Unit D3 - Excretory system Flashcards
Aldosterone:
- acts on distal tubule and collecting duct
- released during dehydration or low blood pressure
- causes increase in Na+(sodium) pump activity
- Na+ to blood (reabsorption) = water moves to blood via osmosis
- H2O reabsorbed, increased blood pressure
- Not released during hydration (high water)
- Na+ stays in filtrate = water is not reabsorped, decrease blood pressure
what transport of matter is the collecting duct associated with?
- reabsorbs water
- reabsorbs Na+ ions
- secretes waste (uric acid, urea, ammonia)
osmosis:
- water moving across the membrane to be with the solute (low to high)
- movement of water to equal solute concentration
- water follows solute
filtrate:
the filtered fluid from the glomerulus to the Bowman’s capsule
- FLUID IN THE NEPHRON
how do the kidneys remove waste products from the body?
- remove ammonia, urea, and uric acid
-maintain water balance
What are the organs that excrete waste products from the body?
Lungs, Liver, Kidneys
what transport of matter is the descending loop of henle associated with?
reabsorbs water
urine formation in four main steps:
- glomerular filtration
- tubular reabsorption
- tubular secretion
- water reabsorption
renal pelvis:
the hollow center, where the kidney joins the ureter
distal tubule:
- mainly secretion
-H2O reabsorption - ADH and Aldosterone
renal medulla:
the inner layer of kidney tissue
Nephritis:
- broad name from inflammation of the nephrons or anything that damages the nephrons
- results in a change in the nephron permeability
- can lead to kidney damage and failure
passive transport:
- high to low concentration
-diffusion- osmosis
- facilitated diffusion
urinary bladder:
where urine is stored
how is the reabsorption of water in the distal tubule and collecting duct regulated?
the ADH and aldosterone hormone
Difference between ADH and aldosterone:
ADH directly increases how much water is reabsorbed, and aldosterone directly increases how much salt is absorbed.
factors that contribute to glomerular filtration:
- permeability of capillaries
- capillaries high blood pressure
glomerulus walls:
- filtration device
- impermeable to proteins, large molecules, and red blood cells
- permeable to water, small molecules, ions, urea(waste products of metabolism)
the big idea of urine formation:
each nephron filters blood, reabsorbs substances such as sodium and glucose fo reuse in the body, and secretes excess or toxic substances such as urea to produce urine.
tubular secretion:
step 3
- adds wastes from the blood to the filtrate
What structure of the nephron is the location with the most reabsorption?
proximal tubule
the tubule part of the nephron:
- connected to the Bowman’s capsule
- twisted to form a loop
- loop = reabsorption device
- absorbs useful substances to the body (glucose, ions, water)
filter part of the nephron:
- the filtration structure at the top of each nephron is a cap-like formation(bowman’s capsule)
- within each capsule, a afferent arteriole enters and splits into glomerulus(network of capillaries)
ADH:
- acts on distal tubule and collecting duct
- released during dehydration or low blood pressure
- dehydration = ADH increases distal tubule and collecting duct permeability = more water absorbed
- Hydration = collecting duct permeability is not increased = less water absorbed
collecting duct:
- water conservation device (reclaims water passing through it ADH)
(these solutes and water are returned to the body via the renal veins) - water reabsorption
- ADH and Aldosterone
how does the body deal with dehydration to maintain homeostasis?
dehydration (concentrated blood) = LOW water in blood = aldosterone and ADH released from brain = increased water reabsorbed = increased blood pressure
how is homeostasis maintained in the nephron
antidiuretic hormone and aldosterone
What transport of matter is the proximal tubule associated with?
- reabsorbs water
- secretes H+ ions
- reabsorbs Na+ ions
- secretes waste (uric acid, urea, ammonia)
ureters:
- 2 muscular long tubes (approximately 28 cm)
- carry urine from the kidney to the bladder by peristalsis
what is the function of the collecting duct in the nephron?
connected to other nephrons, helps with reabsorption of water
secretion=
INTO the nephron
- to secrete is to move into the nephron for excretion(removal out of the body)
what transport of matter is the distal tubule associated with?
- reabsorbs water
- secretes H+ ions
- reabsorbs Na+ ions
- secretes waste (uric acid, urea, ammonia)
where does the compound uric acid come from?
- remember the kidneys remove uric acid***
- uric acid is a by-product of the breakdown of nucleic acids (DNA & RNA)
where is the first point of filtrate secretion in the nephron?
Bowman’s Capsule
where does the compound urea come from?
