Chapter 7 Test review

Part B

1. Homeostasis - Process by which a constant internal enviornment is maintained dispite changes in the external enviornment. For example, sweating to maintain the bodies functional temperature range while excercising.
2. Negative - Mechanisms that bring the body back to normal ranges
   Positive - Process by which a small affect is amplified.
3. Negative feedback systems are most preferred in the body.
4. The Kidney: Removes excess waste
   Maintains water balance
5. Deamination of proteins causes ammonia to be produced. This ammonia combines with CO2 to form urea which is much less harmful to humans and can be transported safely through the body.
6. a molecule will take the following path while being removed from the body:
   
   1)Circulatory system
   2)Renal Artery
   3)Nephron (first glomerulus then into bowman's capsule)
   4)Proximal Tubule
   5)Descending limb of loop of henule
   6)Ascending limb " " " "
   7)Distal Tubule
   8)Collecting duct
   9)Bladder
   10)Urethra
   
   
   
7. It is benifitial to have 2 kidneys because a greater amount of blood can be filtered per minute. Also, if one kidney is damaged or not working at full efficientcy, you can still survive because your blood is still being filtered by the other kidney.
8. Many mitochondria are needed in the cells of the proximal tubule in order to supply energy for the active transport of sodium ions out of the tubule.
9. Having high blood pressure can cause damage to the blood vessels in the kidneys. They may stop removing waste and water from the body properly and this can cause kidney failure. Urine will form faster as a high pressure from the arteries will force water out of your system not being reabsorbed properly.

Part C

1. After a kidney failure, the most effective treatment option is to have a kidney transplant. Today, these are about 85% sucessful. Medical implications include- finding a matching donor, complications during the procedure, the time taken to do the procedure, the chance of the body rejecting the new kidney by recognising it as a forign invader (this is why immunosupresive drugs are given to transplant patients). Social implications: life expectancy changing by donating or recieving a kidney, because of long waiting list for kidney donor, blackmarket of the bodypart (sold for a profit rather than a donation).
2. The Formation of Urine:
   
   1)Filtration - Process by which blood or bodily fluids pass through a selectivley permeable membrane.
   2)Re-absorption - Transfer of glomerular filtrate from the nephron back into capillaries.
   3)Secretion - Movement of materials from the blood to the distal tubule. Products such as ammonia and some drugs.
   
   Discuss
   

Part D

• Refer to pages 346, 347(worksheet 7.4) and350

Part A

1. A patient with renal problems would find a high concentration of waste products in their blood because the kidneys arent functioning properly.
   
2. unknown substances found in bowmans capsule and urine : possibilities = anything in blood other than enthrocytes (red and white blood cells) proteins and platelets
3. Refer to Part A #2
4. blood filtrate is composed of : water, Na, Cl, glucose, amino acids, hydrogen ions, CO2, Carbonate, etc...
5. Refer to Part A #4
6. Organisms adapting to their eniornment.... many possibilities ?
7. Nitrogen waste comes from the Deamination of amino acids, removing the amine group from the molecule.
8. The role of the kidney is to filter out waste products and maintain water balance in the body. Nesesary for maintaining homeostasis.
9. Many possibilities. Anything transported by blood.
10. Active transport - using cellular energy to move substances around to an area desired (not natural occuring)
11. When items enter the interstitial fluid, osmotic pressure is created and water from the surounding tubules will enter the spaces between the cells to attempt to adjust the concentration of the solution.
12. Antidiuretic Hormone (ADH) - Causes kidneys to increase water absorbtion.
    
    Causes parts of the kidney to become semipermeable to water and allows the water to move back into the capilaries conserving water rather than loseing it in urine.
13. Aldosterone - Hormone that increases Na reabsorption from distal tubule and collecting ducts.
14. Refer to Part A #12
15. Refer to Part A #12

good luck ;)
-Brandon

7.7 Kidney diseases

1) Diabetes Mellitus:

• Caused by inadequate secretion of insulin from islet vells in the pancreas
• Blood sugar levels rise.
• Excess sugar remains in the nephron, it is not filtered back into the circulatory system.
• People with this will often urinate a large amount of water because the sugar causes osmotic pressure. This will have to be replenished.
• Type 2 diabetes.
  

2) Diabetes Insipidus:

• Caused by destruction of ADH producing cells or nerve tracts between the hypothalamus and pituitary gland. Without ADH, all 20mL per minute will be urinated and will create a large thirst responce.
  
