
195
what is the alveolar dead space?
comprises alveoli which are ventilated, but not supplied by the pulmonary arterial circulation
196
where is greatest resistance to air flow?
segmental bronchi
197
if diameter is doubled, how does resistance change?
decreases by 1/16
198
if diameter is halved, how does resistance change?
increases 16-fold
199
what is Poiseuille's Law?
R = 8ul/pi x r^4
200
two types of pulmonary stretch receptors
slow and rapidly adapting
201
what is the Hering-Breuer reflex?
inhibits inspiration
smooth muscle response to stretch
202
what are juxtacapillary receptors?
in the alveolar walls, close to capillaries
also called J receptors
respond to
- irritants
- noxious agents
- interstitial fluid volume
leads to bronchoconstriction
203
space between pleural membranes
intrapleural cavity
204
what is type 1 respiratory failure?
hypoxemia
inadequate oxygen
205
definition of type 1 respiratory failure
low level of oxygen with a normal or low level of carbon dioxide
206
definition of type 2 respiratory failure
high carbon dioxide and low oxygen levels
207
causes of type 1 respiratory failure
caused by conditions that affect oxygenation such as
- hypoventilation
- ventilation/ perfusion mismatch e.g pulmonary embolism
- low ambient oxygen at altitude
pneumonia
- shunt - oxygen blood mixes with non-oxygenated blood
208
what is type 2 respiratory failure?
pump failure
ventilation failure due to hypercapnia/ hypoxaemia
209
causes of type 2 respiratory failure
increased airway resistance
- COPD, asthma, suffocation
reduced breathing effort
- drugs
- brain stem lesion
reduction in the area of the lung available for gas exchange e.g chronic bronchitis
210
what is the main driver for respiration?
carbon dioxide
211
upper airways
nose, nasal cavity, pharynx, larynx
212
lower airways
trachea, bronchi, bronchioles, alveoli
213
compare the right and left main bronchus
right is shorter and more vertically aligned
214
how many lobar bronchi does the left lung have?
two
215
how many lobar bronchi does the right lung have?
three
216
what do segmental bronchi supply?
each supplies a bronchopulmonary segment of the lung
217
what are the two pontine respiratory centres?
pneumotaxic and apneuistic
218
what are the two medullary respiratory groups?
dorsal respiratory group
ventral respiratory group
DRG and VRG
219
which respiratory group is predominantly active during inspiration?
DRG
220
which respiratory group is active during inspiration and expiration?
VRG
221
are the DRG and VRG bilateral or unilateral?
bilateral
222
function of the apneustic centre
positive firing
stimulates inspiration
223
function of the pneumotaxic centre?
negative firing
antagonist to the apneustic centre
signals to the dorsal respiratory group
stimulates the external intercostals and diaphragm
224
function of the dorsal respiratory group
signals to the ventral respiratory group
stimulates internal intercostals and accessory respiratory muscles
225
where are central chemoreceptors?
ventral lateral surface of medulla
226
function of central chemoreceptors
detect changes in pH of spinal fluid
so carbon dioxide levels
227
where are peripheral chemoreceptors?
be specific
aortic body - aortic arch
carotid body - bifurcation of the common carotid
228
what do peripheral chemoreceptors in the aortic body detect? and what do they not detect?
changes in blood oxygen and carbon dioxide but not pH
229
what do peripheral chemoreceptors in the carotid body detect?
changes in blood oxygen, carbon dioxide and pH
230
do central chemoreceptors desensitise?
yes
231
do peripheral chemoreceptors desensitise?
no
232
which chemoreceptors have the greater impact on ventilation?
peripheral
233
why is carbon dioxide the main driver to breathe?
chemoreceptors respond to small changes in carbon dioxide but only large oxygen changes
234
what happens when there is an increase in carbon dioxide levels?
decrease in blood pH due to production of H+ ions from carbonic acid when carbon dioxide combines with water
respiratory centre in medulla sends nervous impulses to the external intercostal muscles and diaphragm to increase breathing rate and lung volume during inhalation
235
what happens when a decrease in oxygen is detected?
by peripheral chemoreceptors
low arterial oxygen stimulates chemoreceptors, increasing number of action potentials sent to ceentre in medulla
leads to an increase in ventilation, meaning more oxygen reaches the alveoli
236
how are changes in carbon dioxide detected?
