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Flashcards in GI System Deck (53)
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1
Q

What is the GU system made up of?

A

Kidneys, ureters, urinary bladder, and urethra

2
Q

Excretion

A

Removal of metabolic waste products from body fluids

3
Q

Elimination

A

Discharge of waste products into the environment

4
Q

Homeostatic regulation

A

Regulation of the volume and solute concentration of blood

5
Q

Function of kidneys

A

Excretory functions

- Micturition (urination)

6
Q

Urinary system

A

Removes metabolic wastes generated by body cells

7
Q

Urea

A

Most abundant organic waste; most formed during breakdown of amino acids

8
Q

Creatinine

A

Generated in skeletal muscle tissue through the breakdown of creatine phosphate (high energy compound for muscle contraction)

9
Q

Uris acid

A

Product of the breakdown and recycling of RNA molecules

10
Q

Three processes of kidneys (nephrons)

A
  1. Filtration
  2. Reabsorption
  3. Secretion
11
Q

Filtration

A

Blood pressure forces water across the filtration membrane of glomerular capillaries and into the capsular space (renal corpuscle)

Solute molecules small enough to pass through are carried by surrounding water molecules

12
Q

Reabsorption

A

The removal of water and solutes from tubular fluid and their movement across the tubular epithelium and into the peritubular fluid

  • Reabsorbed fluid re-enters circulation
  • Takes place after filtrate has left renal corpuscle
  • Selective process
13
Q

Secretion

A

Transport of solutes from peritubular fluid, across tubular epithelium, and into tubular fluid

  • Necessary because filtration does not force all dissolved materials out of the blood
  • Can lower plasma concentration of undesirable materials (eg. Drugs)
14
Q

Three levels of control that regulate globular filtration rate (GFR)

A
  1. Autoregulation - local blood flow regulation
  2. Hormonal regulation that is started by kidneys
  3. Autonomic regulation mostly by the sympathetic division of CNS
15
Q

Autoregulation

A

Compensates for minor variations in blood pressure

  • Autonomic changes to afferent/efferent arterioles, and glomerular capillaries
  • Eg., increased BP = stretched afferent arterioles, smooth muscle cells contract
16
Q

Hormonal control

A

Long-term adjustment in BP and blood volume to stabilize GFR

  • Involves angiotensin II, ADH, Aldosterone, and ANP
17
Q

Juxtaglomerular complex

A

Releases renin into circulation

Renin converts angiotensin to angiotensin I, which is converted into angiotensin II by ACE in lung capillaries

18
Q

Angiotensin II

A

Acts at peripheral capillary beds, nephron, adrenal glands, and CNS

  • Vasoconstriction in peripheral capillary beds, raising BP in renal arteries
  • Constriction of efferent arterioles in nephron, raising glomerular pressure/filtration rates
  • Adrenal gland secretes Aldosterone, E and NE also secreted, increasing systemic BP
  • Angiotensin II triggers release of ADH, stimulating reabsorption of water and sodium ions
19
Q

Antidiuretic hormone (ADH)

A

Increases water permeability of DCT and collecting duct, so that water is reabsorbed from tubular fluid

Creates thirst

20
Q

Aldosterone

A

Stimulates reabsorption of sodium ions and secretion of potassium ions

21
Q

Atria natriuretic peptide (ANP)

A

Oppose actions of renin-angiotensin-aldosterone system, lowering blood volume/pressure

In kidneys:

  • decreased sodium ion reabsorption and increased loss in urine
  • dilation of glomerular capillaries, increased filtration and urinary water loss
  • inactivation of renin-angiotensin-aldosterone system
22
Q

Sympathetic activation of GFR control

A

Shifts blood away from kidneys, lowering glomerular filtration rate

Constriction of afferent arterioles, decreasing GFR and slowing production of filtrate

23
Q

Ureters

A

Pair of muscular tubes that move urine from kidneys to bladder

24
Q

Urital orifices

A

Prevent backflow of urine into ureters/kidneys when bladder contracts

25
Q

Kidney stones

A

Calcium deposits, magnesium salts, crystals of uric acid

Nephrolithiasis: presence of stones that can block flow of urine or reduce/prevent filtration in affected kidney

