Renal week 1

Question 1

What are the two major sources for how water is added to the body?

Answer 1

(1) it is ingested in the form of liquids or water in food, which together normally add about 2100 ml/day to the body fluids, and (2) it is synthesized in the body by oxidation of carbohydrates, adding about 200 ml/day. These mechanisms provide a total water intake of about 2300 ml/day.

Question 2

The total body fluid is distributed mainly between two compartments: the_______ fluidand the_______ fluid.

The extracellular fluid is divided into theinterstitial fluidand the bloodplasma

Answer 2

The total body fluid is distributed mainly between two compartments: theextracellular fluidand theintracellular fluid.

The extracellular fluid is divided into theinterstitial fluidand the bloodplasma

Question 3

What is transcellular fluid?

Answer 3

This compartment includes fluid in the synovial, peritoneal, pericardial, and intraocular spaces, as well as the cerebrospinal fluid; it is usually considered to be a specialized type of extracellular fluid, although in some cases its composition may differ markedly from that of the plasma or interstitial fluid. All the transcellular fluids together constitute about 1 to 2 liters.

Question 4

True/False: a person grows older, the percentage of total body weight that is fluid gradually decreases

Answer 4

True. The percentage of total body weight that is fluid gradually decreases

This decrease is due in part to the fact that aging is usually associated with an increased percentage of the body weight being fat, which decreases the percentage of water in the body.

Question 5

Are extracellular (plasma and interstitial) fluids similar?

Answer 5

Yes. Highly permeable capillary membrane

Protein level > in plasma because of low membrane permeability

Question 6

What are the major extracellular cations?

Answer 6

Na and Cl, little bit of Hco3

Question 7

What are the major intracellular cations?

Answer 7

Potassium, mag

Question 8

What is intracellular fluid permeable to?

Answer 8

Highly permeable to water not electrolytes (semi-permeable)

Separated by cell membrane

Question 9

he composition of extracellular fluid is carefully regulated by various mechanisms, but especially by the _________

Answer 9

he composition of extracellular fluid is carefully regulated by various mechanisms, but especially by the KIDNEYS

Question 10

What is the gibbs donnon equilibrium?

Answer 10

When two solutions containing ions are separated by membrane that is permeable to some of the ions and not to others an electrochemical equilibrium is established.

Because of theDonnan effect,the concentration of positively charged ions (cations) is slightly greater (~2 percent) in the plasma than in the interstitial fluid.

Question 11

What are the amounts of extracellular fluid distributed between the plasma and interstitial spaces are determined by?

Answer 11

balance of hydrostatic and colloid osmotic forces across the capillary membranes.

Question 12

What is the distribution of fluid between intracellular and extracellular compartments determined by?

Answer 12

osmotic effect of the smaller solutes—especially sodium, chloride, and other electrolytes—acting across the cell membrane

Question 13

The rate of diffusion of water is called?

Answer 13

therate of osmosis.

Question 14

Just read this

Answer 14

Because cell membranes are relatively impermeable to most solutes but are highly permeable to water (i.e., they are selectively permeable), whenever there is a higher concentration of solute on one side of the cell membrane, water diffuses across the membrane toward the region of higher solute concentration. Thus, if a solute such as sodium chloride is added to the extracellular fluid, water rapidly diffuses from the cells through the cell membranes into the extracellular fluid until the water concentration on both sides of the membrane becomes equal. Conversely, if a solute such as sodium chloride is removed from the extracellular fluid, water diffuses from the extracellular fluid through the cell membranes and into the cells.

Question 15

One osmole (osm) = 1 mole (mol) (6.02 x 1023)*

Answer 15

1 mole (mol) (6.02 x 10 to the 23rd)*

Question 16

Osmolality=

Answer 16

Osmoles / kg of water

Question 17

Osmolarity

Answer 17

Osmoles / liter of solution

Question 18

Osmosis is the net diffusion of water across a ________ _______

Answer 18

Osmosis is the net diffusion of water across a selective membrane
- high water concentration to low water concentration

Question 19

Osmotic Pressure refers to the amount of pressure required to prevent _______

Answer 19

Osmosis.