increased H+ concentration in extracellular fluid and arterial blood
increased stimulation of centre in the medulla and an increase in ventilation
237
what does the ventral respiratory group stimulate?
both inspiratory and expiratory movements
238
what does the dorsal respiratory group stimulate?
primarily inspiration
239
equation for flow of air in/ out of lungs
flow = (p(alv) -p(atm))/R
p(alv) is alveolar pressure
p(atm) is atmospheric pressure
R is a constant
240
when flow is negative, in which direction does air flow?
into lungs
241
is alveolar pressure is less than atmospheric pressure, where does air flow?
into lungs
242
what is Boyle's Law, and what does it mean?
P1V1 = P2V2
at a constant temperature, an increase in the volume of a gas will cause a decrease in pressure
243
equation for transpulmonary pressure
P(tp) = P(alv) - P(ip)
the difference between the alveolar pressure and intrapleural pressure
with intrapleural pressure being the pressure in the pleural space
244
what is transpulmonary pressure?
difference in pressure between the inside and outside of the lungs
245
is transpulmonary pressure always negative or positive relative to atmospheric pressure and why?
positive
because the lungs must always have some air in them
246
what is P(ip)?
pressure of the intrapleural fluid surrounding the lungs
247
is P(ip) negative or positive and why?
negative
the elasticity of the lungs and the chest wall mean they tend towards collapsing and enlarging respectively, so they move apart from each other
this reduces the pressure of the intrapleural fluid
248
what is respiratory failure?
a syndrome in which the respiratory system fails in one or both of its gas exchange functions: oxygen and carbon dioxide elimination
249
what is a drop in arterial oxygen?
hypoxemia
250
what is a rise in arterial carbon dioxide levels?
hypercapnia
251
define hypercapnia
PaCO2 > 6kPa
252
define hypoxemia
PaO2 < 8kPa
253
definition of type 2 respiratory failure
high carbon dioxide and low oxygen levels
254
role of saliva
enzymes, antibacterial, pH control, taste, lubrication
255
muscular composition of the oesophagus
upper 1/3 skeletal muscle
lower 2/3 smooth muscle
256
innervation of the different parts of the oesophagus?
upper 1/3 skeletal muscle supplied by superior laryngeal and recurrent laryngeal nerve
lower 2/3 smooth muscle supplied by enteric nervous system
257
two names for the sphincter at the entrance of the stomach
lower oesophageal sphincter
cardiac sphincter
258
what is GORD?
stomach acid refluxes into oesophagus
oesophageal mucosa is exposed to stomach acid, bile and pepsin which damages the lining
259
what can cause GORD?
cardiac sphincter weakened (also called the LES)
takes less pressure for fluid to move back up
poor oesophageal motility
260
passage of food from the mouth to the duodenum
mouth, pharynx, oesophagus, stomach, duodenum
261
at which spinal level is the oesophagus continuous with the pharynx?
C6
262
at which spinal level does the oesophagus emerge through the diaphragm?
T10
263
arterial supply of the oesophagus
left gastric artery
oesophageal branches from the left inferior phrenic artery
264
which regions of the abdomen does the stomach lie in?
umbilical, epigastric and left hypochondriac
265
regions of the stomach
cardia, fundus, body, pylorus
266
function of the stomach
temporary food storage
mixing and breakdown of food
digestion (gastric juices and digestive enzymes from mucosa)
267
function of the duodenum
receives partially digested food (chyme) from stomach and secretions from the pancreas, liver and gallbladder mix with chyme in duodenum to facilitate chemical digestion
268
in the oesophagus, what is the orientation of the circular and longitudinal muscle layers?
inner circular
outer longitudinal
269
what is a primary peristaltic wave?
occurs when food enters the oesophagus during swallowing and forces food down to stomach
270
what is a secondary peristaltic wave?
if a bolus gets stuck, stretch receptors in oesophageal lining are stimulated and a second wave happens
271
what does GORD stand for?
gastro-oesophageal reflux disease
272
which cells make HCl?
