Lec 21 Ion and Water Balance 2

Vasopressin/Antidiuretic Hormone (ADH)

The concentration of the urine depends on the amount of ______ in the blood stream.

enhanced

H2O reabsorption is _______ by Antidiuretic Hormone (ADH), also called vasopressin

late distal tubule/collecting ducts

ADH acts on epithelial cells of the _________ and the _________ to increase the number of aquaporin channels on the apical membrane.

aquaporin channels/apical

ADH acts to increase the number of _______ on the ______ membrane.

ADH/impermeable

In the absence of ___, these tubules are almost completely ______ to water

bloodstream

The concentration of the urine depends on the amount of Vasopressin/Antidiuretic Hormone (ADH) in the ________

Plasma osmolarity

the concentration of solutes in the blood

receptors/hypothalamus

Plasma osmolarity is monitored by _______ in the _______

dehydration/hypothalamus

If the plasma osmolarity increases, which can occur due to _______, the ________ detects the higher concentration of solutes (such as sodium).

thirst

Hypothalamus also has an area responsible for generating sensation of ______

blood pressure/plasma osmolarity

Both low ______ and high _______ lets the hypothalamic neurosecretory cells to start pathway to release ADH

Carotid/aortic/stretch/medulla

_______ and _____ baroreceptors respond to ______ (blood pressure): axons go to cardiovascular center in _______, which has neurons projecting to the hypothalamus.

pituitary gland

ADH is released by the posterior ______

Aldosterone

Hormone secreted by the adrenal cortex that increases number of Na+/K+ ATPase pumps on basolateral membrane

Adrenal cortex

Adolsterone is released by the _____

collecting ducts/Na+/K+ ATPase pumps

Adolsterone acts on the epithelial cells of the ________ to increase the number of _________ on the basolateral membrane

K+/Na+

Adolsterone causes more ___ to be secreted into urine and more ____ to be reabsorbed

K+ channels/apical

Not only does adolsterone increase Na+/K+ ATPase pumps on the basolateral membrane, but also _____ on the ______ membrane.

Parathyroid hormone

Hormone secreted by parathyroid glands

distal tubule/Ca2+

Parathyroid hormone acts on the epithelial cells of the ______ to increase ____ reabsorption

Bone

To remedy decreasing blood Ca2+, parathyroid hormone can increase blood Ca2+ via the kidneys, but also by the dissolution of CaPO4 crystals in _____

deamination/ammonia

The amino group (NH₂) is removed from the amino acid during ______. The amino group is converted to _______, which is toxic at high levels, so it needs to be excreted or converted into less toxic forms.

Fish

_____ can excrete ammonia directly into the surrounding water

Mammals

_______ excrete ammonia by converting it into urea in the liver and then excreting urine

Birds

____ convert ammonia and excrete it as uric acid

H+ ions

Metabolic processes lead to the production of _____

HCO3-

_____ in the blood buffers acid load so blood pH doesn’t drop

kidney/HCO3-

The ____ makes _____ to replace that which is lost buffering the H+ ions

buffering

If bicarbonate (HCO3-) was not replaced continuously, the ______ capacity of the blood would be lost.

Phosphate buffer

______ prevents urine from becoming acidic

proximal/distal/carbonic anhydrase

In the _____ and _____ tubules, H2O and CO2 are being converted into H+ and bicarbonate by _______.

HCO3-/Cl-/HCO3- exchanger/Cl-

After carbonic anhydrase converts in the tubular epithelial cells, the _____ is moved into circulation (blood) via ___________ (uses concentration gradient of ____).

H+/H+ ATPase

After carbonic anhydrase converts in the tubular epithelial cells, the ___ is secreted into the urine by active transport (_______)

metabolic

The bicarbonate ion in blood used to mop up free H+ produced by ______ processes throughout body

collecting duct

In addition to the proximal and distal tubules, additional reabsorption of HCO3 - occurs in the _______

juxtaglomerular apparatus

Specialized structure in the kidney, made up of cells that surround the afferent arteriole and secrete renin when blood pressure decreases

Renin

Cells in the juxtaglomerular apparatus secrete ______ when BP is low

Renin-Angiotensin System

Hormonal system that regulates long-term blood pressure and body fluid volume by involving the kidneys, liver, lungs, and adrenal glands

Juxtaglomerular cells/stretch receptors

________ in the walls of the afferent arterioles receive information about blood pressure from __________

angiotensinogen

Inactive precursor protein produced by the liver waiting to be activated by renin

