Lecture 12 Flashcards
Define Countercurrent Exchange
a pair of adjacent channels or tubes containing fluids flowing in opposite directions and having a gradient directed between one channel and the other. (In other words, stuff can flow between the tubes.)
can be used in temperature
counter current exchange has to work with what direction
opposite
artery is higher temperature coming in not looking at the beginning at the vein but at the end blood comes into the artery at the end with the vein which is colder
look up videos about
counter current exchange
cold environment you use
counter current exchange
artery heat goes into the vein
gradient never changes
return warmer blood to core instead of cold blood thanks to ccxchange
Kidneys:
Toxic waste prodKidneys: ucts Kidney: filters Has a filitration membrance Filtering blood 1 single nephron can do it all focusing on that nephron little loop- flow going one direction flow- other side two tuber with flow ex. Of counter current exchange change whats happening in tissue around the tube
whats the collecting duct?
a tiny tube collecting from multiple nephrons several nephrons that can empty into collecting duct, receiving fluid from multiple nephrons- not a part of the nephron seperate structure recieves from multiple nephrons
Receives from many distal convoluted tubules.
Collecting duct now passes through the concentration gradient set up by many adjacent nephrons.
So, as glomerular filtrate passes down collecting tubule, it moves through higher and higher concentration of salts that were set up by loops of Henle.
getting into the glamarius
by afferent arterile- gets sent in small capilarries, leaves renal corpuscle by using the efferent arteriosle
whats in the lumen- blood-plasma-water
pathway of nephron
glomerulus- wall of capillaries have holes-proximal convuluted tubule-descending loop of henle-ascending loop of henle-distal tubule-collecting duct
A COUNTERCURRENT EXCHANGE SYSTEM can only work if there is an asymmetry in the system.
In this case, there is active transport in only one direction. In the case of the kidney, salts are being transported to concentrate salts in the urine.
remove spdoium-pushed out of glumerous and out into bowmen capsule- need sodium for nerves
why would you force water out urinate them out need water for the solvent
what the waste products are dissolved in- lumen of bomen’s capsule
with water solution travels all the way through what’s in distal thingy- water
area where you have a little tube lots of water inside of them exerts pressure from tubes
increases the tube pressure cells around sital tubule,that where you have the justux glamerial cells(granular cells) which sense pressure, use that pressure of fluid as a proxy to tell our body/brain of how much water we have in our system,
vitally important for water balance regulation- in the pathway getting through fluid, getting through the distal covalent tubule, remained unchanged? Reabsorb some of water if you need it, don’t need water, then not reabsorb water, whats the pressure in that area there? Water balance regulation
Bowman’s capusle
is a cup-like sac at the beginning of the tubular component of a nephron in the mammalian kidney that performs the first step in the filtration of blood to form urine. A glomerulus is enclosed in the sac. Fluids from blood in the glomerulus are collected in the Bowman’s capsule (i.e., glomerular filtrate) and further processed along the nephron to form urine. This process is known as ultrafiltration.
Glomerulus
American /ɡlɒˈmɛrələs/) is a network (as a tuft) of capillaries located at the beginning of a nephron in the kidney. It serves as the first stage in the filtering process of the blood carried out by the nephron in its formation of urine.
The glomerulus is surrounded by a cup-like sac known as Bowman’s capsule. The blood plasma is filtered through the capillaries of the glomerulus into the capsule. The Bowman’s capsule empties the filtrate into the proximal tubule that is also part of the duct system of the nephron.
A glomerulus receives its blood supply from an afferent arteriole of the renal circulation. Unlike most other capillary beds, the glomerulus drains into an efferent arteriole rather than a venule. The resistance of these arterioles results in high pressure within the glomerulus, aiding the process of ultrafiltration, where fluids and soluble materials in the blood are forced out of the capillaries and into Bowman’s capsule.
Proximal Convoluted Tubule
The proximal tubule regulates the pH of the filtrate by exchanging hydrogen ions in the interstitium for bicarbonate ions in the filtrate; it is also responsible for secreting organic acids, such as creatinine and other bases, into the filtrate.
The proximal tubule is the portion of the duct system of the nephron of the kidney which leads from Bowman’s capsule to the loop of Henle.
Loop of Henle
is the portion of a nephron that leads from the proximal convoluted tubule to the distal convoluted tubule. Named after its discoverer, the German anatomist Friedrich Gustav Jakob Henle, the loop of Henle’s main function is to create a concentration gradient in the medulla of the kidney
The loop of Henle is supplied by blood in a series of straight capillaries descending from the cortical efferent arterioles..[3]
Distal Convoluted Tubule
In addition to sodium – chloride, calcium, bicarbonate, and H2O are reabsorbed here. Ammonium, hydrogen, and some drugs or toxins can be secreted here.
