Urinary system Flashcards
The urinary system consists of what?
The urinary system consists of two kidneys, two ureters, one urinary bladder, and one urethra.
Function of the kidney in the urinary system
After the kidneys filter blood and return most of the water and many solutes to the blood, the remaining water and solutes constitute urine
The kidneys help maintain homeostasis throughout the body by performing the following 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.
Whats the path of urine drainage?
- Collecting duct
- Papillary duct
- Mirror calyx
- Major calyx
- Renal pelvis
- Ureter
- Urinary bladder
Structure of the kidney
the kidneys are made up of two distinct areas: the cortex and the medulla
Nephron
It regulates the concentration of water and minerals such as sodium by filtering the blood and reabsorbing the important nutrients.9 Jun 2020
Function of Nephron
- Glomerular filtration
- Tubular reabsorption
- Tubular secretion
The function of Nephron - Glomerular filtration
the first step of urine production – blood pressure forces water and most solutes in blood plasma across the wall of glomerular capillaries.
The function of Nephron - 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.
The function of Nephron - Tubular secretion
the tubule and duct 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.
Angiotensin II
enhances reabsorption of Na+ and Cl–. Angiotensin II also stimulates the adrenal cortex to release aldosterone, which stimulates the collecting ducts to reabsorb more Na+ and Cl– and secrete more K+. Atrial natriuretic peptide (ANP) inhibits reabsorption of Na+ (and Cl– and water) by the renal tubules, which reduces blood volume.
How many nephrons in each kidney?
1 million
Slide 3
Transportation, Storage, and Elimination of Urine
- Urine produced by the nephrons drains into the minor calyces, which join to become major calyces that unite to form the renal pelvis.
- From the renal pelvis, urine drains first into the ureters and then into the urinary bladder; urine is then discharged from the body through the urethra.
- The two ureters transport urine from the renal pelves of the right and left kidneys to the urinary bladder.
Walls of the uterus contains of which 3 layers?
transitional epithelium on the inside (mucosa), smooth muscle in the middle, and an outer layer of areolar connective tissue
Function of the urinary bladder
function is to store urine prior to micturition.
mucosa of the urinary bladder contains what?
transitional epithelium and rugae
The muscular layer of the wall consists of three layers
smooth muscle called the detrusor muscle. The outer coat is a fibrous covering.
Physical characteristics of normal urine - Volume
One to two liters (about 1 to 2 quarts) in 24 hours but varies considerably
Physical characteristics of normal urine - Colour
Yellow or amber, but varies with urine conc and diet. Colour is due to urochrome (pigmented product from breakdown of bile) and urobilin (from breakdowndown and hemoglobin). Concentrated urine darker in colour.
Physical characteristics of normal urine - Turbidity
Transparent when freshly voided, but becomes turbid (cloudy) after a while.
Physical characteristics of normal urine - Odor
Mildly aromatic but becomes ammonia- like after a time. Some people inherit the ability to form methylymercaptam from digested asparagus , which gives urine a characteristic colour
Physical characteristics of normal urine - pH
Between 4.6 and 8.0; average is 6.0
Physical characteristics of normal urine - Specific gravity
Specific gravity (density) is the ratio of the weight of a volume of a substance to the weight of an equal volume of distilled water. Urine specific gravity ranges from 1.001 to 1.035
Abnormal constituents in urine - albumin
A normal constitude of blood plasma usually appears in only very small amounts in urine because it is too large to be filtered.
An increase of albumin indicates what?
Indicates an increase in permeability of filtering membranes due to injury or disease, increased blood pressure, or damage to kidney cells.
Abnormal constituents in urine - Glucose
Presence of glucose in urine, usually indicates diabetes mellitus
Abnormal constituents in urine - Red blood cells (erythrocytes)
The presence of hemoglobin from ruptured red blood cells in the urine, can occur with acute inflammation of the urinary organs as a result of disease or irritation from kidney stones, tumors, trauma, and kidney diisease
Abnormal constituents in urine - white blood cells (leukocytes)
The presence of white blood cells and other components of pus in the urine, indicates infection in the kidneys or other urinary organs
Abnormal constituents in urine - Ketone bodies
High levels of ketone bodies in the urine, may indicate diabetes mellitus, anorexia, starvation or too little carbohydrate in the diet
Abnormal constituents in urine - Bilirubin
When red blood cells are destoryed by macrophages, the globin portion off hemoglobin is spplit off and thee heme is converted to biliverdin.