- remember the kidneys remove urea***
- urea is formed in the liver when ammonia is combined with carbon dioxide
- less toxic
Step 1 of urine formation:
- glomerular filtration
- first point of contact
- moves water and solutes(except proteins) from blood plasma into the nephron(filtrate)
- glomerulus filters fluid out of the blood and into Bowman’s Capsule
- dissolved solutes are forced out with the plasma into Bowmans capsule(everything except RBC, WBC, Proteins, platelets)
- proteins, blood cells, and platelets are too large to be filteres and they stay in the blood
capillary net:
small capillaries that surround the nephron
what matter is directly managed by ADH (anti-diuretic hormone)?
water
step two of urine formation:
- tubular reabsorption
- removes useful substances from the filtrate and returns them into the blood for reuse by body systems
- useful substances include: water, salt, H+ ions, glucose, amino acids
- approximately 65% of filtrate that passes through the proximal tubule is reabsorbed and returned to the body
- reabsorption occurs through active and passive transport
- the cells of the proximal tubule have MANY mitochondria = lots of ATP available
- ATP drive the active transport of sodium ions, glucose, and other solutes back into the blood
-descending and ascending loop of henule
what does the body do with hydration to maintain homeostasis?
hydration (dilute blood) = HIGH water in blood = no ADH or Aldosterone released = Decreased water absorbed = decreased blood pressure
kidney dysfunctions:
- diabetes
- nephritis
- kidney stones
- dialysis
the duct part of the nephron:
- the tubule empties into the collecting duct (a large pipe-like channel)
- the filtrate remains in the ducts = urine
diabetes:
- diabetes insipidus
- ADH activity is insufficient
- person urinates excessively which leads to
severe dehydration
- Diabetes Mellitus
- inadequate secretion of insulin by the pancreas
- results in high blood glucose levels which leads
to large amounts of sugary urine
reabsorption=
OUT of the nephron
- to absorb is to absorb into the blood (out of the nephron)
Nephrons:
- inside the renal medulla/cortex
- the functional unit of the kidneys
- over 1 million per kidney
- responsible for filtering various substances from the blood, transforming it into urine
diuretic:
anything that makes you pee or poo
How does the liver excrete waste products from the body?
- removes bile pigments(from breakdown of hemoglobin)
- removes lactic acid (from anaerobic cellular respiration)
- eliminates toxins such as alcohol and heavy metals
What does the blood pathway in the kidney consist of?
renal artery and renal vein and capillary net
descending loop of Henle:
permeable to water
- results in reabsorption of water through osmosis
active transport:
- low to high concentration
- requires energy
- against the concentration gradient
step 3 of urine formation:
- tubular secretion
- movement from blood to tubules
- moves additional wastes and excess substances from the blood into the filtrate
- the active transport of waste from the blood into the nephrons(uric acid, ammonia, urea)
- the pH balance of blood is also adjusted by the secretion of H+ ions (low blood pH = high H+ concentration/ H+ secretion)
- occurs mainly in the distal tubule
are nephrons and the glomerulus semi-permeable or permeable membranes?
semi-permeable
glomerular filtration:
step 1
creates a plasma-like filtrate of the blood
tubular reabsorption:
step 2
- removes useful substances from the filtrate and returns them to the blood for reuse
urinary sphincter:
controls the release of urine into the urethra
water reabsorption:
step 4
- removes water from the filtrate and returns it to the blood for reuse
renal artery:
carries blood into the kidney (glomerulus)
-afferent arteriole is into, efferent arteriole is out
of
Kidneys:
- 2 fist-sized, located on either side of the spine in the lower back
- filter waste from blood
- create urine
- adjust the concentration of ions in the blood(potassium and sodium)
- humans are capable of functioning with only one.
Where does the compound ammonia come from?
- remember the kidneys remove ammonia***
- ammonia gas is the by-product when excess protein undergoes deamination in the liver
- very toxic
renal cortex:
outer layer of kidney tissue
ascending loop of Henle:
permeable to sodium ions
- results in reabsorption of sodium
- active transport
urine:
- in the collecting duct, reabsorptionof water occurs to increase the concentration of filtrate(urine)
- urine goes to the renal pelvid
- down to ureters to bladder
- out urethra
What are the three parts of the nephron?
a filter, a tubule, a duct
what transport of matter is the ascending loop of henle associated with?
reabsorbs Na+ ions (sodium)
What is the function of the excretory system:
- regulates the volume & composition of body fluids
- removes metabolic wastes from the blood, excretes waste out of the body
what are the three sections of the kidney tissue:
- renal cortex, renal medulla, renal pelvis
step 4 of urine formation:
- water reabsorption
- mainly occurs in the collecting duct but also distal tubule
- the filtrate entering the collecting duct and distal tubule still contains a lot of water
- removes water from the filtrate and returns it to the blood for reuse by body systems
- the filtrate in the duct is 4 times as concentrated as the original filtrate
urethra:
- tube that carries urine from the bladder out of the body
- in males, its roughly 20 cm long and merges
with the reproductive tract - in females, it’s roughly 4 cm long and the
reproductive and urinary tracts have separate
openings
- in males, its roughly 20 cm long and merges
kidney stones:
precipitation of mineral solutes creates sharp stones
what happens if plasma is too acidic in the glomerulus:
H+ actively transported into nephron from capillaries(secretion)
what matter is directly managed by aldosterone?
Sodium (Na+) ions
bowman’s capsule:
- filtration structure at the top of each nephron that is in a cap-like formation
- filtration by size(everything except proteins and cells)
- forms filtrate
How do the lungs remove waste from the body?
They remove carbon dioxide (from cellular respiration)
dialysis:
- treatment for renal insufficiency
- treatment that filters and purifies the blood using a machine
2 types
-hemodialysis and peritoneal dialysis
renal vein:
carries blood away from the kidneys (nephron)
- blood leaving kidney is cleaner but has less
oxygen
