Chapter 16 Flashcards

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1
Q

What are the functions of the urinary system?

A

Excretion of metabolic wastes, osmoregulation, regulation of acid-base balance, and secretion of hormones.

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2
Q

Describe excretion of metabolic wastes.

A

Most are nitrogenous, like urea and uric acid.

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3
Q

Describe osmoregulation.

A

Maintenance of the proper balance of water and salt in the blood. Blood volume and pressure are related to salt balance. The kidneys also regulate other ions like potassium, bicarbonate and calcium.

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4
Q

Describe regulation of acid-base balance.

A

Along with the respiratory system, the kidneys regulate the acid-base balance of the blood.

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5
Q

What is the pH of the blood always kept around?

A

7.4

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6
Q

Describe secretion of hormones.

A

Renin- leads to secretion of aldosterone. From there, aldosterone has to do with regulating blood pressure in arteries.
Erythropoietin- stimulates red blood cell production.
And vitamin D activation- to promote calcium absorption.

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7
Q

Describe the kidneys.

A

Paired, bean shaped. Located in lumbar regions. Covered by renal capsule.

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8
Q

What happens at the hilum on the concave side of the kidneys?

A

The renal artery enters and the renal vein and ureter exits.

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9
Q

Describe the ureters.

A

Small muscular tubes that conduct urine from kidney to bladder.

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10
Q

How do the ureters convey urine?

A

Peristalsis.

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11
Q

Describe the walls of the ureters.

A

Three layered,
Inner mucosa
Smooth muscle
Outer connective tissue.

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12
Q

Describe the urinary bladder.

A

Stores urine until expelled from the body, has 3 openings: two for the ureters, one for the urethra. Has expandable wall and 2 sphincter muscles.

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13
Q

Describe the urethra.

A

Small tube that leads from urinary bladder to an external opening. Removes urine from body.

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14
Q

When is urination triggered?

A

When bladder fills to 250 mL.

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15
Q

How does urination occur?

A

Stretch receptors send signals to spinal cord. Motor nerve impulses cause: sphincters to relax and bladder to contract, then urination. Brain controls this reflex.

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16
Q

Name and describe the three sections of the kidneys.

A

Renal cortex- outer granulated layer
Renal medulla- contains cone-shaped tissue masses called renal pyramids.
Renal pelvis- central cavity continuous with ureter.

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17
Q

What is a kidney composed of?

A

Millions of nephrons which has it’s own blood supply, including two capillary regions.

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18
Q

What happens from the renal artery?

A

The afferent arteriole leads to the glomerulus.

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19
Q

How does blood leave the glomerulus?

A

An efferent arteriole.

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20
Q

What does the efferent arteriole do?

A

Takes blood to the peritubular capillary network which surrounds the rest of the nephron. Blood then after enters the renal vein.

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21
Q

Describe the glomerular capsule.

A

Cup-like structure, inner layer is composed of podocytes. They form pores for passage of small molecules from capillaries. This is the first filtration of blood.

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22
Q

Describe the proximal convoluted tubule.

A

Cells with microvilli, increased surface area for absorption. Here, the nephron gives back to the blood.

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23
Q

What does the PCT return to the peritubular capillary network?

A

Sugar, sodium, chloride, and water.

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24
Q

Describe the loop of henle.

A

U-shaped tube, the function is to recover water and sodium chloride from urine to peritubular capillary network.

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25
Q

Describe the loop of henle in greater detail.

A

Has two parts: descending and ascending limb. Water diffuses out of the lower part of ascending limb. Salt is actively transported out of the upper part of the ascending limb which is impermeable to water.

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26
Q

Describe the distal convoluted tubule.

A

Hydrogen can be taken from the blood here as well as potassium and urea from blood and sometimes water. Another place of filtration.

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27
Q

Describe the collecting ducts.

A

Several nephrons connect to one collecting duct. Urine may become more concentrated with water going back to blood.

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28
Q

What are the 3 steps of urine formation.

A

Glomerular filtration, tubular reabsorption, tubular secretion.

29
Q

When does glomerular filtration occur?

A

When blood enters the afferent arteriole and glomerulus.

30
Q

How does glomerular filtration occur?

A

Blood pressure forces water and small molecules into the glomerular capsule.

31
Q

What does the glomerular filtrate contain?

A

Small dissolved molecules in similar concentration as plasma.

32
Q

How do unfiltered molecules and components leave the glomerulus?

A

The efferent arteriole.

33
Q

How are molecules and ions reabsorbed?

A

Both actively and passively.

34
Q

Where do reabsorbed materials travel?

A

From the nephron into the blood of the peritubular capillaries.

