Ch1 Structure and Functionality Flashcards
The urinary system consists of:
Two Kidneys
Two Ureters
One Bladder
One Urethra
Scientific study of the anatomy, physiology, and disorders of the kidneys
Nephrology
Branch of medicine that deals with male and female urinary system, and the male reproductive system
Urology
Five functions of the kidneys
Regulation of ION levels in the blood
Regulation of blood VOLUME and PRESSURE
Regulation of blood pH
Production of HORMONES
Excretion of WASTE
What enzyme helps regulate blood pressure?
Renin
What helps regulate the blood pH?
Bicarbonate ions (HCO3-) and Hydrogen ions (H+)
What two hormones does the kidneys produce?
Calcitriol
Erythropoietin
Stimulates the production of red blood cells
Erythropoietin
Active form of vitamin D, helps regulate calcium homeostasis
Calcitriol
Wastes that the kidneys excrete
Ammonia (amino acids)
Bilirubin (hemoglobin)
Creatinine (muscle fibers)
Uric Acid (nucleic acids)
Other wastes (Diet, Drugs, Environmental toxins)
What vertebrae do the kidneys lie on?
12th Thoracic and first Three lumber vertebrae
Provide some protection for the superior parts of the kidneys
11th and 12th ribs
Which kidney is lower?
Right
An adult kidney is about the size of a:
Bar of soap
Where the ureter, blood vessels, lymphatic vessels, and nerves enter/exit the kidney
Renal Hilum
A connective tissue sheath that helps maintain the shape of the kidney and serves as a barrier against trauma
Smooth, transparent renal capsule
Surrounds the renal capsule, cushions the kidney, and anchors the kidney to the posterior abdominal wall
Adipose tissue
Two main regions of the kidneys
Renal Cortex
Renal Medulla
Outer light-red region
Renal cortex
Darker red-brown region
Renal Medulla
Within the renal medulla are several:
Cone-shaped renal pyramids
What fills the spaces between renal pyramids?
Renal Columns (extension of the renal cortex)
Urine formed in the kidney passes from thousands of papillary ducts within the renal pyramids into cuplike structures called:
Minor Calyces
Each kidney has ___ minor calyces
8-12
From the minor calyces, urine flows into __ major calyces
2-3
After major calyces, urine flows into:
Single large cavity, Renal Pelvis
What drains urine into the ureter?
Renal pelvis
___% of resting cardiac output flows into the kidneys through the right and left renal arteries
20-25% (1200 mL per minute)
Renal artery divides into smaller vessels that eventually deliver blood to the:
Afferent arterioles
Each afferent arteriole divides into a tangled capillary network called:
Glomerulus
The capillaries of the glomerulus reunite to form:
Efferent arteriole
Each efferent arteriole divides to form a network of capillaries around the:
Kidney tubules
Peritubular capillaries reunite to form bigger veins which eventually drain into the:
Renal vein
Functional unit of the kidney
Nephron
Number of nephrons in each kidney
1 million
Two parts of the nephron
Renal Corpuscle
Renal Tubule
Where blood plasma is filtered
Renal Corpuscle
Where filtered fluid, called glomerular filtrate passes
Renal Tubule
As fluid moves through the renal tubules, wastes and excess substances are added, and useful materials are returned to blood in the:
Peritubular capillaries
Two parts that make up a renal corpuscle
Glomerulus
Glomerular (Bowman’s) capsule
Glomerular filtrate first enters the glomerular capsule and then passes into the:
Renal Tubule
The order fluid passes through the three main sections of the renal tuble
Proximal convoluted tubule
Loop of Henle
Distal convoluted tubule
Means the tubule is tightly coiled rather than straight
Convoluted
The renal corpuscle and both convoluted tubules lie within the:
Renal cortex
Location of the loop of Henle
Begins in the cortex and extends into the renal medulla
Hairpin turn back into the cortex
Distal convoluted tubules of several nephrons empty into a:
Common collecting duct
Several collecting ducts merge to form a:
Papillary duct
Order in which papillary ducts merge into:
Minor calyx
Major calyx
Renal pelvis
Ureter
Three basic functions of nephrons
Glomerular Filtration
Tubular reabsorption
Tubular secretion
Forcing of fluids and dissolved substances smaller than a certain size through a membrane by pressure
Filtration
First step in urine production
Glomerular filtration
What forces water and most solutes in blood plasma across the wall of glomerular capillaries to form glomerular filtrate?
