Excretory System Not On Nov 10

Front 1

Bladder: Detrusor (smooth muscle)

Back 1

-parasympathetic (causes contraction)
-during filling: inhibited
-during micturition: stimulated

Front 2

Bladder: Internal Urethral Sphincter

Back 2

-sympathetic (causes contraction)
-during filling: stimulated
-during micturition: inhibited

Front 3

Bladder: External Urethral Sphincter

Back 3

-somatic motor (causes contraction)
-during filling: stimulated
-during micturition: inhibited

Front 4

Renin-Angiotension system

Back 4

Liver: secretes angiotensinogen
Kidneys: secrete renin
- renin convertes angiotensinogen to Angiotensin I
- a converting enzyme converts it to Angiotensin II
- the Angiotensin II has a positive feedback and makes the adrenal cortex secretes aldosterone
- aldosterone enters the blood

Front 5

An abnormal increase
in blood volume “stretches out” the atria, stimulating
secretion of ANP (atrial natriuretic peptide).

Back 5

ANP promotes vasodilation, thus increasing GFR, and inhibits sodium reabsorption in the distal tubule, leading to natriuresis (increased levels of sodium in urine), which increases urine volume as it decreases blood volume.

Front 6

An abnormal decrease
in blood volume and pressure

Back 6

activates baroreceptor neurons in the aorta and carotid sinuses, leading to increased secretion of vasopressin, also known as anti-diuretic hormone (ADH); which increases water permeability in the collecting ducts, which decreases the volume of excreted urine.

Front 7

Drinking too much water

Back 7

causes an abnormal decrease in fluid osmolarity, which alters the activity of
hypothalamic osmoreceptors,
which then reduces activity of ADH neurons, leading to decreased secretion of ADH; water permeability in the collecting ducts is reduced, thus increasing the volume of excreted urine, a condition called diuresis.

Front 8

Severe loss of body water

Back 8

decreases GFR and increases levels
of aldosterone, vasopressin, and angiotensin II (not shown);
these adaptive responses act to promote water conservation
in the renal system to help restore blood volume and pressure.

Front 9

Decreased blood volume
and ingesting too much
potassium

Back 9

both stimulate
aldosterone secretion from
the adrenal cortex;
aldosterone increases
sodium reabsorption at
the “expense” of increased
potassium secretion.

Front 10

Bicarbonate Handling

Back 10

-The excretion of a bicarbonate in the urine increases the plasma hydrogen-ion concentration just as if a hydrogen ion had been added to the plasma.
-The addition of a bicarbonate to the plasma lowers the plasma hydrogen-ion concentration just as if a hydrogen ion had been removed from the plasma.
-HCO3- excretion = HCO3- filtered + HCO3- secreted - HCO3- reabsorbed
-For simplicity the bicarbonate secretion is ignored because it is always quantitatively much less than tubular reabsorption.
-Thus bicarbonate excretion is treated as the difference between filtration and reabsorption.

Front 11

Osteoblasts and Osteoclasts

Back 11

-Osteoblasts build bone.
Osteocytes have long
processes that connect
with each other and to
osteoblasts via tight
junctions.
-Osteoclasts catalyze bone degradation, when stimulated by
parathormone (PTH).

Front 12

The four parathyroid glands are located adjacent to the much larger thyroid gland.

Back 12

-Secretion of
parathormone (PTH)
is a direct response
to an abnormal
decrease in the
concentration of
calcium ions.
-Parathormone’s action to restore normal calcium levels include increased calcium reabsorption in the kidneys, increased calcium-liberating activities of osteoclasts, and increased formation of vitamin D, which increases uptake of dietary calcium in the gastrointestinal tract.

Front 13

Activated 1,25 (OH)2D3

Back 13

is a
steroid hormone that causes
cells in the gut to increase
the expression of genes
whose products
take up dietary calcium.