26
Q

Internal urethral sphincter

A

Smooth muscle that provides involuntary control over discharge of urine from bladder

27
Q

Detrusor muscle

A

Contracts to compress bladder and expel contents into urethra

28
Q

Urine storage reflex

A

When stored, afferent (sensory) impulses from stretch receptors in bladder stimulates sympathetic impulses, permitting filling of bladder

Pontine storage centre: inhibits urination by decreasing parasympathetic activity and increasing somatic nerve activity at external urethral sphincter

29
Q

Voiding reflex

A

Occurs when using volume is 300-400 mL

Afferent (sensory) impulses from stretch receptors in bladder stimulate interneurons that relay sensations to pontine micturition centre

Less than 10 mL remains afterwards

30
Q

Functions of urinary system

A
  1. Adjust blood volume and blood pressure
  2. Regulate plasma concentrations of sodium, potassium, chloride and other ions
  3. Stabilize blood pH
  4. Conserve valuable nutrients
  5. Remove drugs, toxins, and metabolic wastes from bloodstream
31
Q

Nephron

A

Microscopic structure that performs essential functions of kidneys

Renal corpuscle: water and dissolved solutes forced out of glomerular capillaries into capsular space in process of filtration (moves into tubules)

Renal tubule: modifies and carries filtrate

32
Q

Collecting system

A

Series of tubes carrying tubular fluid away from nephron

33
Q

Proximal convoluted tubule

A

Where solute is reabsorbed or secreted, and water reabsorbed

34
Q

Distal convoluted tubule

A

Where variable water reabsorption and variable solute reabsorption/secretion occurs

35
Q

Oliguria

A

50-500 mL/day of urine output (low)

36
Q

Anuria

A

0-50 mL/day or urine output

37
Q

Renal failure

A

Kidneys unable to perform excretory functions to maintain homeostasis

  • reduced urine production
  • disturbed fluid balance, pH, muscular contraction, metabolism and digestive function
  • hypertension
  • anemia from decline in erythropoietin production
  • CNS problems (sleepiness, seizures, delirium, coma)
38
Q

Pyelonephritis

A

Kidney infection

39
Q

Renal calculi

A

Kidney stones

40
Q

Dysuria

A

Painful/difficult urination

41
Q

Signs of urinary system disorders

A

Edema from protein loss in urine

Fever from pathogens infecting system

42
Q

Stress incontinence

A

Periodic involuntary leakage

43
Q

Urge incontinence

A

Inability to delay urination

44
Q

Overflow incontinence

A

Continual, slow trickle of urine from bladder that is always flow

45
Q

Urinary retention

A

Kidney function is normal but no urination

46
Q

Fluid balance

A

Amount of water gained/day = amount of water lost/day

H2O gained through digestive tract and metabolic processes
Lost through urination, feces, evaporation

47
Q

Acid-base balance

A

pH of body is within normal limits (7.35-7.45)

Production of hydrogen ions is precisely offset by loss of hydrogen ions

48
Q

Factors involved in acid-base balance

A
  1. Tissue cells- carbon dioxide from cells is converted into carbonic acid in solution; metabolic processes produce acids
  2. Buffer system - temporary storage of H+ ions, providing short-term pH stability
  3. Kidneys - secrete H+ ions into the urine and generate buffers that enter bloodstream
  4. Respiratory system - eliminates CO2
49
Q

Acidosis

A

PH of less that 7.35

  • CNS function deteriorates
  • Cardiac contractions are weak/irregular
  • Peripheral vasodilation causes severe drop in blood pressure
50
Q

Alkalosis

A

pH greater than 7.45

Relatively rare, but dangerous

51
Q

Renal compensation

A

Kidneys secrete or generate H+ or HCO3- to compensate for shift in pH

52
Q

Respiratory compensation

A

Respiratory rate increases/decreases controlling rate of CO2 being eliminated

53
Q

Hemodialysis

A

Filtration of blood palms across an artificial membrane

Patients blood is circulated next to dialysis fluid