Angiotensin I

Renin converts Angiotensinogen to _______

Angiotensin-converting enzyme

Enzyme that converts Angiotensin I to Angiotensin II

Angiotensin II

Hormone that causes vasoconstriction and aldosterone release from the adrenal gland

vasoconstriction/aldosterone

Angiotensin II (hormone) causes ________ and _________ release from the adrenal gland

salt/water/blood pressure

In the angiotensin system, once aldosterone is released, it leads to _____ and ____ retention, which also increases _______

Starling Equation for Net Glomerular Filtration Pressure

P_GC - P_BS - pi_GC = Net glomerular filtration pressure

P gc

Glomerular capillary blood pressure, favors filtration

P bs

Fluid pressure in Bowman’s space, opposes filtration

pi gc

Osmotic force due to protein in plasma, opposes filtration

0

The osmotic force of the Bowman’s capsule (π BS) is typically __

Glomerular Filtration Rate

Volume of fluid that enters Bowman’s capsule per unit time

GFR formula

GFR = Rate of urine (ml/min) x (Urine concentration of solute (mol/ml))/(Plasma concentration of solute (mol/ml))

Rate of urine

The volume of urine produced by the kidneys per minute. (for GFR calculations)

Urine concentration of solute

The concentration of a specific solute in the urine. (for GFR calculations)

Plasma concentration of solute

The concentration of the same solute in the blood plasma. (for GFR calculations)

filtered/reabsorbed/secreted

When calculating GFR, the solute needs to be something that is ______ but then neither ______ nor _______, otherwise will not get accurate measure of GFR

Inulin

A substance that is freely filtered but neither reabsorbed nor secreted. It requires constant intravenous infusion into the patient over several hours. This is an invasive procedure but gives a very accurate measurement of GFR.

creatinine

A metabolite of creatine (found in muscle cells). It is a commonly used solute to estimate GFR because it is filtered by the kidneys, but only a small amount is secreted into the urine.

Experimental/metabolic

Unulin is a ______ solute while creatinine is a _____ solute

secreted/urine

Creatinine has no reabsorption but a small amount is ______ into the _______

invasive

Creatinine is less ______ than metabolic but slightly less accurate than inulin

afferent arteriole/efferent arteriole

If GFR is low, _____ constricts and _____ dilates

efferent arteriole/afferent arteriole

If GFR is high, ______ constricts and _____ dilates

Landd

The ability to control internal osmolarity independent of external conditions was essential for the success of the animal lineages that invaded ____

Kidney/malpighian tubules/gills/salt glands

Osmoregulatory Organs:

1. ______

2. ______

3. ______

4. ______

length/kidney medulla/urine

The ______ of the loops of henle correspond to the thickness of the _______ and the ability to concentrate _______

concentration gradient/water

The longer the LOH the larger the _________ in the medulla and the more _____ can be reabsorbed

Long/concentration/Kangaroo Rat

_____ Loops of Henle allow the extreme _________ of urine in the Desert ________

Malpighian Tubule

Site of urine formation in insects

secretion

Most ______ occurs in the Malpighian tubules, producing the primary urine

reabsorption/rectum

Unlike vertebrates, most water and ion _______ occurs in the ______ for insects

midgut/hindgut

The malpighian tubules can be used as a landmark to distinguish between the _____ and ______

Principal/stellate

The malpighian tubules is made up of ______ cells and _____ cells

Principal cells

Cells found in the malpighian tubules that have microvilli, many mitochondria to power active transport of positively charged ions into the lumen of the tubule

Stellate cells

Cells found in the malpighian tubules that mainly function in secreting Cl-

microvilli/mitochondria/positive ions

Principal cells have ______ and many ______ to power active transport of ______ into the lumen of the tubule

Aquaporins

Both principal and stellate cells have ________

water/salts

Freshwater fish are in constant danger of taking on too much ______ and diluting necessary body ______

permeability/water

To combat taking on too much water, freshwater fish have low ________ of skin to ________

drink

To combat taking on too much water, freshwater fish don’t _____ water

dilute

To combat taking on too much water, freshwater fish produce a _____ urine

reabsorb

To combat taking on too much water, freshwater fish actively _____ salts

salty

To combat taking on too much water, freshwater fish ingest ______ foods

Na+/gills

To combat taking on too much water, freshwater fish actively pump ___ from water into cells in ______

permeability

Similar to freshwater fish, marine fish have a low ______ of skin to water

seawater/salts/gills

Marine fish drink lots of _______ and then activelly secrete ____ through ____ into water

losing/excess

Air Breathing Marine Animals are in constant danger of ______ water to the environment and taking _____ salt

Marine fish/salt/salt glands

Air breathing marine animals have similar adaptations to _______. For example, air breathing marine animals actively secrete ___ with _______

hyperosmotic

Salt glands produce _________ secretions

high salt

Salt glands allow survival in ______ environments