29-33 lectures Flashcards
1
Q
what is the process of the filtration?
A
blood passes through the glomerlus and anything small enough can pass through like salt and water
2
Q
how much filtrate do we carry around with us?
A
150 liters
3
Q
what do each nephron comprise of?
A
a glomerular capsule, renal tubules and a collecting duct
4
Q
what is each nephron associated to?
A
glomerulus and peritubular capillaries
5
Q
what can control blood pressure of the glomerulus?
A
smooth muscle
6
Q
what are fenestrated epithelia?
A
leaky and allow substances to pass through
7
Q
what feeds and drains fenestrated epithelia cells?
A
arterioles
8
Q
what type of arterioles are peritubular capillaries?
A
efferent
9
Q
what are peritubular capillaries?
A
specialized for absorption and wrap around renal tubules
10
Q
what do the peritubular capillaries recieve?
A
filtered blood from the glomerulus and reabsorbed filtrate from the nephrons
11
Q
what is the vasa recta do?
A
a long straight capillaries that follows the nephron deep into the medulla and drains into the venous system
12
Q
what are the only nephrons the vasa recta follow?
A
juxtamedullary
13
Q
what encloses the glomerulus ?
A
the glomerular capsule
14
Q
what is the glomerular capsule?
A
a double layer that encloses the glomerulus
15
Q
what are the 2 layers of the glomerular capsule?
A
parietal and viceral
16
Q
what is the visceral layer consist of?
A
podocytes
17
Q
what is the parietal layer of the glomerular capsule made of?
A
simple squamous cells
18
Q
what does the parietal layer of the glomerular capsule do?
A
stops liquid from leaking out
19
Q
what do podocytes do?
A
allow fluids to pass into the celluar space
20
Q
what is the area called beteen the 2 layers of the glomerular capsule?
A
capsular space
21
Q
what does the capsular space do?
A
regulate blood flow and remove anything trapped in the glomerulus
22
Q
what are the structures of podocytes?
A
branched with intertwinning foot processes
23
Q
what are the intertwinning foot processes called of podocytes called?
A
pedicels
24
Q
what do pedicels do?
A
interdigitate and have small spaces inbetween
25
where do filtration slits form?
between pedicels
26
what do filtration slits do?
allow things to pass based on the size
27
what is the filtration barrier known as?
glomerular capsular membrane
28
what does the filtration barrier do?
allows free passage of small molecules and water anmd restricts passage of most proteins, and RBCs
29
what are the 3 layers of the filtration barrier?
fenestrated endothelium
fused membrane
filtration slits
30
what shares the fused membrane of the filtration barrier?
podocytes and the endothelia cells
it helps with diffusion of molecules
31
what is the urine equation?
urine = filtered - reabsorbed + secreted
32
what is PCT?
proximal convoluted tubule
33
what are PCT do?
used for bulk reabsorbtion about 2/3
34
what are some factors of the body of the PCT?
proximal so close to the glomerulus and runs in random directions
35
what helps with the bulk reabsorbtion in the PCT?
active sodium and potassium pumps for chloride and water to be reabsorbed
36
what are some functions of the PCT structure?
has a brush border of microvilli to increase surface area
it is made of cuboidal epithelium cells and has a tightly folded basolateral membrane and many mitochondria for active transport
37
what is the apical surface of the PCT?
tight junctions that make selective to substances passing and this can make them leaky as sodium and water can easily pass through
38
where does the nephron loop go to?
the medulla
39
what surrounds the loop of the juxtamedullary nephrons?
vasa recta
40
What does the structure of the nephron loop start as?
thick decending lim which is cuboidal epithelia
41
what is the structure of the nephron loop?
thick decending limb of cuboidal epithelia and then a thinner decending limb of simple squamous cells then a shorter thin acsending limb of simple squamous cells and then thye rest of the loop is a thick ascending limb of cuboidal cells
42
what parts of the loop are permeable to water?
the thinner segments of simple squamous cells
43
what parts of the loop are permeable to sodium?
the thick limbs with simple cuboidal cells
44
what does DCT mean?
distal convoluted tubule
45
where are the DCT?
further from the glomerulus
46
what do the DCTs do?
they reabsorb less of the fitrate
47
what is the structure of the DCT?
lees microvilli so no brush border aswell os fewer mitochondria
48
what influences reabsorbtion in the DCT?
aldosterone
49
what does the collecting duct do?
recieves the urine from the nephrons and empties it into the calices
also does some fine tuning of the urine
50
how many DCTs can drain into one collecting duct?