35
Q

How is sodium reabsorbed?

A

By active transport (about 65%). Chloride follows but is passively absorbed. This causes an increased osmolarity.

36
Q

What does an increased osmolarity of the blood do?

A

Allows water to be absorbed by osmosis from the tubule into the blood.

37
Q

Do nutrients such as glucose and amino acids return to the blood?

A

Yes.

38
Q

How are nutrients returned to the blood?

A

Selective process because only molecules recognized by carrier proteins are actively reabsorbed.

39
Q

What do nephrons try to return to the blood?

A

Most water, nearly all nutrients, and required amount of ions that blood needs for regulation.

40
Q

What do nephrons keep?

A

Excess water, nitrogen containing wastes, and excess salts.

41
Q

What 2 things does the urine end up containing?

A

Filtered substances that have not been reabsorbed, and substances that have been actively secreted.

42
Q

What do the kidneys do to the blood?

A

Maintain the water-salt balance which automatically affects blood volume and pressure.

43
Q

What is osmoregulation?

A

Excretion of hypertonic urine depends on: reabsorption of water to blood from the loop of henle and collecting duct.

44
Q

What does the reabsorption of water back to the blood require?

A

Reabsorption of salt from nephron.
Establishment of solute gradient.
Reabsorption of water through channels called aquaporins.

45
Q

What do hormones do?

A

Control sodium reabsorption at the distal convoluted tubule.

46
Q

When is renin released and what does it do?

A

It is released when blood pressure is low and it leads to aldosterone release.

47
Q

What does aldosterone do?

A

Promotes the excretion of potassium ions to filtrate and the reabsorption of sodium ions to blood. Then, the reabsorption of sodium is followed by the reabsorption of water. Then blood volume and pressure increase.

48
Q

What is atrial natriuretic hormone?

A

A hormone secreted by the atria of heart. It occurs when the cardiac cells are stretched due to increased blood volume.

49
Q

What happens when urine needs to be hypertonic?

A

Antidiuretic hormone is produced by the posterior pituitary gland.

50
Q

What happens in the presence of ADH?

A

The collecting duct becomes more permeable to water and concentrated urine is produced.

51
Q

What happens in the absence of ADH?

A

Collecting duct is impermeable to water and dilute urine is produced.

52
Q

Describe diuretics.

A

Increase the flow of urine. Results in both water and salts being excreted from body and can be helpful in lowering blood volume.

53
Q

What are some diuretic examples?

A

Alcohol, caffeine, and diuretic drugs.

54
Q

What is alkalosis?

A

pH is greater than 7.4

55
Q

What is acidosis?

A

pH is less than 7.4

56
Q

What are some mechanisms that maintain pH of 7.4

A

Acid-base buffer system, respiratory center, and the kidneys.

57
Q

How does the pH of blood stay near 7.4?

A

Because the blood is buffered.

58
Q

What is a buffer?

A

Chemical or combination of chemicals that can take up excess hydrogen or hydroxyl, and prevents large changes in pH.

59
Q

What happens when hydrogen is added to the blood?

A

Bicarbonate links with hydrogen to make carbonic acid which reduces acidity.

60
Q

What is reabsorbed in the blood?

A

Kidneys reabsorb bicarbonate ions as needed and can also reabsorb hydrogen ions too.

61
Q

What is absorbed in urine?

A

Ammonia can absorb hydrogen ions, and kidneys then excrete ammonia with hydrogen ions as needed.

62
Q

What are some major illnesses that can cause kidney disease?

A

Diabetes, hypertension, and certain autoimmune diseases.

63
Q

How do illnesses cause kidney disease?

A

They tend to damage the glomeruli, resulting in a decreased glomerular filtration rate and eventually kidney failure.

64
Q

What is pyelonephritis?

A

Infection of the kidneys/inflammation of kidney tissue. It is commonly from a bacterial infection.

65
Q

What are kidney stones?

A

Hard granules that form in the renal pelvis. Composed of substances such as calcium, phosphate, uric acid, and protein.

66
Q

Describe albumin.

A

One of the first signs of kidney damage is when albumin is present in the urine. It is a protein that helps blood from leaking out of vessels and helps with healing.

67
Q

Describe uremia.

A

When more than 2/3 of the nephons have been destroyed by a disease process, urea and other waste products accumulate in the blood and aren’t excreted as much.

68
Q

What is hemodialysis?

A

Patients whose kidneys are failing may undergo this. It is diffusion of dissolved molecules through the membrane.

69
Q

What are bladder stones?

A

Result of bladder infections with associated inflammation or prostate enlargement in men. Can be kidney stones that were carried to the bladder.