Anatomy Test 4 (Final!) Flashcards

1
Q

The Urinary System

A

kidney
ureter
urinary bladder
urethra

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2
Q

The Urinary System: Kidney

A

produces urine

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3
Q

The Urinary System: Ureter

A

transports urine toward the urinary bladder

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4
Q

The Urinary System: Urinary Bladder

A

temporarily stores urine prior to elimination

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5
Q

The Urinary System: Urethra

A

Conducts urine to exterior

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6
Q

Drinking water absorption by GI Tract

A

To where?- blood
Then to where?- renal arteries supply kidneys
Becomes what?- urine

nephron what is left empties into collecting system
reabsorption, filtration, excretion

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7
Q

Functions of the Kidneys (1)

A

Excretion:
-removal of wastes from body fluids in urine

Regulation of Blood:

  • ions: control blood NA+, K+, and Cl- levels
  • pH: control blood H+ and HCO3- levels
  • pressure and volume: control blood fluid volume and thus blood pressure
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8
Q

Functions of the Kidneys (2): Kidneys accomplish this by three processes

A
  • filtration of water, ions, nutrients and waste products from the blood
  • reabsorption of most of the water, ions and nutrients back into the blood
  • excretion of metabolic wastes into the urine
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9
Q

The Kidneys are our heros!

A
  • “Insensible” water loss is occurring as I speak and you breathe!
  • We lose water constantly though our: skin, lungs, digestive system
  • The Kidneys can regulate water volume in our bodies because they can: Concentrate or dilute the urine
  • The Kidneys are responsible for our ability to survive on land without dehydration!
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10
Q

The Position of the Kidneys

A

The kidneys are located:

  • on either side of the vertebral column
  • partly protected by the rib cage
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11
Q

The divisions of the Kidney

A
  • Renal cortex: outer portion of kidney

- renal medulla: inner portion of kidney, separated into renal pyramids by renal columns

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12
Q

Blood Supply to the Kidneys

A

-Each kidney receives blood from a renal artery

It branches into many smaller and smaller arteries which…

  • travel between renal pyramids within the renal column s and
  • ultimately deliver blood via arterioles to a capillary network called “glomerulus”
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13
Q

Facts about the Blood Supply to Kidneys

A
  • Kidneys receive 20-25% of total cardiac output
  • 1.2 liters of blood flows through kidneys each minute
  • The entire blood volume is filtered by the kidney 60 times/day
  • If the blood filtered by the kidney were entirely excreted, your entire blood volume would be excreted in 25 minutes
  • (99% of the filtered blood is actually returned to the cardiovascular system)
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14
Q

Kidney Histology

A
  • The Kidney is composed of: nephrons and a collecting system
  • The Kidney contains about 1.25 million “nephrons” (85 miles in combined length)
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15
Q

The Nephron

A

-The Nephron is the functional unit of the kidney

Urine production begins in the nephron

  • blood is filtered into the nephron
  • composition changes during the process

Composed of: Renal corpuscle and renal tubule

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16
Q

Renal corpuscle: Spherical structure is composed of

A
  • Glomerulus
  • Bowman’s capsule
  • Urinary Space
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17
Q

Renal Corpuscle (2): Glomerulus

A
  • Glomerulus: intertwining network of capillaries
  • receives blood from the afferent arteriole
  • blood leaves through the efferent arteriole
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18
Q

Renal Corpuscle (3): Bowman’s capsule

A
  • Composed of squamous epithelial cells

- Sac-ike structure surrounds the glomerulus encloses the urinary space

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19
Q

Renal Corpuscle: Urinary Space

A

-space between the inner layer lining of the glomerulus and the outer layer of the capsule

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20
Q

Filtration of fluid from blood into the nephron

A
  • Occurs in the ventral corpuscle
  • Blood pressure forces H2O and dissolved substances out of the glomerulus into the urinary space
  • produces a protein free solution called filtrate similar to blood
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21
Q

Three layers of filtration

A
  1. ) The Glomerulus (capillary): endothelial call layer
  2. ) Middle connective tissue layer
  3. ) Inner lining of the Bowman’s capsule: epithelial cell layer
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22
Q

The role of the glomerular endothelial layer

A
  • Specifically, there are pores, in the endothelial cells lining the glomerular capillaries
  • They are small enough that they prevent passage of blood cells into the filtrate
  • But they do allow some proteins to get through
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23
Q

The role of the podocyte layer of the inner lining of Bowman’s capsule (1)

A
  • However, the glomerural capillaries are surrounded by epithelial cells “foot cell” called podocytes of the inner lining of Bowman’s capsule
  • composed of many foot processes called pedicles
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24
Q