parietal cells
273
physiology of acid production in the stomach
water and carbon dioxide combine in the parietal cell to form carbonic acid (H2CO3)
this is catalysed by carbonic anhydrase
carbonic acid dissociates into a proton (H+) and a bicarbonate (HCO3-)
H+ enters the stomach lumen via an H+ - K+ ATPase on the apical membrane
this channel uses ATP to exchange k+ ions in the stomach with H+ ions in the parietal cells
bicarbonate ion is transported out of the cell into the blood in exchange for a chloride ion (Cl-) using an ion exchanger located on the basolateral membrane
chloride ion is transported into the stomach lumen through a chloride channel
the H+ and Cl- associate in the stomach lumen to form HCl
274
3 ways of increasing acid production
ACh from vagus nerve
- released firstly during the cephalic phase of digestion
- activated upon seeing food
- directly stimulates parietal cells
- also produced during the gastric phase of digestion when intrinsic nerves detect distension of the stomach, stimulating ACh production
gastrin
- hormone secreted from stomach G cells
- G cells activated by vagus nerve
- gastrin released into blood until it reaches the parietal cells
- gastrin binds to CCK receptors on the parietal cells
enterochromaffin like cells in the stomach secrete histamine which binds to H2 receptors on the parietal cells
these cells secrete histamine in response to the presence of gastrin and ACh
275
decreasing stomach acid production
low pH
- accumulation of acid in the stomach between meals leads to a lower pH
- inhibits gastrin secretion via the production of somatostatin from D cells
when food passes into duodenum, enterogastric reflex
- inhibitory signals sent to stomach via enteric nervous system
- signals to medulla to reduce vagal stimulation of the stomach
presence of chyme in the duodenum stimulates entero-endocrine cells to release cholecystokinin and secretin
- both complete digestion and inhibit gastric acid secretion
276
defences of gastric and duodenal mucosa against acid damage
produce HCO3-
- alkaline neutralises stomach acid on top of epithelial surface
mucous production
277
which glands in the duodenal mucosa secrete alkaline mucus?
Brunner's glands
278
what is dyspepsia?
group of symptoms altering doctors to consider disease of the upper GI tract
- nausea
- vomiting
- heartburn
279
risk factors for GORD
family history
older age
obesity
hiatus hernia
280
risk factors for reflux
overweight
- extra pressure on stomach/ diaphragm
smoking
- loosen sphincter
alcohol
- damage stomach lining/ glands
large meals
- stomach stretches increasing pressure on lower oesophageal sphincter
pregnancy
- more pressure on sphincter
- generalised smooth muscle relaxation due to progesterone
281
why can acid reflux cause a sore throat?
acid enters pharynx
282
what divides the liver into anatomical left and right lobes?
falciform ligament
283
how is the liver divided into a functional left and right?
line vertically halfway through the IVC and gallbladder
284
which lobes are present on the visceral surface of the liver?
caudate and quadrate
285
which accessory lobe of the liver is superior?
caudate
286
what separates the caudate and quadrate?
porta hepatis
287
what is the porta hepatis?
bundle of blood vessels, nerves and ducts entering or leaving the liver
excludes the hepatic vein which drains into the IVC
288
arrangement of hepatocytes
hexagonal lobules
portal triad at each corder
surround a central vein
289
what is the portal triad?
venule of a portal vein
arteriole of hepatic artery
bile duct
along with lymphatics and vagus nerve fibres
290
function of sinusoids
deliver blood to central vein
291
what is the space of Disse?
between the sinusoid endothelium and hepatocytes
292
what does the space of Disse contain?
blood plasma
293
where are Ito cells found?
space of Disse
294
another name for Ito cells
hepatic stellate cells
295
function of Ito cells
store fat
produce proteins such as collagen when liver is damaged
296
action of Kupffer cells in the walls of the sinusoids
phagocytose blood borne pathogens
297
what happens to old erythrocytes in the liver, bone marrow and spleen?
phagocytosed by macrophages
globin portion of Hb is metabolised into amino acids and reused for protein synthesis
organelles are recycled
haem portion is broken down into biliverdin for transport in the blood
the iron ions bind to the blood protein transferrin for transport
unused haem groups can be used for haematopoesis or converted into bilirubin and used to make bile in the liver
iron ions can be transferred into ferritin for storage in the liver
298
where are old red blood cells broken down?
spleen, liver, bone marrow
299
how are old red blood cells broken down?
macrophages
300
when red blood cells are broken down, what happens to the globin portion?
