BIOL 2710 Exam 4

organs of the urinary system

kidney, ureter, bladder, and urethra

kidney role in the urinary system

main organ, filters waste out of blood, reabsorption of nutrients from urine, and secretion of wastes into urine, maintains blood pH, ion balance (including sodium and potassium), and water balance

ureter role in urinary system

transports urine to bladder and conducts waste from kidney to bladder

bladder role in urinary system

store urine prior to elimination

urethra role in urinary system

transport urine out of body and conducts waste from bladder to the outside of the body

overall functions of the urinary system

filtration, reabsorption, secretion, maintains water balance, maintains blood pressure, maintains ion balance and osmolarity, maintains pH, and eliminates metabolic wastes

characteristics of elimination of metabolic wastes in the urinary system

excess nitrogen from deamination of amino acids during protein metabolism are eliminated as urea, uric acid from nucleic acid metabolism, and creatine from creatine phosphate

characteristics of maintaining pH in the urinary system

kidney is the main regulator of pH in the body and it eliminates or retains H+ ions

characteristics of maintaining ion balance and osmolarity in the urinary system

retains needed ions and eliminates excess ions

characteristics of maintaining blood pressure in the urinary system

water balance and secretes renin which triggers the RAAS system

characteristics of maintaining water balance in the urinary system

restricts water loss in urine and contributes to regulation of blood pressure

characteristics of secretion in the urinary system

tubules secrete additional wastes into urine including hydrogen ions, NH₃ (ammonia), and uric acid

characteristics of reabsorption in the urinary system

tubules of the nephron recover or reabsorb useful molecules from the filtrate including glucose, ions, and water

characteristics of filtration in the urinary system

kidney filters blood plasma at the glomerulus of the nephron

where is urea (water soluble) filtered from?

the blood in your kidneys

what occurs when amino acids are used for energy or taken apart to store the energy in them?

the amine group (NH₂) is stripped off and the group will pick up another H+ to make ammonia,

define waste

any substance that is useless to the body or present in excess of the body’s needs

define metabolic waste

waste substance produced by the body

urea formation

proteins → amino acids → NH₂ removed → forms ammonia, liver converts to urea

what is uric acid a product of?

nucleic acid catabolism

what is creatine waste (creatine phosphate) from?

muscle metabolism

pathways of excretion in the bodu

sweat, fecal matter, respiration, and urinary system

sweat excretion in the body

removes uric acid, ammonia, urea, lactic acid, and water

fecal matter excretion in the body

undigested components of food and excess ions

respiration excretion in the body

CO₂, water, and alcohol

in the ______ section, the kidney is shown to have an outer cortex and an inner medulla

coronal

what does the medulla in the kidney consist of?

a series of pyramidal shaped tissue separated by extensions of the cortex tissue (renal columns)

where does each pyramid of the kidney empty into?

a minor calyx

several calyces gather in a ______ ______

major calyx

all the major calyces empty into the ______ _______ via renal papillae, which exits the hilum as the ureter

renal pelvis

ch 23 slide 19

ch 24 part 1 1-22

what causes retention of electrolytes in the interstitial tissue?

increased aldosterone levels causes more sodium reabsorption and retention (to conserve water loss)

true or false: albumins, blood proteins, are the first to go when hungry and are negtatively charged

true

what do decreases in blood albumin levels cause?

increases in cations and decreases in anions in the interstitial fluid from malnutrition, kidney disease, or liver disease

what does albumin in the interstitial tissue cause?

an increase in cations and a decrease in anions to the interstitial fluid from damaged capillaries due to injury or infection

what chemical reactions are ions involved in in the body?

calcium in blood clotting and protein and enzyme formation

what does the ability of an ion to react chemically depend on?

the presence of competing or inhibiting ions

the ability of an ion to react chemically with ions they are supposed to react with depends on their _____

charge

charge of a monovalent ion

one

charge of a divalent ion

2

charge of a trivalent ion

3

a __________ ion is more reactive than a monovalent

divalent

divalent ions are counted as two __________ ions

monovalent

three ways we take in water and by how much

drinking (1500 mL/day), foods (700 mL/day), and catabolism (200 mL/day)

what does oxidative metabolism result in?

water being created when oxygen accepts the electrons and combines with hydrogen

oxidative metabolism equation

C₆H₁₂O₆ + 6 O₂ → 6 CO₂ + 6 H₂O

ways we lose water and by how much

lungs (350 mL/day), skin permeability (350 mL/day), sweat (100 mL/day) urine (1400 mL/day), and feces (200 mL/day)

typical water intake and output is ___________ mL/day

2,500

water intake and water loss must _________ out and the __________ maintain that balance.

balance, kidneys

kidneys compensate very well for ________ fluid intake, but not for __________ fluid intake.

excessive, inadequate

what does a blood pressure decrease or a decrease in plasma Na+ stimulate?

juxtaglomerular cells in the kidney to secrete renin which is converted to angiotensinogen in the blood to angiotensin l which is converted in the lungs to angiotensin ll

angiotensin ll roles

increases aldosterone production in the adrenal cortex, ADH production in the hypothalamus, and vasoconstriction. also acts on the brain to cause thirst

what is sodium needed for?