The role of the podocyte layer of the inner lining of Bowman’s capsule (2): Filtration slits

A
  • Filtration slits (narrow gaps) between adjacent pedicles of podocyte
  • smaller than the pores of the endothelial cells
  • they only allow H2O and dissolved solutes from the blood into the urinary space
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25
Q

Blockade of the middle connective tissue layer induces kidney disease

A

1) endothelial cells (pores)
2) connective tissue
3) podocyte cell (slits)

  • The connective tissue layer between the pores and slits can become clogged with “debris”!
  • This leads to kidney disease and to kidney failure!
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26
Q

Renal Tubule (1)

A

-a long U-Shaped tube extending from the cortex into the medulla and back to the cortex

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27
Q

Renal Tubule (2): structures that make up this

A

-It begins at renal corpuscle

  • It is composed of the:
  • proximal convoluted tubule (PCT)
  • loop of Henle
  • distal convoluted tubule (DCT)

It ends at the collecting duct

28
Q

Composition of the wall of the tubule

A
  • The wall of the renal tubule is composed of epithelial cells:
  • from squamous
  • to columnar
  • depending on the degree of activity of that portion of the tubule
29
Q

Return of Filtrate from the nephron back into the blood (1): Functions

A
  • Functions of renal tubule cells:
  • reabsorb nutrients from the filtrate
  • return them to the blood
  • reabsorb water (90%) from filtrate
  • return it to the blood
  • what is left in the tubule is excreted in the urine
  • filtrate traveling along the tubule composition changes
30
Q

Peritubular capillaries and vasa recta

A

-The reabsorbed H2O and solutes returns from the filtrate in the tubule to the blood via

  • Pertibular capillaries
  • Vasa rectal
    - both are branches of efferent arteriole (so leaves kidney)
    - they drain blood into the venous system and back to the heart
31
Q

What does PCT stand for?

A

Proximal convoluted tubule

32
Q

The PCT (proximal convoluted tubule)

A
  • The 1st segment of renal tubule
  • bulk reabsorption of filtrate occurs here:
  • 60-70% of the filtrate is reabsorbed here: epithelial cells have microvilli to increase surface area for absorption
33
Q

The loop of henle

A

-Middle segment of the renal tubule

Composed of a:

  • descending limb, fluid flows “down” into the medulla
  • ascending limb, fluid flows “back up” into the cortex
34
Q

How the Loop of Henle Concentrates Urine

A
  • Na+ and Cl- are actively pumped out of the ascending limb (and back into the bloodstream)
  • H2O follows out of the descending limb (and back into the bloodstream)
  • tubular fluid becomes very concentrated
    • urea
35
Q

Urea

A
  • the most abundant organic waste from amino acid breakdown

- is now the main solute left in the tubular fluid, hence “urine”

36
Q

The DCT (distal convoluted tubule) (1)

A

-Last segment of the renal tubule

Note that the epithelial cells lining the DCT:

  • are smaller than those of the PCT and do NOT have microvilli
  • these cells are less active than the cells of the PCT
  • but these cells are more highly specialized than the cells of the PCT
37
Q

What does DCT stand for?

A

distal convoluted tubule

38
Q

The DCT (distal convoluted tubule) (2)

A
  • further adjustment to the filtrate are made in the DCT
  • very selective reabsorption occurs here in response to hormones
  • to regulate blood pressure and volume, blood pH
39
Q

A word about the Real anatomy of the Nephron

A
  • Let’s return to the renal corpuscle and related structures…
  • First, it is important to note that the DCT is related to the renal corpuscle like this
  • Not this

Look at PG. 106

40
Q

The Juxtaglomerular apparatus

A

This is an endocrine structure composed of:

  • Macula densa: specialized epithelial cells in the DCT
  • Juxtaglomerular JG cells: specialized smooth muscle cells of the afferent arteriole
41
Q

What does juxta mean?

A

close to

42
Q

How the DCT regulates blood pressure and volume (1)

A
  • if decreased blood pressure is sensed by the JG cells
  • the JG cells release renin (a hormone)
  • renin activates angiotensin (another hormone)
43
Q

What does JG stand for?