many
51
what si the structure of the collecting duct?
simple cuboidal epithelium
it has principal cells for reabsorbtion of sodium and water
it has intercalated cells for acid/base balance to maintain pH
52
what influences reabsorbtion in the collecting duct?
aldesterone and ADH
53
what epithelium lines the bladder and the ureter?
transitional epithelium
54
what is transitional epitheloium made out of?
stratified round cells which means it is multi layered and flattens when stretched
55
what is transitional epithelium important?
to not let substances out of the organ and cause damage aswell as osmotic gradients in the body
56
what produces umbrella cells?
cytokeratin
57
what do umbrella cells have alot of?
tight junctions that dont allow the movement of fluid between them
and desmosomes to not pull apart
58
what can umbrella cells produce?
proteins that form a plaque that is waxy to protect the epithelial surface from the urine
59
where do urethers arise from?
the renal pelvises of the hilum of the kidneys
60
what do the ureters do?
they are slender tubes that take urine from the kidneys to the bladder
61
where are the ureters in the abdomen?
retroperitoneal
62
what helps move urine through the ureters?
peristalic waves
63
how do the ureters enter the bladder?
posteriorly and laterally
64
why do the ureters enter the bladder weird?
when the bladder muscles tense it closes the openings of the ureters and prevents backflow
65
what is the three layers of the ureters made of?
inner most layer is made of transitional epithelium
then the muscularis layer with the inner layer being longitudinal and the outer layer being circular
the last layer is the adventia which covers the outside with fibourus connective tissue
66
what is the structure of the urinary bladder?
a collapsable muscular sac that stores and expells urine
67
what happens when the bladder collapses?
it empty and collapses along the rugae flods
68
what happens when the bladder is full?
the bladder expands without increasing pressure
69
what do the supporting ligaments of the bladder do?
keeps the bladder in position
70
what gives the brain signals that the bladder is full?
when the rugae are flat
71
what are the 3 holes of the bladder?
the 2 openings of the ureters and 1 opening for the urethra
72
what does the urethra do?
carries the urine away from the bladder
73
what is the trigone?
the triangular area of the bladder between all 3 openings
74
what surround the urethra in men?
the prostate
75
what is the shape of an empty bladder?
pyramidal an lies in the pelvis
76
what is the shape of a full bladder?
becomes spherical and expands superiorly into the abdomenal cavity
77
where is the male bladder located?
anterior to the rectum and superior to the prostate
78
where does the female bladder located?
anterior the vagina and the uterus
79
what si the thick smooth mucsle layer of the bladder called?
the detrusor
80
how many layers is the detrusor?
3
81
what are the 3 layers of the detrusor?
longitudinal, circular and oblique fibers
82
what does the detrusor muscles do?
contract to collapse the bladder uniformly and incraese pressure to expell urine out of the urethra
83
what is the urethra?
a thin walled muscular tube that drains urine from the bladder out of the body
84
what is the changes of the epithelium of the urethra?
transitional near the bladder
columinar in the spongy urethra
simple squamous near the external opening of the urethra
85
what does the simple squamous area of the urethra do?
prevents abrasion of the urethra
86
what do the columinar cells of the urethra do?
have goblet cells to secrete mucus to prtect the underlying cells and the bacteria gets stuck in the mucus
87
how long about are females urethras?
around 5 cm
88
how long about are male urethras?
around 25 cm
89
why are male urethras longer?
for reproductive purposes
90
what are the 3 regions of the male urethra called?
prostatic
membranous
spongy/penile
91
what does the internal urethral sphincter do?
keeped shut by the sympathetic system
this is involuntary and is made of detrusor muscle
92
what does the extranal urethral sphincter do?
keeped shut by the parasympathetic system
is voluntary control so we arecontious of passing of urine and is made up of skeletal muscle
93
what do we need kidneys for?
to controls whats in our blood and how much blood we have
keeps our bodies in homeostasis and controls the pH
94
what are the endocrine functions of the kidney?
erythropoietin
activation of vitamin
renin secretions
95
what are RAAS?
renal secretions
96
what are metabolic functions of the kidneys?
makes new glucose through gluconeogensis
97
what is EPO?
erythropoietin
98
what does EPO have to do with the kidneys?
the kidneys detect how much oxygen is in the blood and if its low then it releases EPO which stimulates the red marrow to produce more RBCs which have more haemoglobin to carry more oxygen around the body
99
what happens if the kidneys cant produce EPO well?
then it can lead to anaemia so there will be less oxygen in the blood so the body cant function aswell
100
how do we control the pH of the blood through our urine?
