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Flashcards in GRFC - renal system Deck (32)
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1

General functions of the renal system

*Elimination of waste products (bilirubin, uric acid, urea)

*Controls plasma volume in the body

*Acid-base balance

*Controls BP (via renin through RAAS)

*Produces hormones

2

RAAS

*Activated by renin in response to dehydration or excessive bleeding

*Decreased BP --> activation of juxtaglomerular cells --> kidneys produce renin

*Increased renin --> renin converts angiotensinogen to angiotensin I

*Increased angiotensin I --> as blood flows in the capillaries of the lungs --> ACE converts angiotensin I into angiotensin II

--Angiotensin II is a potent vasoconstrictor (increases BP)

--Angiotensin II stimulates adrenal cortex to produce aldosterone (resorption of H2O; normalize BP by increasing it)

3

Calcitriol

1,25-dihydroxylcholecalciferol

Active form of Vitamin D; for resorption of calcium

4

Erythropoeitin

Stimulation of new RBCs in the bone marrow

*90% produced in kidneys
*10% produced in liver

5

Kidneys

*Bean-shaped

*Level of kidneys: T12 - L3

*Right kidney is lower d/t the presence of the liver

*Location: Retroperitoneal (thus protection by lower ribs)

6

External anatomy of kidneys

*Renal capsule - barrier to trauma

*Adipose tissue - contains fats; middle layer of tissue (if decreased fats, kidney will fall [ptosis], called nephroptosis)

*Renal fascia - anchors the kidneys to the abdominal wall

7

Internal anatomy of kidney

*Renal cortex - outer region

*Renal medulla - inner region; contains renal pyramids

8

Nephron

Functional unit of kidneys

Responsible for urine formation
*2 million nephrons in the body

9

2 main structures of a nephron

*Renal corpuscle: glomerulus + bowman's capsule

*Renal tubule: PCT, LoH, DCT, CT

10

2 types of nephrons

*Cortical nephron: part of the nephron that lies in the renal cortex

*Juxtamedullary nephron: part of the nephron that lies in the renal medulla

11

Types of collecting ducts

*Cortical collecting duct: collecting duct on the renal cortex

*Meullary collecting duct: collecting duct on the renal medulla

12

Formation of urine

1. Glomerular filtration

2. Tubular reabsorption

13

Glomerular filtration

Filtered by filtration membrane composed of podocytes and endothelial cells

Allows H2O snd small solutes to pass through

Does not permit proteins, platelets, and blood cells to pass through

14

Net filtration pressure

10 mmHg

15

Glomerular filtration rate

Amount of filtrate found in all renal corpuscles in both kidneys

*Male: 125 mL/min
*Female: 105 mL/min

16

Tubular reabsorption

1. PCT (workhorse of nephron):
*Loves H2O: 65% reabsorption (most H2O reabsorption)
*100% absorption of glucose
*Luminal fluid is concentrated (decreased H2O)

2. Thin descending LoH
*Loves H2O: Reabsorption of H2O
*Hates solutes: No reabsorption of Na, urea, and Cl
*Luminal fluid is concentrated

3. Thin ascending LoH
*Hates H2O: No absorption of H2O
*Loves Na and Cl: Reabsorption of Na and Cl
*Luminal fluid is diluted

4. Thick ascending LoH
*Hates H2O: No absorption if H2O
*Loves ions: Reabsorption of Na, Cl, K, other ions
*Luminal fluid: More diluted

5. DCT + CT
*No reabsorption of H2O
*Receives diluted luminal fluid
*If with ADH, with reabsorption of H2O (receives concentrated fluid)

17

From DCT and CT

To:
*Medullary collecting duct
*Minor calyx
*Major calyx
*Ureter

18

Urochrome/ urobilin

Responsible for urine color

Urine is diluted in nature (pale yellow to orange)

19

ADH/ vasopressin

Secreted by neurohypophysis

Attaches on DCT

20

Ureter

Composed of smooth muscles

25 - 30 cm long

21

Urinary bladder

Has a smooth muscle called "detrusor muscle"

500 mL, normal storage

700 - 800 mL, dribbles

Innervated by S2, S3, S4 (or S2, S3)

At 200 - 300 mL, can be suppressed

Micturition reflex - voiding

22

Urethra

Terminal end organ of the renal system

*Male: ~20 cm
*Female: 3 - 4 cm

23

UTI

Females more than males

24

2 urethral sphincters

Internal urethral sphincter: involuntary

External urethral sphincter: voluntary sphincter

25

Overflow incontinence

Inability to empty completely

Caused by atonic bladder

(+) dribbles

26

Stress incontinence

Normal bladder

Weakness of supporting structures

Increased abdominal pressure facilitates urination

27

Urge incontinence

Caused by neurogenic bladder/ overactive bladder

Caused by damage to nerves, the urinary system, or the muscles

Bladder has involuntary contractures

Urinates >8 times a day

28

Functional incontinence

Physical or mental problems preventing the person to reach the bathroom/ toilet in time

No nerve, urinary system, or muscle damage

29

Mixed incontinence

Combination of stress and urge incontinence

30

Transient incontinence

Temporary incontinence brought about by a short-lived medical condition or medications