Topic 11.3 Flashcards
1
Q
Osmolarity
A
The solute concentration of a solution
2
Q
Osmoregulators
A
- Maintain a constant internal solute concentration, even when living in marin environental with very different osmolarities
- All terrestrial animals, freshwater animals, and some marin organisms (bony fish)
- Maintain their solute concnetration at about 1/3 of the concentration of seawater
3
Q
Osmoconformers
A
- Animals whose internal solute concentration tends to be the same as the cocnetration of solutes in the environment
4
Q
Hemolymph
A
circulating fluid in arthropods that combines the characteristics of tissue fluid and blood
5
Q
Malpighian tubule system
A
- a system in insects that carries out osmoregulation and the removal of nitgroneous wastes
- insects have tubes that branch off from their intestinal tract known as Malpighian tubules
- cells lining the tubules actively transport ions and uric acid from the hemolymph into the lumen of the tubules
- this draws water by osmosis from the hemolymph through the wals of the tubules into the lumen
- the tubules empty their contents into the gut
- in the hindgut, most of the water and salts are reabsorbed while the nitrogenous waste is excreted with the feces
6
Q
Annotate the following diagram of the malpighian tubule system
A
Refer to picture
7
Q
Draw and label a diagram of the human kidney
A
Refer to picture
8
Q
Compare and contrast the composition of blood in the renal artery and renal vein
A
Blood in the renal vein (i.e. after the kidney) will have (in comparison to the renal artery):
- Less urea (large amounts of urea is removed via the nephrons to form urine)
- Less water and solutes / ions (amount removed will depend on the hydration status of the individual)
- Less glucose and oxygen (not eliminated, but used by the kidney to generate energy and fuel metabolic reactions)
- More carbon dioxide (produced by the kidneys as a by-product of metabolic reactions)
- The same amount of plama proteins because they are not filtered by the kidney
9
Q
Outline the three components of the ultrastructure of the glomerulus
A
- Fenestrations between the cells in the wall of the capillaries
- about 100nm in diameter
- allow fluid to escape, but not blood cells - The basement membrane
- covers and supports the wall of the capillaries
- made up of negatively
- charged glycoproteins, which form a mesh
- prevents plasma proteins from being filtered out, due to their size and negative charges - Podocytes
- form the inner wall of the Bowman’s capsule
- have extensions that wrap around the capillaries of the glomerulus
- have many short side branches called foot processes
- very narrow gaps between the foot processes help prevent small molecules from being filtered out of blood in the glomerulus
10
Q
Define ultrafiltration
A
- The separation of particles differeing in size by a few nanometres
11
Q
Label the following diagram of the ultrafiltration system of the glomerus
A
Refer to picture
12
Q
Label the following diagram
A
Refer to picture
13
Q
Label the following diagram of the proximal convoluted tubule
A
Refer to picture
14
Q
What is the role of the proximal convoluted tubule?
A
- selective reabsorption of useful substances
15
Q
List the substances that the proximal convoluted tubule reabsorbs
A
- All glucose
- All amino acids
- Most water
- Most sodium ions
- Most chloride ions
16
Q
How are sodium ions reabsorbed by the PCT?
A
- moved by active transport from fiiltrate to space outside the tubule where they pass to the peritubular capillaries
- pump proteins are located in outer membrane of tubule cells
17
Q
How are chloride ions reabsorbed by the PCT?
A
- attracted from filtrate to the space outside the tubule because of the charge gradient set up by active transport of sodium ions
18
Q
How is glucose reabsorbed by the PCT?
A
- co-transported out of filtrate and into fluid outside the tubule by co-transporter proteins in outer membrane of tubule cells
- sodium ions move down the concentration gradient from outside tubule into tubule cells, providing energy for glucose to move at the same time to fluid outside the tubule
19
Q
How are amino acids reabsorbed by the PCT?
A
- co-transported out of filtrate and into fluid outside the tubule by co-transporter proteins in outer membrane of tubule cells
- sodium ions move down the concentration gradient from outside tubule into tubule cells, providing energy for amino acidsto move at the same time to fluid outside the tubule
20
Q
How is water reabsorbed by the PCT?
