ANSC 300 Quiz 9

What occurs to the vascular network when the volume of water it not regulated?

Too little water = failure of blood flow

Too much water = vessels burst

What occurs to the vascular network cells when the concentration of salt it not regulated?

Too concentrated = cells shrink

Too dilute = cells burst

How is solute concentration adjusted in the cells?

Removing Na ions, BUT not H2O

In the kidney, how is the volume of solution controlled?

Adjusting H2O loss

What is the relationship between volume of solution and blood pressure in the body?

Increased volume = high blood pressure

Decreased volume = low blood pressure

What is the unique way camelids can produce heat tolerance in hot environments?

Can increase and decrease body temp during day and night and lose 25% of body water and drink it all back with no side effects

What is the relationship between salt concentration vs. H2O when regulating blood pressure?

Increase salt = increased H2O

Decreased salt = decreased H2O

What are the 3 main functions of the kidney?

1. Flitration

2. Detox

3. Cardiovascular homeostasis (blood pressure)

What are the 3 endocrine signals that impact the function of the kidney?

1. Erythropoietin

2. Vitamin D3

3. Renin

What are the 6 structures that urine will flow through in the kidney before reaching the renal pelvis?

1. Glomerulus (surrounded by Bowman's capsule)

2. Proximal tubule

3. Descending loop of Henle

4. Ascending loop of Henle (thin + thick)

5. Distal tubule

6. Collecting duct

What is the purpose of the glomerulus in the renal system?

Filters out plasma from blood flowing through to get the proteins and cells out

What are the 2 blood vessels that flow through the glomerulus and where do they end up going?

Afferent arteriole- high pressure since blood is carried into glomerulus

Efferent arteriole- blood flowing to nephron from the glomerulus

What is the purpose of fenestrations in the capillaries of the of the glomerulus?

Allows exit of plasma, BUT not proteins or cells

What are the 2 factors that impact the production of renin from the JG (juxtaglomerular) cells?

Macular densa salt concentration decrease + afferent arteriole pressure

What is the use of the capillary concurrent between the blood and the secretent (urine) around the Loop of Henle?

Allows blood to pick up proteins and nutrients that were taken in the glomerulus earlier

What is the movement of H2O and sodium/salt through the loop of henle and the collecting duct associated with urine movement?

1. H2O diffuses out osmolarity increases moving down the descending loop of henle tubule

2. Na+ diffuses out while H2O remains within the thin ascending loop of henle tubule

3. Na+ is pumped out while H2O remains within the thick ascending loop of henle tubule

4. Everything stays within the collecting duct unless AVP/ADH is present which will make it permeable to H2O

What are the 4 hormones/ hormone systems that control blood volume?

1. Renin-Angiotensin 2-Aldosterone system

2. AVP/ADH (vasopressin + antidiuretic)

3. Angiotensin 2

4. ANP/ANF (peptide factors)

What are the 3 hormones that control salt concentration?

1. Aldosterone

2. ANP

3. Angiotensin 2

What are the 2 common hormones that control vascular resistance, vasoconstriction or vasodilation?

AVP- causes vasoconstriction to increase blood pressure

Angiotensin 2

What type of receptor controls the release of vasopressin's when sodium concentrations cause cells to change shape?

Osmoreceptors detect cell expansion/shrinking from varying sodium concentrations to call ADH into action

What is the other type of receptor used to control the release of vasopressin's into action?

Baroreceptors found in large arteries will sense stretching of vessels when volume decreases to call AVP into action

What is the definition of osmolality when discussing renal function?

Measure of solute concentration in osmoles/kg in solution

What hormone are associated with the V1 and V2 receptors and where are the common places to find these receptors?

V1- AVP used to increase vasoconstriction which will increase blood pressure

V2- ADH used to add aquaporins into collecting duct for water permeability when dehydrated

What are the 3 polypeptides that make up the prepro-vasopressin gene structure?

1. Vasopressin

2. Neruophysin 2

3.Glycoprotein

Since neruophysin has no distinct biological activity, what is its purpose in renal function?

