# data[].attributes.body
Excretion: process in which living organisms remove waste materials from the body
(urea or carbon dioxide)

Excretory organs include kidneys, skin, lungs
(products should not still be in the bloodstream)

# data[].attributes.body
Excretion - The removal of waste products (feces, urea, carbon dioxide, toxic substances) from the body
Kidney
Egestion - The removal of UNdigested food, feces
Kidneys (nephrons, tubules) - Management Absorption of urea from the bloodstream, osmoregulation
Lungs - Carbon dioxide removal
Osmoregulation - The regulation of water content

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Excretion is the removal of waste products of metabolic activity from the body. Waste products such as carbon dioxide, salts and excess water that is not required in the body. This is usually done by the kidneys.

Excretory Organs
- Kidneys
- Skin (SWEAT)
- Lungs (Carbon dioxide after respiration)
Another term that we can link to excretion is osmoregulation. Osmoregulation is linked to kidney as the kidney controls the water balance in the blood.

# data[].attributes.body
Excretion - the removal of waste substances of metabolic activity from the body.

Excretory organs
- lungs
- kidneys
- bladder/urethra etc
- Rectum/Anus

Kidneys -  function to extract urine from the bloodstream, and filter water.
- functional unit of kidney is a Nephron

# data[].attributes.body
- Excretion : Removal of metabolic waste materials from the body

Kidneys control osmoregulation by using nephrons to filter the blood.
Those who are unable to filter their blood themselves need to use a kidney dialysis.

Glomerulus are a bunch of capillaries with large surface area where blood filters through. This is a part of the bowman capsule

# data[].attributes.body
Excretion is the removal of toxic and urea from the body after the digestion of food.
Remove of waste product
Excretory Organs: Kidney, Liver, Intestines, urinary system, skin, Lugs.

# data[].attributes.body
Excretion: Removal of toxic material(waste) out of the body.
Excretory organ: Kidney removal of urea after detoxification of amino acid in liver, lung: removal of CO2 from respiration, skin:sweat gland remove extra water from body .

# data[].attributes.body
Excretion: removal of toxic substances and waste products of metabolism from the body
- Kidney: removes material and excess water from the bloodstream in the form of urine (consist of renal vein & artery, loop of Henle, medulla)
- Liver: aids in removal of toxic substances
- Sweat glands: removes excess salt and water

# data[].attributes.body
Excretion is the removal of waste products as a result of metabolic reactions in the body.

Excretory organs:
-Kidney
-Lungs
-Glands
-

# data[].attributes.body
Excretion: waste( waste products of metabolic activity) removal
(toxic) waste: urea,
removal of excess water
osmoregulation- control of internal solute concentration of an organism.

# data[].attributes.body
excretion:
removal of waste outside the body.
waste products: excess water/salt/CO2
kidney:organ that filter blood and produce urine
skin: produce sweat
lung: exhaust co2

# data[].attributes.body
- Excretion is the removal of all metabolic waste
- Kidney urea (osmoregulation)
- rental artery, nephrons,loop of Henle, collecting ducts
- secretion of ADH to influence permeability of cells in the collecting duct and influence water reabsorption
- Lungs removal of carbon dioxide
- alveolus high surface area to increase level of digestion
- enriched supply of blood capillaries to maintain concentration gradient

# data[].attributes.body
Excretion
-a product excreted by a living organism or cell.
-metabolism
-removal of toxic waste
-energy lost
-regulation of water
-kidney
-medula
-urinary track
-excretion of carbon dioxide
-sweating through glands
-vasodilation
-vasoconstriction

# data[].attributes.body
Excretion
- expel of metabolic waste
- faeces/ CO2/ water

Organ:
- kidney
- lungs
- anus

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Osmoregulators - Organisms which maintain the optimum osmolarity within their body Maintenance of osmolarity within the body
Osmoconformers - Maintain the

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ADH --> Vasopressin

Kidney removes waste products form the body such as Urea and
Uric acid

Kidney consists of Cortex, Medulla, Pelvis
Supplied by Renal artery and blood extracted by renal vein

Urine extracted via ureter

Nephron is the functional unit of the Kidney.
Composed of
Afferent and Efferent arterioles
Glomerulus and Bowman's Capsule
Proximal convoluted tubule
Loop of Henle and Vesa recta
Distal convoluted tubule
Collecting duct

Ultra filtration occurs at Glomerulus due to high pressure
All substances in blood plasma removed from blood except plasma proteins

Selective reabsorption occurs in convoluted tubules, Reabsorption of Ions, Amino Acids, Glucose

