A&P of Kidneys Flashcards
DESCRIBE the components of the urinary system
Two kidneys (left and right)
Two ureters (left and right)
One urinary bladder
One urethra
What do the kidneys help maintain throughout the body?
The kidneys help maintain homeostasis throughout the body by performing certain functions.
The kidneys maintain homeostasis throughout the body by performing what functions?
Regulation of ion levels in the blood.
Regulation of blood volume and blood pressure.
Regulation of blood pH.
Production of hormones.
Excretion of wastes.
The kidneys help regulate the blood level of several ions. What are these ions?
What function of the kidney does this fall under?
Sodium Ions
Potassium Ions
Calcium Ions
Chloride Ions
Phosphate Ions
Regulation of ion levels in the blood
Kidney’s help regulate blood pressure by secreting what enzyme?
What function of the kidney does this fall under?
Renin
Renin activates the angiotensin-aldosterone pathway by adjusting blood flow in and out of the kidneys, and by adjusting blood volume.
Regulation of blood volume and blood pressure.
How do kidneys adjust the volume of blood in the body?
By returning water to the blood or eliminating it in the urine.
How do the kidneys regulate the PH of blood?
By regulating the concentration of H+ in the blood. Excreting a variable amount of H+ in the urine.
Kidneys produce what hormones?
What function of the kidney is this?
The kidney produces Calcitriol and EPO.
Production of Hormones.
What is the active form of vitamin D, that also helps regulate calcium homeostasis?
Calcitriol
What hormone stimulates the production of red blood cells?
Erythropoietin (EPO)
Kidneys excrete what things as waste?
Ammonia/Urea: breakdown of amino acids
Bilirubin: breakdown of hemoglobin
Creatinine: breakdown of creatine phosphate in muscle fibers
Uric Acid: breakdown of nucleic acids
Drugs. Environmental Toxins, Foreign Substance from Diet.
What is a substance that has no useful function in the body?
Waste
Give a general description of the kidneys.
Pair of reddish organs shaped like kidney beans
Lie on either side of the vertebral column, between the peritoneum and back wall of abdominal cavity
At level of T12-L3.
11th and 12th ribs provide protection for superior parts of the kidneys.
Right kidney is lower than left kidney due to liver occupying large area above kidney on the right side.
Adult kidney is about size of a bar of soap.
The center of the medial border of the kidney is an indentation known as what?
Renal Hilum
What enters and exits the Renal Hilum?
Ureter leaves the kidney and blood vessels.
Lymphatic Vessels and Nerves enter and exit the renal hilum
What is the renal capsule?
A connective tissue sheath that helps maintain SHAPE of the kidney and serves as a BARRIER against trauma.
What is anchors the kidney the posterior abdominal wall?
Adipose tissue surrounds the renal capsule and cushions the kidney.
What are the two main regions of the kidney (internally)
Renal Cortex
Renal Medulla
What is the outer lighter region of the internal portion of the kidney?
Renal Cortex
What are within the renal medulla?
What are extensions of the renal cortex? And what do they do?
Cone Shaped Renal Pyramids
Renal columns, fill the spaces between renal pyramids.
What is the flow of urine through the body?
Minor Calyces, Major Calyces, Renal Pelvis, Ureters, Urinary Bladder, Urethra, Ocean
How many minor calyces are there?
8-12 Minor Calyces
How many Major Calyces are there?
2-3 Major Calyces
How much of resting cardiac output (1200 milliliters of blood per minute) flows
into the kidneys through the right and left renal arteries?
About 20–25% of the resting cardiac output.
Each afferent arteriole divides into a tangled capillary network called a what?
GLOMERULUS
The capillaries of the glomerulus reunite to form what?
Efferent Arteriole.
Within each kidney, the renal artery divides into smaller and smaller vessels (segmental,
interlobar, arcuate, interlobular arteries) that eventually deliver blood to what?
Afferent arterioles.
Upon leaving the glomerulus, each efferent arteriole divides to form a network of
what?
Capillaries around the kidney tubules.
The functional units of the kidney is what?
Nephrons,
A nephron consists of how many parts and what are they?
Two parts
(a) Renal corpuscle, where blood plasma is filtered.