By this point, the nephron loop has used materials IN the glomerular filtrate to set up a concentration gradient in the interstitial space of the kidney.
lots of water- exerts pressure more water- more pressure
juxtamurlelar cells- sensing pressure
water balance regulation
Collecting
Duct
The collecting duct system of the kidney consists of a series of tubules and ducts that connect the nephrons to the ureter. It participates in electrolyte and fluid balance through reabsorption and excretion, processes regulated by the hormones aldosterone and vasopressin (antidiuretic hormone).
Proximal Convoluted Tubule:
explain the physiology
Initiate concentration of glomerular filtrate.
About 75% of sodium removed by active transport here, and chloride follows passively.
Remaining fluid in nephron tube is about same concentration as that of surrounding interstitial fluid.
Remaining fluid reduces to about 25% original volume
Loop of Henle:
Acts in manner of counter current exchanger. Note that each limb of loop has fluid moving in opposite directions (even though connected at one end).
Further concentrates urine.
Also means that salt concentration will be highest near bend in the loop.
fanestra walls of capillaries
coating top of the capillary, window holes thingys represent where endotheliumof capillary bottom picture above the blue line very top coating of capillary inner lying of bowman’s capsule both of them have openings
endothelium of bowman capsule
endothelium of bowman capsule called slit whores holes
substances can pass from blood inside glamarus go across filtration memberane
openings have a finite, large red blood cells- blood in urine wrong with filtration in blood allowing filtration to allow things to large- from bowmans capsule go- proximal tubule- not initating filtration we are intiating the concentration of the substances of glumorial filtrate, use active transport to change concentrations of the tubule, remove sodium using active transport
glumerli filtrate
Glomerular filtration is the renal process whereby fluid in the blood is filtered across the capillaries of the glomerulus.
sodium is disscolved inside water- do you need to get some sodium back of what? Need sodium for muscle, nerves-out of gumerus inside the bowmans capsule
depolrize axolema
what you need to understand
reabsorbing from lumen to tubule to intersticial fluid of the medulla
ASCENDING LOOP OF HENLE:
Chloride ions actively transported out of loop into the interstitial space. Oppositely charged sodium ions follow. However, water does not move out of the ascending loop. Ascending loop is permeable to solute, not H2O.
A concentration gradient IN THE INTERSTITIAL SPACE is being set up by the chloride ( plus sodium) transport.
By setting up a countercurrent system, a salt concentration gradient is
set up in the interstitial space (highest concentration near curve of loop of Henle).
goes
descending-then ascending
ASCENDING LOOP OF HENLE: Chloride ions actively transported out of loop into the interstitial space. Oppositely charged sodium ions follow. However, water does not move out of the ascending loop. Ascending loop is permeable to solute, not H2O.
A concentration gradient IN THE INTERSTITIAL SPACE is being set up by the chloride ( plus sodium) transport.
DESCENDING LOOP OF HENLE: No active transport of salt out of the descending loop of Henle. Descending loop is permeable to H2O, not solute. This H2O moves down the concentration gradient created by the ascending loop
phrase
water follows salt in descndng limb
CORTEX –
part that contains the convoluted tubules and proximal part of Loop of Henle, and proximal part of collecting tubules.
MEDULLA
contains distal part of Loop of Henle, and distal part of collecting tubules. Where most of the active transport takes place.
ascending limb
conentration- allow descending limb to reabsorb water- ascending puts the conentration gradient in the intersitical fluid
collecting duct goes the same fluid flow as
descnding limb
Same exact flow of the descending loop of henle
2050
Permable to water- collecitng duct
Basically same loop of henle
Passing thgouh same gradient as descending limb
2nd chance to reabsorb water
KIDNEYS AND BLOOD PRESSURE REGULATION
Kidneys are intimately tied to fluid regulation (water balance), and therefore blood pressure regulation.
counter current
never stop conentrate urine-retain water
water reabsorbed conntrate filtrate
WATER BALANCE:
The Amount of water to be removed or retained is controlled in part by the kidneys.
Water Gain:
Ingested food and fluid; metabolic water
Carbohydrates + Oxygen Water + CO2
C2H12O6 + O2 H2O + CO2
water loss
urine, feces, sweat, evaporation at lungs or skin
ADH makes the DCT and collecting duct
MOREpermeable to water. Thus, secretion of ADH causes the retention of water in the body, and more concentrated urine. (ADH is usually secreted in response to environmental situations that require the retention of water.)
A diuretic(increase flow)
will have opposite effect: decreases permeability of collecting tubule, so you lose lots of water (copious, dilute urine). Examples of diuretics: caffeine, alcohol (beer, particularly due to the hops), capsaicin (the active ingredient in hot peppers), large quantities of vitamin C, others.
sweating water
relreases ADH decreases permatbility DCT and collecting duct reabsorb more water - contrate more urine more darker
HORMONAL CONTROL OF EXCRETION
Inhibition of ADH
decreases permeability of collecting tubule to water. Less water CAN ESCAPE OUT OF IT INTO THE INCREASING CONCENTRATION GRADIENT that was set up by the Loops of Henle. (The filtrate retains more water, leading to a less concentrated urine.)
