Excretory System Flashcards
What is the excretory system?
the excretory system is used to regulate the volume and the composition of body fluids by removing waste and returning useable substances to the body
Why is it important for waste to be removed?
- examples of waste
- how is waste removed
Waste should be removed as it can be a threat to our health. though some can be reuseable others can pose a greater threat to our body as they can raise our body pH.
Examples of waste would be carbon dioxide, ions like sodium (Na+), chloride (Cl-), and hydrogen (H+).
to get rid of these, our body excretes them.
Excretion is the process by which waste is separated from the body fluids and eliminated.
Organs in the Excretory system
- kidneys
- renal artery - aorta
- renal vein - inferior vena cava
- ureters
- urinary bladder
- urethra
Function of the organs
1. kidneys
2. renal artery - aorta
3. renal vein - inferior vena cava
4. ureters
5. urinary bladder
6. urethra
kidneys: produce urine
renal artery: provide kidneys with blood
renal vein: filtered blood from kidney
ureters: transports urine
urinary bladder: stores urine until it needs to be excreted
urethra: excretes urine
Parts of the kidney
- renal medulla
- renal cortex
- filtering areas (nephrons)
- renal pelvis where everything is connected1
How does the kidney filter?
- what does it consist of
the kidney’s filtering site is called the nephron which consists of the glomerulus, the Bowmans capsule, the proximal as well as distal tubule, the loop of Henle, capillaries the cortex, and medulla side of the collecting duct and the collecting duct itself
What are the functions of the filtration system in the kidney?
- glomerulus
- bowmans capsule
- proximal and distal tubule
- loop of Henle
- collecting duct
Glomerulus:
the walls of the glomerulus act as the filtration. they are impermeable ( don’t allow) to proteins or other large molecules and red blood cells so these stay with the blood. *However water, small molecules like amino acids and ions such as sodium and chloride as well as waste can pass through and further into the nephron.
Bowman’s Capsule:
the capsule wraps around the glomerulus and will then branch into the tubules
the tubule is divided into three sections:
Proximal Tubule
absorbs useful solutes back into the blood vessels (capillaries)
Loop of Henle:
The loop reabsorbs water by osmosis
Distal Tubule
The distal tubule actively transports waste and hydrogen (H+) out to be excreted.
Reabsorption of Chloride and bicarbonate
Collecting Duct
the tubule empties into a larger pipe-like channel this is called the collect duct.
the collecting duct. the collecting duct is used as a water-conserving device reclaiming water so that very little water is lost from the body.
Process and Location
- FRSR
Filtration happens from the glomerulus to the Bowman’s capsule. The filtration happens because of a pressure gradient or blood pressure as the blood pressure in the glomerulus is about 4 times greater, this is what causes the filtration. Small molecules such as sodium, amino acids, glucose, chloride, and waste can pass through the glomerulus but bigger solutes such as red blood cells will be left in the blood.
Process and Location
- FRSR
» loop of Henle:
descending
ascending
Reabsorption happens in the proximal tubule. In this process, we are trying to reabsorb nutrients and then they are returned to the body. These substances/solutes are moved by active transport as they are moving from an area of even concentration to an area of uneven. Negatively charged ions such as Chloride will move passively and water is moved in by osmosis and into the capillaries.
In the loop of Henle, we reabsorb water. The loop of Henle passes through the medulla region and then loops to go back to the cortex area. The medulla region is a salty environment therefore its HYPERTONIC.
The descending part of the tubule is permeable to water so it lets water into the capillaries as water moves by osmosis due to high to low concentration.. It’s also semi-permeable to certain ions which it’ll let into the tubule. When water moves the concentration of sodium rises.
The ascending part of the loop, the thin part of the tubule is now impermeable to water and slightly permeable to solutes. sodium will now pass into the blood vessels nearby by diffusion. In the thick segment, sodium ions are moved out of the filtrated fluid by active transport. The transport of sodium helps with two things
1. it helps the hypertonic environment of the medulla by restoring it and letting water be absorbed from the filtered liquid in the descending limb.
2. the absorbed sodium also makes the filtrate less concentrated than the tissues and blood surrounding the cortex tissue.
The reabsorption of solutes help decrease the concentration of the filtrate
However, the active reabsorption of sodium ions depends on the needs of the body.
Passive reabsorption of negative ions such as chloride happens to due electrical attraction.
Process and Location
- FRSR
- secreted meaning
secreted means to remove
Secretion of waste happens in the distal tubule. Potassium ions (K+), Hydrogen ions (H+) which make our blood pH acidic and other substances like waste penicillin and other drugs are actively secreted/ just secreted into the distal tubule.
Process and Location
- FRSR
- dehydrated and hydrated
Reabsorption of water happens in the collecting duct.
The collecting duct extends deep into the medulla which increases the concentration of ions along its length. because of this, the passive reabsorption of water from the filtrate into the collecting duct is done by osmosis. However, reabsorption can be affected by how hydrated or dehydrated a person is.
HDRATED** If a person is hydrated the permeability to water will be decreased so that not much water will be reabsorbed.