• Type 1 Diabetes.

3) Bright's Disease:

• AKA- Nephrititis
• many diseases characterized by inflammation of the nephrons.
  
• Filtration system doesn't work properly and allows proteins to stay in the kidney which causes them to swell with water because there is no mechanism to remove proteins from the kidney.
• Increases output of urine.
  

4) Kidney Stones:

• Caused by the percipitation of mineral solutes from the blood.
• Two groups: Alkaline and acid stones.
  
• These stones can tear delicate tissues as they move toward the bladder.
• can lodge in the urethra and cause alot of pain trying to pass these stones.

Dialysis technology

• People that cant properly filter their blood with the use of their own kidneys can use technology to mechanicly filter out impurities and toxins from their blood.
  

-Brandon

7.6 Water Balance

Definitions:

• Antidiuretic Hormone (ADH) - Causes kidneys to increase water absorbtion.
  
• Osmoreceptors - specialized nerve cells in the hypothalamus that detect changes in the osmotic pressure of the blood and surrounding the extra-cellular fluids (ECF's)
• Aldosterone - Hormone that increases Na reabsorption from distal tubule and collecting ducts.

Balance

• Body adjusts for increased water intake by increasing urine output.
• Urine output is decreased when excercise is increased or water intake decreased.
• These adjustments involve interaction by the bodys two communication systems, the nervous system and the endocrine system.

ADH and the Nephron:

• 85% of water filtered into nephron is reabsorbed in the proximal tubule.
• Proximal tubule is permeable to water, but this permeability dosn't extend to the other parts of the nephron.
• the loop of henle is permeable to water and hydrogen ions, the ascending tubule is semipermeable to NaCl.
• Active Transport of Na ions concentrates solutes within the medula of the kidney.
• Without ADH, the tubule remains impermeable to water but still activlet transports Na ions from the tubules (oter 15%of water filtered into the nephron is lost)

-Brandon

7.5 Formation of Urine

Definitions:

• Filtration - Process by which blood or bodily fluids pass through a selectivley permeable membrane.
• Re-absorption - Transfer of glomerular filtrate from the nephron back into capillaries.
• Secretion - Movement of materials from the blood to the distal tubule. Products such as ammonia and some drugs.

• Water, NaCl, Glucose, amino acids, Hydrogen ions, Plasma proteins, red and white blood cells and blood platelets enter the glomerulus.

The following will NOT enter the Bowman's Capsule:

• Proteins
• Erythrocytes (Red and White Blood cells)
• Blood Platelets

Filtration:

1. Aorta
2. Renal Artery
3. Afferent tubule
4. Glomerulus - Capillary network
   - The location of filtration
   Blood enters at high pressure of 65mmHg (mm of mercury). This pressure causes the filtration.
   

Re-Absorption:

1. 600mL of blood passes through the kidneys per minute.
2. 120mL passes through the nephron.
3. 100mL is returned to the circulatory system
   -20mL will be controlled by the hypothalamus and pituitary gland.
   -ADH and Aldosterone released to increase H2O retention. 19 of the 20ML can be re-absorbed.
   

Passive Transport:

1. Osmosis - Water
2. Diffusion - materials within a solution

• Sodium ions move from kidney back into circulatory system. Proximal tubule to the peritubular capillary. Negative ions such as Carbonate and chlorine follow the sodium. Amino acids and glucose are also moved from the proximal tubule to the peritubular capillaries.

Active Transport:

• Amino Acids and Glucose must be completly retained to the circulatory system.
• Carrier molecules deliver remaining glucose and amino acids back into the blood.
• Creates an osmotic gradient so H2O moves back into capillaries.

-Brandon

7.4 How the Nephron Works

The Nephron:

• Each of the 1 million nephrons in each kidney filters a tiny amount of blood plasma. Combined they filter 120mL of plasma each minute.

