Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Animal Physiology: Homeostasis > Week 11 > Flashcards

Week 11 Flashcards

1
Q

What are the main sources of water loss?

A

REGULATED PROCESSES
- Urination, sweating feces
UNREGULATED PROCESSES
- respiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Extracellular fluid composition

A
  • Sodium
  • Chloride
  • Bicarbonate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Intracellular Fluid Composition

A
  • Potassium
  • Magnesium
  • Organic Ions
  • Proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How does the composition of of interstitial fluid differ from plasma

A

Greater protein concentration in plasma due to capillary filtration
- Plasma also contains several non-ionic substances

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the two core concepts underlying the regulation of body fluid volumes and composition?

A

FLOW DOWN GRADIENTS: Osmosis, diffusion of ions and other solutes due to chemical and/or electrical gradients
MASS BALANCE: The contents of water/solute in any body compartment is determined by inputs and outputs
- Accumulation = input + generation - output - consumption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Mass balance of Sodium with intake

A

Excretion delayed compared to intake
- Sodium retention occurs (+ accumulation)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Isotonic

A

Same Ion concentration inside and out - no change in cell size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Hypotonic

A

More ion in cell compared to environment
- Cell swells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Hypertonic

A

More ions outside the cell compared to inside
- cell shrinks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the effect of adding an isotonic NaCl solution to normal state conditions on osmolarity and volume

A

Increases overall volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the effect of adding a hypotonic NaCl to normal state conditions on osmolarity and volume

A
  • Decrease overall osmolarity
  • increase volume of intracellular
  • smaller increase in extracellular volume
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the effect of adding a hypertonic NaCl to normal state conditions on osmolarity and volume?

A
  • Increase overall osmolarity
  • Increased extracellular volume
  • decrease in intracellular volume
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the main purposes of the kidneys

A
  • Regulation of body fluid volume
  • Regulation of electrolyte composition
  • Excretion of metabolic wastes
  • foreign substances
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Kidney Nephron

A
  • The functional unit of the kidney
  • Approximately 6 nephrons per cortical collecting duct, 8-10 cortical ducts per medullary collecting but, which merge into progressively larger ducts then discharge into renal pelvis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Renal Capillary beds

A

Two capillary beds in series
- Glomerular capillaries
- Peritubular capillaries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the blood flow rate to the kidneys at rest

A

20% of CO

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Cortical Nephrons

A
  • Glomeruli in the outer cortex
  • Loops of Henle only penetrate outer medulla
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Juxtamedullary Nephrons

A
  • Glomeruli lie deeper in the cortex
  • Loops of Henle descend into inner medulla, alongside vasa recta (specilized peritubular capillaries)
  • Specilized for producing concentrated urine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the 3 urine formation processes?

A
  1. Glomerular Filtration
  2. Reabsorption from tubules
  3. Secretion into tubules
20
Q

What is the rate of glomerular filtration and how does it compare to urine volume

A

Glomerular filtration of fluid: 180L/day
Only 1.5 L/day of urine

21
Q

What substances are just filtered

A

Many waste products

22
Q

What substances are filtered and partially reabsorbed

A

Water and many electrolytes

23
Q

What substances are filtered and completed reabsporped

A

Many nutritional substances (macro components)

24
Q

What substances are filtered and secreted

A

Some organic acids and bases

25
Q

The Bladder

A
  • Urine travels from renal pelvis to bladder via ureters
  • Smooth muscle chamber, formed by the detrusor muscles, whose contraction empties the bladder
  • Internal (involuntary, smooth) and external (voluntary, skeletal) muscle sphincters prevent emptying
  • bladder and internal sphincter are innervated by ANS
  • External sphincter in innervated by motor neurons
26
Q

Micturition Reflex

A
  1. Stretch receptor on bladder senses filling
  2. Sensory PNS sends signal to sacral spinal cord
  3. Sensory neuron synapses with motor neuron of PNS and ascending fibers that synapse in the pons and then cortex for conscious control
  4. Motor neuron of PNS causes a contraction of detrusor muscles and relaxes internal sphincter, Central command innervates somatic motor fiber of pudendal nerve to control external sphincter
27
Q

What is glomerular filtration rate

A

20% of renal plasma flow rate
- Filtration fraction is much greater than most other capillaries

28
Q

What pressures determine fluid flow across capillaries?