we can excrete the acidic ions in the urine to control the pH of the blody
101
what are the 2 main sources of acid in the body?
metabolism of food and drink that we consume
metabolism of carbon dioxide
102
what are the 2 syystems to control the acid in the body?
exhaling the carbon dioxide
kidneys reabsorb bicarbonate and hydrogen ions which can then be excreted
103
what is potassium important for in the body?
for resting membrane potentials in the cells and is involved in action potentials
104
what does the build up of potassium lead to?
hyperkalemia which can lead to death
105
what are the 2 classes of drugs?
hydrophillic drugs
lipophillic drugs
106
what do lipophillic drugs do?
travel in the blood bound to a protein which is then taken to the liver to be metabolised and become hydrophillic drugs
107
what do hydrophillic drugs do?
can be filtered in the kidneys and can become urine
goes directly to the kidneys
108
what is the ECF made out of?
1/5 plasma
4/5 interstitial fluids
109
what can the increase of plasma lead to?
the increase of blood pressure
110
what is osmolarity?
the total number of solutes molecules in a solution
111
what is the normal osmolarity of the ECF?
275-300 mosmol/L
112
what is the normal osmolarity of the ICF?
275-300 mosmol/L
113
what is isosmotic?
the same amount of solute molecules per liter so they have the same osmolarity
114
what is hyposmotic?
when the water in in the ECF incraeses which means there is less solute molecules per liter so the osmolarity decreases
115
what is hyperosmotic?
when the water in the ECF decreases which mean that there is more solute molecules per liter so the osmolarity increases
116
what happens to the osmolarity if we change the isosmotic fluid
osmolarity doesnt change
117
where is filtration of the nephron occuring?
in the renal capsule
118
what is the plasma like filtrate?
the filtration in the capsular space of water and ions without the large plasma proteins
119
how do the nephrons secrete substances?
from the peritubular capillaries
120
what happens to the filtrate that is reabsorbed?
goes into the blood so it is not excreted
121
what happens to substances that are screted by the peritublar capillaries?
it adds substances that are still in the blood to the fitrate being excreted and is excreted with it
122
where is the main area where scretion occurs from the peritublar capillaries?
PCT
123
where is the main area where reabsorbtion occurs from the nephron?
PCT
nephron loop
fine tuning in the collecting duct and DCT
124
what are the 3 things that determine glomerular filtration?
filtration barrier
renal bloodflow
driving force
125
what is the filtration barrier?
allows small substances to be freely filtered and large substances to not be filtered
126
what is the renal blood flow?
the kidneys recieve about 20% of the cardiac output
they need this much blood to filter the plasma and helps with the bulid up of toxins and changes in water concentration
127
what is the driving force of the glomerular filtration
the reason to move
128
what are the 2 types o driving forces?
hydrostatic pressures
colloid osmotic pressure
129
what is hydrostatic pressure?
how much volume of fluid there is in the renal capsule which can lead to high pressure
the more fluid in the capsule, the more the fluid is pushed back
130
what is colloid osmotic pressures?
caused by proteins as they pull fluid towards itself
131
what are positive pressure?
favour filtration so it pushes fluid where it wants to go
132
what is negative pressure?
oppose filtration so its pushing fluid in the wrong direction
133
what are the 4 forces in glomerular filtration?
glomerular hydrostatic pressure
blood colloid osmotic pressure
capsular hydrostatic pressure
capsular colloid osmotic pressure
134
what is GHP?
glomerular hydrostatic pressure
how much blood and pressure there is in the glomerular capillaries
135
what is BCOP?
blood colloid osmotic pressure
its albumin which pulls fluid towards itself back from the capsule into the glomerulus
136
what is CsHP?
capsular hydrostatic pressure
its the pressure from the filtrate already present
137
what is CsCOP?
capsular colloid osmotic pressure
usually zero as protein cant pass through the fitrating barrier
138
what is filtration fraction?
how much of the kidneys plasma flow is filtered
139
how do we calculate the filtration fraction?
glomerular fitration rate (GFR)
over
renal plasma flow (RPF)
140
what si the glomerular filtration rate?
the amount of plasma being filtered per minute
141
what is the GFR normally?
125ml/minute
142
how much urine do we produce each day?
around 1.5 L
143
what is the renal filtered load?
how much substavnce is fitered per minute
144
how do we calculate the renal filtered load?