it is protein
metabolised into amino acids and reused for protein synthesis
301
when red blood cells are broken down, what happens to the cell organelles?
recycled
302
when red blood cells are broken down, what happens to the haem groups?
separated into iron ions and haem group
haem group broken down into biliverdin for transport in the blood
biliverdin is used in haemopoesis or converted into bilirubin for bile
iron ions bind to the blood protein transferrin for transport
iron ions stored as ferritin in liver or used for haemopoiesis
303
describe the formation and recycling of bile
formed from haem group
haem portion is converted to biliverdin by haem oxygenase (Fe2+ is liberated)
biliverdin is converted into unconjugated bilirubin by biliverdin reductase 6
unconjugated bilirubin undergoes biotransformation to form bilirubin in the liver
bilirubin dissolves in bile, and through digestive processes end up in the small intestine
bacteria remove glucuronic acid to form urobilinogen
urobilinogen is recycled by enterohepatic circulation or oxidised by different bacteria to form stercobilin
stercobilin is excreted in faeces to give it a brown colour
304
subcostal plane
10th costal cartilage
lower most bony point of the rib cage
body of L3 vertebra
305
which spinal level does the inferior mesenteric artery arise from?
L3
306
which part of the duodenum is at L3?
third
307
transtubecular plane
unites the tubercles of the iliac crests
upper border of L5
confluence of the common iliac veins (i.e IVC origin) lie on this plane
308
where and how does the IVC originate?
confluence of the common iliac veins
L5
309
what is haemolytic/ pre-hepatic jaundice?
increased unconjugated bilirubin due to excess erythrocyte breakdown, exceeding the capacity of the liver to transport it
310
which jaundice is present in newborns and why?
haemolytic/ pre-hepatic
foetal haemoglobin is broken down
311
causes of pre-hepatic jaundice
infection, trauma to erythrocytes, sickle cell anaemia, drugs and toxins and antibodies
312
signs of haemolytic/ pre-hepatic jaundice
absence of bile pigments in urine and normal stool colour
this is because unconjugated bilirubin is insoluble so not filtered by kidney and bile can circulate to enter the intestine as normal
313
what is hepatocellular/ hepatic jaundice?
hepatocytes are damaged so unable to transport bilirubin into the biliary system, so it enters the bloodstream instead
the bilirubin may be conjugated
314
which type of bilirubin is elevated in haemolytic/ pre-hepatic jaundice?
unconjugated
315
which type of bilirubin is elevated in hepatocellular/ hepatic jaundice?
conjugated and unconjugated
316
what causes heptocellular/ hepatic jaundice?
hepatitis, cirrhosis and congestive liver disease
317
signs of hepatocellular/ hepatic jaundice
dark amber urine due to water soluble conjugated bilirubin that has been filtered by the kidneys
normal stools because some bile pigment manages to be excreted into the biliary tract and intestine
318
what is cholestatic/ obstructive/ post-hepatic jaundice?
obstruction in the biliary system due to anatomical obstructions e.g gallstones, cancers of the pancreas of ampulla of Vater
319
what causes post hepatic jaundice?
hepatitis
intrahepatic cholestasis
extra hepatic cholestasis
320
signs of post-hepatic jaundice
amber urine - bilirubin is conjugated so can be filtered by kidneys
pale stools as the bile cannot enter the intestine
itching of the skin as bile salts build up below skin, triggering an inflammatory response
321
function of the frontal lobe
motor cortices and association areas
regions controlling behaviour, decision making and personality (prefrontal association area)
Broca's area in the left frontal lobe - responsible for fluent speech
322
role of Broca's area
motor control of speech
323
consequence of damage to Broca's area
expressive aphasia
no motor control of speech
when you know what you want to say, but you have trouble saying or writing your thoughts
324
blood supply to Broca's area
middle cerebral artery
325
blood supply to Wernicke's area
middle cerebral artery
326
role of temporal lobe
auditory cortices
medial temporal lobe for long term memory and emotion
- hippocampus
- entorhinal and perirhinal cortex
limbic system
Wernicke's area for understanding speech and written language
327
role of Wernicke's area
understanding speech and written language
328
consequence of damage to Wernicke's area
receptive/ fluent aphasia
when someone is able to speak well and use long sentences, but what they say may not make sense
329
function of the parietal lobe
somatosensory cortices
330
where is the primary somatosensory cortex?