Loop of Henle has discending and ascending limb. Descending limb permeable to Water but not Salt
Ascending limb permeable to Salt but not Water. Surrounded by Vesa Recta, large network of capiliaries that run counter current to the loop of henle, which establishes a salt gradient, which allows water and salts to be reabsorbed into the blood.

the collecting duct transports all the waste products extracted from the blood through the ureter into the bladder to be excreted

Blood in renal artery
High concentrations
- amino acids
- oxygen
- ions
- glucose
- urea
Renal vein
High concentrations
- carbon dioxide
Lower concentrations
- urea
- uric acid
Plasma proteins
- remain the same concentration in both

# data[].attributes.body
Osmoregulators - Organisms which maintain the optimum osmolarity within the body, regardless of external conditions

Osmoconformers - Organisms which maintain the osmolarity within the body based on external conditions

Excretion - The removal of waste products (urea, carbon dioxide) from the body, includes processes; Ultrafiltration, osmoregulation, selective reabsorption

Kidney - Absorbs urea and water from the bloodstream, consists of the cortex, medulla, pelvis, renal artery, and the ureter

Kidney Nephron - Located near the medulla and aids excretion

Process of Ultrafiltration
- First step in excretion

Selective reabsorption
-

Osmoregulation
-

Composition of blood in:
Renal Vein - Less urea, oxygen, water, ions, glucose, and more carbon dioxide
Renal Artery - More urea, oxygen, water, ions, glucose, and less carbon dioxide

ADH - Anti-duretic Hormone? Vasopressin

# data[].attributes.body
Excretion: Removal of metabolic waste products from the body such as excess water and nitrogenous waste

- Nitrogenous waste comes in the form of urea for most mammals, but animals such as fish produce ammonia which is very concentrated and insects produce uric acid which is the least concentrated.
- Some are osmoregulatory and some as osmoconfirmers

ULTRAFILTRATION
- Kidneys control blood filtration and thus homeostasis of water control in the body.
- Nephrons are main units of kidneys which produces urine
- Nephrons have the loop of henle, glomerulus, afferent arteriole, efferent arteriole, and capillaries, bowman's capsule
- Bowman's capsule filters blood at first in the glomerulus which is a dense network of capillaries

SELECTIVE REABSORPTION
- urine is formed from the filtration of blood
- proximal and distal convoluted tubes contain microvilli and mitochondria for large surface area and ATP for active transport
- Reabsorption of glucose, amino acids,

OSMOREGULATION
- Loop of henle has selective permeability where the ascending limb is permeable to salts and impermeable to water, and vice versa for descending limb.
- It also descends into the medulla to establish a salt gradient
- ADH is a hormone

Composition of blood in renal artery: Urea, oxygen, salts and ions, glucose, CO2, proteins

Composition of blood in renal vein: more CO2, very little urea and lowered glucose, ions + salts and O2 levels, protein level remains

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osmocomformer-the internal condition is balance to the osmolarity of external environment .
osmoregulation- the internal osmolarity is constant.

structure of kidney: cortex/medulla/pelvis/renal artery/ renal vein/ ureter

nephron is the unit of kidney,

sturcture of nephron: bowman's capsule/proximal convoluted tubule/loop of henle/distal convoluted tubule/collecting duct

process of exertion:
ultrafiltration,selective reabosrption,osmoregulation

ultrafiltration:
blood enters kidney through renal artery, it further enters the glomrulus within bowman's capsule. The blood vessel becomes narrower, which provide pressure for substances filterd into bowman's capsule.

selective reabsorption
in convoluted tubule, usable substances such as glucose, salt, amino acid back into the blood vessel.
in loop of henle, the descending loop is permeable to water but not salt, the ascend loop is permeable to salt but not water

osmoregulation
osmoregualtion is controlled by hormone called ADH which released from postier pituitary in the brain.
ADH allows collecting duct more water peremeable, so more water is reabsorbed back into the blood vessel.

in insects, they have excretion sturcture called malpighian tubule.

dehydration: lack of water in the body

overhydration: excess of water in the body

compostion of blood in renal artery:water (more),glucose,amino acid,protein,salt(more),urea,creatinine
renal vein:  water(less),glucose,amino acid,protein,salt(less)

# data[].attributes.body
Most of our metabolic waste is in the form of nitrogen; ammonia, urea and uric acid.

Osmoconformers maintain an internal environment that are equal to the osmolarity of the environment. (Minimising osmotic gradient).

Osmoregulators regulate their body osmolarity which stays constant regardless of their environment. (regulating amount of water absorbed)

In insects, the removal of nitrogenous waste and osmoregulation occurs through the Malphagian Tube.

Hemolymph is the fluid that circulates in the interior of the insects body remaining in contact with the rest of its tissues.

In Humans, the kidney is the blood filtration system.

The medulla is for the reabsorption of water

The cortex is for the ultrafiltration of the blood contents such as glucose

The afferent vein is thicker and the efferent vein is thicker.

The nephron is the functional unit of the kidney.

Ultrafiltration occurs in the Bowmans capsule

The high pressure forces water and blood contents (except large plasma proteins, platelets and blood cells) across the walls of the capillaries in the Bowman's Capsule.

Selective Reabsorption occurs in the proximal convoluted tube.

Selective Reabsorption; glucose, amino acids, vitamins and hormones. (80% of the minerals absorbed)

Osmoregulation occurs in the Loop of Henle

The Loop of Henle generates a high concentration of solutes in the cells and fluid of the medulla.

The descending loop of Henle is permeable to water and impermeable to salts. The ascending Loop of Henle is permeable to salts and not permeable to water.

Vasopressin (ADH) is a hormone that is secreted by the pituitary gland that is found in the brain.

This hormone is released in high concentrations if there is a dehydration in the body. This creates more aquaporines to allow more absorption of water into the body.

The collecting duct allows urine to pass to the pelvis.

The blood in the renal vein contains less urea, more carbon dioxide, less oxygen, less water and less salts. In comparison to the renal artery which has a higher concentration of oxygen, water, salts and less carbon dioxide.

The reason why the renal artery has a higher oxygen concentration and carbon dioxide is due to the ATP production for kidney function.

The reason why the glucose concentration is slightly lower in renal vein is because the glucose is used in aerobic respiration.

The urea concentration is higher in renal artery than vein because there is an excretion of urea in urine.

Both have equal concentrations of plasma proteins however. The blood in the renal vein is described as filtered whereas renal artery is unfiltered.

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- osmoconfomers: same internal osmolarity as the environment
- osmoregulators: constant osmolarity

- ammonia is a very toxic waste (aquatic animals)
- urea forms in human body (less toxic)

- structure of kidney: cortex, medulla, Bowman's capsule, Loop of Hengle, distal convoluted tubule, collecting duct

renal artery: sending blood to the kidney (oxygenated)
renal vein: sending blood from kidney (deoxygenated, less urea)

- stages of excretion: ultrafiltration, selective reabsorption and osmoregulation

1. ultrafiltration (Bowman's capsule/ glomerulus)
- wider afferent, narrower efferent
--> maintain high pressure within

2. selective reabsorption  (convoluted tubules)
- active transport across membrane
- including glucose, ions, H2O

3. osmoregulation (loop of Henle)
- descending limb: permeable to water but not salt
- ascending limb: permeable to salt but not water

ADH: vasopressin

# data[].attributes.body
Osmoregulation: maintenance of water balance inside the body of an organism
Kidney: cortex: bomancapsule and proximal covuluted tubule. medulla: loop of Henle and distal covuluted tubule.
Ultrafiltration: use of high pressure in glomerulus due to smaller diameter of efferent arteriole compare to afferent tubule. glucose, urea, salt is filtered.and fenestrated wall of glomerulus.
Podocytes provides extension that provides gaps for filtration of salt
Selective reabsorption: Active transport of 60% of salt 100% of glucose to peritubule capillaries in proximal covulated tubule.
Loop of Henle, ascending limb permeable to salt, allow active facilitated diffusion of salt from the filtrate into the vesta recta. generate region of high conc gradient.
Water in descending limb move into vesta recta by osmosis.
counter current mechanism to maintain concentration gradient.
osmoregulation
ADH(antidiutery hormone(vasopressin)released from pituitary gland monitored by hypothalamus.
promote formation of aquaporins on collecting duct. more water reabsorbed.
Insect use malpighian tube to remove water from ureic acid in hemolyph. Ureic acid is least toxic so can be removed in semi-solid faeces.
Osmoconformer: organism that changes osmolarity of internal condition so that it is isotonic to the external environment to prevent net water movement.
Blood in renal artery: oxygen, glucose, salt, urea, protein and amino acid
Blood in renal vein: less oxygen, carbon dioxide, same amount of glucose, less salt, same amount of protein and amino acid
Two solutions to kidney failure: hemodialysis and kidney transplant

# data[].attributes.body
Waste products include: Ammonia, Urea and Uric acid (decreasing order of toxicity)

Unit of kidney = nephron

Ultrafiltration
-occur due to the difference in pressure in glomerulus due to different diameters of afferent and efferent arteriole

