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142 Cards in this Set

  • Front
  • Back
Organs that form urine
lead urine to the bladder
lead urine to the outside of the body
Roles of Urinary Homeostasis
1.regulating composition of body fluids 2.remove wastes (from metabolism, etc.) 3.kidneys are minor endocrine organs
location of kidneys
between twelfth thoracic and third lumbar vertebrae
What enters and exits the bladder?
renal artery enters and renal vein and urethra exit
outer portion of kidney
renal cortex
inner, triangular portion(s) of kidney
renal medulla (renal pyramids)
a sudden loss of kidney function, usually associated with shock or intense renal vasoconstriction, from a few days to a few weeks
acute renal failure
inflammation of the urinary bladder
blood in the urine
a method of clearing waste products from teh blood in which blood passes by the semipermeable membrane of the artificial kidney and waste products are removed by diffusion
night urination (during sleep)
the condition of having urinary volumes of less than 500 ml/day (normal is 1000 ml/day)
excessive urine output (as with diabetes insipidus)
retention of urinary constituents in the blood owing to kidney dysfunction
functional unit of the kidney
T or F: one collecting duct serves one nephron
F: one collecting duct serves several nephrons
How many nephrons are there in each kidney?
one million
How many capillaries are there in the glomerulus?
50 capillaries
How much more permeable is the glomerulus than typical capillaries?
100 to 1000 times more permeable
feet processes that hold capillaries in place
What is the purpose of brush border microvilli in the proximal convoluted tubule?
increase surface area
T or F: the nephron loop and distal convoluted tubule contain as much microvilli as the proximal convoluted tubule
F: the nephron loop has NO microvilli and the distal convoluted tubule has much less
empties into the collecting duct
distal convoluted tubule
the portion of the blood plasma that enters the capsule
glomerular filtrate
mechanisms that cause fluid to be filtered
1. high hydrostatic pressure of blood (45 to 60 mmHg) 2.large number of pores
How much blood plasma is filtered in a day?
180 L or 45 gallons
What is filtered and what is too big?
water electrolytes, glucose, amino acids, urea, hormones and vitamins ARE filtered plasma proteins, RBC, WBC, and platelets are too big (albumin would be first to filter if something was damaged)
What is the GFR or glomerular filtration rate?
120 ml per minute
How is GFR regulated?
vasoconstrition or dilation of afferent arterioles by extrinsic and intrinsic mechanisms
What are the extrinsic and intrinsic factors?
extrinsic (sympathetic nerves) and intrinsic (locally produced chemicals)
What is used to measure GFR?
GFR (ml/min)= (urine volume ml/min x inulin conc. in urine mg/ml)/(inulin conc. in plasma mg/ml)
Where does reabsorption take place?
in ALL parts of the nephron
transfer of fluid and solutes out of the lumen of the nephron through the interstitial space and into peritubular capillaries
tubular resabsorption
How much filtrate is reabsorbed?
99% we only produce 1 to 2 L of urine per day
no energy required
requires energy
active transport
sodium Na filtration
99.5% reabsorbed, 67% in proximal tubule, 25% in loop of Henle, 8% in distal tubule
What regulates sodium reabsorption?
aldosterone of renin-angiotensin system
Under normal conditions, how much of the glucose is reabsorbed?
What is the transport maximum Tm for glucose?
375 mg/minute filtered
A glucose value above 375 will not be reabsorbed and will appear in the urine as a sign of what?
the secretion of substances from the peritubular capillaries into the lumen of the tubule
tubular secretion
(to selectively move substances into the lumen for excretion into the urine)
What are the most important substances excreted by the tubules?
hydrogen ions, potassium ions, and some organic anions
Why is H+ secretion important?
acid-base balance in the body
What does aldosterone stimulate?
Pootassium secretion and sodium reabsorption
How do the kidneys regulate acid-base balance?
by secretion of H+ ions into the tubules and the reabsorption of bicarbonate
the ratio of CO2 to bicarbonate in the extracellular fluid is increased because of the production of CO2 or an increase of H+ formation
Renal response of acidosis?
1)increased amounts of CO2 enter the tubular cells from EFC
2)increased amounts of H+ are secreted into lumen of nephron
3)bicarbonate in the lumen of nephron is reabsorbed into EFC
net result of acidosis
H+ ions are secreted into the urine and bicarbonate ions are retained
the ratio of bicarbonate increases as the pH rises
Renal response of alkalosis?