(b) Renal tubule into which the filtered fluid, called glomerular filtrate, passes
What are the two parts that make up the renal corpuscle?
The two parts that make up a renal corpuscle are the glomerulus and the glomerular
(Bowman’s) capsule,
What is the order that fluid passes through the renal tubule?
In the order that fluid passes through them, the three main sections of the renal tubule
are the proximal convoluted tubule, the loop of Henle, and the distal convoluted
tubule.
The basic functions performed by the nephron.
Glomerular filtration, tubular reabsorption, and tubular secretion
What is filtration?
Filtration is the forcing of fluids and dissolved substances smaller than a certain size
through a membrane by pressure.
What is the first step of urine production?
Glomerular filtration is the first step of urine production. Blood pressure forces water
and most solutes in blood plasma across the wall of glomerular capillaries, forming
glomerular filtrate
What is happening during tubular reabsorption?
Filtered fluid flows along the renal tubule and through the collecting duct:
Tubule and duct cells return about 99% of the filtered water and many useful solutes
to the blood flowing through peritubular capillaries.
What is taking place during tubular secretion?
Tubular secretion also takes place as fluid flows along the tubule and through the collecting duct:
The tubule and duct cells remove substances, such as wastes, drugs, and excess ions,
from blood in the peritubular capillaries and transport them into the fluid in the renal
tubules.
When can something be called urine?
By the time the filtered fluid has undergone tubular reabsorption and tublar secretion and
enters the minor and major calyx it is called urine.
As nephrons perform their functions, what are they helping to maintain?
They help maintain homeostasis of the blood’s
volume and composition.
The cells that make up the inner wall of the glomerular capsule are called what?
Podocytes,
Blood cells and most plasma proteins remain in the blood because of what reason?
They are too large
to pass through the filtration membrane.
What is the pressure that causes filtration?
Blood pressure in the glomerular capillaries
What are the two pressures that oppose glomerular filtration?
Blood Colloid Osmotic Pressure
Glomerular capsule pressure
What is the equation for Net filtration pressure?
Glomerular capillary blood pressure - two opposing pressures. (blood colloidal + glomerular capsule pressure)
Constriction of the afferent arteriole decreases blood flow into the glomerulus, which
increases or decreases net filtration pressure?
Decreases
Constriction of the efferent arteriole slows outflow of blood and increases or decreases net
filtration pressure?
Increases
What is Glomerular Filtration Rate
The amount of filtrate that forms in both kidneys every minute is called the glomerular
filtration rate (GFR)
What is the GFR for females per minute?
105mL/min in females
What is the GFR for males per minute?
125mL/min in males
What is a hormone that promotes loss of sodium ions and water in
the urine in part because it increases glomerular filtration rate?
Atrial natriuretic peptide (ANP)
If the GFR is too high what happens?
Needed substances pass so quickly through the renal tubules
that they are unable to be reabsorbed and pass out of the body as part of urine
If the GFR is too low what happens?
Nearly all the filtrate is reabsorbed and waste
products are not adequately excreted
How does ANP act on the kidneys?
ANP then acts on the kidneys to increase loss of sodium ions and water in urine,
which reduces the blood volume back to normal.
The blood vessels of the kidneys are controlled by what?
By sympathetic neurons of the autonomic nervous
system
What is tubular reabsorption?
Returning most of the filtered water and many of the filtered solutes
to the blood-is the second basic function of the nephrons and collecting ducts
When does filtered fluid become tubular fluid?
The filtered fluid becomes tubular fluid once it enters the proximal convoluted tubule.
What percentage of filtered water is reabsorbed?
About 99% of filtered water is reabsorbed.
What percentage of water in glomerular filtrate actually leaves the body in urine?
Only 1% of the water
What cells all along the renal tubules and collecting ducts carry out tubular
reabsorption?
Epithelial cells
What cells make the largest contribution to reabsorption?
Proximal convoluted tubule cells.
What ions get reabsorbed in the proximal convoluted tubule?
Sodium, Potassium, Chloride, Bicarbonate, Calcium, and Magnesium
What percentage of filtered water, glucose, and amino acids gets reabsorbed?
65% filtered water
100% filtered glucose, and amino acids.
