Physiology exam 4

Functions of the kidneys include all but one of the following. Identify the exception.

-Homeostatic regulation of blood pH Regulation of blood protein levels
-Maintenance of ion balance in body fluids -Regulation of extracellular fluid volume
-Regulation of blood osmolarity

Regulation of blood protein levels

Ions directly regulated by the kidney include all EXCEPT which of the following?

-HCO3-
-Ca2+
-Na+
-OH-
-K+

OH-

The characteristic yellow color of urine is attributed to the presence of what?

The presence of Urobilinogen

Urine is produced by the what?

The Kidney

Blood flow through the kidney includes a feature seen in only a few organs. What is it?

The Portal system

Which structure is not part of the blood circulation through the kidney?

The Loop of Henle

When blood pressure and volume decrease the cardiovascular system increases _______ ______ and causes ________________.

cardiac output, vasoconstriction

The adrenomedullary hormone most involved in acute responses to sudden stress is ____________ whereas the adrenocortical hormone mediating long-term responses to persistent stress is __________.

epinephrine, cortisol

In normal kidneys, blood cells and plasma proteins are

not filtered

What is the most potent vasoconstrictor discussed?

Angiotensin II

The most important factor affecting the pH of plasma is the concentration of what?

The concentration of Carbon dioxide

The enzyme renin is responsible for the conversion of what?

Angiotensinogen to angiotensin I

A predominant indicator of respiratory alkalosis is what?

An increase in respiratory rate

Aldosterone does what?

Promotes sodium resorption in the kidneys

George has high H+ levels, low pH and low bicarbonate levels. He is most probably suffering from _________ ________

Metabolic acidosis

Mineralocorticoids are secreted from what?

Zona glomerulosa of the adrenal cortex

The reason that respiratory compensation for metabolic alkalosis can never fully return plasma pH to normal is that

High PaCO2 stimulates respiratory ventilation

Most water is reabsorbed within a nephron in the ________ ______

Proximal tubule

A rise in angiotensin II levels would result in:

-elevated blood pressure
-increased retention of sodium ions at the kidney
-increased water retention
-increased blood volume
-all of the above

all the above

The primary function of the descending leg of the Loop of Henle in the kidney is to do what?

Reabsorb water

Calculate the net filtration pressure if the hydrostatic pressure in the glomerulus is 53 mm Hg, the colloid oncotic pressure is 33 mm Hg, and the pressure of the filtrate in Bowman's capsule is 12 mm Hg. Report your value to the nearest whole mm Hg.

53-33-12= 8 mmHg

Uncontrolled Diabetes Mellitus produces many homeostatic imbalances, including acidosis. The pH imbalance is due to ketoacidosis, which results from an excessive accumulation of byproducts of fat metabolism, as the body cannot meet its energy needs from carbohydrate metabolism. Sally is a teenage diabetic who sometimes rebels by not taking her insulin. Her body is just beginning to develop ketoacidosis as a result. What is happening to her blood pH and HCO3-?

Decreasing pH, decreasing HCO3-

ADH has what effect on the distal convoluted tubule of the kidney?

Increases water re-absorption

A person who suffers from emphysema will primarily exhibit signs of ___________ ________

Respiratory acidosis

The enzyme that catalyzes conversion of H2O and CO2 to H2CO3 is called ________ _________

Carbonic anhydrase

Insulin is secreted by specific what in the pancreas?

Endocrine cells (called beta cells)

Of the hormones in the hypothalamic-pituitary-adrenocortical axis, the non-CNS targets of __________ respond most slowly because their primary responses involve changes in gene expression.

Cortisol

The secretion of what hormone in the hypothalamic-pituitary-adrenocortical axis is a direct consequence of its source cells firing action potentials?

Corticotropin-releasing hormone

The ________________ and _________________ effects of cortisol and drugs that mimic its actions refer to its effects on cytokine release, antibody production, and leukocyte migration.

anti-inflammatory; immunosuppressant

Prolonged vomiting of the stomach's contents can cause what?

It can cause Metabolic alkalosis

Dan has been lost in the desert for two days with very little water. As a result, you would expect to observe what?

Elevated ADH levels

The amount of filtrate entering the proximal tubules of the kidneys each minute is called the what?

GFR (Glomerular filtration rate)

When the pH rises above 7.45, a state of __________ exists.

Alkalosis

When the pH falls below 7.0, a state of __________ exists.

Acidosis

In response to an aspirin (acetylsalicylic acid) overdose, you would expect to observe which acute compensatory response?

Increased alveolar ventilation

The approximate osmolarity of filtrate in the proximal tubule is

300 mOsM

Urine passes from the kidney to the urinary bladder through a pair of _______.

Ureters

The Bowman's capsule is the site of plasma __________ with that glomerulus; together referred to as the what?

Filtration; renal corpuscle

The adrenal cortex contains:

All of the Bowman's capsules, proximal and distal tubules

The medulla contains:

The loops of Henle and collecting ducts

Filtration occurs at the what?