A
  • Hydrostatic pressure
  • Colloid osmotic pressure
    Pc> Pif = filtration
    piC>piIF = absorption
29
Q

Net filtration pressure

A

(Pc-Pif) - (piC - piIF)

30
Q

Net filtration rate

A

NFP x Kf (Volume/min)
where Kf is the permeability coefficient of the capillaries

31
Q

What accounts for the high filtration rate of glomerular capillaries?

A

High permeability coefficient relative to other capillary beds (400x higher)

32
Q

How does the NFP in the glomerular capillaries compare to other capillaries?

A
  • NFP: same
  • Glomerular Hydrostatic Pressure: higher
  • Bowman’s capsule pressure: Higher
  • Glomerular colloid osmotic pressure: about same
33
Q

Layers of glomerular capillaries

A
  1. Endothelial cell
  2. Basement Membrane
  3. Epithelial cells (podocytes)
34
Q

What accounts for the high permeability in the glomerular capillaries

A

Fenestrations: Wide endothelial perforations
Slit Pores: wide opening between podocytes

35
Q

Why do proteins tend not to get filtered through glomerular capillaries

A

Although wide enough for plasma proteins, the negative charged molecules on surface of endothelial cells, basement membrane and podocytes deter negatively charged proteins

36
Q

How will obstruction of urinary outflow affect glomerular filtration rate

A

Increase capsule pressure causing decrease in net filtration pressure

37
Q

What is the primary way the GFR is regulated

A

Glomerular hydrostatic pressure

38
Q

What 3 variables determine glomerular hydrostatic pressure

A
  1. Arterial Pressure
  2. Afferent arteriole resistance
  3. Efferent arteriole resistance
39
Q

How is renal blood flow calculated

A

= (Pa - Pv)/ total renal vascular resistance

40
Q

What happens if resistance increases in the afferent arterioles of the glomerulus

A
  • Flow decreases and glomerular pressure decreases causing increase in change in pressure
41
Q

What happens if resistance increases in the efferent arterioles of the glomerulus

A
  • Increase glomerular pressure
  • decrease in flow
  • increase in change in pressure
  • decrease in peritubular capillary pressure
42
Q

Control of filtration by afferent arterioles

A
  • Constriction of afferent arterioles increase renal vascular resistance
  • leads to reduce in renal blood flow and glomerular pressure
  • decreasing glomerular filtration rate
43
Q

Control of filtration by efferent arterioles

A
  • Constriction of efferent arterioles increase renal vascular resistance, thus reducing renal blood flow
  • Increasing resistance to outflow from glomerular capillaries initially increases glomerular pressure and GFR
  • With larger reductions in renal blood flow, colloid osmotic pressure in glomerular capillaries can start to rise and limit GFR
44
Q

Autoregulation of filtration rate

A
  • Feedback mechanism intrinsic to the kidneys normally keep renal blood flow and GFR relatively constant
  • Tubulo-glomerular feedback mechanism acts to maintain relatively constant delivery of NaCl to the distal tubule (GFR is proportional to NaCl delivery)
  • Mechanism involves the juxtaglomerular complex between the distal tubule and glomerular arterioles
45
Q

Tubulo-Glomerular feedback

A
  • Decrease in GFR due to decrease in arterial pressure
  • Macula Densa, which are specialized epithelial cells that release prostaglandins in response to low NaCl in the distal tubule
  • Prostaglandins cause afferent arterioles to vasodilate, and stimulate renin release from juxtaglomerular cells into blood
  • Renin catalyzes production of angiotensin I, which is converted to angiotensin II
  • Angiotensin II stimulates constriction of efferent arterioles
46
Q

Effect of SNS on renal blood flow

A
  • Causes constriction
  • decreased flow
  • opposed by autoregulation

Animal Physiology: Homeostasis (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions