Terms in this set (57)
body is hypotonic [less salty than surrounding water] to environment à water is constantly lost by osmosis, constant drinking, rarely urinate, and secrete accumulated salts through gills.
Absorption and excretion of water and dissolved substances (solutes) so that proper water balance is maintained between the organism and its surrounding
The Excretory System
Maintain homeostasis by regulating water balance and by removing harmful substances
body is hypertonic [more salty than surrounding water] to environment; water moves in => rarely drink, constantly urinate, and absorb salts through gills.
Protists, such as amoebas and paramecia
possesses contractile vacuole for XS H2O excretion by active transport. They vacuoles accumulate water, merge with the plasma membrane, and release water into the environment
Flame cells / protonephridia
Platyhelminthes, such as the planaria
distributed along branched tube system that permeates the flatworm
Body fluids filtered across flame cells, whose cilia move fluids through tube system; wastes exit through pores of tube
Nephridia / metanephridia
Occurs in pairs within each segment of most annelids, such as earthworms
ANNELIDS CO2 EXCRETION DIRECTLY THRU SKIN
CO2 excretion directly through moist skin
Arthropods (terrestrial insects)
Tubes attached to mid digestive tract (midgut) collect body fluids from hemolymph that bath the cells; fluids are deposited into midgut. Fluids include nitrogen wastes (in form of uric acid crystals; H2O, salt retained. As fluid passes through hindgut, retained materials pass out of walls and wastes continue down the tract for excretion through anus.
all cells in contact with external, aqueous environment
Protozoans and Cnidarians
What are the three regions of the kidney?
Three regions: 1) outer cortex, 2) inner medulla, and 3) renal pelvis which drains to ureter. Each has many nephrons
What is a common byproduct?
Ammonia, which is toxic.
Can convert into urea, ammonia, and CO2. Advantage is that it won't be toxic but you need extra water to dissolve it. Others will convert to uric acid (bird poop)
What does renal mean?
Blood enters the kidneys via ??? and then enters the ???
Renal arteries, glomerulus / Bowman's capsule
Skin, lungs, liver, and kidneys
CO2 and water vapor diffuse from the blood and are continually exhaled
sweat glands excrete water and dissolved salts (and a small quantity of urea)
Perspiration serves to regulate body temperature since the evaporation of sweat removes heat from the body
processes nitrogenous wastes, hemoglobin, and other chemicals for excretion
urea is produced from the deamination of AA in the liver and diffuses into the blood for ultimate excretion in the kidneys
---Bile salts excreted through feces
Kidneys function to maintain the osmolarity of the blood, excrete numerous waste products, and toxic chemicals and conserve glucose, salt, and water
Kidneys three sections
Cortex, medulla, and pelvis
Special capillary bed located in the Bowman's capsule
The medulla houses what?
Loop of Henle and collecting duct
The cortex houses what?
Convoluted tubules and Bowman's capsule
Concentrate urine in the ??? flows into the ??? of the kidney, a funnel-like region that opens into the ??? and the ureters from the kidneys empty into the ??? where urine collects until expelled via the ???
What are the three phases of urine formation?
§ Blood pressure forces 20% of blood plasma entering the glomerulus through its capillary walls and into the surrounding Bowman's capsule
§ The fluid and small solutes entering the nephron are called filtrate (which is isotonic with the blood plasma)
Large particles such as blood cells and albumin will remain in the circulatory system
The name given to the fluid and small solutes that are entering the nephron. This is isotonic to the blood plasma
Filtration is active/passive ???process that is driven by the ??? of the blood, so having high blood pressure results in an increased hydrostatic pressure, which exerts extra pressure on the kidney tissues and can lead to kidney damage over time
Passive, hydrostatic pressure
The nephron secretes waste substances such as acids, ions, and other metabolites from the interstital fluid into the filtrate by passive and active transport
As the filtrate passes through the proximal tubule and through the distal tubule, additional material from the interstital fluids joins the filtrates ---> selectively secreted
Essential substances such as glucose, salts, and amino acids and water are reabsorbed from the filtrate and returned to the blood
Occurs primarily in the proximal convoluted tubule and is an active process and movement is accompanied by the passive movement of water because water passively follows solute. This results in the formation of concentrated urine which is hypertonic to blood
Where does reabsorption mostly occur
Proximal convoluted tubule
When does the filtrate become more concentrated? Why?
Down the loop of Henle, because of the passive flow of H2O out of tube
When does filtrate become less concentrated? Why?
Up the Loop of Henle, because of the dilution (due to passive and active transport of salts out of the tubule)
Primary function of nephron?
is able to regulate the balance of salt and water in the body
Because the blood plasma contains both wanted and unwanted substances, the nephron will selectively reabsorb wanted substances back into the plasma, while the remaining substances are excreted in the urine
Nutrient reabsorption mostly occurs
Proximal conv. tubule
major site for secretion of substances into the filtrate
Distal conv. tubule
Permeable to water, but not to ions or urea
Impermeable to water, but permeable to ions, allowing for passive diffusion of ions
Thick ascending limb
sodium, potassium and chloride are actively reabsorbed from the urine
The two hormones that influence osmoregulation are?
1. ADH / Vasopression
cause a decrease in urine output and a corresponding increase in blood pressure, allowing the human body to compensate for periods of dehydration or other causes of blood pressure
- Opens up aquaporins to allow water to be reabsorbed more easily
-Increases the permeability of the collecting duct to water
-Allows more water to be absorbed and more concentrated urine to be formed and in some diseased states, people have excess secretion of ADH which causes them to retain too much fluid
Increases the permeability of collecting duct to water
Urine becomes (more / less)  as water diffuses out
Increases the reabsorption of water and reabsorption of Na+
steroid hormone that causes increased transport of sodium and potassium ions along the distal convoluted tubule and collecting duct, resulting in decreased excretion of sodium ions and increased execretion of potassium ions in the urine
drugs that target different parts of the kidneys to cause an increase in urine production
??? diuretics inhibit sodium reabsorption in the ascending loop of the nephron, wheras ??? diuretics inhibit the sodium chloride transporter in the distal convoluted tubule
Both have the net effect of increasing the amount of water present in the urine and therefore increase urine excretion
inhibit the sodium chloride transporter in the distal convoluted tubule
inhibit sodium reabsorption in the ascending loop of the nephron
pH is assessed by
Arterial partial pressure of CO2 (PCO2)
and plasma bicarbonate (HPO3-)
Disorders dealing with HCO3- (bicarbonate); difference in treatment, say for respiratory or metabolic?
® The disorders can be respiratory or metabolic, and depending on which, the treatment is different. For example, the respiratory system (PO2 affected) can change quite quickly, but when metabolic (HCO3- is affected) it can take longer because it deals with the kidneys.
Respiratory vs metabolic disorder
A change in pH due to a chance in respiratory rate may be a result of airway obstruction or chronic obstructive pulmonary disease (COPD),
whereas metabolic acidosis may be due to a kidney dysfunction or volume loss
Where is urea made?
Liver, but removed from the body via kidneys
Infection of the kidney?
high blood urea nitrogen levels
Which structure monitors blood volume? Which structure monitors the osmolarity of the blood?
When blood volume/blood pressure is not enough to promote glomerular filtration, the juxtaglomerular apparatus secretes renin (changes angiotensinogen into angiotension I, II) which increases blood volume/blood pressure by stimulating aldosterone release
Has contractile vacuole
Protists (such as paramecium and amoeba) - active transport