quiz 5 Flashcards
(94 cards)
1
Q
What are the two ways for water to move across cell membranes?
A
- simple diffusion
- facilitated diffusion
2
Q
what do osmotically active solutes do?
A
- set up a pressure gradient that drives a net movement across the membrane.
3
Q
Osmosis definition
A
simple diffusion and facilitated diffusion
- more dominant since most cells have aquaporins on the membrane
4
Q
tenicity definition
A
way of describing outcome. we determine it by doing an experiment.
5
Q
if a cell shrivels up it is _____
A
hypertonic
6
Q
if a cell swells/lyses, it is _____
A
hypotonic
7
Q
if a cell stays the same, it is ___
A
isotonic
8
Q
When should a solute matter?
A
Only if they are osmotically active
9
Q
penetrating solute
A
it can move faster than water will move out
10
Q
what happens if a cell is impermeable to water?
A
every cell is isotonic
11
Q
What are the two functions of the urinary system?
A
- Excretion of nitrogenous wastes
- homeostatic regulation
12
Q
excretion of nitrogenous wastes
A
- mostly urea for humans
- removal of metabolic waste from the body
- most common is ammonia
13
Q
in the urinary system there is homeostatic regulation of what?
A
- extracellular fluid
- blood pressure
- blood osmolarity
- blood pH
14
Q
what are the two extracellular fluids in the urinary system?
A
interstitial fluid & blood volume
15
Q
what isn’t metabolic waste a why?
A
feces isn’t metabolic waste, it consists of the stuff you couldn’t absorb out of food
16
Q
what are the 3 main forms of nitrogenous waste?
A
- Ammonia
- Urea
- Uric Acid
17
Q
Ammonia description
A
- highly soluble in water, basic, highly toxic
- strong base
- will be converted to urea after first circulation
18
Q
Urea description
A
- only slightly less soluble, neutral, much less toxic
- pH neutral
19
Q
Uric Acid description
A
- Solid and largely insoluble in water, acidic, non-toxic
- produces a bitter taste
20
Q
gout description
A
Uric acid crystals in joints
21
Q
where is urine produced?
A
kidneys
22
Q
what do the ureters do?
A
transmit fluid urine to a holding container called the urinary bladder
23
Q
two layers of the kidneys
A
- renal cortex
- renal medulla
24
Q
cortical layer osmolarity description
A
is low in osmolarity
25
osmolarity description in the middle of the kidneys (pink areas)
osmolarity raises towards the middle
26
nephrons
- 2 types
- located in the kidney
- produce urine
27
what are the two types of nephrons?
- cortical nephrons
- juxtamedullary nephrons
28
cortical nephrons
good at moving urea but bad at reabsorbing water
- sits shallow in the medulla
29
juxtamedullary nephrons
good at reclaiming water when dehydrated but bad at getting rig of waste
- goes deep into the medulla
- the deeper in, the more reabsorption occurs
30
bowmans capsule
- like a cup and funnel that surrounds the glomerulus
- urine will flow down into the nephron
31
proximal convoluted tubule
first place that urine is modified
32
loop of henley
the part of the nephron that extends into the medulla
33
distal convoluted tubule
- where we measure the amount of urine being produced
- after this point, it will go to the collecting duct and the urine will flow into the ureter
34
what are the four stages of urine production?
- filtration
- reabsorption
- secretion
- excretion
35
filtration
- blood will be filtered from the glomerulus
- it will not have cells in it & will be missing protein
- we will chemically modify the urine
36
reabsorption
- as soon as it ends up in the filtrate, parts of the nephron are going to pull ALL the glucose out of the urine
- the glucose will then be moved to storage
37
secretion
- active transport will be used to force things out into the urine
- most secretion is a form of active transport (secondary or further)
38
excretion
- urine is sent out of the body
39
when the glomerulus is under pressure, what will happen to the capillaries
they will leak out as they are highly fenestrated
- higher the pressure, the more they leak
40
podocyte cells
- "foot cells"
- leg-like appendages that wrap around capillary and further restrict what materials make it out
- can also have transcellular processes, letting them go through the actual cell itself
41
how is flow rate controlled?