sodium co-transport, nerve signal transmission, muscle and heart contraction, blood clotting, and maintenance of cell volume

hypernatremia

plasma sodium concentration greater than 145 mEq/L, from administration of lV saline, water pretension, hypertension, and edema

hyponatermia

plasma sodium concentration less than 130 mEq/L, person loses large volumes of sweat or urine, replacing it with drinking water, result of excess body water, quickly corrected by excretion of excess water

functions of potassium

produces (with sodium) the resting membrane potential and action potential of nerve and muscle cells, most abundant cation of ICF, greatest determinant of intracellular osmolarity and cell volume, and essential cofactor for protein synthesis and other metabolic processes

Na+-K+ pump use

pumps 3 sodium ions out and 2 potassium ions in, for cotransport, thermogenesis (basal metabolism), and in potassium balance

___________ homeostasis is closely linked to that of sodium

potassium

_____% of K+ in glomerular filtrate is reabsorbed by the PCT and the rest is excreted in urine

90

what does the DCT and cortical portion of the collecting duct secrete in repsonse to blood levels?

K+

what stimulates renal secretion of K+?

aldosterone

what does a lack of extracellular fluid cause?

slowing of the production of the saliva glands, mouth becomes dry, and stimulates thirst response

what do osmoreceptors in the supraoptic nucleus of the hypothalamus sense?

increased osmotic pressure

steps to the regulation of fluid balance (ADH)

Osmoreceptors in the supraoptic nucleus of the hypothalamus sense increased osmotic pressure, ADH secreting cells in the hypothalamus secrete and send ADH to the neurohypophysis or posterior pituitary which releases it into the blood. ADH makes the distal convoluted tubules and collecting duct more permeable to water. Aquaporins are created that let the water flow out by diffusion. Increased fluid retention and intake raise blood volume and pressure. ADH affects the cerebrum reinforcing thirst response and awareness of dry mouth

characteristics of ADH regulation of fluid balance by water retention

ADH reduces water excretion independently of sodium excretion, it creates more aquaproins in the collecting ducts of the nephron, high sodium levels in the blood trigger ADH production by posterior pituitary

steps of fluid regulation of fluid balance (ANH)

ANH (atrial natriuretic hormone) is released by cells in the atria in response to stretching due to high blood pressure or volume. Causes the loss of sodium in urine, which causes water loss and lowers blood volume and pressure. Sodium loss also inhibits ADH. ANH also promotes vasodilation.

what is urine volume regulated by?

ADH from posterior pituitary, renin from the kidney and aldosterone from the adrenal cortex (RAAS), and the ANH from the atria.

what is the primary response of the body systems?

water conservation

what is a secondary response in the regulation of fluid balance?

increased intake

what is the movement of fluid between the interstitial and plasma compartments dependent on?

the hydrostatic pressure of the blood and blood colloid osmotic pressure (blood proteins) and the balance of all these determine rate and direction of fluid flow

how do cells regulate intracellular and extracellular fluid exchange?

by the movement of ions across the cell membrane

loss of ____________ (Na+) from the interstitial fluid makes it hypotonic to the cells

electrolytes

dehydration from excessive vomiting and diarrhea from a bacterial infection

continually flushes out ions that are not replaced by diet and there is little potassium in water. this potassium loss can cause nerve signal failure and a heart attack.

dehydration from direct water loss not replaced by drinking

causes interstitial fluid to become hypertonic to the cells, the cells will shrivel and die as water leaves them, the cell will open sodium channels to draw water in, but eventually there is no water outside of the cell to be drawn in.

what does the process of ADH causing water to be reabsorbed in the kidney tubules and collecting ducts lead to?

lowers the electrolyte concentration in the ECF

what does the process of aldosterone causing sodium to be reabsorbed in the kidney tubules lead to?

increasing the electrolyte concentration in the ECF

the kidneys are capable of recovering all _________ from the urine.

sodium

______ the Na+ in the body is used every day to create bile, pancreatic fluid, salica, and other gastric and intestinal secretions

half

what is the primary intracellular cation?

potassium

what does a deficit in potassium result in?

injury, starvation, burns, or dehydration from diarrhea

what does the cell put out to balance electrolyte loss after mucous membranes are flushed?

potassium

what does the loss of fluid from diarrhea, sweating, and vomiting cause?

a loss of sodium

what does the loss of extracellular ions (Na+) cause?

cells to be hyperosmotic to interstitial fluid

what happens if no fluid intake occurs?

the body goes into shock as circulation stops

what happens if fluid intake is maintained?

the cells release potassium to prevent excessive swelling

potassium loss leads to ________ _______ failure.

nerve signal

characteristics of a cell in normokalemia

K+ concentrations in equilibrium, equal diffusion into and out of the cell, and normal resting membrane potential (RMP)

characteristics of a cell in hyperkalemia

elevated extracellular K+ concentration, less diffusion of K+ out of cell, elevated RMP (cells partially depolarized), and cells more excitable

characteristics of a cell in hypokalemia

reduced extracellular K+ concentration, greater diffusion of K+ out of cell, reduced RMP (cells hyperpolarized), and cells are less excitable