A

juxtaglomerular apparatus

44
Q

How the DCT regulates blood pressure and volume (2): angiotensin

A

Angiotension

  • Causes: vasoconstriction (look at its name!)
  • and secretion of aldosterone (a mineralcorticoid hormone) by the adrenal cortex

(increased BP)

45
Q

How the DCT regulates blood pressure and volume (3): Aldosterone

A

Aldosterone
Causes DCT cells:
-raise Na+ reabsorption (both always follows Na+)
-Both are returned to the blood
-This raises blood pressure and raises blood volume

46
Q

How the DCT regulates blood pressure and volume (4)

A
  • If increase blood pressure or volume is sensed by stretch receptors of the heart walls, atria of the heart releases atrial natriugetic peptide (ANP hormone)
  • causes decrease in Na+ (and H2O) reabsorption at the DCT so raises Na+ (and H2O) excretion into the urine
  • results in decrease BP and volume
47
Q

What does Natrium mean?

A

sodium

48
Q

What does natriuresis mean?

A

urinary excretion of sodium

49
Q

Summary of DCT

A
  • decrease blood pressure leads to:
  • renin-> angiotensin->aldosterone
  • raises Na+ and H2O reabsorption at DCT
  • raises blood volume and therefore pressure
  • less water in the urine
  • urine becomes more concentrated
  • raises blood pressure leads to:
  • ANP->
  • decrease Na+ and H2O reabsorption at DCT
  • decrease blood volume and therefore pressure
  • more water in the urine
  • urine becomes more dilute
50
Q

How the dCT regulates blood pH

A

The DCT controls blood pH by both

  • H+ excretion into the forming urine
  • HCO3- (bicarbonate) production and reabsorption into the blood
  • HCO3- buffers the blood
51
Q

The Collecting Ducts

A
  • determine final urine composition and volume
  • hypothalmic neurons are stimulated by decrease blood pressure or increase blood Na+/Cl- concentration:
  • they release ADH (antidiuretic hormone): causes increase H2O reabsorption at the collecting duct
52
Q

Collecting system: Collecting duct

A

variable reabsorption of water and reabsorption or secretion of sodium, potassium, hydrogen, and bicarbonate ions

53
Q

Collecting system: Papillary duct

A

delivery of urine to minor calyx

54
Q

Summary of how 2 important hormones increase blood pressure and volume

A
  • aldosterone binding here causes Na+ reabsorption (H2O follows)
  • ADH binding here causes only H2O reabsorption

collecting duct

55
Q

Overview of the functions of the Components of the Nephron and Collecting Duct

A
Proximal convoluted tubule-bulk reabsorption
Renal corpuscle-filtration
Distal convoluted tubule-fine toning
Collecting duct-hormones fine tuning
Loop of Henle-concentration
56
Q

The Collecting System of the Kidney

A
  • The filtrate continues to pass through the collecting duct where its final composition is determined
  • collecting ducts converge to empty into a minor calyx, which ends at the renal papilla of each renal pyramid
57
Q

The Renal Calyces and Pelvis: Minor Calyx

A
  • cup-like structure surrounding each renal pyramid
  • collects urine from each renal __pg 108____
  • several join to form a major calyx
58
Q

The Renal Calyces and Pelvis: Major Calyx

A
  • collects urine from several minor calyces

- join to form the renal pelvis

59
Q

The Renal Calyces and Pelvis: Renal Pelvis

A

-acts as a funnel to drain urine from the kidney to the ureter

60
Q

Urine Transport, Storage, and Elimination

A

-Takes place in the urinary tract: ureter, urinary bladder, urethra

Ureter- transports urine toward the urinary bladder
Urinary Bladder- temporarily stores urine prior to elimination
Urethra- conducts urine to exterior

61
Q

The Ureters

A

Muscular tubes (smooth muscle)

  • collect urine from renal pelvis
  • empties urine into the urinary bladder

Pass through bladder wall at an angle

  • prevents back flow of urine
  • flatten as the bladder filled with urine and when bladder contracts to void the urine
62
Q

The Urinary Bladder

A
  • hollow, muscular organ (smooth muscles)
  • temporary reservoir por urine storage
  • a full bladder can contain 1 liter of urine
63
Q

Urothelium

A
  • AKA transitional epithelium (a type of stratified epithelium)
  • lines the urinary bladder and ureters
  • composed of cells that are impermeable to water and can rearrange themselves an spread out as the bladder fills with urine
64
Q

The Male Urethra

A
  • The male urethra is 7 to 8 inches long

- Begins at the inferior pole of the bladder passes through the prostate gland and penis

65
Q

The Female Urethra

A
  • The female urethra is much shorter, 1 to 2 inches long

- Therefore, a female is prone to more frequent infections of urinary bladder than is the male

66
Q

The external urethral sphincter

A

In Both Sexes:

  • skeletal muscle surrounds the urethra
  • (voluntary muscle) (under conscious control)
  • relaxation permits microturition (urination)