Label the human excretory system.
Bladder, Ureter, Kidney, urethra, Renal artery, Renal vein
Transports urine to bladder.
1. Formation of urine
2. Homeostasis of blood volume
Homeostasis of blood pH.
Conducts urine from bladder to outside body.
Oxygentated and ;unfiltered blood tot he kidney.
Deoxygenated blood, filtered blood away from the kidney.
Difference between male and female urethra in humans?
Male urethra is longer.
What is exretion?
The removal of metabolic wastes from the body.
What creates metabolic waste?
When amino acids are broken down in the liver ammonia (NH3) is produced. The liver converts this to a less toxic substance called urea. This product then enteres the blood and is excreted by the kidney. Creatine phosphate produce cratinine, and nucleotides break down into uric acid
What is creatine phosphate used for in muscles?
For building up muscles protein
What nitrogenous waste is produced by the breakdown of creatine phosphate?
How does uric acid get produced?
When nucleotides are broken down.
How is solute concentration in our blood (osmolarity) related to blood volume and blood pressure?
A high salt (solute) concentration leads to high blood volume and then high blood pressure.
What happens to blood volume and pressure if we produce more urine?
They will decrease because water is removed from the blood.
What is a helath pH for our blood?
Why does our blood tend to be slightly basic rather than slightly acidic?
Blood act as as a buffer in homeostasis. The kidneys reduce blood acidity b y excreting more H+ ions or by reabsorbing more HCO3- ions back into the blood.
Label the digram of the kidney.
Contains Bowman's capsule of the nephron for initial filtration and proximal and distal tubules.
Contains the collecting duct and the loop of Henle for each nephron.
Collects urine from the nephrons and passes it to the ureter.
Parts of the nephron?
Bowman's capsule, Proximal convoluted tubule, Distal convoluted tubule, loop of Henle, collecting duct.
Millions of tubules that make up the kidney and are involved in filtering blood to produce urine.
First part of nephron that receives filtrate from the glomerulus (blood vessels that sit inside of the bowman's capsule). This is the location of glomerular filtration.
Proximal convoluted tubule?
Part of nephron after bowan's capsule. Substances leave the proximal tubule so that they can be reabsorbed back into the blood vessels. This is the location of tubular reabsorption.
Loop of Henley?
Loop of nephron that comes down from the proximal convoluted tubule. In the descending portion water leaves the nephron. In the the ascending portion NaCl leaves the loop through the process of diffusion in the first part and active transport in the second part. The reason water leaves in the descending portion is because the surrounding tissue is salty from the salt that leaves in the second part.
Distal convoluted tubule?
Tubule after loop of henle where some substances from the blood are reabsorbed back into the nephron. This is the location of tubular secretion.
Last portion of the nephron where the urine is refined. Some water leaves the collecting duct and goes back into the surrounding capillaries. The collecting duct leads to the renal pelvis.
Arteriole that leads into the glomerulus.
Arteriole that leaves the glomerulus.
Capillaries that surround the nephron.
Also called glomerular fitratoin. This takes place between the bowman's capsule and the glomerulus. High blood pressure in the glomerulus forces H2O, and solutes (NaCl2, HCO3-) ions of H+ and K+, also urea, glucose, amion aicds, and some drugs into the capsule. Blood cells plasma proteins, and some water do not leave the capillaries.
Tubular (Selective) Reabsorption:
Refines the filtrate (what is in the nephrons) at the proximal convoluted tubule. Water, valuble solutes, glucose, amion acids, sodium chloride and other ions are re-absorbed back into the blood. Glucose and amion acids require active transport. Water and some ions diffuse.
Occurs in the distal convoluted tubule. Active transport moves molecules of creatinine, uric acid, ammonia, urea, drugs and ions of H+ back into the tubule.
Final refining of the urine in the collecting ducts. This is important in homeostasis of NaCl (salt) in tissue fluid and blood. Walls of the collecting duct are permeable to urea and some of this urea leaks out into the interstitial fluid. As a result, some H2O will diffuse out of the collecting duct into tissues and into capillaries.
What is in the final urine product?
Water, salts, urea, uric acid, ammonium, and creatinine.
What causes water to leave the nephron and enter the blood in the loop of Henle?
The walls of the descending limb of the loop of henle are permeable to water which leaves by osmosis. Salt is transported out of the ascending loop of Henle, which is impermeable to water. THis increase in the salt concentration of the surrounding tissue is the reason water is leaving the descending limb.
How does the kidney maintain homeostasis with respect to pH?
If the blood in the renal arteries is acidic, nephrons allow:
1. HCO3- (bicarbonate ions) to be reabsorbed into the blood. These act as a buffer into the blood in the formation of H+ + HCO3- --->H2CO3 (carbonic acid)--->H2O + CO2 (exhaled)
2. H+ are excreted, acidfying urine
NH3 + H+ --->NH4+ (ammonium)
ammonia acts as a buffer
How does the urea and glucose content in the renal artery compare with that of the renal vein?
The renal artery has a higher concentration or urea than the renal vein, however, 44% of the urea is reabsorbed. Glucose concentration is almost equal in the renal artery and vein. If there is glucose in the urine the person has diabetes mellitus and therefor the liver fails to convert enough glucose to glycogen and the kidneys can not reabsorb all of the gluscoes from the filtrate.
Antidiuretic hormone produced by the hypothalamus in the brain and released into the posterior pituitary. It is used to regulate blood osmolarity (homeostasis of water levels in the blood)
An endocrine gland because it is ductless and secretes into the blood stream.
How does th ehypothalamus, posterior pituitary, ADH and the nephron achieve homeostasis of water levels in the blood?
When Blood osmolarity increases above a set point (eg. due to dehydration or eating saltly food), this stimulus sends a message to the osmoreceptors in the hypothalamus which then tells the Pituitary gland to release ADH. ADH travels through the blood and makes the collecting duct more permiable to water so H2O) can leave the collecting duct and be reabsorbed into the blood stream causing osmoregularity to fall back to a set point. When blood becomes dilute less ADH is realeased. At the same time the hypothalamus gives us a message that we are thirsty so that we will drink more. This whole process involves a negative feedback loop
How does the adrenal cortex, aldoterone, and the nephron achieve homeostasis of water and sodium levels in the blood?
When blood pressure is too low to promote good filtration the JGA secretes renin, which then stimulates angiotensinogen which forms angiotensin II which 1). stimulates vsoconstriction and 2) stimulates the adrenal gland to secrete aldosterone which allows increase in the reabsorption of Na+ and H2O into the distal tubule.