8b Renal system Flashcards
renal system:
Mammals in general require a means to:
- Regulate the composition of body fluids
- Regulate fluid volume
- Excrete wastes from the body
Which structure produces urine?
kidney
What structure propels urine from kidneys to bladder?
ureter
What is function of bladder?
hold urine
What structure connects bladder to external environment?
urethra
The kidney is organized into 2 layers – name them and describe their location:
- cortex (outer layer)
2. medulla (inner region)
- collecting ducts are found in what layer of the kidney and converge to what structure?
- The region this is found is known as ??
inner medulla
renal papilla
- renal pelvis
Monocalyceal kidney
one single renal pelvis and set of papillae (together called a calyx)
i.e.: mouse kidney
Multicalyceal kidney
divided into multiple calcies
i.e.: humans, mammals
Multireniculated kidney
separated into distinct lobes each individual lobe called reniculum acts as a serape little kidney having its own cortex and medulla
i.e.: marine mammals, few terrestrial males that need to conserve water
What is unique about Sirenia kidneys?
DO NOT have TRUE reniculated kidneys; cortex is continuous
What is the name given to the kidney found in pinniped and cetaceans?
multireniculated kidney
Describe the structural anatomy of this style of kidney
A. hilus
renal arter energy; renal vein exits; ureter exists
b. renal capsule
CT and peritoneum
c. renicule
= single until of kidney has own cortex, medulla and pelvis
hilus
renal arter energy; renal vein exits; ureter exists
Renal capsule
CT and peritoneum
Gross overview in marine mammals
A: renicule
medulla = pink lighter aarea
cortex is the redder area
b. capsule of the kidney
Harbor seal bladder opened to expose inside
A. bladder inside view
muscular wall capable of significant expansion
b. urethra opening bladder side
- What forms the basic functional filtration unit of the kidney?
- Are there few or many of these per kidney?
- What exactly do they do? What is their end product?
- What, if anything, can these structures resorb?
- nephrons
- hundred of thousands
filter the blood to removes metabolic waste and excess minerals and excrete it as urine - filter out everything that is smaller than 68 kda
- selectively reabsorb what the body requires.
What is the nephron function and urine concentration dependent on? What happens here to allow urine to be produced?
the cortico-medullary acts as the kidney
establishes a counter current concentrator to produce urine
Thin segment of ascending limb
passive transport of cl-
descending limb
water reabsorbed, urine concentration
thick LOH
active transport of Na+, K+
collecting duct
selectively permeable to h20 reabsorption
Describe 2 structural differences that the kidney can increase ability to concentrate urine ?
deep the medulla is relative toe the cortex
the longer the LOH (marine mammals do not have long loops though)
The urine that mammals excrete is dependant upon what 3 processes?
- what is filtered out
- what is reabsorebed
- what is actively secreted
Describe 2 unique strategies that marine mammals have developed to minimize water loss
- increased reabsorption of water
2. increased filtration nada secretion of salts and waste products
Marine mammals are presented with unique challenges: - list 3 key ones relevant to the renal system.
- coping with increased salt intake
- coping with long fasting periods
- finding fresh water
Marine mammals have to adapt their renal system to:
- extreme the large amounts of minerals injected
control the amount info water loss to prevent dehydration
number of reticule correlates to…
The number of reticule correaltes with the salinity of the diet and is associate with an increased capacity to excrete urine
Describe the 3 basic sources of water that mammals obtain water from to use for osmoregulation?
- drinking fresh water directly
- h2o in food; most fish and invertebrates consists of 60-80% water
- metabolic water: synthesis of fat or metabolism of protein
Do marine mammals that live in freshwater lakes or rivers have to worry about removing huge amounts of minerals from their bodies ?
Give 2 examples of such species?
NO
ir; manatees, amazing river dolphins
What do some pinnipeds do to directly access fresh water either in the wild or in captivity?
chew on ice or snow
captive: drink water from hose or trough
What was the outcome with respect to urine output, of a study wherein West Indian Manatee maintained in salt water, deprived of fresh water but fed a diet of leafy green vegetables (~70% fresh water)?
produced normal urine output
What are the 2 main compounds that are broken down by the body and how much water can each provide?
What is the implication of this for a marine mammal?
During fasting are these sources available and why?
fatty acid catabolism i gram of palmitate –>beta oxidation) –>1.07grams of h20
proteolysis
1 gram of protein –> 0.4 g h20
eat more fatty fish
yes because of storage of fat and protein
A sea lion is deprived of both salt and fresh water for 45 days. Describe what will happen
along with fasting, the marine mammal will also decrease its urine output for further conservation of water
What is one consequence of protein breakdown relevant for the kidney?
urea
what is the impact of urea on water retention
urea must be excreted in the ruin resulting water loss
What do marine mammals with high protein diet do to deal with this situation?
Give the scientific name for this and describe it
Mariposa = intentional ingestion of sea water
beneficial to marine mammals who have high protein diets, as the sea water an pride urinary osmotic space for urea, minimizing water loss
Give one example of this from otariids, phocids and dolphins and the relative magnitude (daily) with mariposa
northern fur seal = 1.8 mL.kg per BW
harbour seal= 4.8mL/kg BW
common dolphin 12-13mL/kG per BW
Discuss sea otters, their diet, eating habits and how relevant this issue is for them and what they do to cope.
Sea otters freely swallow sea water (avg. 62 ml’kg per body weight of saw water per day) to help extreme the high amount of urea it forms.
Reducing Water Loss
What are 3 other key non-renal adaptations to conserve water in marine mammals:
- skin of pinnipeds have FEW sweat glands
- cetaceans have NO sweat glands
- water loss from breathing is reduced by conserving breaths and cooling expressed air (countercurrent exchanges)