Blood pressure
Filtered fluid flows along the renal tubule and through the collecting duct
Tubular reabsorption
Tubular secretion
Tubule and duct cells return about __% of the filtered water to blood through peritubular capillaries
99%
Filtered fluid has undergone tubular reabsorption and tubular secretion and enters the minor and major calyx
Urine
Two layers of cells that compose the glomerular capsule
Podocytes
Glomerular endothelium
Space between the renal corpuscle and the glomerular capsule
Capsular space
Cells that make up the inner wall of the glomerular capsule
Podocytes
Podocytes and glomerular endothelium form a filtration membrane that permits the passage of _____ from blood into the capsular space
Water and solutes
Forms the outer layer of the glomerular capsule
Simple squamous epithelial cells
Pressure that causes filtration
BP in the glomerular capillaries
Two pressures that oppose glomerular filtration
Blood colloid osmotic pressure
Glomerular capsule pressure
Net filtration pressure is normally:
10 mmHg
Net filtration forces how many liters of fluid into the capsular space for males & females daily?
Males: 180 L
Females: 150 L
Glomerular capillary blood pressure - (Blood colloidal pressure + Glomerular capsule pressure)
Net filtration pressure
Constriction of the afferent arteriole
Decreases blood flow into the glomerulus
Decreases net filtration pressure
Constriction of the efferent arteriole
Slows outflow of blood
Increases net filtration pressure
The amount of filtrate that forms in both kidneys every minute
Glomerular filtration rate (GFR)
GFR for adult males and females
Males: 125 mL/min
Females: 105 mL/min
Hormone that promotes loss of sodium ions and water in the urine in part because it increases glomerular filtration rate
Atrial Natriuretic Peptide
Cells in the atria of the heart secrete more ANP if the heart is:
Stretched out (More blood volume)
ANP acts on kidneys to increase loss of:
Sodium ions and water
Blood vessels of the kidneys are ______ neurons of the autonomic nervous system
Sympathetic
Filtered fluid becomes tubular fluid once it enters the:
Proximal convoluted tubule
__% of the water in glomerular filtrate actually leaves the body in urine
1%
What cells carry tubular reabsorption?
Epithelial cells all along the renal tubules and collecting ducts
Tubule cells that reabsorb 65% of filtered water, 100% of the filtered glucose and amino acids, and large quantities of ions
Proximal convoluted tubule
What cells fine-tune reabsorption to maintain homeostatic balances of water and selected ions?
Cells located distal to the proximal convoluted tubule
Kidneys
Secreted substances include:
Hydrogen ions (H+)
Potassium (K+)
Ammonia (NH3)
Urea
Creatinine
Drugs (Penicillin)
Poisonous waste product that is produced when amino groups are removed from amino acids
Ammonia
Liver cells convert most ammonia into:
Urea
Urea and ammonia in blood are both filtered at the glomerulus and secreted by the:
Proximal convoluted tubule cells into the tubular fluid
Normal blood pH
7.35-7.45
To eliminate acids, the cells of the renal tubules secrete
H+ (hydrogen)
Most important hormonal regulators of ion reabsorption and secretion are:
Angiotensin II
Aldosterone
Found in the proximal convoluted tubules, enhances the reabsorption of Na+ and Cl-
Angiotensin II
Angiotensin II stimulates the adrenal cortex to release:
Aldosterone
Hormone that stimulates the tubule cells in the last part of the distal convoluted tubules and through the collecting ducts to reabsorb more Na+ and Cl- and secrete more K+
Aldosterone
Major regulator of blood K+ level
Aldosterone
An elevated level of K+ in plasma causes:
Serious disturbances in cardiac rhythm or cardiac arrest
Plays a minor role in inhibiting the reabsorption of Na+
ANP
GFR increases
Na+, Cl-, and water reabsorption decrease
More water and salt are lost in urine, lowering Blood Pressure
The major hormone that regulates water reabsorption is
Antidiuretic hormone (ADH)
ADH operates via:
Negative feedback loop
Stimulates the release of ADH
Osmoreceptors in the hypothalamus stimulate the release from the posterior pituitary
ADH is stimulated to be released when the concentration of water in blood decreases by __%
1%
ADH acts on tubule cells in ____ convoluted tubules and through the collecting ducts
Last part of the distal convoluted tubules
Increases water permeability in the last part of distal convolute tubules by insertion of proteins that function as water channels
ADH
With ADH the kidneys can produce as little as ____ mL daily of very concentrated urine
400-500mL
Lower than normal levels of Ca2+ in blood stimulates the parathyroid glands to release:
Parathyroid hormone (PTH)
PTH stimulates cells in the _____ convoluted tubules to reabsorb more Ca2+ into the blood
Distal convoluted tubules
PTH inhibits _____ reabsorption in proximal convoluted tubules, thereby promoting _____ excretion
Phosphate - HPO4(2-)
Volume of urine eliminated per day in a normal adult
1-2 liters
Water accounts for about __% of the total volume of urine
95%
Ureters transport urine from ______ of one of the kidneys to the bladder
Renal Pelvis
If the physiological valve of the ureters under the bladder is not functional, what may occur?