Pressure applied in opposite direction of osmosis

Question 20

Interstitial Fluid & Plasma

Answer 20

80% due to sodium & chloride

Plasma is 1 mOsm/L > interstitial fluid

Plasma proteins maintain 20 mmHg greater pressure in capillaries than surrounding tissues

Question 21

Intracellular Fluid

Answer 21

Almost 50% due to potassium ions

Remainder divided among other intracellular substances

Total osmolarity of each compartment @ 300 mOsm/L

Question 22

What is the most important difference between plasma and interstitial fluids?

Answer 22

The higher concentration of protein in the plasma.

Because the capillaries have a low permeability to the plasma proteins, only small amounts of proteins are leaked into the interstitial spaces in most tissues.

Question 23

Hyper/hypo/isotonic

Answer 23

Hyper - water out, cell shrinks
Iso - equal
Hypo - water in, cell expands

Question 24

If ahypertonicsolution is added to the extracellular fluid..

Answer 24

The net effect is an increase in extracellular volume (greater than the volume of fluid added), a decrease in intracellular volume, and a rise in osmolarity in both compartments.

Question 25

If a hypotonic solution is added to the extracellular fluid

Answer 25

the osmolarity of the extracellular fluid decreases and some of the extracellular water diffuses into the cells until the intracellular and extracellular compartments have the same osmolarity (C). Both the intracellular and the extracellular volumes are increased by the addition of hypotonic fluid, although the intracellular volume increases to a greater extent.

Question 26

HYPONATREMIA

Answer 26

Excess water Loss of sodium Diarrhea & Vomiting Diuretic abuse Addison’s Disease Excess water retention (ADH)

Question 27

HYPERNATREMIA

Answer 27

Loss of water Excess of sodium Lack of ADH Diabetes insipidus Dehydration Aldosterone secretion

Question 28

A primary loss of sodium chloride usually results in hyponatremia and dehydration and is associated with decreased ________ fluid volume.

Answer 28

extracellular

Question 29

If plasma sodium concentration rapidly falls below _____ to ______ mmol/L, brain swelling may lead to seizures, coma, permanent brain damage, and death. Because the skull is rigid, the brain cannot increase its volume by more than about ____ percent without it being forced down the neck (herniation), which can lead to permanent brain injury and death.

Answer 29

115 to 120 10%

Question 30

A rapid _______ in plasma sodium concentration, for example, can cause brain cell edema and neurological symptoms, including headache, nausea, lethargy, and disorientation.

Answer 30

reduction

Question 31

Primary loss of _____ from the extracellular fluid results in _______ and dehydration.

Answer 31

water, hypernatremia

Question 32

Causes of hypernatremia An inability to secrete ______ ______, which is needed for the kidneys to conserve water. As a result of lack of antidiuretic hormone, the kidneys excrete large amounts of dilute urine (a disorder referred to as “central” diabetes insipidus), causing dehydration and increased concentration of sodium chloride in the extracellular fluid. In certain types of renal diseases, the kidneys cannot respond to antidiuretic hormone, causing a type of “______” diabetes insipidus.

Answer 32

antidiuretic hormone nephrogenic

Question 33

Thus, in analyzing abnormalities of plasma sodium concentration and deciding on proper therapy, one should first determine whether the abnormality is caused by a primary loss or gain of sodium or a primary loss or gain of water.

Answer 33

Just read

Question 34

What is more common, hypernatremia or hyponatremia?

Answer 34

Hyponatremia is much more common

Question 35

When do severe symptoms of hypernatremia start to show?

Answer 35

severe symptoms usually occur only with rapid and large increases in the plasma sodium concentration above 158 to 160 mmol/L. One reason for this phenomenon is that hypernatremia promotes intense thirst and stimulates secretion of antidiuretic hormone, which both protect against a large increase in plasma and extracellular fluid sodium.

