10.1/10.2/10.3 Flashcards

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1
Q

Excretion

A

The process of separating wastes from body fluids and eliminating them from the body.

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2
Q

Body Systems that Perform Excretion

A

Respiratory-carbon dioxide
Skin-water, salts, urea
Digestive-water, salts, lipids

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3
Q

Excretory System

A

The system that regulates the volume and composition of body fluids by excreting metabolic wastes and recycling some substances for reuse.

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4
Q

Organs of the Excretory System

A

Kidneys, Ureters, Bladder, Urethra

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5
Q

Urine

A

In the kidneys, filtrate of the nephron upon leaving the collecting duct, exits the body through the urethra.

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6
Q

Functions of the Excretory System

A

1) Excretion of Metabolic Wastes
2) Maintenance of Water-Salt Balance
3) Maintenance of Acid-Base Balance
4) Secretion of Hormones

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7
Q

Excretion of Metabolic Wastes

A
  • notably nitrogenous (nitrogen-containing) wastes

- eg. ammonia, urea, uric acid

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8
Q

Maintenance of Water-Salt Balance

A
  • by regulating salts in the blood, the kidneys are involved in regulating blood pressure
  • maintain appropriate levels of potassium, bicarbonate, and calcium in the blood
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9
Q

Maintenance of Acid-Base Balance

A

-maintain blood pH at about 7.4 by excreting hydrogen ions and reabsorbing bicarbonate ions

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10
Q

Secretion of Hormones

A

-secrete calcitriol (active form of vitamin D and erythropoietin (stimulates red blood cell production)

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11
Q

Kidneys

A

One of a pair of organs that filters waste from the blood (which is excreted in urine) and adjusts the concentrations of salts in the blood.

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12
Q

Ureter

A

A pair of muscular tubes that carry urine from the kidneys to the bladder.

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13
Q

Urinary Bladder

A

Organ where urine is stored before being discharged by way of the urethra.

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14
Q

How is drainage from the bladder controlled?

A

Sphincters

  • innermost sphincter is involuntarily controlled by brain
  • learn how to voluntarily control relaxation of the other sphincter
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15
Q

Urethra

A

The tube through which urine exits the bladder and the body.

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16
Q

Renal Cortex

A

Outer Layer of Kidney

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17
Q

Renal Medulla

A

Inner Layer Containing Cone-Shaped Tissue Masses

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18
Q

Renal Pelvis

A

Central Space, or Cavity, that is Continuous With the Ureter

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19
Q

Renal Artery

A

Blood vessel that originates from the aorta and delivers blood to the kidneys; splits into a fine network of capillaries (the glomerulus) within the Bowman’s capsule of the nephron.

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20
Q

Renal Vein

A

Blood vessel that drains from the kidney; returns to the body the solutes and water reabsorbed by the kidney.

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21
Q

Nephron

A

Microscopic tube-like filtration unit found in the kidneys that filters and reabsorbs various substances from the blood; produces urine.

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22
Q

Three Main Regions of a Nephron

A

Filter, Tubule, Collecting Duct

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23
Q

Filter

A
  • filtration structure is the Bowman’s capsule
  • renal artery enters and splits into network of capillaries called glomerulus which acts as a filtration device
  • water, small molecules, ions and urea pass through walls and proceed further into nephron
  • new substance is called filtrate
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24
Q

Bowman’s Capsule

A

The cap-like formation at the top of each nephron that serves as a filtration structure; surrounds the glomerulus.

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25
Q

Glomerulus

A

A fine network of capillaries within Bowman’s capsule of the nephron; arising from the renal artery, the walls of the glomerulus act as a filtration device.

26
Q

Filtrate

A

Filtered fluid that proceeds from the glomerulus into Bowman’s capsule of the nephron.

27
Q

Tubule

A
  • Bowman’s capsule is connected to a small, long narrow tubule that is twisted back on itself to form a loop
  • loop is a reabsorption device
  • proximal tubule, loop of Henle, distal tubule
  • tubule absorbs substances that are useful to the body
28
Q

Duct

A
  • tubule empties into a larger pipe-like channel called a collecting duct
  • water-conservation device, reclaiming water from the filtrate
  • filtrate is now urine
  • solutes and water reclaimed during reabsorption are returned to the body via the renal vein
29
Q

Collecting Duct

A

The large pipe-like channel arising from the tubule connected to the Bowman’s capsule in the nephron; functions as a water-conservation device, reabsorbing water from the filtrate in the nephron

30
Q

Four Processes that are Crucial to Urine Formation

A
  • glomerular filtration
  • tubular reabsorption
  • tubular secretion
  • water reabsorption
31
Q

Glomerular Filtration

A

Process that results in the movement of water and solutes, except proteins, from the blood plasma into the nephron down a pressure gradient.

32
Q

Tubular Reabsorption

A

Process in which water and useful solutes are reabsorbed from the filtrate in the nephron and transported into the capillaries for reuse by the body.

33
Q

Tubular Secretion

A

Process that moves additional wastes and excess substances from the blood into the filtrate in the nephron; uses mainly active transport.

34
Q

Water Reabsorption

A

Process that removes water from the filtrate in the nephron and returns it to the blood for reuse by body systems.

35
Q

Two Factors Contributing to Glomerular Filtration

A

1) Permeability of the capillaries.
- many large pores to let water and most dissolved
substances to pass into Bowman’s capsule.
- pores are small enough to prevent red blood cells
and proteins from entering
2) Blood Pressure
-four times greater in glomerulus than in capillaries
elsewhere
-provides force for filtration

36
Q

Proximal Tubule

A

Tubular portion of the nephron that lies between the Bowman’s capsule and the loop of Henle; main function is reabsorption of water and solutes, as well as secretion of hydrogen ions.