via blood pressure in the glomerulus (+/+) and osmotic colloid pressure (+/-)
42
if there is a decrease in efferent arterioles, what happens to the flow?
increase in flow
43
if there is a decrease in afferent arterioles, what happens to flow?
decrease in flow
44
colloid proteins
- proteins that cause an osmotic gradient that pulls materials back towards the blood stream
45
what is osmotic diuresis?
you make a lot of urine due to water being pulled into the blood stream
46
what happens when you build up pressure in the bowmans capsule?
- it will produce back pressure
47
colloid osmotic pressure
as water is forced into the filtrate, they will exert a backwards pull that keeps water from entering.
48
albumin
- the main colloid protein in the blood to prevent some amount of filtration
49
If we close the efferent down what will happen to urine?
more urine/ filtrate will occur
50
if we dilate or open the efferent, what happens to the urine?
urine will lower and less filtration will occur
51
what are the 2 general mechanisms involved with reabsorption?
- epithelial transport
- para-cellular pathway
52
epithelial transport
- AKA transcellular transport
- cell will have control on how substances are absorbed & and will also do active transport to remove all the glucose and move through actual cells
53
para-cellular pathway
- fits through the space between cells
- can never reabsorb anything above the blood concentration limit (when blood and urine concentration are at equilibrium, process will stop)
54
fixed reabsorption
always absorbs a certain amount
55
how do we concentrate glucose?
glucose itself cannot be pumped but sodium anti-porters can move Na+ and glucose in the opposite or the same direction
56
how do we make urine volume increase?
- increase in secretion
- this also enhances nephron secretion
57
penecillin and probenecid
- 1st mass produced drug
- if given alone, it is entirely cleared from the body within two hours so it was given with probenecid so it could occupy the transporters for penicillin to do its job and stay in circulation
58
when can urine no longer be chemically modified?
once urine leave the collecting duct
59
where does urine from all nephrons collect?
in the renal pelvis
60
how does urine get from kidneys to the bladder?
pushed into the bladder by smooth muscle contractions in the ureters
61
micturition
a reflex that is the process of urination
62
what controls excretion?
- spinal reflex that is inhibited by the brain
- involuntary at first then once matured, becomes voluntary
63
internal sphincter
made of smooth muscle and always contracted unless too much pressure is on it has built up too high
64
external sphincter
made of skeletal muscle and isn’t always contracted until signaled by motor neuron (unless a baby then it will be open).
65
signal process of urination in the bladder
- Stretch receptors will send a signal to the spinal cord, they will communicate with two different sets of neurons (parasympathetic & sympathetic)
- Parasympathetic: signal smooth muscle to relax, and internal sphincter will open, and bladder will contract
- Motor neuron was telling the external sphincter to stay contracted so we will now inhibit this one (shut it off to make it stop releasing acetylcholine) and urine will leave.
66
what are the two endocrine pathways used to control urine volume and osmolarity?
- ADH (antidiuretic hormone)
- RAAS (Renin-Angiotensin-Aldosterone Sytem)
67
Antidiuretic hormone (ADH)
- promotes water reabsorption
- Allows us to concentrate the urine and prevent urine from being loss
- Raise blood volume but dilute the blood down
68
RAAS
- promotes Na+ reabsorption
- Allow us to regulate blood pressure
- Part of RAAS pathway
69
antidiuretic hormone vasopressin
- Released from posterior pituitary when blood volume decreases and blood osmolarity increases
- Promotes reabsorption of water from the urine by increasing aquaporin density on the cells lining the collecting duct
70
when you are dehydrated, what is released to promote water reabsorption?
The more dehydrated you are, the more ADH is released since it promotes/enhances water reabsorption from the urine by targeting the cells in the collecting duct that are able to reabsorbe water called p-cells.