1)decreased amounts of CO2 enter tubular cells from EFC
2)decreased amounts of H+ are secreted into the lumen of the nephron
3) less bicarbonate is reabsorbed
net result of alkalosis
H+ ions are retained and bicarbonate ions are excreted
Where are the mechanisms that the kidneys use to regulate urine concentration?
medullary interstitium, tubules, vasa recta (medullary capillaries)
Which part of the nephron loop is permeable to water?
the descending limb
What part of the nephron loop is IMpermable to water?
the ascending limb
Where do sodium and chloride ions diffuse in and out of?
Na+ and Cl- diffuse into the descending vasa recta and diffuse out of the ascending vasa recta
What quantity of renal blood flow passes through the vasa recta?
1 to 2 percent
Net result of Regulation of Urine Concentration?
high osmotic concentration ithe medulla
Low levels of ADH?
diluted urine because more water is produced in the urine
High levels of ADH?
concentrated urine because ADH inhibits formation of water in urine
How is it decided which things will be retained and which will be expelled in the urine?
it depends on the body's need to retain or eliminate that substance
clearance (plasma clearance) of a certain substance
Clearance (ml/min)= UxV / P
If a substance is filtered and reabsorbed but not secreted...
its plasma clearance rate is always less than the GFR (less than 120 ml/min)
If a substance is filtered and secreted but not reabsorbed...
its plasma clearance rate is always greater than the GFR (greater than 120 ml/min)
length of the urethra in men vs. women
it is significantly shorter in women than in men which means more urinary tract infections for women because bacteria doesn't have to travel as far
where renin is produced and secreted
juxtaglomerular apparatus
kidneys play an important role in regulation of blood pressure via...
the renin-angiotensin-aldosterone system
Effects of renal failure
water and salt retention
high plasma urea, creatine uric acid
coma-due to acidosis death if below 6.8
What senses the need to release renin from the juxtaglomerular cells?
macula densa (wall of the distal tubule)
What causes release of renin?
decrease in blood volume/pressure or an increase in sodium chloride concentration in the distal tubule
action of hormones vs. nerves
action of hormones is relatively slow and effects are prolonged, nerve impoulses are faste and effects are short
the study of endocrine glands, the hormones they secrete, and th effects they have on their target cells, or target tissues
How do hormones influence their target cells?
chemically binding to integral membrane protein receptors that bind and recognize that hormone
Generally, how many receptors for a particular hormone does a target cell have?
when a hormone is present in excess and the number of target cell receptors decreases
when a hormone is deficient and the number of receptors increases (makes target tissue more sensitive to hormone)
all steroid hormones are lipids that are derived from cholesterol
characteristics of steroids
lipid soluble and enter cells rapidly
Ex: estrogens, progesterone, testosterone, aldosterone, cortisol
biogenic amines
synthesized by modifying amino acids
Ex: T3 and T4, epinephrine, histamine, serotonin
Peptides and proteins
consist of chaines of 3 to 200 amino acids, synthesized on rough endoplasmic reticulum
Ex: oxytoci, ADH, parathyroid hormone, calcitonin, CCK, gastin
Electrical vs. chemical communication of the brain
nervous system vs. endocrine system, respectively
General Characteristics of Hormones
-physiological regulators
-effective in minute quantities
-synthesized by living cells
-secreted into and carried by the blood (some exceptions)
-initiate specific actions
the study fo the interactions between the nervous system and the endocrine system
once called the master gland
the pituitary gland, which is controlled by the hypothalamus
anterior pituitary secretes 7 hormones
growth hormone, ACTH, Thyroid stimulating hormone, prolactin, FSH, LH, melanocyte stimulating hormone
posterior pituitary secretes 2 hormoes
ADH and oxytocin (milk production)
Where are the two hormones from the posterior pituitary made?
in neurosecretory neurons (hormones from anterior pituitary are made in hypothalamus)
Where are the hormones from the anterior pituitary made?