At the Renal corpuscle

Secretion is

the materials from the blood into the lumen of the tubule

The approximate osmolarity of filtrate in the Loop of Henle is

100 mOsm

The approximate osmolarity of filtrate in the distal tubule and collecting duct is

100-200 mOsm, depending on the hydration state

What is the function of the Renal Corpuscle (glomerulus+Bowman's capsule)

Filtration of mostly protein free plasma from the capillaries into the capsule

What are the three pressure influences for glomerular filtration?

-Capillary blood pressure (PH)
-Capillary colloid osmotic Pressure (pi)
-Capsule fluid pressure (P fluid)

Glomerular filtration rate (GFR) is defined as

Volume of fluid filtered per unit time

GFR is influenced by

net filtration pressure and filtration coefficient

Increased resistance in afferent arterioles decreases or increases GFR?

Decreases GFR

Increased resistance in Efferent arterioles decreases or increases GFR?

Increases GFR

Decreased resistance in afferent arterioles decreases or increases GFR?

increases GFR

Decreased resistance in efferent arterioles decreases or increases GFR? (low caps)

decreases GFR

Vasoconstriction of the afferent arterioles

Increases resistance and decreases renal blood flow, capillary blood pressure (PH), and GFR

Increased resistance of efferent arteriole

Decreases renal blood flow, increases capillary blood pressure (PH) and GFR.

Reabsorption is the active transport of what?

Of Na+

Na+ is pumped out by sodium-linked reabsorption through which ions?

Na+, K+, and ATPase

Glycosuria or glucosuria is

glucose in the urine, and the body will filter the water

Peritubular capillary pressures favor what?

They favor Reabsorption

Secretion is important in homeostatic regulation of which two ions?

K+ and H+

Increasing secretion increases what?

Nephron excretion

Clearance is a ___________ way to measure GFR

Noninvasive

______ and ___________ are used to measure GFR

Inulin, creatinine

__________ is the breakdown product of phosphocreatine

Creatinine

Clearance of X is less than GFR =

Net absorption of X

Clearance of X is greater than GFR =

Net secretion of X

Clearance of X is equal to GFR=

X is neither reabsorbed nor secreted

___________ is the process of urination

micturition

What are the two sphincters that control urine flow?

Internal and external sphincters

Parasympathetic fibers in a simple spinal reflex do what?

Induce bladder smooth muscle contraction

Sympathetic neurons in a simple spinal reflex to the external sphincter are what?

They are inhibited

Glucose is reabsorbed across the apical membrane in the proximal tubules by what?

Secondary transport

Which of the following hormones would you expect to be the most lipophilic?

Aldosterone

Which of the following cortisol hypersecretion scenarios points to an example of a primary endocrine disorder?

A adrenal tumor leading to increased cortisol, but decreased CRH and ACTH secretion

What is the primary route for excreting ions and water?

The kidney

In fluid and electrolyte homeostasis the lungs lose _____ and ______ via ____

water, bicarb, CO2

ECF (extracellular fluid) osmolarity affects what?

affects cell volume

The respiratory and cardiovascular systems induce a _____ response under ______ control

rapid, neural

The kidneys induce a ___ response under endocrine/_____________ control

slow, neuroendocrine

If body fluid volume falls too short what stops?

GFR stops

The primary function of the ascending limb of the Loop of Henle in the kidney is the reabsorption of what?

Of ions

The primary function of the distal tubule and collecting duct in the nephron is the reabsorption of what?

of water and solutes

Low osmolarity causes

-Lack of thirst -> decreased water intake
-Decreased ADH release -> water lost in the urine due to high water

High osmolarity causes

-thirst (increased water intake)
-ADH release (water reabsorbed from urine)

Diuresis is what?

removing excess water in urine

How does the fluid in the descending limb of the loop of Henle lose water?

By osmosis to the medulla

Cells in the thick portion of the ascending limb of the loop are ___________ to _____ and actively transport Na+ out of the lumen into the medulla

Impermeable, water

Vasopressin is also known as

Arginine vasopressin (AVP) or antidiuretic hormone (ADH)

Vasopressin only acts on what?

On the Collecting ducts

If blood volume and blood pressure decrease what is the reaction of the kidneys?

Conserving salt and water to minimize further volume lost

The loop of Henle results in what?

Greater ECF osmolarities

What does the vasa recta do?

-Returns water that was reabsorbed from the filtrate back to the bloodstream
-Removes water

When kidneys excrete salt and water what is the response rate?

It is a Slow response

When the cardiovascular reflexes lower blood pressure what is the response rate?

It is a Rapid response

Angiotensin-converting enzyme (ACE) converts

Angiotensin I to angiotensin II

Extra NaCl raises osmolarity which causes

The release of Vasopressin, water conservation, and thirst.

Aldosterone targets what cells?

Principal cells (P cells)

ANG II stimulates

The adrenal cortex to produce aldosterone

ANG II increases blood pressure through which pathways?

Vasopressin secretion, thirst, and vasoconstriction

What happens when ANG II receptors are activated?

Increases sympathetic output to the heart and blood vessels

ANG II increases the absorption of what ion in what tubule?

Sodium in the proximal tubule