postcentral gyrus
parietal lobe
331
function of the occipital lobe
vision
332
where exactly is the primary visual cortex?
calcarine fissure of occipital lobe
333
function of the cerebellum
balance, posture, receiving information from vestibulocochlear organs
334
symptoms of cerebellar damage
DANISH
dysdiadokokinesia, ataxia, nystagmus of eyes, intention tremor, slurring of speech, heel-shin test positive
335
parts of midbrain
tectum and tegmentum
336
parts of the brainstem
midbrain, pons, medulla
337
grey matter surrounding the cerebral acqueduct
periaqueductal grey
338
function of the pons
breathing, sleeping, swallowing, bladder control
339
function of the medulla
autonomic regulation, corticospinal pyramids
340
what does the anterior cerebral artery supply?
corpus callosum and medial region of the brain
341
what does the middle cerebral artery supply?
lateral parts of the hemisphere and anterior deep structures
342
what does the posterior cerebral artery supply?
posterior region and the posterior inferior structures
e.g caudate nucleus, occipital lobe
343
draw and label the circle of willis
.
344
what is myasthenia gravis?
autoimmune destruction of nicotinic ACh receptors
345
role of upper motor neurons
cell body originates in the cerebral cortex or brainstem and terminates within the brainstem or spinal cord
346
role of lower motor neurons
alpha motor neurons exiting the spinal cord to innervate muscles
347
cause of upper motor neuron weakness
brain injury and trauma
capsular stroke
spinal cord lesion
cerebral palsy
348
symptoms of upper motor neuron lesion
effects will be mainly contralateral if damaged above the medulla, or ipsilateral if below
develop spasticity and stiffness over time
abnormal increased reflexes, such as babinski's sign
clonus
349
cause of lower motor neuron weakness
peripheral trauma
Guillain-Barre syndrome
botulism
nonclassical polio
cauda equina syndrome
amyotrophic lateral sclerosis
350
symptoms of lower motor neuron lesion
weakness and atrophy of muscle
spontaneous neuronal discharge causing fasciculations
loss of reflexes - areflexia
351
does the frontal lobe control movement in the ipsilateral or contralateral part of the body?
contralateral
352
which hemisphere is dominant in a right handed person?
left
353
which sulcus separates the frontal and parietal lobes?
central sulcus
354
function of the primary somatosensory cortex
receive and interpret sensations e.g pain, touch, pressure
355
which cranial nerves originate from the cerebrum?
olfactory and optic
356
two major groups of descending tracts
pyramidal and extrapyramidal
357
why do the pyramidal tracts have that name?
they pass through the medullary pyramids of the medulla oblongata
358
where do pyramidal tracts originate?
cerebral cortex
359
what are descending tracts?
pathways by which motor signals are sent from the brain to lower motor neurons in efferent neurons
the lower motor neurons then directly innervate muscles to produce movement
360
function of the pyramidal tracts
voluntary control of body and face musculature
361
which pyramidal tract supplies the musculature of the body?
corticospinal
362
which pyramidal tract supplies the facial and neck muscles?
corticobulbar
363
where do the corticobulbar tracts begin?
lateral aspect of primary motor cortex
364
path of corticobulbar tracts
cortex, descends through internal capsule, crus cerebri, brainstem (pons and medulla), terminate on motor nuclei of cranial nerve
365
where do extrapyramidal tracts originate?
brainstem
366
what aspect of the primary motor cortex supplies the facial and neck muscles?
corticobulbar tract - lateral
367
function of extrapyramidal tracts
involuntary and autonomic control of musculature
carry motor fibres to spinal cord from brain stem
368
name the extrapyramidal tracts
vestibulospinal, reticulospinal, rubrospinal, tectospinal
369
function of the vestibulospinal tract
balance and posture
has medial and lateral pathways
370
function of the medial reticulospinal tract
facilitates voluntary movement by increasing muscle tone
371
function of the lateral reticulospinal tract
inhibits voluntary movements by decreasing muscle tone
372
function of the rubrospinal tract
fine control of hand movement
373
function of the tectospinal tract
coordinates movement of head in relation to visual stimuli
374
where do upper motor neurons travel between?