**DEHYDRATED* if a person is hydrated then permeability to water will be increased so that water is reabsorbed.
The reabsorbed water causes the filtrate to become four times concentrated by the time its out of the duct and is now urine.
What affects the amount of water reabsorbed from filtrate?
- its volume
- concentration of blood plasma
Osmotic Pressure
- what does osmotic pressure affect
the force generated as water is moved by the process of osmosis.
the greater the concentration gradient, the greater the osmotic pressure will be. the weaker the concentration gradient the weaker the osmotic pressure will be.
Osmotic pressure affects many cellular activities especially the exchange of materials between cells and blood.
Antidiuretic Hormone
what is involved?
Diuretic means to increase urine excretion, anti means against so together antidiuretic is to stop the increased amount of urine being excreted.
Examples of diuretics would be alcohol and coffee.
1. Osmoreceptors
2. Hypothatemus
3. pituitary gland
What does each do?
1. Osmoreceptors
2. Hypothalamus
3. pituitary gland
Osmoreceptors
sensitive to osmotic pressure
Hypothatemus
part of the brain that regulates hunger, thirst, blood pressure, body temperature, fluid balance, and salt balance. in other words, regulates mechanisms to enable the body to maintain homeostasis.
Pituitary Gland
is to produce and release several hormones that help carry out important bodily functions such as the release of ADH.
How do all of these work together?
ADH
Osmoreceptors located in the hypothalamus are cells sensitive to osmotic pressure. When you’re dehydrated, your blood plasma becomes concentrated meaning it becomes stronger(?) so the osmotic pressure increases. the osmoreceptors will sense this and in response, the hypothalamus sends signals to the pituitary gland located in the brain as well and releases ADH.
– ADH will then travel through the blood to the kidneys where it will increase the permeability of the distal tubule and collecting duct that’ll stimulate the reabsorption of water in the blood. This dilutes blood, lowering osmotic pressure. When it becomes too dilute, osmoreceptors will stop the release of ADH so that the distal tubule and collecting duct will become less permeable to water.
- ADH travels everywhere but only some tissues will respond to it
Diabetes Insipidus
Diabetes Mellitus
Insipidus is when our urine is really dilute. this means that ADH activity is either insufficient or the collecting duct and tubule aren’t responding. The person who has diabetes insipidus would pee a lot and would be very thirsty
Mellitus is when glucose is present in pee. this would be due to the fact reabsorption in the proximal tubule isn’t functioning well or there’s too much glucose to keep up with.
Reabsorption of Salt
- aldosterone
- kidneys regulate salt balance in the body by controlling what it absorbs or lets out. Sodium is the most plentiful but it could also rise and fall dramatically.
Aldosterone stimulates the reabsorption of Na+ and the secretion of potassium by actively moving potassium if blood concentration is too high
when Na+ decreases, the body will release aldosterone from the adrenal gland in an attempt to increase body salts. In the collecting duct and distal tubule aldosterone will increase the reabsorption of Na+ and this will be done through active transport.
- Because of ion charges, chloride will follow Na+ because of charge attraction
- increased salt absorption making kidney tissues hypertonic
- to balance its water will be reabsorbed by osmosis so that we won’t become too salty
Blood pH
the normal pH of our body would 7.4
By adding or removing hydrogen (H+) which will prevent changes in pH.
if the blood pH is too acidic it will then reabsorb the bicarbonate ions so it will go back to the blood and maintain the blood
If its too basic, it’ll stop supply of bicarbonate
Renal Insufficiency
- what could these be
When kidneys don’t work as they should
- kidney infection
- high blood pressure
- diabetes mellitus
- trauma from a blow to the lower back or constant vibration from machinery
- poisoning
- atherosclerosis reduces blood flow to kidneys
- blockage
Urinary Tract Infection
- cystitis
- urethritis
Cystitis is when the bladder has bacterial or viral infection
Urethritis only happens in the urethra
Symptoms of Urinary Tract Infection and Treatments
Symptoms could be that u need to urinate much more even if there is no urine coming out, brown or bloody pee, lower , and upper body may feel tender, fever, nausea, and vomiting.
could possibly lead to urine infection
Treatments could be antibiotics or surgery if it becomes really serious
Kidney stones
kidney stones are when there are a lot of excessive amounts of calcium in our nephron located in the loop of Henle. Calcium will crystalize as in the loop of Henle, there are parts where it is very hypertonic so there isn’t much water. (water is removed)
1-2 mm can be passed in our system
up to 2 cm can be broken down using ultrasound soundwaves
but if it over 2 cm we will need to be surgically removed the kidney stones or if it gets bad enough the whole kidney.
however, kidney surgery isnt preferred because our own body can attack the transplant if we get or cut off circulation to that transplanted organ.
Dialysis
- types of dialysis
- stimulates FRSR by using diffusion principles.
- dialysis is the diffusion of dissolved substances through a semipermeable membrane, moving from an area of high to low concentration.
- substances that are more concentrated in blood will be diffused into the dialysis solution called the dialysate.
- substances that are more concentrated than the dialysis fluid will be diffused back into the blood.
- other substances can be added into the dialysate to balance other stuff like our pH levels.
types of dialysis
1. hemodialysis
2. peritoneal dialysis