How it works:

1. The high blood pressure of the blood traveling through the arteries toward the kidney causes plasma to pass through the capilary walls of the glomerulus into the Bowman's Capsule.
2. Filtered Blood enters the tubules of the kidney. Filtrate contains substances that are still needed by your body such as glucose and amino acids as well as waste products that need to be removed from the body. Blood cells, proteins and Platelets are too large to enter Bowman;s capsule.
3. Capillaries around the proximal tubule re absorb needed substances by diffusion. Other substances remain in the tubule.
4. Sodium ions must be actively transported out of the tubules. They are pumped back into the capillaries.
5. Negative ions such as chloride follow the sodium and combine to form salts. These salts draw water from the tubules to be reabsorbed by the capillaries.
6. 20mL of the original 120mL remains in the tubule and of this 20mL, 19mL can be kept or lost depending on the body's need for water. This is controlled by the hormone ADH (antidiaretic hormone)
7. The reabsorbed substances, needed by the body, are returned to the veins and enter the circulatory system. The wastes, dissolved in small amounts of water, remain in the tubule and form urine. Urine produced by the nephrons enters the collecting tubules which eventualy reaches the bladder.

7.3 The importance of Excreting Wastes

Metabolic Reactions - Breakdown complex organic molecules into simpler, but "Toxic" compounds. to maintain life, waste products must be removed.

Lungs - remove CO2
Large Intestines - Remove toxins during digestion
Liver - Toxins from Protein digestion (amines)
Kidneys - Excrete metabolites, balance PH and water

Deamination:

• Removes amino Group From protein (NH2)
• occurs in the liver, produces amonia
• Toxic to humans at <0.005mg>
• Water soluble
  

Land animals must store their wastes. 2 molecules of ammonia combine with CO2 to form urea.

Urea:

• Nitrogen waste, ammonia combined with CO2.
• 100 000 times less toxic than ammonia
  
• Blood can dissolve 33mg/mL of Urea

Kidneys:

• Maintain Water balance
• Humans cant survive without water (only a few days)
• 2L per day is lost (urine, perspiration, air)
• Humans must consume water to account for this
• 1%loss=thirsty, 5%loss=pain, 10%loss=Death

Excretion: simple to complex organisms

• Unicellular - Maintain everything through direct diffusion with the environment.
• Multicellular (simple) - Must have fluid regulation (i.e = earthworms, hydra)
• Multicellular (complex) - 3 layers, cells not in direct contact with environment. Specialised cells needed to remove wastes. (i.e = nephrons in kidneys)

-Brandon

7.2 Thermo-Regulation

Deffinitions:

• Thermo-regulation - maintanence of body temperature within a range that enables cells to function properly. Standard body temperature = 37 degrees C
• Hypothalamus - a region of the vertebrate's brain responsible for coordinating many nerve and hormone functions.

Response to heat stress

• Sensors in the brain detect a rise in body temperature, a nerve message is coordinated within the hypothalamus and a signal is sent, telling your sweat glands to initiate sweating.
• Evaporation of this sweat cools the body and at the same time, blood vesicles in the skin dilate allowing blood flow to the skin to cool your blood.
• This cooled blood is circulated and keeps your organs cool.
• Salts are lost from your body during perspiration. (electrolytes- this is why athletes use sports drinks such as Gatorade to replenish their electrolytes while exercising)

Response to Cold stress

• Message again sent to hypothalamus, telling your body to attempt to heat itself up.
• Nerves going to arterioles of the skin cause smooth muscles to contract and arterioles constrict to limit blood flow. This keeps heat in your core.
  
• you get goosebumps because smooth muscles are around the hair follicles.
• prolonged exposure to the cold can increase your metabolism to create heat.
  
• A drop of a few degrees in your core body temperature can cause a coma or death.

-Brandon

7.1 Homeostasis and Control Systems

Deffinitions:

• Homeostasis - Process by which a constant internal enviornment is maintained dispite changes in the external enviornment. For example, sweating to maintain the bodies functional temperature range while excercising.
• Dynamic Equilibrium - Condition that remains stable within fluctuating limits.
  
• Negative Feedback - Process by which a mechanism is activated to restore conditions to original state.
• Positive Feedback - Process by which a small affect is amplified.

Homeostatic Control Systems

Have 3 functional components:

1. A Monitor - Sensors in the organs of the body signal a coordinating center when an organ is functioning outside its normal limits.
   
2. A Coordinating Center - Relays information to the regulator.
   
3. A Regulator - Restores limit to normal range.

Homeostasis and Feedback

Negative

• Mechanisms that bring the body back to normal ranges are Negative Feedback Systems.
• Prevent small changes from becoming too large.

Example, Thermostat in a house controlling temperature of the house.


Positive

• Less common in the body.
• Allows an event to happen quickly and once the event occurs, the feedback system stops.
• A good example is the birth process where different hormones are produced.
• Something in this case is amplified to happen even more in your body.
  

-Brandon