brain and brainstem to ventral horn of the spinal cord
375
where do lower motor neurons travel between?
ventral horn of the spinal cord to the peripheral muscles
376
what is the cortical homunculus?
contains the motor and sensory homunculus
region of the brain dedicated to processing motor and sensory functions for different parts of the body
377
motor homunculus
motor processing for different bodily anatomical positions
378
where does the motor homunculus handle signals coming from?
premotor area of frontal lobes
379
sensory homunculus
sensory processing for different anatomical positions
380
where does the sensory homunculus handle signals coming from?
thalamus
381
what is the corona radiata?
white matter sheet that continues ventrally as the internal capsule and dorsally as the centrum semi ovale
group of nerves key for sending messages between regions of the brain
382
internal capsule
white matter structure situated in the inferomedial part of the cerebral hemisphere of the brain, carrying information past the basal ganglia
connects the midbrain and cerebral cortex
383
which blood vessels are part of the anterior circulation?
anterior and middle cerebral arteries
384
which blood vessels are part of the posterior circulation?
posterior cerebral, vertebral, basilar and their branches
385
what links the posterior and anterior circulations?
circle of Willis
386
largest terminal branch of the internal carotid arteries
middle cerebral artery
387
occlusion of which artery causes hemianopia?
posterior cerebral artery
this stroke affects the visual pathways from the optic chiasm onwards towards the occipital lobe
388
can a stroke of the posterior circulation also cause muscle weakness? why?
corticospinal tracts have to travel through the brainstem and spinal cord
389
which neurotransmitter do upper motor neurons use?
glutamate
390
which receptors detect the neurotransmitter glutamate?
glutamatergic receptors
391
function of lower motor neurons
receive impulses from the upper motor neurons and connect the spinal cord and brainstem to the muscle fibres
392
do upper or lower motor neuron disorders cause spacicity?
upper
393
do upper or lower motor neuron disorders cause flaccidity?
lower
394
symptoms of an upper motor neuron lesion
muscle weakness in the extensors (in the flexors for the legs)
hypermedia and muscle spacicity
weakness on the contralateral side of the lesion due to 85% of the fibres crossing over (decussation)
395
upper or lower motor neurons cause forehead sparing?
upper
396
symptoms of lower motor neuron lesions
severe atrophy, hypotonia, hypoflexia, flaccid muscle weakness
affects the whole side of the body, including the forehead
397
what is muscular dystrophy?
X-linked genetic disorders resulting in malformed dystrophin
loss of cell membrane cytoskeletal connections, unregulated influxes of calcium to sarcolemma
e.g Duchenne's
398
what is the CNS?
brain and spinal cord
399
is the somatic nervous system always stimulatory?
yes
400
function of the somatic nervous system
voluntary movement - skeletal muscles
reflex arcs involving muscles
401
functions of the ANS
heart rate, digestion, salivation, urination, digestion
402
main parasympathetic neurotransmitter
ACh
403
main sympathetic neurotransmitter
noradrenaline
404
what is the resting potential?
-70mV
405
which pump maintains the resting potential and how?
Na+/ K+ pump
3 Na out, 2 K in
406
describe the physiology of an action potential
action potential begins with a depolarising stimulus e.g neurotransmitter binding to ion channel
cell is depolarised (becomes less negative)
voltage gated Na+ channels open
influx of sodium ions
threshold potential reached at -55mV
action potential occurs if threshold potential reached
influx of sodium ions continues until +30mV via a positive feedback loop
the sodium channels close
potassium voltage gated channels open and potassium ions leave the cell to repolarise the membrane
membrane potential approaches resting potential
potassium channels experience a delay in closing resulting in hyperpolarisation
once voltage gated potassium channels close, resting potential is restored
407
what is hyperpolarisation
potassium voltage gated channels experience a delay in closing
potential falls below -70mV
408
what is the absolute refractory period?
no stimulus can produce a second action potential
409
what is the relative refractory period?
second action potential can happen, but needs stronger stimulus
410
is there a higher or lower concentration of sodium ions on the inside or outside during the resting potential of the cell?
outside
411
what do sensory receptors respond to?
stimuli
412
what are sub-modalities?
different variations within a stimulus e.g pitch and volume in audible stimuli
413
how are sensory receptors triggered?
ion channels if the stimulus is large enough
414
types of sensory receptors
tonic - slow adapting receptors
phasic - rapid adapting receptors
415
which receptors detect pain?
nociceptors
416
are nociceptors phasic or tonic?
phasic
417
what are Pacinian corpuscles?
phasic receptors
respond to pressure changes and vibration
418
which spinal segments control the knee jerk reflex?