made by the hypothalamus and transported in small blood vessels
releasing hormones or inhibitory hormones
CRH-stimulates ACTH
TRH-stimulates TSH and prolactin
GnRH-stimulates FSH and LH
GIH or somatostatin-inhibits growth hormone secretion
Giantism and Agromegaly-excess GH
giantism-excess before puberty
agromegaly-excess inadults
major source of IGF-I (insulin-like growth factor)
pituitary dwarfism
lack of GH or GRH before puberty, may also be hypothalamic pituitary tumor
production of milk
Thyroid stimulating Hormone-TSH
T3 and T4
Follicle Stimulating Hormone-FSH
stimulates egg to maturity, estrogens, testicular growth
Luteinizing Hormone-LH
ovulation, corpus luteum, estrogen and progesterone, males-testosterone
ACTH or adrenocorticotropin
normal growth of adrenal cortex and secretion of glucocorticoids, increased lipids and skin pigmentation
milk secretion and uterine contraction
ADH or Vasopressin
released in response to rising plasma tonicity or falling blood pressure
diabetes insipidus
lack of ADH due to damage of the pituitary or hypothalamus
symptoms: polyuria, polydipsia, dehydration, fever, dry tongue and delirium
tumor of the chromaffin cells in the medulla
symptoms: high blood pressure
location of adrenal gland
on top of the kidney
adrenal gland secretes?
catecholamine hormones for sympathetic nervous system, mineral balance, energy balance, and reproductive function
mineral corticoids (aldosterone)
sodium, potassium, and water balance
zona glomerulosa
glutocorticoids (cortisol)
anti-inflammatory, metabolism of carbs, proteins, and fats
zona fasciculata
gonadocorticoids (sex hormones)
zona reticularis
secretion of chromaffin cells in the adrenal medulla
catacholamines, epinephrine (80%), norepinephrine (20%), dopamine (<1%)
Inadequate secretion of glucocorticoids and mineralocorticoids = hypoglycemia, sodium and potassium imbalance, deydration, weight loss, weakness
Addison's disease (President Kennedy had it)
hypersecretion of corticosteroids usually from tumor or oversecretion of ACTH, puffy moon face, decreased antibodies, hyperglycemia
Cushing's syndrome
Alteration of enzymes required to produce mineralcorticoids, increase production of sex hormones, masculization of females
Adrenogenital syndrome
How many thyroid follicles do humans have?
one million
What do T4 and T3 make?
a protein-rich fluid called colloid
What do T4 and T3 do?
regulate metabolism and body temperature, growth (hypothalamus and release of TSH regulate)
What does Calcitonin do?
lowers blood calcium by inhibiting the release of calcium from bone tissue
insiffucient secretion of T4 and T3 in infants, stunted growth and thickened facial features
cretinism (hypothyroidism)
insufficient secretion fo T4 and T3 in adults
pathological enlargement of the thyroid gland due to insufficient iodine intake
excessive secretion of T4 and T3, bulging eyes
Graves' disease
Calcium and...
1) bones
2) digestive
3) kidneys
Vitamin D helps to absorb
Calcium distribution in the body
99% crystalline in bone, .9% in body cells, .1% in EFC
How does calcitonin lower blood calcium?
descreases bone resorption by inhibiting the activity of osteoclasts
stimulates urinary excretion of calcium and phosphate by inhibiting their reabsorption in the kidneys
T or F: PTH is essential for life
PTH increases blood calcium by...
stimulating activity of osteoclasts to reabsorb bone
stimulates kidneys to reabsorb calcium from filtrate
promotes formation of vitamin d
usually caused by a tumor in one of the parathyroid glands. characterized by hypercalcemia
used to be caused by remove of parathyroids during thyroid surgery
pancrease exocrine function
secretion of pancreatic juice (enzymes) goes into intestinal tract
pancreas endocrine function
Alpha cells-secrete glucagon
Beta cells-secrete insulin
What does Glucagon do?
elevates blood glucose stimulating glycogenolysis in the liver
What does insulin do?
promotes the cells to take up glucose (brain, kidney, intestinal and red blood cells don't need insulin) lowers blood glucose levels and stimulates glycolysis
lack of ADH from the posterior pituitary
diabetes insipidus
insulin deficiency
diabetes mellitus
Juvenile onset
Type I insulin-dependant
maturity onset
Type II noninsulin-dependant
How can juvenile diabetes be complicated?
by ketoacidosis
glucose in the urine
increased urine volume
increased drinking
What happens to the excess blood sugary during hyperglycemia?
it is shunted to the polyol pathway, or the organs that don't need glucose
reactive hypoglycemia
caused by an exaggerated response of the beta cells to a rise in blood glucose
gestational diabetes
happens to 2 -5 % of pregnant women then disappears after delivery