Cystitis then Kidney Infection
Three layers of a ureter
Mucosa (transitional epithelium - stretch)
Smooth muscle
Areolar connective tissue (blood vessels, lymphatic vessels, nerves)
Hollow muscular organ behind the pubic symphysis
Bladder
Location of the bladder for females
Infront of the vagina and below the uterus
Bladder capacity
700-800 mL
The mucosa of the bladder contains
Transitional epithelium
Muscular layer of the urinary bladder that consists of three layers
Detrusor muscle
Peritoneum forms what kind of coat on the superior surface of the bladder?
Serous outer coat
Terminal portion of the urinary system
Urethra
Location of the urethra in females
Directly behind the pubic symphysis, embedded in the front wall of the vagina
Females
Opening of the urethra lies between:
Clitoris and vaginal opening
Males
Urethra passes directly through:
Prostate, deep perineal muscles, and penis
The opening and closing of the internal urethral sphincter is:
Involuntary
External urethral sphincter:
Composed of skeletal muscle
Voluntary
The urinary bladder stores urine prior to its elimination and then expels urine into the urethra by an act called:
Micturition
Stretch receptors of the bladder transmit nerve impulses to the spinal cord when how much volume is present?
200-400 mL
Nervous system
Impulses from the spinal cord cause contraction of the detrusor muscle and relaxation of the internal urethral sphincter muscle
Parasympathetic
Spinal cord inhibits ______ motor neurons, causing relaxation of skeletal muscle in the external urethral sphincter
Somatic
Causes a sensation of fullness that initiates a conscious desire to urinate before the micturition reflex actually occurs
Bladder filling
Body fluids make up __% of total body mass
55-60%
____ of body fluid is intracellular fluid (cytosol)
Two-thirds
1/3 of body fluid
Extracellular
__% of extracellular fluid is interstitial fluid
80%
__% of extracellular fluid is blood plasma
20%
Other extracellular fluids that are grouped with interstitial fluid:
Lymph
CSF
Synovial joint fluid
Aqueous humor
Endolymph/perilymph (ears)
Pleural, pericardial, peritoneal fluids
Two barriers that separate intracellular fluid and extracellular fluid
Plasma membranes of cells
Blood vessel walls
Small enough to permit the exchange of water and solutes between blood plasma and interstitial fluid
Capillaries
Largest single component of the body
__% of total body mass
Water
45-75%
Provide for the continual exchange of water and solutes among body fluid compartments
Filtration, reabsorption, diffusion, and osmosis
Primary means of water movement between intracellular and interstitial fluid
Osmosis
Determines the direction of water movement
Concentration of water solutes
Most solutes in the body are
Electrolytes
Main contributors to the osmotic movement of water
Electrolytes
The body can gain water by:
Ingestion and metabolic reactions
Ingested liquids
1600 mL
Moist foods
700 mL
Metabolic water gain
200 mL
Metabolic water production is mainly produced during
Aerobic cellular respiration
Dehydration
Daily water gains total
2500 mL
Kidney volume of secreted urine
1500 mL
Volume of water evaporated from skin
600 mL
Lungs exhale ___ mL of water vapor
300 mL
Water eliminated from feces
100 mL
Governs the urge to drink
Hypothalamus “Thirst Center”
Mild dehydration occurs when __% of fluid loss occurs
2%
Stimulate the thirst center
Osmoreceptors
Increased Angiotensin II
Elimination of excess body water or solutes occurs mainly by:
Controlling the amount lost in urine
The extent of ____ loss is the main factor that determines body fluid volume
Urinary Salt (NaCl)
Two main solutes in ECF and urine
Sodium (Na)
Chloride (Cl)
Three hormones that regulate the extent of renal Na and Cl reabsorption
Atrial natriuretic peptide (ANP)
Angiotensin II
Aldosterone
A salty meal leads to:
Increase in blood volume
The major hormone that regulates water loss is
Antidiuretic hormone (ADH)
Stimulates the release of ADH
Increase in osmotic pressure (decrease in water concentration)
Promotes the insertion of water channels into the plasma membranes of cells in the collecting ducts of kidneys