Selective reabsorption
Proximal Convoluted tubule
Loop of Henle
-Ascending limb: permeable to salts, impermeable to water
-Descending limb: permeable to water, impermeable to salts

Osmoregulation
Collecting duct
- controls secretion of ADH (vasopressin) released by pituitary gland
-> more ADH secreted when there is dehydration, causing collecting duct to be more permeable to water, hence urine is concentrated and small in volume
-> converse is true

Osmoconformers
-animals that have similar internal solute concentration in comparison to the solute concentration of surrounding environment

Blood concentration in renal artery and renal vein
-Blood in renal artery has more oxygen, more urea than blood in renal vein

Insects
-waste excreted in form of uric acid instead of urea
-Malpighian tubule

# data[].attributes.body
-the urinary tract system
-the kidney retains water before it is passed out of the body.
-the water is retained in the loop of henle and the collecting duct.
-the ascending loop of henle is permeable to Na+ and impermeable to water
- the descending loop henle is permeable to water but impermeable to Na+
-ADH (Anti-diuretic horomone) causes the aquatoirs to open up, making it more permeable to water. This allows more absorption of water before it goes to the ureter to be pass out of the body.
-the nephron is made out of 4 sectors
-the glomerus
-the bowsman capsule
-the loop of henle
-the collecting duct
-Selective reabsorption
selective reabsportion is the absorption certain molecules like glucose and amino acids.
-Ultrafiltration
Ultrafiltatiom

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- osmoconformers
- presence of contractile vacuole to expel water by exocytosis
- Uric acid is least toxic
- hemolymph insects blood
- malpighian tubes that branches out from the intestinal tract that aids in excretion by active transport
- glomerulus have basement membranes
- many large pores fenestrations
- Podocytes
- loop of Henle ascending limb is impermeable to salts but permeable to water
- 100% of glucose are reabsorbed
-

# data[].attributes.body
-Excretion is the removal of waste products of metabolic reactions from the body
-osmoregulators keep their body's osmolarity constant regardless of the surrounding
-whereas osmoconformers maintain internal conditions that are equal to the osmolarity of the environment
-osmoregulation in an organism is done by the kidney
-in the kidney, three main processes happen: ultrafiltration, selective reabsorption and osmoregulation
-during ultrafiltration, the afferent blood flows to the bowmans capsule and glomerulus
-the glomerulus would then act as a filter, filtering bigger substances while letting smaller substances such as glucose, amino acid and urea to pass through
-the filtrate would then be selectively reabsorbed by the kidney
-selective reabsorption involves the proximal and distal convoluted tubules and loop of henle
-in the proximal convoluted tubule, glucose, amino acis, mineral ions, vitamins, hormones and water is reabsorbed through the process of active transport and osmosis.
-the loop of henle consists of two parts: descending and ascending limb
-the descending limb is permeable to water but not salts whereas the ascending limb is permeable to salts but not water.
-the concentration gradient established by the vasa recta blood network that surrounds the loop of henle and travels in the opposite direction results in diffusion and osmosis to happen
-

# data[].attributes.body
Excretion: removal of waste products of metabolism from the organism.

Osmoregulators: freshwater environments (with lower solute concentration outside the cell) utilise contractile vacuoles to remove water by exocytosis.

Osmoconformers: live in saltwater environments (with higher solute concentration outside the cell) maintains concentration gradient by active transport so that water is not lost by the cell to the environment.

Marine animals excrete in the form of ammonia (most toxic), mammals in the form of urea (moderate) and insects in the form of uric acid (least toxic)

Function of nephron
1. Ultrafiltration: afferent arteriole has a wider lumen while efferent arteriole has a narrower lumen. This allows ultrafiltration of blood where solutes (eg. ions, glucose, amino acids, salts) are filtered from the glomerulus into the Bowman's capsule.
2. Selective reabsorption: occur in the proximal and distal convoluted tubules where amino acids, glucose (not protein as its too large) and water are reabsorbed back into the blood. Descending limb of the loop of Henle is permeable to water but not to salts, ascending limb is permeable to salts but not to water.
3. Osmoregulation: maintenance of water balance in the body - when solute concentration is high, ADH is released by the pituitary gland, causing the formation of aquaporins which causes more reabsorption of water. When solute concentration is low, less ADH is released, forming less aquaporins and leading to urine having a lower concentration of urea.

Blood content in renal vein
- less oxygen content, higher carbon dioxide content

Blood content in renal artery
- higher oxygen content, lower carbon dioxide content