L3 L4
419
describe the knee jerk reflex
patellar ligament is struck
afferent signal travels to spinal cord
synapses with 1 interneurons and 2 alpha-motor neurons
inhibitor - via interneuron, goes to flexor (hamstrings). polysynaptic
excitatory, via alpha motor neurons, to extensor (quadriceps)
monosynaptic
extensor contracts and flexor relaxes
knee jerks
420
brown sequard syndrome
an incomplete spinal cord lesion, typically in cervical region
lesion in one half of the spinal cord due to hemisection
usually cervical
weakness on one side (hemiparaplegia) and loss of sensation on the opposite side (hemianaesthesia)
ipsilateral loss of
- motor function
- vibration
- proprioception
- deep touch
to lesion
contralateral loss of
- pain
- temperature
421
how does diameter affect conduction speed?
larger fibre has a faster action potential as more ions can flow in a given time
422
are sodium channels found in the nodes of ranvier or myelinated regions?
nodes of ranvier
423
what is saltatory conduction?
action potentials jump from node to node
424
what are the four aspects of a stimulus?
modality, intensity, location, duration
MILD
425
absence of the patellar reflex
Westphal's sign
426
causes of brown sequard - traumatic and non traumatic
traumatic
- bullet, stab wound, kick, car accident
non-traumatic
- tumour
- disc hernia
- MS
427
what happens if the lesion is below the point of decussation?
ipsilateral side is affected
428
what happens if the lesion is above the point of decussation?
contralateral side is affected
429
what is the spnothalamic tract?
ascending tract which carries pain sensation
430
does the spinothalamic tract decussate, and where?
yes
spinal cord
431
which spinal segments are responsible for
a. achilles
b. patellar
c. biceps
d. triceps
reflexes
S1, S2 - achilles
L3, L4 - patellar
C5, C6 - biceps
C7, C8 - triceps
1,2 buckle my shoes
3,4 kick down the door
5,6 pick up the sticks
7,8 lay them straight
432
layers of the kidney
outer cortex
inner medulla
433
kidney anatomy
pyramids taper to form the papilla
from the papilla, the urine drips into a minor calyx
several minor caylx form a major calyx
major calyx empty into the renal pelvis
pelvis empties into ureter
434
where does the ureter narrow?
where the pelvis of the kidney becomes ureter (ureteropelvic junction)
pelvic brim
where the ureter passes through the bladder (uretovesical junction)
435
what stops urine passing back up from the bladder into the ureter?
ureter enters bladder at oblique angle
as pressure in bladder rises, it presses on part of ureter which is in the bladder wall so stops urine from passing back up to the kidney
436
what is the tube through which urine passes from the bladder to the exterior?
urethra
437
length of female urethra
2 inches
438
length of male urethra
8-10 inches long
439
where does the female urethra end?
inferior to clitoris and superior to vaginal opening
440
where does the male urethra end?
tip of the penis
441
functional unit of the kidney
nephron
442
cortical nephron
tubules extend only a short distance into medulla then back into cortex
443
juxtamedullary nephrons
tubules extend deep within the medulla - have a vasa recta around them
444
what is the part of the nephron in which blood plasma is filtered?
renal corpuscle
445
glomerulus
capillary tuft formed by the afferent and efferent arterioles and encased in Bowman's capsule
446
where does bulk of reabsorption happen?
PCT
447
what type of epithelium is the PCT?
cuboidal epithelium
448
what type of epithelium is the loop of henle?
squamous epithelium
449
is the descending limb permeable or impermable to water?
permeable
450
where does solute reabsorption take place in the LOH?
ascending limb
451
is the ascending limb permeable or impermeable to water?
impermeable
452
function of the DCT
fine regulation of Ca2+, Na+, K+ and HCO3
453
what size molecule can get through tthe filtration barrier?