HORMONAL CONTROL OF EXCRETION
Inhibition of ADH
decreases permeability of collecting tubule to water. Less water CAN ESCAPE OUT OF IT INTO THE INCREASING CONCENTRATION GRADIENT that was set up by the Loops of Henle. (The filtrate retains more water, leading to a less concentrated urine.)
Nervous system is predominantly
electrical in nature, though neurotransmitters are chemicals that diffuse between neurons. The synaptic cleft is very narrow, so nervous transmission remains high.
ENDOCRINE structures communicate by secreting chemicals
INTO THE CIRCULATORY SYSTEM
Because the endocrine system is a system wherein chemicals diffuse through the circulatory system, it is slower, but often long-lasting in effect.
might not get to target structure right away
what r the TYPES OF CHEMICAL REGULATORY AGENTS
Simple, Widespread, Nonspecific (e.g. carbon dioxide, oxygen, calcium, etc.)
More Complex and Specific: MESSENGERS.
Animals have specialized tissues that secrete regulatory molecules into the interstitial tissue and blood, and act on remote TARGET CELLS within the same organism (person).
The tissues that produce these molecules are ENDOCRINE GLANDS. The messenger molecules are called HORMONES.
only cells that contain receptors specific for the hormone are affected by the hormone. These types of cells are or organs are called
TARGET CELLS or TARGET ORGANS
PROPERTIES OF HORMONES 5
hormones are produced and secreted by endocrine cells in TRACE AMOUNTS.
Hormones circulate in the blood to reach all tissues.
But, hormones react only with specific receptor molecules present in certain target cells/tissues.
Hormones can have CATALYTIC QUALITIES, frequently activating enzymes.
A single hormone may have multiple effects on a single target tissue, or on several different target tissues.
Many structures are endocrine organs, and
have other functions as well
CLASSIFICATION OF HORMONES
(Hormone Classification by Function)
Kinetic Effects
generally MOVEMENTS OF SOME KIND. (e.g. pigment migration, muscle contraction, glandular secretion.)
CLASSIFICATION OF HORMONES
(Hormone Classification by Function)
Metabolic Effects
consisting mainly of changes in the RATE and balance of chemical reactions and concentrations in the body.
REGULATION OF HORMONE SECRETION
Generally modulated by
NEGATIVE FEEDBACK. That is, the concentration of hormone itself (once it reaches a certain critical level or concentration), or a product of the response to the hormone by a target tissue, will have an INHIBITORY EFFECT on the synthetic or secretory processes responsible for the original production of the hormone renin
- Decrease in blood pressure causes decrease in amount of extracellular fluid.
what next?
Decrease in extracellular pressure and blood pressure near distal convoluted tubule causes juxtaglomerular cells to release the hormone RENIN-goes into blood until it reaches target strucutre
A change in fluid pressure in the extracellular region is sensed by the JUXTAGLOMERULAR CELLS.
2Decrease in extracellular pressure and blood pressure near distal convoluted tubule causes juxtaglomerular cells to release the hormone RENIN
what next
3RENIN in blood stream converts the liver enzyme ANGIOTENSINOGEN into ANGIOTENSIN I
3.RENIN in blood stream converts the liver enzyme ANGIOTENSINOGEN into ANGIOTENSIN I what next
4ANGIOTENSIN CONVERTING ENZYME (in the lung capillaries) converts Angiotensin I into ANGIOTENSIN II.
4ANGIOTENSIN CONVERTING ENZYME (in the lung capillaries) converts Angiotensin I into ANGIOTENSIN II.
what next
- Angiotensin II causes ADRENAL GLAND to secrete/release ALDOSTERONE: stimulates ADH secretion; stimulates thirst; constricts arterioles. High concentrations of ADH also cause vasoconstriction. higher body temp
- Angiotensin II causes ADRENAL GLAND to secrete/release ALDOSTERONE: stimulates ADH secretion; stimulates thirst; constricts arterioles. High concentrations of ADH also cause vasoconstriction.
Aldosterone stimulates the RETENTION OF SODIUM IONS. -more sodium more water in kidneys becaus eof collecting duct and DCL of henle-Coupled with the effects of ADH, this leads to an increase in H2O reabsorption.
6Aldosterone stimulates the RETENTION OF SODIUM IONS. Coupled with the effects of ADH, this leads to an increase in H2O reabsorption.
7Urine volume decreased
Fluid retained
Blood volume increases
Blood pressure increases.
negative feedback loop
produce renin-stop renin