Stabilizes VP (vasopressin)

What is the mutation to neurophysin 2 that causes autosomal dominant neuropophyseal diabetes insipidus?

Cystine 73 change to phenylalanine which disrupts disulfide bridge between Cys73 + Cys61

What is diabetes insipidus and what are the 2 types?

Excessive loss of water

1. Central- lack of AVP secretion

2. Nephrogenic- nephron doesn't respond to AVP

How does an animal get central or nephrogenic diabetes insipidus?

Central

- NP2 mutation

- head truama

- tumor

Nephrogenic

- receptor malfunction via hereditary X-linked recessive

What are the common treatments of central + nephrogenic diabetes insipidus?

Central

- adequate hydration

- infusion of hypotonic solution

- vasopressin therapy

- mild salt depletion

Nephrogenic

- adequate hydration

- mild salt depletion

- non-steroidal anti-inflammatory drugs

What is the process and structures invloved in the production of angiotensin 2?

1. Renin made from JG cells

2. Angiotensinogen is made from the liver

3. Renin converts angiotensin into angiotensin 1

4. Angiotensin 1 is converted into angiotensin 2 which has numerous effects on the renal system

What are all of the actions of angiotensin 2 on the kidney, adrenal gland, heart, hypothalamus, and the arterioles?

Kidney

- increased sodium absorption

Adrenal

- increased aldosterone secretion

Heart

- contractility

Hypothalamus

- increased thirst

- increased salt appetite

- ADH secretion

Arterioles

- increased vascular resistance (vasoconstriction)

What is the 2 actions of direct stimulation of angiotensin 2 in the kidney?

Na uptake by kidney cells in exchange for H+

Na export from basal side of cell via sodium potassium pumps

What kind of cells are stimulated by angiotensin in the adrenal gland instead of ATCH?

Z. Glomerulosa

What is the purpose of aldosterone in the kidney?

Stimulates sodium retention resulting in potassium excretion to increase blood volume when low pressure is sensed

How does angiotensin 2 biologically increase the production of aldosterone?

Angiotensin 2 stimulate StAR production which responsible for allowing cholesterol into the mitochondria to be converted into aldosterone from pregnenolone

What are the two changes that occur within the blood that result in aldosterone secretion in order to correct them?

Blood potassium + blood volume changes

What are the acute effects of aldosterone on the kidney regarding Na transport?

- Aldosterone block degradation of Na channels to allow for more Na to be retained

- Stimulates Na/K pump

What is the overall chronic effect of aldosterone in the kidney?

Increased expression of E-Na-C and Na/K pumps to decrease Na concentration and increases ATP that is used for powering the pumps

What are the 2 hormones that bind to the mineralcorticoid receptor in order to make cortisone?

Aldosterone + Cortisol

What does the 11beta HSD 2 mutation cause to occur regarding the mineralocorticoid receptor and renal function?

Causes an increase in aldosterone and cortisol which would elevate Na and H2O levels resulting in high blood pressure

What is the overall effect of the renin-angiotensin-aldosterone system regarding what hormone does in the body and what occurs overall?

1. Blood pressure is low as sensed by the JG cells around the afferent arteriole

2. Changes in pressure sensed by JG cells causes a release of renin

3. renin with angiotensinogen converts into angiotensin 2

4. Angiotensin 2 causes vasoconstriction to increase the low blood pressure

5. Angiotensin release stimulates aldosterone production which causes Na to be retained to increase blood volume + pressure

6. Angiotensin 2 also stimulates CNS to intake more H2O using ADH

Since it is well know how to handle low blood pressure, what are the hormones that handle high blood pressure/high blood volume?

ANP (atrial natriuretic peptide) or ANF (atrial natriuretic factor)

How do ANP/ANF function to actually stabilize higher blood pressure/volume?

They will decrease the function of the renin-angiotensin-aldosterone pathway which results in decreased Na+ retention and increased salt + water excretion to decrease blood volume in order to decrease blood pressure