10kDa
454
what prevents albumin getting through the filtration barrier?
podocytes with negatively charged foot processes
455
what does the Bowman's capsule contain?
glomerular filtrate
456
whaich factors affect the filtration of the glomerulus?
size of molecule
pressure
charge of molecule
rate of blood flow
457
what percentage of cardiac output is renal blood flow?
20%
458
normal cardiac output
5L min
459
normal renal blood flow (RBF)?
1L/ min
460
volume of liquid filtered by the kidneys per day/ GFR per day
180L
461
GFR per minute
125ml/ min
462
how many times is the blood plasma filtered per day?
60
463
how many capillary beds does the nephron have?
two
464
when does glomerular filtration occur?
blood hydrostatic pressure exceeds hydrostatic pressure of glomerular capsule and blood colloid pressure
465
blood filtration barrier layers
fenestrated capillary endothelium
glomerular basement membrane
podocytes
466
GFR means
glomerular filtration rate
volume of fluid filtered by the renal glomeruli per unit time
467
renal clearance
virtual plasma volume per minute, from which a substance is completely eliminated
468
which types of substances have serum concentrations in direct dependence with GFR?
substances with exclusive glomerular filtration (without tubular secretion or reabsorption)
469
what percentage of glomerular filtrate is reabsorbed?
99%
470
what does the PCT have to increase surface area?
villi
471
function of the PCT
reabsorption of Na, Cl, glucose, amino acids, bicarbonate
472
what is diabetes insipidus?
deficiency of ADH
massive diuresis and excessive thirst
473
which protein is produced in the nephron?
Tamm Horsfall/ uromoduliin
474
urine flow rate
1ml/kg/hr
475
what is the rate determining step of RAAS?
renin
476
which cells release renin?
granular cells of juxtaglomerular apparatus
477
what 3 things trigger renin release?
reduced NaCl delivery to distal tubule detected by macula densa
reduced perfusion pressure in kidney detected by baroreceptors in afferent arteriole
sympathetic stimulation of JGA cells
478
which nerve fibres innervate JGA cells?
beta 1 adrenergic sympathetic nerve fibres
479
where is angiogensinogen produced?
liver
480
action of renin
cleaves angiotensinogen to angiotensin 1
481
action of ACE (angiotensin converting enzyme)
converts angiotensin I to angiotensin II
482
where is ACE found?
renal endothelium , lungs, capillary endothelium
483
action of angiotensin II
ADH release
aldosterone release
sympathetic stimulation
484
another name for ADH
vasopressin
485
what are mineralocorticoids?
class of steroid hormones that regulate salt and water balances
486
which is the principal mineralocorticoid?
aldosterone
487
which cells does aldosterone act on?
principal cells of the collecting duct
488
action of aldosterone
regulates blood pressure by altering the amount of Na that is reabsorbed
increases the retention of sodium and excretion of potassium
489
action of ADH
affects blood pressure by causing release of aquaporin channels into the membrane of principal cells of the collecting duct
causes increased water retention
490
causes of chronic renal failure
high blood pressure
diabetes
high cholesterol
491
complications of chronic renal failure
fluid retention - oedema
hyperkalaemia - usually excess potassium is removed from the blood by the kidneys
cardiovascular disease - chronic renal failure causes high blood pressure
weak bones
492
how is GFR regulated?
myogenic reflex
tubuloglomerular feedback
RAAS system
493
describe the kidney myogenic reflex
not dependent on nerve supply or blood-bornee substances
intrinsic property of the smooth muscle in the capillaries of glomerulus
494
what happens to the GFR when the macula densa detect a fall in sodium chloride levels?
increases
495
which mechanism regulates GFR?
tubuloglomerular feedback
496
if a substance is not secreted or reabsorbed in the renal tubules, how do we measure renal clearance?
GFR
497
what is the most common drive for reabsorbtion?
sodium potassium pump
498
what is prerenal kidney failure?
sudden reduction of blood flow to the kidneys
499
causes of pre-renal kidney failure?
hypotension
volume depletion e.g vomiting
oedema
500
what is renal kidney failure?
direct damage to kidney
501
causes of renal kidney failure
glomerular disease
acute interstitial nephritis
eclampsia
allergic reactions to medications
502
what is post-renal kidney failure?
obstruction in the urinary tract
503
causes of post renal kidney failure
kidney stones
urethral stricture
bladder tumour