An above level is bilirubin is called bilirubinuria.
Abnormal constituents in urine - Urobilinogen
The presence of urobillinogen (brwakdown product of hemoglobin) in urine is called urobilinogen. Trace amounts are normal but larghe amounts may be due to hemolytic or permicious anemia, infectious hepatitis, obstrcution of bile ducts , jaundice, cirrhosis, congestive heart failure or infectious mononucleosis.
Abnormal constituents in urine - Casts
Casts are tiny masses of material that have hardened and assume the shape of the lumen of a tubule in which the formed. They are flushed out of the tubule when glomerular filtrate builds up behind them. Casts are named after the cells or substances that compose them or based on their appearance
Abnormal constituents in urine - Microbes
The number and type of bacteria vary with specific infections in the urinary tract. One of the most common is E. coli. The most common fungus to appear in urine and candida albicans, a cause of vaginitis. The most frequent protozoan seen is thrichomonas vaginalis
Detrusor muscle
stretches when the urinary bladder fills and contracts to push out urine
Urethra
A small tube that leads from the urinary bladder to the outside
Ureters
Transport urine from the kidneys to the urinary bladder. As the urinary bladder fills, It expands and compresses the ureters, thereby preventing the backflow of urine
Rugae
Allow the urinary bladder to expand as it fills
Peritoneum
Helps holds the urinary bladder in place
Internal urethral sphincter
an involuntary smooth muscle that opens and closes the urethra
External urethral sphincter
An voluntary skeletal muscle that opens and closes urethra
External urethral office
The opening of the urethra to the outside
Actions of buffer systems
Buffers are substances that act quickly to temporarily bind H+, removing the highly reactive, excess H+ from solution but not from the body.
normal pH of systemic arterial blood
7.35 to 7.45
Homeostasis of pH is maintained by which buffer systems
- Protein buffer system
- Carbonic acid–bicarbonate buffer system
*Phosphate buffer system
Acid- Base balance - Exhalation of carbon dioxide
Breathing plays an important role in maintaining the pH of body fluids. An increase in the carbon dioxide in body fluids increases H+ concentration and thus lowers the pH (more acidic). A decrease in carbon dioxide raises the pH (makes body fluids more alkaline).
Acid- Base balance - Kidney excretion of H+
The slowest mechanism for removal of acids us also the only way to eliminate most acids that form in the body: Cells of the renal tubules secrete H+, which then is excreted in urine
Acid- Base balance - Acidosis
The systematic arterial blood pH below 7.35; it causes depression of the central nervous system (CNS)
Acid- Base balance - Alkalosis
The systematic arterial blood pH above 7.45; its principal effect is overexcitability of the CNS
Mechanisms that maintain pH of the body fluids
- Buffer systems
- Proteins
- Carbonic acid- bicarbonate
- Phosphates
- Exhales of C02
- Kidneys
Mechanisms that maintain pH of the body fluids - Buffer systems
Convert strong acids and bases, preventing drastic changes in body fluid pH
Mechanisms that maintain pH of the body fluids - Proteins
The most abundant buffers in body cells and blood. Hemoglobin is a buffer in the cystosol of red blood cells; albumin is a buffer in blood plasma
Mechanisms that maintain pH of the body fluids - Carbonic acid- bicarbonate
Important regulators of blood pH; The most abundant buffers in extracellular fluid
Mechanisms that maintain pH of the body fluids - Phosphates
Important buffers in intracellular fluid and in urine
Mechanisms that maintain pH of the body fluids - Exhalation of C02
With increased exhalation of C02, pH rises (fewer H-); with decreased exhalation of C02. pH falls (more H+)
Mechanisms that maintain pH of the body fluids - Kidneys
Kidney tubules secrete H+ into the urine and reabsorb HCO-3, so it is not lost in the urine
