Urinary system Flashcards
Functions of the urinary system
-Elimination of waste products such as nitrogenous waste ( urea, creatinine, ammonium and uric acid) toxins and drugs
- Regulation of aspects of homeostasis
- RBC production
- Activation of vitamin D
- water balance
Organs of the urinary system
- Kidneys
- ureters
- urinary bladder
- urethra
Three region of kidney
- Renal cortex
- Renal medulla
- Renal pelvis
Each nephron consists of two main structures
- Renal corpuscle
2. Renal tubule
The subdivision of the renal tubule are
- proximal convulated tubule
- Nephron loop
- Distal convulated tubule
Urine formation is the result of three processes
- glomerular filtration
- tubular reabsorption
- Tubular secretion
Glomerula filtration occurs when blood enters the __________
glomerulus via the afferent ateriole
The afferent arteriole has a
_________ diameter than the efferent arteriole, resulting in _______. This increased blood pressure _______________.
larger, an increase in glomerular blood pressure , forces more fluid and molecules to leave the glomerulus than in typical capillaries
fluid that enters the glomerular capsule is called
glomerular filtrate
glomerular filtrate enters the
glomerular capsule
(Glomerular filtration) Filterable components of plasma :
Water, nitrogenous wastes, nutrients and salts
(glomerular filtration )Non-filterable components of plasma
Formed element (blood cells and platelets), plasma proteins
How do the non- filterable components leave the glomerulus
by way of the efferent arteriole
Why are plasma proteins or formed elements will not be filtered
Larger solutes
How is water and solutes filtered from the blood
Blood pressure forces water and small solutes to be filtered from blood into the bowman’s capsule
What is glomerular filtration rate ?
Amount of filtrate kidneys produce each minute
What happens when the glomerular capillaries is damaged?
larger molecules will be filtered into the filtrate and excreted in the urine
What happens during glomerular filtration
water and solutes smaller than proteins are forced through the capillary walls and pores of the glomerular capsule into the renal tubule
What happens during tubular reabsorption
Water ,glucose, amino acids , and needed ions are transported out of the filtrate into the tubule cells and then enter the capillary blood
What happens during tubular secretion
H+, K+ , creatine and drugs are removed from the peritubular blood and secreted by the tubule cells into the filtrate
Tubular reabsorption
The capillaries around the tubules reabsorbed ________________.
useful substances from the renal tubule cells such as water, glucose, amino acids, ions
Most reabsorption occurs in the __________.
proximal convulated tubule.
tubular reabsorption
______________ are poorly reabsorbed
Nitrogenous waste products are poorly reabsorbed
Second way by which substances move from the blood to the tubular fluid
tubular secretion
what are secreted (tubular secretion )
h+,creatine and drugs such as penicillin are secreted
Tubular secretion occurs _________
along the length of the kidney tubule
Secretion is important for
- Getting rid of substances not already in the filtrate
- Removing drugs and excess ions
- Maintaining acid-base balance of blood
Series of tubes carrying tubular fluid away from the nephron
- collecting duct
- papillary duct
Collecting duct
collect fluid from many nephrons
Papillary duct
collect fluid from multiple collecting ducts
In the end urine contain
substances that have been filtered but not reabsorbed, plus what has been secreted
Solutes normally found in urine
Sodium and potassium ions
Urea, uric acid, creatine
Ammonia
Bicarbonate ions
Solutes not normally found in urine
- Glucose
- Blood proteins
- Red blood cells
- Hemoglobin
- Pus
- Bile
Ureters
Slender tubes attatching the kidney to the urinary bladder
what aids gravity in urine transport
peristalsis aids gravity in urine transport
What is a urinary bladder
It temporarily stores urine
Trigone
triangular region of the urinary bladder base
Urinary bladder has three openings
two from the ureters, one to the urethra
Wall of the urinary bladder
Three layers of smooth muscle collectively called the detrusor muscle
Mucosa made of transitional epithelium
Walls are thick and folded in an empty urinary bladder
Urethra
Thin-walled tube that carries urine from the urinary bladder to the outside of the body by peristalsis
Function of urethra
females - only carries urine
males- carries urine and sperm
Release of urine is controlled by
sphincters
Two sphincter that control the release of urine is called
Internal urethral sphincter and external urethral sphincter
Internal urethral sphincters
involuntary and made of smooth muscle
external urethral sphincter
voluntary and made of skeletal muscle
Micturition
Voiding , emptying of urinary bladder
Micturition reflex causes _________________
involuntary internal sphincter to open when stretch receptors in the bladder are stimulated
Micturition can usually be delayed as
the external sphincter is voluntarily controlled
Intracellular fluids
fluid inside the cells , about two-thirds of body fluids
Extracellular fluid
Fluids outside cells which includes
- interstitial fluid
- blood plasma, cerebrospinal and serous fluids, humors of the yes and lymph
_________ and _______ participate in the reabsorption of water
Tubules of a nephron and the collecting duct
The reabsorption of ______ always precedes the reabsorption of ______, which occurs by
salt , water , osmosis
Water reabsorption in collecting ducts is proportion to
Antidiuretic hormone release
Abnormalities of water balance
Dehydration
Edema: atypical accumulation of interstitial fluid, resulting in tissue swelling.
Solutes in the body include
electrolytes such as sodium, potassium and calcium ions
_________ increases sodium and water reabsorption and decreases potassium reabsorption
Aldosterone (a hormone)
Normal pH for body fluids is
7.35 to 7.45
Alkalosis
blood pH above 7.45
blood pH above 7.45
alkalosis
Acidosis
blood pH below 7.35
blood pH below 7.35
acidosis
The pH of body fluids is maintained via several mechanisms
- acid-base buffer systems
- the respiratory center
- the kidneys
renal mechanisms
when blood ph rises:
- bicarbonate ions are excreted
- hydrogen ions are retained by kidney tubules
renal mechanisms
when blood pH fails:
- bicarbonate ions are reabsorbed
- hydrogen ions are secreted
Kidney assist other systems such as
- secretes erythropoietin , a hormone that stimulates production of RBCs in the red bone marrow
- They regulate the amount of Ca2+ in the blood by converting vitamin D to its active form, which is needed for Ca2+ absorption in the digestive tract. They also regulate the excretion of electrolytes, inc Ca2+
Renal failure develops when
there is a reduction in the kidneys’ ability to sufficiently filter waste products from the blood
Renal failure may require
renal replacement therapy : dialysis or renal transplant
What is an Acute Kidney Injury
Sudden decline in glomerular filtration rate. This results in elevations in serum creatinine , blood urea nitrogen and electrolyte levels
Chronic Kidney disease
Presence of kidney damage or decreased GFR for greater than 3 months