37
Q

What does tubular reabsorption require?

A

Active and Passive Transport (cells contain mitochondria that release ATP to drive active transport)

38
Q

How are negative ions and water reabsorbed

A
  • Negative ions tag along passively

- water follows ions by osmosis

39
Q

Loop of Henle

A

Tubular portion of the nephron that lies between the proximal tubule and the distal tubule; main function is reabsorption of water and ions.

40
Q

What happens in the descending loop of Henle?

A
  • plunges into the renal medulla where it is really salty
  • extremely permeable to water and slightly to ions
  • water diffuses from the filtrate to the capillaries by osmosis
41
Q

Permeability of Ascending Loop of Henle

A
  • impermeable to water

- slightly permeable to solutes (sodium diffuses into blood vessels)

42
Q

Result of Na+ Transport Out of the Filtrate

A
  • replenishes salty environment of the medulla (aids in reabsorption of water)
  • makes filtrate less concentrated
43
Q

Distal Tubule

A

Tubular portion of the nephron that lies between the loop of Henle and the collecting duct; main function is reabsorption of water and solutes, and secretion of various substances.

44
Q

What happens during tubular secretion?

A
  • potassium ions are actively secreted into the distal tubule
  • hydrogen ions are actively secreted from the blood into the distal tubule to maintain pH of the blood
  • penicillin and other drugs are secreted into distal tubule
  • under control of hormones
45
Q

What happens in the collecting duct?

A

-passive reabsorption of water from the filtrate by osmosis

46
Q

Homeostatic Functions of the Kidneys

A
  • maintaining water-salt balance of the blood
  • regulating blood pH
  • secreting some hormones
  • regulate blood volume and blood pressure
47
Q

Regulating Water-Salt Balance (Water Reabsorption)

A
  • when blood plasma becomes too concentrated osmotic pressure increase signalling the release of ADH which increases the permeability of the distal tubule and collecting duct to allow more water to be absorbed (blood is more dilute)
  • when blood plasma is too dilute ADH release is stopped and distal tubule and collecting duct are less permeable to water
48
Q

Antidiuretic Hormone

A

-hormone regulated by the hypothalamus and released by the pituitary gland that increases the permeability of the distal tubule and the collecting duct in the nephrons of the kidneys; allows more water to be reabsorbed into the blood from the filtrate

49
Q

Diabetes Insipidus

A
  • condition where ADH activity is insufficient
  • excessive urination (4 L to 8 L per day)
  • intense thirst
  • Rx. take synthetic ADH
50
Q

Regulating Water-Salt Balance (Salt Reabsorption)

A
  • controlling excretion and reabsorption of various ions
  • aldosterone stimulates excretion of K+ and reabsorption of Na+
  • low blood pressure (kidneys secrete renin (an enzyme) which releases aldosterone and stimulates reabsorption of Na+
51
Q

Maintaining Blood pH (Acid-Base Buffer System)

A
  • takes up H+ or OH- that enter the blood
  • when excess H+: H+ + HCO3- –> H2CO3
  • when excess OH-: OH- + H2CO3 –> HCO3- + H2O
52
Q

Maintaining Blood pH (Respiratory Centre)

A

-if H+ increases it is detected by the medulla and increases breathing rate which rids the body of hydrogen ions

53
Q

Maintaining Blood pH (the kidneys)

A
  • only the kidneys can rid the body of a wide range of acidic and basic substances and otherwise adjust the pH
  • more slower acting than the previous 2 methods but a more powerful effect
  • too acidic (H+ excreted, HCO3- is reabsorbed)
  • too basic (opposite of above)
54
Q

Releasing Hormones

A
  • renin: leading to secretion of aldosterone
  • EPO: released if oxygen-carrying capacity is reduced or oxygen demand increases, stimulates production of red blood cells in bone marrow
  • Calcitriol: promotes absorption of calcium from the digestive tract
55
Q

Urinary Tract Infection (UTI)

A
  • bacterial or viral infection of bladder, urethra or may spread to the kidneys
  • painful burning during urination, frequent urination, bloody urine, lower back pain
  • can result in permanent kidney damage
56
Q

Kidney Stones

A
  • crystalline formation of excess calcium in urine
  • small stones pass on their own, medications to break down crystals, ultrasound shock waves for smaller stones, surgery for larger stones
57
Q

Renal Insufficiency

A
  • the state in which the kidneys cannot maintain homeostasis due to nephron damage
  • caused by kidney infection, high blood pressure, diabetes mellitus, PKD, trauma from a blow to lower back or vibration
  • if short term, nephrons can regenerate
  • more than 75% of nephrons are destroyed, urine output is inadequate to maintain homeostasis (dialysis)
58
Q

Dialysis

A

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

59
Q

Hemodialysis

A

-uses an artificial membrane in an external device and is connected to an artery and a vein in the person’s arm to remove waste and excess fluid from the blood

60
Q

Peritoneal Dialysis

A

-uses the lining of the intestines, called the peritoneum, as the dialysis membrane to remove waste and excess fluid from the blood

61
Q

Polycystic Kidney

A

-kidney that has many cysts on it causing it to become extremely large in size

62
Q

What factors are examined in urine tests?

A
  • acetone and ketones
  • albumin
  • bilirubin (protein)
  • calcium
  • colour
  • glucose
  • pH
  • urea
  • uric acid