Water moves by what into the peritubular capillaries?
Osmosis
The third function of the nephrons and collecting ducts is tubular secretion. Define tubular secretion. the transfer of
materials from the blood through tubule cells and into tubular fluid
The transfer of
materials from the blood through tubule cells and into tubular fluid
What are some substances that are secreted during tubular secretion?
Hydrogen ions, potassium, ammonia, urea, creatinine, drugs (penicillin)
What is a poisonous waste product that is produced when amino groups are
removed from amino acids?
Ammonia
What helps control blood pH?
Tubular secretion.
What is a normal blood pH?
7.35 to 7.45
To eliminate acids, the cells of the renal tubules secrete what into the tubular fluid,
which helps maintain the pH of blood in the normal range?
H+ Hydrogen ions,
Due to H+ secretion, is urine typically acidic or basic? (has a pH below 7)
Acidic (has a pH below 7)
What affect the extent of Na+, Cl-, Ca2+, and water reabsorption as well as K+
secretion by the renal tubules?
Hormones
The most important hormonal regulators of ion reabsorption and secretion are
what?
Angiotensin II and Aldosterone.
The major hormone that regulates water reabsorption is what?
Antidiuretic hormone (ADH)
When calcium is low in the blood, what gland is stimulated to release parathyroid hormone (PTH)
Parathyroid Gland.
When the concentration of water in the blood decreases by as little as 1%,
osmoreceptors located where, stimulate release of ADH from the posterior
pituitary?
Hypothalamus
What is a urinalysis?
An analysis of the volume and physical, chemical, and microscopic properties of urine
The volume of urine eliminated per day in a normal adult is how much? 1 to 2 liters
1 to 2 liters
Water accounts for what percentage of the total volume of urine?
95%
What kind of solutes are normally present in urine?
Urea, creatinine, potassium, and ammonia, uric acid, s sodium, chloride, magnesium, sulfate,
phosphate, and calcium ions.
What are the structures that transport, store and eliminate urine?
Ureters, Urinary Bladder, Urethra
If this physiological valve is not operating what may happen?
Cystitis (urinary bladder inflammation) may develop into a kidney infection.
The wall of the ureter consists of three layers, what are they?
Inner layer, middle layer, and outer layer.
In the ureter the inner layer contains what? What is special about this?
Transitional epithelium is able to stretch—a marked advantage for any organ that
must accommodate a variable volume of fluid.
What layer of the ureter wall contains smooth muscle?
The middle layer
How is urine transported from the renal pelvis the the urinary bladder?
Peristaltic contractions
What does the outer layer of the ureter wall consist of?
Areolar connective tissue containing blood vessels, lymphatic vessels, and nerves.
What is a hollow muscular organ situated in the pelvic cavity behind the
pubic symphysis?
The urinary bladder
Where is the urinary bladder located for males?
It is directly in front of the rectum.
Where is the urinary bladder located for females?
It is in front of the vagina and below the uterus.
What holds the urinary bladder in position?
Folds of the peritoneum
Urinary bladder capacity averages what?
700–800 mL
Like the ureters, the mucosa the mucosa of the urinary bladder contain what which allows for stretching?
Contains transitional epithelium.
The muscular layer of the urinary bladder wall consists of three layers of smooth muscle
called what?
The detrusor muscle
What is , the terminal portion of the urinary system, a small tube leading from the
floor of the urinary bladder to the exterior of the body?
The urethra
The opening and closing of the internal urethral sphincter is involuntary or voluntary?
Involuntary
Below the internal sphincter is what which is composed of
skeletal muscle and is under what kind of control?
External sphincter, voluntary control.
In both males and females, what is the passageway for discharging urine from the
body?
The urethra
What also serves as the duct through which semen is ejaculated?
The male urethra
The urinary bladder stores urine prior to its elimination and then expels urine into the urethra
by an act called what?
Micturition, commonly known as urination.
Micturition requires a combination of what?
Involuntary and voluntary muscle contractions.
When the volume of urine in the urinary bladder exceeds what, pressure within the
bladder increases considerably, and stretch receptors in its wall transmit nerve impulses into
the spinal cord?
Exceeds 200 to 400 mL
Stretch receptors in its wall transmit nerve impulses into the spinal cord.