71
RAAS Pathway
used to correct low blood pressure
- released aldosterone to promote reabsorption of Na+
72
how is the RAAS pathway triggered?
when blood pressure decreases
- when you have a loss of blood or other issues occur
73
how does RAAS correct low blood pressure?
producing more red blood cells
- the release of aldosterone will increase blood pressure
74
what is the normal pH of plasma?
7.38-7.42
75
what happens when pH of plasma changes
changes outside the normal pH will be problematic and can cause change in protein shape making function catastrophic
76
Acidosis
neurons become less excitable; CNS depression
77
Alkalosis
hyper-excitable
78
how can changes be made to the pH of plasma?
altering activity of the respiratory and excretory systems
79
what do buffers do to pH of plasma?
- Moderate changes in pH
- combine with or release H+
80
ventilation for plasma pH homeostasis
- rapid response
- corrects 75% of disturbances yet can also cause them
81
renal regulation
- by directly excreting or reabsorbing H+
- by indirectly changing the rate at which bicarbonate buffer is reabsorbed or excreted
82
what are the major functions of the urinary system?
- Filter blood
- eliminate waste as urine
- regulate fluid and electrolyte balance
83
distinguish between cortical and juxtamedullary nephrons (anatomical and functional differences)
cortical:
- short loops of henle
- located in outer cortex
- focusses on filtration and excretion
juxtamedullay:
- long loops of henle
- extends into the medulla
- crucial for urine concentration
84
list and describe the 4 processes involved in urine production
- glomerular filtration
- tubular reabsorption
- tubular secretion
- excretion
85
how is glomerular filtration rate controlled? think about local and global control mechanisms.
local:
- controlled by myogenic mechanisms
global:
- sympathetic nervous system
- hormonal regulation
86
how are the following substances reabsorbed: Sodium, water, small anions, glucose?
sodium:
- from renal tubules back into the blood stream
water:
- amount of water reabsorbed is regulated by ADH which increases the permeability of the collecting duct to water
small anions:
- reabsorbed passively following the electrochemical gradients established by sodium reabsorption
Glucose:
- in the proximal convoluted tubule
87
how are organic anions secreted into the urine? why is secretion considered to be a competitive process?
- via active transport across the proximal tubule cells
- multiple organic anions compete for the same transport mechanisms, leading to reduced secretion of one if the other is present in high concentrations
88
how do ADH and the RAAS pathway regulate urine osmolarity/pressure? when are each of these pathways used respectively?
ADH: increasing water reabsorption in the kidneys
- when body is dehydrated or has high concentrations of solutes in the blood
RAAS: influencing Na+ and water retention
- blood pressure is love and blood volume is reduced or sodium levels are low
89
how does the urinary system help regulate blood pH?
reabsorbing bicarbonate from the urine and secreting hydrogen ions into the urine.
90
briefly explain the difference between OSMOLARITY and Tonicity
- osmolarity depends on the concentration of osmotically active solutes. penetrating/non-penetrating doesn't matter
- tonicity is the movement of water, the outcome of osmolarity. with respect to environment of cell
91
what anatomically and functionally distinguishes cortical and juxtamedullary nephrons?
cortical- short loop of henle is only in the cortex layer and it is good at producing urine and getting rid of urea but bad at reapsorbing water.
juxtamedullary- long loop of henle extends all the way down into medulla. good a reabsorbing water but bad at producing urine.
92
many substances are found at higher concentrations in the urine than they are in the blood. briefly discuss two different mechanisms that allow this to happen.
- substances actively transported from blood to urine in secretion making the concentration of substances in urine go up.
- when water is reabsorbed, concentration of substances in urine automatically goes up.
93
in a normal kidney, what condition would cause an increase in the glomerular filtration rate (GFR)?
a decrease in the concentration of colloid proteins in the blood
94
dan has been lost in the desert for 2 days with very little water. As a result, you would expect to observe.....
elevated ADH levels