ADH
An increase in osmotic pressure of interstitial fluid causes:
Fluid being drawn out of cells (shrinkage)
A decrease in osmotic pressure causes cells to:
Swell
Changes in osmotic pressure most often result from changes in the concentration of:
Na+
Inhibits the secretion of ADH
Decrease in the osmotic pressure of interstitial fluid
Most abundant extracellular ions
Representing 90%
Na+ ions
Accounts for almost half of the osmotic pressure of extracellular fluid
Na+
Necessary for the generation and conduction of action potentials in neurons and muscles fibers
Na+
Most prevalent anions in extracellular fluid
Chloride ions (Cl-)
Most plasma membranes contains __ leakage channels
Cl-
Most abundant cations in intracellular fluid
Potassium ions (K+)
Play a key role in establishing the resting membrane potential and in the repolarization phase of action potentials in neurons and muscle fibers
Potassium (K+)
When K+ move into or out of cells, it often is exchanged for ____ and thereby helps regulate the pH of body fluids
H+
__% of the calcium in adults is in the skeleton and teeth
98%
In body fluids calcium is mainly an:
Extracellular cation (Ca+)
Two main regulators of Ca2+ (calcium) level in blood plasma are:
Parathyroid hormone (PTH)
Calcitriol
Form of vitamin D that acts as a hormone
Calcitriol
Low plasma of Ca2+ promotes release of more PTH which stimulates ______ to release Ca2+
Osteoclasts
Enhances reabsorption of Ca2+ from glomerular filtrate back into blood and increases production of calcitriol
PTH
Increases Ca2+ absorption from the GI tract
Calcitriol
Fours general functions of electrolytes
Ions control the OSMOSIS of water
Ions help maintain the ACID-BASE balance
Ions carry ELECTRICAL CURRENT
Serve as COFACTORS needed for optimal ACTIVITY of enzymes
Difference between plasma and interstitial fluids
Plasma has many protein ions
The difference in protein concentration is largely responsible for the
Blood colloid osmotic pressure
The difference in osmotic pressure between blood plasma and interstitial fluid
Blood colloid osmotic pressure
Diet containing large amount of proteins can result in:
Cellular metabolism which produces more acids
pH of blood
7.35-7.45
Three mechanisms that remove H+ from body fluids
Buffer Systems
Exhalation of carbon dioxide
Kidney excretion of urine
Substances that act quickly to temporarily bind H+, removing the highly reactive, excess H+ from solution but not from the body
Buffers
The principle buffer systems of the body fluids
Protein buffer system
Carbonic acid-bicarbonate buffer system
Phosphate buffer system
Most abundant buffer in intracellular fluid and plasma
Protein buffer system
Buffer system based on HCO3-
Carbonic Acid-Bicarbonate Buffer System
Components of the phosphate buffer system are the ion:
Dihydrogen phosphate H2PO(4)-
Mono-Hydrogen phosphate HPO4(2)-
Concentration of phosphates is highest in:
Intracellular fluid
An increase in CO2 results in:
Increase in H+
Decrease in pH
Decrease in CO2 results in:
Decrease in H+
Increase in pH
Increased ventilation results in:
More CO2 exhaled
H+ falls
pH rises
Low ventilation rate results in:
Increase in CO2
Increase in H+
Decrease in pH
What stimulates the inspiratory area of the medulla oblongata when blood acidity increases?
Chemoreceptors in the medulla oblongata and in the aortic and carotid bodies
Slowest mechanism to remove acids
Urination
Acidosis is a condition in which arterial blood pH is below:
7.35
Principal physiological effect of acidosis is:
Depression of the CNS
Depression of the nervous system is so severe that the individual becomes disoriented, comatose, and may die
pH below 7
Alkalosis is a condition when blood pH reaches higher than:
7.45
Over-excitability in both the CNS and peripheral nerves can be caused from:
Alkalosis
The physiological response to an acid-base imbalance that acts to normalize arterial blood pH
Compensation
Respiratory compensation may begin in minutes and reaches maximum effectiveness within:
Hours
Renal compensation begins in minutes and takes _____ to reach maximum effectiveness
Days