A
- water moves by osmosis due to the solute concentration gradient created by pumping out solutes out of the filtrate and into the fluid outside the tubule
21
Q
Draw and label a diagram of the nephron
A
Refer to picture
22
Q
Define Bowman’s capsule
A
cup-shaped structure; highly porous inner wall collects fluid from the filtered blood
23
Q
Define proximal convoluted tubule
A
highly twisted, contains many mitochondria and microvilli
24
Q
Define loop of Henle
A
- a tube shaped structure consisting of a decending limb and an ascending limb
- descending limb: carries filtrate into medulla which has a higher [solute]; porous to water, so water moves by osmosis
- ascending limb: carries filtrate back into the cortex; impermeable to water; sodium ions are actively pumped out to maintain high [solute] in the medulla
25
Define distal convulted tubule
highly twisted section like the PCT but contains fewer, shorter microvilli and fewer mitochondia
26
Define collecting duct
wider tube; carries filtrate (urine) to the renal pelvis
27
Define blood vessels
blood flows through them in the following sequence
1. afferent arteriole
2. glomerulus
3. efferent arteriole
4. peritubular capillaries
5. vasa recta
6. venules
28
Define afferent arteriole
brings blood from the renal artery
29
Define glomerulus
a tight, knot-like, high-pressure capillary bed that is the site of blood filtration
30
Define efferent arteriole
a narrow vessel that restricts blood flow, helping to generate high presure in the glomerulus
31
Define peritubular capillaries
a low-pressure capiliary bed that runs around the convoluted tubules, absorbing fluid from them
32
Define vasa recta
unbranched capillaries that are similar in shape to the loops of Henle, with a descending limb that carries blood deep into the medulla and an ascending limb bringing it back to the cortex
33
Define venules
carry blood to the renal vein
34
Explain how the loop of Henle maintains hypertonic conditions in the medulla
- the overall effect of the loop of Henle is to create a gradient of solute concentration in the medulla
- the energy to create the concentration gradient is expended by walls in the ascending limb
- in the ascending limb, sodium ions are pumped out of the filtrate into the institial fluid
- the wall of the ascending limb is impermeable to water - meanwhile, the descending limb is permeable to water but impermeable to sodium ions and so water will move out by omosis due to the hypertonic conditions in the interstitial fluid created by the sodium pumps in the ascending limb
35
Label the following diagram of the loop of Henle to illustrate the solute concentrations and movement of ions/water
Refer to picture
36
What is the correlation between the length of the loop of Henle and need for water conservation in animals? Suggests reasons why this may be.
- animals that require water conservation (ie. because they live in dry habitats) tend to have longer loops of Henle
- this is because longer loops of Henle allow for greater reabsorption of water
- in order to accomodate longer loops of Henle, the medulla must also become relatively thicker
37
What is the function of ADH?
- antidiuretic hormone; controls reabsorption of water in the collecting duct
- if the [solute] of the blood is too low, relatively little water is reabsorbed, causing large volumes of urine to be produced with low [solute] which causes the [solute] of the blood to increase
- if the [solute] of the blood is too high, ADH is secreted from the pituitary gland which causes the walls of the DCT/collecting duct to become much more permeable to water, causing small volumes of urine to be produced with high [solute] which causes the [solute] of the blood to decrease
38
Giving examples, explain how the type of nitrogenous waste in animals is correlated with evolutionary history and habitat
- the type of nitrogenous waste in animals is correlated with evolutionary history and habitat
- ammonia is produced when amino/nucleic acids are broken down but it is highly basic and can alter pH balance
- converting ammonia to urea requires energy and converting it to uric acid requires even more energy
- terrestrial organisms use energy to convert the ammonia into urea/uric acid
- marine/freshwater organisms can release this waste directly into the water, because the water can dilute the ammonia
- marine mammals convert the ammonia due to evolutionary history
- birds excrete the waste as uric acid because it requires less water (carrying water would impede flight)
- amphibians release the waste as ammonia when they are larva and after metamorphosis, release the waste as urea.
- nitrogenous wastes are released by the developing organism within eggs; uric acid is released as it is not soluble and crystallizes rather than building up to toxic concentrations
39
Dehydration
Causes:
- exercise
- insufficient water intake
- diarrhea
Consequences
- disruption of metabolic processes
- darkened urine (high [solute])
- tiredness/lethargy
- low blood volume
- increased heart rate
- inability to sweat
40
Overhydration
Causes:
- consuming large amounts of water after intense exercise without replacing electrolytes
Consequences:
- dilution of blood solutes
- swelling of cells
- headache
- nerve function disruption
41
List two ways that kidney failure can be treated
1. hemodialysis
2. kidney transplant
42
Evaluate hemodialysis as a method of treating kidney failure
- hemodialysis is a procedure used by people whose kidneys are no longer able to filter waste products from the blood properly
- during the procedure, a steady floy of blood passes over an artificial semi-permeable membrane in the dialysis machine
- the small waste products in the blood pass through the membrane, but the larger blood cells and proteins do not
- the purified blood is returned to the patient via a vein
Pros:
- no issues with rejection (unlike kidney transplant)
Cons:
- limited freedom while connected to the machine
- the procedure takes several hours and may need to be done several times a week
- risk of infection/other complications
43
Evaluate kidney transplants as a method of treating kidney failure
- kidney transplanation is a surgical procedure in which a kidney from another person (doner) is placed into the body of the patient whose kidneys are not functioning
- the donor can be either living or dead; people have two kidneys but only one is required to survive
Pros:
- greater freedom; no need to connect to a machine
Cons:
- chance of rejection by the body
- may have to take anti-rejection medications
44
Urinary tests
- can be used to detect/test for blood cells, proteins and drugs in urine
- having glucose and/or blood cells in your urine is abnormal and is likely a symptom of an infection/disease