GFR * solute plasma conc
145
what is renal clearance?
how much plasma is cleared or emptied of a particular substance
the clearance is the volume (ml) of plasma that is cleared of a substance by the kidneys per unit of time
146
what is the renal clearance of creatinine and insulin?
freely filtered, not secreted, not reabsorbed
147
what si the renal clearance of medications and toxins?
freely filtered, entirely secreted, not reabsorbed
148
what is PAH?
medications and toxins
149
what happens to all the PAH that is passing through the kidneys?
it is all secreted and excreted with the urine
150
what is the renal clearance of glucose?
freely filtered, not secreted, fully reabsorbed in the proximal tubule
151
should there be glucose in a healthy person urine?
no
152
what is the renal clearance of sodium?
freely filtered, not secreted, almost fully reabsorbed so small amount is excreted in the urine
153
how do we calculate the clearance?
(concentration of X in urine (Ux) (times) volume of urine produced per unit of time (V))
over
concentration of X in plasma (Px)
154
what is Px?
concetration of X in plasma
155
what is Ux?
concentration of X in urine
156
what 2 substances can we use to eliminate GFR?
creatinine and insulin
157
what is an indicator of kidney function?
plasma creatinine conc
158
what should the plasma conc of creatinine be if both kidneys are working well?
low
159
what happens when GFR is less than 25ml/min?
plasma creatinine conc incraeses as the kidneys ability to clear waste products from the blood is reduced
160
what happens to nephrons as you get older?
die and stops working as you get older meaning there is a build up of things like toxins and medications in the blood and can lead to medical effects
161
what percentage of reabsorbtion of water occurs in the PCT?
66%
162
what percentage of reabsorbtion of water occurs in the decending limb?
25%
163
what percentage of reabsorbtion of water occurs in the colloecting duct?
2-8%
164
why does bulk reabsorbtion of water occur in the PCT and the decending klimb?
because it has leaky epithelium can pass cells paracellularly
165
what do aquaporins do?
allow transcellular pathway of water
166
where does regulation of water reabsorbtion happen and why?
collecting duct
because it is made of tight epithelium so water cant pass paracellular
167
what hormones regulate water reabsorbtion in the collecting duct?
anti-diuretic hormone
168
what does ADH mean?
anti-diuretic hormone
169
what does ADH do?
the more you have the less urine you make as it bind to the cells in the collecting duct and activate the transcelular pathway of reabsorbing water using aquaporins
170
what percentage of reabsorbtion of sodium occurs in the PCT?
66%
171
what percentage of reabsorbtion of sodium occurs in the acsending limb?
25%
172
what percentage of reabsorbtion of sodium occurs in the collecting duct?
2-3%
173
what hormone regulates the reabsorbtion of sodium?
aldosterone
174
what is RAAS?
aldosterone
175
what drives the reabsorbtion of sodium in the PCT?
NA+
water follows other solutes, where the osmolarity is higher
176
glucose is transported out of the cell how?
via the glucose transporter
177
what pumps sodium out of the cell?
Na+/K+ ATPase
178
what does chloride follow and why?
sodium as chloride is negative and sodium is positive
179
what is the decesnding limb made of?
leaky epithelium
180
what is HOMG?
hyper-osmotic medullary gradient
181
what is the HOMG do ?
the deeper we go into the medullary the higher the osmolarity outside of the nephron loop
182
what are the only nephron affected by the HOMG?
juxtamedullary
183
what percentage of reabsorbtion of sodium occurs in the DCT?
7-8%
184
what regulates the reabsorbtion of sodium in the DCT and the collecting duct?
aldesterone (RAAS)
185
what does the TBW change alter?
the plasma osmolarity (ECF)
186
what detects the plasma osmolarity change?
osmoreceptors in the hypothslamus
187
what do the osmoreceptors do?
stimulates the pituatary gland to screte more/less ADH
188
what is the basic function of ADH?
alters the permeablity of the collecting duct so water can be obtained/excreted to balance any change in TBW
189
what are aquaporins doing in the cells?
they are in bubbles, when the ADH binds to the apical membrane it increases permeability
190
what is the driving force of water in the collecting duct?
HOMG
191
what does ANP do?
makes pee more isosmotic fluid and will return solutes to the plasma
192
what does the gain or lose of isosmotic fluid effect?
the ECF
193
what does normal urine consist of?
95-98% water, creatinine, urea, uric acid, H+, Na+, medications, toxins
194
what does pathological urine consist of?
glucose, proteins especially albumin, blood, haemoglobin, WBCs, bacteria
195
what is the pH of a vegeterians urine?
around 8
196
what is the average pH of the average persons urine?
6-7.5
197
what is the pH of a person who has a high protein diets urine?
4.6
