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Biology (Grade 12) > Excretory System > Flashcards

Excretory System Flashcards

includes what the excretory system is, the formation of urine, and kidney disorders

1
Q

What are the 4 main steps of urine formation?

A
  1. Glomerular Filtration
  2. Tubular Reabsorption: proximal tubule & Loop of Henle
  3. Tubular Secretion: Distal tubule
  4. Water Reabsorption: Collecting Dust
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2
Q

Whats the first step, “Glomerular Filtration”, of urine formation about?

A
  • Blood carrying water and wastes enters the bowman’s capsule
  • the glomerulus filters out water, solutes, urea, and uric acid which forms a fluid called FILTRATE
  • impermeable large proteins & red blood cells remain behind in the blood
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3
Q

Whats the third step, “Tubular Secretion” of urine formation about?

A
  • here hydrogen ions and potassium ions are actively secreted into the tubule from the blood capillaries
  • this process is under hormonal control to help maintain blood pH
  • acid base buffer system:
    ~ if the blood is too acidic, more H+ is excreted from body
    ~ if blood is too basic, H+ is not excreted. Urine is slightly acidic.
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4
Q

Whats the fourth step, “Water Reabsorption”, of urine formation about?

A
  • passive reabsorption of water occurs here, depending on the concentration of the blood plasma
  • if too concentrated from dehydration, more water is reabsorbed back into the surrounding capillaries
  • if plasma is not concentrated, less water is reabsorbed
  • process is under hormonal control: ADH
  • as it leaves, filtrate only consists 1% of the original volume that entered the glomerulus and this is called URINE
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5
Q

What’s the second step, “Tubular Reabsorption”, of urine formation about?

A
  • proximal tubule uses active transport to reabsorb sodium ions, glucose & other solutes into blood capillaries
  • water follows the ions and is reabsorbed by osmosis

Loop of Henle:

  • descending portion is full permeable to water; slightly to sodium
    ~ due to increasing salty environment in the inner medulla region, water leaves the filtrate and is absorbed back into blood
    ~ this increases sodium ion concentration within the tubule (filtrate)
  • ascending part is impermeable to water; slightly to ions, allows sodium ions to pass back into the blood
  • near the top, sodium ions are actively transported out (maintains saltiness of medulla region)
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6
Q

What is the composition of urine? What should it not include?

A

96% water, 2% urea, and 2% other molecules like uric acid, ammonia, sodium, etc.

SHOULD NOT INCLUDE GLUCOSE

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7
Q

Whats a diuretic? Give an example.

A

a substance that increases urine production to help remove excess water/fluid and salts from the body

ex. ethanol in alcoholic beverages

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8
Q

What is diabetes insipidus?

A
  • when ADH activity is insufficient, causing excessive urination (about 4L to 8L a day)
  • intense thirst but water is excreted more quickly than consumed, leading to severe dehydration & ion imbalances
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9
Q

What is excretion?

A

the process of separating wastes from body fluids (blood) and eliminating them

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10
Q

What are the wastes that need to be removed from the body?

A
  1. products like ingested toxins, alcohol, and heavy metals via the liver
  2. products of protein metabolism such as urea (made from ammonia) and uric acid (breakdown of nucleic acids)
  3. metabolic wastes:
    - excess proteins become carbohydrates
    - amino group removed via deamination
    - ammonia released as a byproduct
    - in the liver, 2 ammonia molecules combine with CO2 to form urea
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11
Q

What happens if there is dehydration

A
  1. blood plasma is too concentrated
  2. osmotic pressure increases
  3. osmoreceptors in hypothalamus send impulses to pituitary gland
  4. pituitary releases antidiuretic hormone (ADH) which acts on kidneys to increase permeability of the distal tube and the collecting dust

action: more water is reabsorbed into the blood, lowering osmotic pressure

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12
Q

What happens if blood plasma is too dilute?

A

ADH does not get released which allows more water to be excreted in the urine, increasing osmotic pressure

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13
Q

What organ regulates water balance and osmotic pressure? How is it regulated?

A

kidneys

special osmoreceptors located in the hypothalamus sense changes in osmotic pressure and coordinate a hormonal response: antidiuretic hormone

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14
Q

what is urine formation dependent on?

A

concentration gradients

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15
Q

describe the location of the proximal and distal tubules

A

proximal - closer to glomerulus
distal - farther from glomerulus

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16
Q

describe the importance of water

A
  • average adult loses 2L per day
  • a 1% decrease in body water causes thirst
  • a 5% decrease causes extreme pain & collapse
  • a 10% decrease causes death
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17
Q

give an overview of the excretion process

A
  1. kidneys filter blood
  2. ureter conducts waste to bladder
  3. bladder stores urine
  4. urethra voids the urine from the bladder
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18
Q

what is the importance of kidneys?

A
  1. to eliminate harmful waste
  2. to balance blood pH
  3. to maintain water balance
  4. maintains ion balance and osmolarity
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19
Q

whats a urinary tract infection (UTI)?

A

an infection in the urinary system, usually caused by bacteria

symptoms: painful burning sensation during urination, frequent urination, bloody urine, upper or lower back pain
treatment: antibiotics, kidney infection surgery, fluid consumption

20
Q

What is Brights Disease/Nephritis?