These impulses propagate to the lower part of the spinal cord and trigger a reflex called
what?
The micturition reflex
What is happening during the micturition reflex?
In this reflex, parasympathetic impulses from the spinal cord cause contraction of the
detrusor muscle and relaxation of the internal urethral sphincter muscle
Simultaneously, the spinal cord inhibits somatic motor neurons, causing relaxation of
skeletal muscle in the external urethral sphincter.
Upon contraction of the urinary bladder wall and relaxation of the sphincters,
urination takes place.
In lean adults, body fluids make up what?
55% and 60% of total body mass.
Fluids are present in two main “compartments, what are they?
Inside and Outside cells.
What part of body fluid is intracellular fluid (ICF) or cytosol, the fluid within
cells?
About two thirds
What part of the body, called extracellular fluid (ECF), is outside cells and includes all other
body fluids?
One third
What percentage of the ECF is interstitial fluid?
What percentage of the ECF is blood plasma, the liquid portion of the blood
80%, 20%
Other extracellular fluids that are grouped with interstitial fluid include what?
1) lymph in lymphatic vessels;
2) cerebrospinal fluid in the nervous system;
3) synovial fluid in joints;
4) aqueous humor and vitreous body in the eyes;
5) endolymph and perilymph in the ears;
6) pleural, pericardial, and peritoneal fluids between serous membranes of the lungs,
heart, and abdominal organs.
What barriers separate intracellular fluid?
Blood plasma, and interstitial fluid.
What are the main contributors to the osmotic movement of water?
Electrolytes
Fluid balance primarily depends on what?
Electrolyte balance
How can the body gain water?
Ingestion and by metabolic reactions.
What are the main sources of body water?
Ingested liquids -1600mL
Moist Foods-700mL
Absorbed from GI tract -2300mL
Metabolic water is mainly produced through what?
During aerobic cellular respiration and to a smaller extent during dehydration synthesis reactions.
What are daily water gains throughout the day?
2500mL
Metabolic water gains are how much?
200mL
Normally, body fluid volume remains constant because of what?
Water loss equals water gain.
List how water is lost throughout the body?
kidneys excrete about 1500 mL in urine,
600 mL evaporates from the skin surface,
lungs exhale about 300 mL as water vapor,
gastrointestinal tract eliminates about 100 mL in feces.
What is known as the thirst center and governs the urge to drink?
Hypothalamus
What stimulates thirst?
When water loss is greater than water gain, dehydration—a decrease in volume and
an increase in osmotic pressure of body fluids—stimulates thirst
What stimulates the thirst center in the hypothalamus?
Osmoreceptors in the hypothalamus and increased angiotensin II in the blood
Elimination of excess body water or solutes occurs mainly by controlling what?
The amount lost in urine.
What is the main factor that determines body fluid
volume?
The extent of urinary salt (NaCl) loss
What are the two main solutes in extracellular fluid?
Sodium ions
Chloride ions
Three hormones regulate the extent of renal Na+ and Cl- reabsorption, what are they?
Atrial natriuretic peptide (ANP), angiotensin II, and aldosterone.
The major hormone that regulates water loss is what?
Antidiuretic hormone (ADH).
Sodium ions (Na+) are the most abundant what? extracellular ions, representing about 90% of
extracellular cations.
Extracellular ions, representing about 90% of
extracellular cations.
What are the most prevalent anions in extracellular fluid?
Chloride ions (Cl-)
What are the most abundant cations in intracellular fluid?
Potassium ions (K+)
The level of K+ in blood plasma is controlled mainly by what?
aldosterone
About 98% of the calcium in adults is where?
In the skeleton and teeth, where it is combined with phosphates to form mineral salts
In body fluids, calcium is mainly what? an extracellular cation
An extracellular cation
The two main regulators of Ca2+ level in blood plasma are what?
Parathyroid hormone (PTH) and calcitriol,
What are the functions of electrolytes?
(a) Ions control the osmosis of water between fluid compartments
(b) Ions help maintain the acid–base balance required for normal cellular activities.
(c) Ions carry electrical current, which allows production of action potentials.
(d) Several ions serve as cofactors needed for optimal activity of enzymes.
