Anatomy II: CH 25 and 26 Urinary and Fluid Acid Base

During reabsorption in the nephron, substances move from the tubules to the ________.

peritubular capillaries

Reabsorption is VERY selective unlike _____.

filtration

How much urine can you make a day?

800 milliliters to 2 liters of urine per day

Sodium (Na+) reabsorption is controlled by the hormone _______.

aldosterone

Aldosterone is a hormone secreted by the…

outer part (cortex) of the adrenal glands.

If body needs more sodium (Na+) more ________________ is secreted.

aldosterone

In the proximal convoluted tubule, water reabsorption is driven by…

sodium reabsorption and is considered obligatory

_______ means “has to happen”.

Obligatory

The blood in the peritubular capillaries becomes ______ as it takes up salt (under the influence of aldosterone in the tubular system).

hypertonic

As salt (Na+) is shipped out of the very permeable membrane that makes up the PCT, _____________ will follow salt (Na+) out because of ____________.

water; osmosis

Water follows…

salt

As more water moves into the vessels, blood pressure increases, similar to how more water in a garden hose causes water pressure to increase. This is due to:

the increased volume of fluid in the vessels

As more H₂O moves into the vessels, blood pressure will _____—just like more water in a garden hose causes water pressure in the hose to increase.

increase

Cells in the ________ detect BP changes.

juxaglomerular apparatus

Juxaglomerular apparatus cells secrete _____ that causes the plasma protein angiotensinogen to be transformed into angiotensin.

renin

______ signals the adrenal cortex to secrete aldosterone.

Angiotensin

Amount of water reabsorbed in the collecting duct depends on a hormone made by the _______ and released by the _______.

hypothalamus; pituitary gland

What does antidiuretic hormone (ADH) do when your body needs more water?

Tells the DCT and collecting duct to reabsorb more water

Total body water is a function of ____, ____, and ____.

age, body mass, and body fat

The body water content of infants is approximately:

73%

The body water content of men is approximately:

60%

The body water content of women is approximately:

50%

The body water content of old age is approximately:

45%

For the body to remain properly hydrated, water ___ must equal water ___.

in; out

Most water enters the body through ingestion, but is also produced by ________.

cellular metabolism

______ makes us thirsty.

Hypothalumus

A decrease in _______ triggers the thirst mechanism, leading to a dry mouth as a signal to drink water

plasma osmolarity

The amount of water reabsorbed in the renal collecting ducts is directly proportional to the release of:

antidiuretic hormone (ADH)

When ADH levels are low, most water in the collecting ducts is not reabsorbed, leading to…

large quantities of dilute urine

When ADH levels are high, water is reabsorbed, resulting in…

a lower volume of concentrated urine.

ADH secretion is regulated by the hypothalamus in response to changes in:

solute concentration of extracellular fluid, blood volume, or pressure

4. If more water is still needed the ______ signals cells in DCT & the collecting duct of the tubule system to conserve water.

antidiuretic hormone

_______ occurs when water output exceeds water intake

dehydration

________ is a result of renal insufficiency, or intake of an excessive amount of water very quickly.

hypotonic hydration

______ is the accumulation of fluid in the interstitial space, which may impair tissue function.

edema

_____ is the most important cation in regulation of fluid and electrolyte balance in the body.

Sodium

A change in sodium levels causes a shift in water, affecting:

plasma volume, blood pressure, and fluid volumes

High aldosterone secretion leads to nearly all filtered sodium being reabsorbed in the:

distal convoluted tubule and collecting duct

The most important trigger for the release of aldosterone is the _______ mechanism.

renin-angiotensin

_______ is a plasma protein made by the liver and constantly circulates in blood

Angiotensinogen

Renin converts ______ to ______.

Angiotensinogen ; angiotension I

Where is Angiotensin-converting enzyme (ACE) located?

in capillaries of lungs and other tissues

Angiotensin-converting enzyme (ACE) Converts angiotensin I to _____.

angiotensin II

What 3 mechanisms regulate acid base balance?

1. BUFFER SYSTEMS

2. EXHALATION of CO2

3. SECRETION of H+ ions by KIDNEY

The _______ is the main buffer of the extracellular fluid, and consists of carbonic acid and its salt, sodium bicarbonate.

bicarbonate buffer system

The _______ operates in the urine and intracellular fluid similarly to the bicarbonate buffer system.

phosphate buffer system

The protein buffer system helps regulate pH by:

releasing H+ when pH rises and binding H+ when pH declines

Usually low pH is the troublecalled _____.

acidosis

When breathing is inadequate, carbon dioxide (respiratory acid) accumulates, leading to:

respiratory acidosis

The extra CO2 molecules combine with water to form ______ which contributes to an acid pH.

carbonic acid

If all else fails, the treatment for elevated respiratory acidosis is to:

lower the PCO2 by using a ventilator

Metabolic acidosis can occur when normal metabolism is impaired, leading to the formation of:

lactic acid

In severe cases of metabolic acidosis, treatment may involve:

neutralizing excess acid with bicarbonate or allowing time for excretion/metabolism

____ in the brainstem control the rate and depth of breathing

centers

Increasing the rate and depth of breathing helps to decrease carbonic acid formation by:

Removing CO2 from the blood

Kidneys remove excess ___ ions and excrete them in the urine

H+

Only the _____ can rid the body of acids generated by cellular metabolism

kidneys

Bicarbonate ion reabsorption is dependent on:

H+ secretion

Special cells of the ______ can synthesize new bicarbonate ions while excreting more hydrogen ions.

renal tubules