A

tissues in the kidney become inflamed and have problems filtering waste from the blood

symptoms: blood in urine, decreased urine output, swelling of the body, high BP and pelvis pain
treatment: antibiotics, medication, diet changes, dialysis or kidney transplant

21
Q

What are kidney stones?

A

the development of crystalline formations due to excess calcium in the urine; also formed because of UTI’s or insufficient water consumption

symptoms: severe back pain, blood in urine, nausea, fever, cloudy/smelling urine, vague pain
treatment: can pass through on their own, medications, ultrasound shock waves, surgery

22
Q

What is PKD - polycystic kidney disease?

A

a genetic disorder in which cysts grow in the kidneys, impairing proper function

symptoms: abdominal pain, blood in urine, excessive urination drowsiness, joint pain, high BP
treatment: medication, blood pressure control, fluid intake, antibiotics, dietary changes, dialysis or kidney transplant if serious

23
Q

What is a dialysis?

A

a procedure that removes wastes and excess fluid from the blood when kidney function is lost due to renal failure

  • the diffusion of dissolve substances through a semipermeable membrane
24
Q

What is hemodialysis?

A

type of renal dialysis that utilizes an artificial membrane in an external device and is connected to an artery and vein in a person’s ARM to remove excess fluid from the blood

25
Q

What are the advantages and disadvantages of hemodialysis?

A

ADVANTAGES:

  • helps control blood pressure and balance important minerals (ex. potassium, sodium)
  • effectively removes waste products, toxins, and excess fluid

DISADVANTAGES:

  • strict renal diet & fluid restrictions are required
  • risk for infection
  • could cause low BP, shortness of breath and nausea
26
Q

What is peritoneal dialysis?

A

type of renal dialysis that utilizes the lining of the intestines, called the peritoneum, as the dialysis membrane to remove waste and excess fluid from the blood when kidney function is lost

27
Q

What are the advantages and disadvantages of peritoneal dialysis?

A

ADVANTAGES:

  • fewer restrictions on diet & fluid intake
  • longer-lasting kidney function
  • can be carried out at home or any place that is clean

DISADVANTAGES:

  • risk for infections
  • development of a weakness in the abdominal muscles
  • needs to be done daily; strict schedule
28
Q

Why is a real kidney better than dialysis treatment?

A

even though dialysis enables people with kidney diseases to continue daily activities, it is neither a cure nor a long-term solution

  • individuals with 10% or less kidney function will eventually have to replace their kidneys as a real kidney does a better job at filtering wastes and keeping you healthy
29
Q

What is the long-term disadvantage of having a kidney transplant? How is this disadvantage overcome?

A

infections & cancer; can be overcome by antibiotics, medication, and maintaining a healthy lifestyle

30
Q

what can end stage renal failure be cured by?

A

kidney transplant

31
Q

what is the urinary system’s function?

A
  • excretion of urea and uric acid
  • maintain water balance
32
Q

What is a nephron?

A
  • unit of filtration
  • found in the kidneys; filters and reabsorbs various substance from the blood and produces urine
33
Q

What are afferent arterioles?

A

part of the nephron; carry blood to the glomerulus

34
Q

What are efferent arterioles?

A

part of the nephron; carry blood away from the glomerulus

35
Q

What is the glomerulus?

A

a high-pressure capillary bed enclosed by the Bowman’s capsule; walls of the glomerulus act like filtering devices

36
Q

What is the proximal tubule?

A

part of the nephron; helps with reabsorption of water and solutes, as well as secretes hydrogen ions

37
Q

What is the loop of Henle?

A

in the nephron; tubular portion which helps reabsorb water and ions

  • lies between the proximal tubule and distal tubule
38
Q

What is the distal tubule?

A

part of the nephron; reabsorbs water and solutes, and secretes various substances

  • lies between the loop of Henle and collecting dust
39
Q

What is the collecting dust?

A

part of the nephron; function is passive reabsorption of water by osmosis

40
Q

What is the origin of waste and organ of excretion for ammonia?

A

origin of waste: deamination of amino acids by the liver

organ of excretion: kidneys

41
Q

What is the origin of waste and organ of excretion for urea

A

origin of waste: deamination of amino acids by the liver

organ of excretion: kidneys

42
Q

What is the origin of waste and organ of excretion for uric acid

A

origin of waste: products of the breakdown of nucleic acids, such as DNA

organ of excretion: kidneys

43
Q

What is the origin of waste and organ of excretion for carbon dioxide?

A

origin of waste: waste product of cellular respiration

organ of excretion: lungs

44
Q

What is the origin of waste and organ of excretion for bile pigments

A

origin of waste: breakdown of red blood cell pigment, hemoglobin

organ of excretion: liver

45
Q

What is the origin of waste and organ of excretion for lactic acid

A

origin of waste: products of anaerobic respiration

organ of excretion: liver

46
Q

What is the origin of waste and organ of excretion for solid waste

A

origin of waste: by-product of digestible and indigestible material

organ of excretion: large intestine

Biology (Grade 12) (13 decks)

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