Question 36

How do you correct hypernatremia?

Answer 36

Correction of hypernatremia can be achieved by administering hypo-osmotic sodium chloride or dextrose solutions. However, it is prudent to correct the hypernatremia slowly in patients who have had chronic increases in plasma sodium concentration because hypernatremia also activates defense mechanisms that protect the cell from changes in volume.

Question 37

What compartment does edema usually occur?

Answer 37

Occurs mostly in the extracellular fluid compartment

Question 38

What are the two general causes of extracellular edema?

Answer 38

Abnormal leakage from plasma -Excessive capillary filtration rate Filtration dependant on permeability & surface area of capillary Starling factors: hydrostatic pressure & colloid osmotic pressure Lymphatic failure to return fluids to blood -Lymphatic blockage preventing return of proteins to plasma Increased interstitial colloid osmotic pressure Cancer, surgery, infection (filaria nematodes)

Question 39

filaria nematodes (Wuchereria bancrofti)

Answer 39

Blockage of lymph flow can be especially severe with infections of the lymph nodes, such as occurs with infection by filaria nematodes (Wuchereria bancrofti), which are microscopic, threadlike worms. The adult worms live in the human lymph system and are spread from person to person by mosquitoes. People with filarial infections can have severe lymphedema and elephantiasis and men can have swelling of the scrotum, called hydrocele. Lymphatic filariasis affects more than 120 million people in 80 countries throughout the tropics and subtropics of Asia, Africa, the Western Pacific, and parts of the Caribbean and South America.

Question 40

Causes of abnormal leakage from plasma

Answer 40

Increased capillary filtration coefficient Increased capillary hydrostatic pressure Decreased plasma colloid osmotic pressure

Question 41

What are the causes of extracellular edema?

Answer 41

Increased capillary pressure - Retention of sodium & water - High venous pressure - Decreased arteriole resistance Decreased plasma proteins Increased capillary permeability - Immune reactions - Infection & toxins - Burns & ischemia Blockage of lymph return

Question 42

Edema Caused by Heart Failure

Answer 42

The heart fails to pump blood normally from the veins into the arteries, which raises venous pressure and capillary pressure, causing increased capillary filtration. The arterial pressure tends to fall, causing decreased excretion of salt and water by the kidneys, which causes still more edema. Blood flow to the kidneys is reduced and this reduced blood flow stimulates secretion of renin, causing increased formation of angiotensin II and increased secretion of aldosterone, both of which cause additional salt and water retention by the kidneys.

Question 43

Safety Factors That Prevent Edema

Answer 43

Low interstitial compliance (usually -3 mmHg) Ability to increase lymphatic drainage “Wash down” of interstitial fluid proteins (as lymphatic flow increases proteins are washed away)

Question 44

Total safety factor against edema is about ____

Answer 44

17 mmHg (3,7,7)

Question 45

Capillary pressure can _____ before significant edema occurs

Answer 45

double

Question 46

What is the functional unit of the kidney?

Answer 46

The Nephron

Question 47

Where does plasma filtration occur?

Answer 47

The glomerulus

Question 48

Renal bloodflow is ___% of cardiac output

Answer 48

22%

Question 49

Highest metabolism is in the ____ ____

Answer 49

renal cortex

Question 50

True/false: renal blood flow is the highest of any organ

Answer 50

True

Question 51

True/false: Each kidney has 1.25 million nephrons

Answer 51

True

Question 52

What are the 2 types of nephrons?

Answer 52

Cortical -Short loops of Henle, extend to outer medulla -Outnumber juxtamedullary nephrons ~7:1 Juxtamedullary - Extend deep into medulla with long loops of Henle - Play a big role in concentrating urine

Question 53

After age 40 years, the number of functioning nephrons usually decreases about 10 percent every 10 years; thus, at age 80 years, many people have _____ fewer functioning nephrons than they did at age 40 years.

Answer 53

40% fewer at 80