the urinary system Flashcards
what are the 4 components of the urinary system?
- kidney
- ureters
- urinary bladder
- urethra
what does the kidney do?
- fitter (extracts and removes metabolic waste from the blood)
- blood pressure (provides the force)
what is used to help the kidney filter blood?
the force of blood pressure
what do the ureters do?
internal transportation
what does the urinary bladder do
store the urine
what does the urethra do?
internal to external transportation
Where are the kidneys located?
- dorsal aspect of the abdominal cavity
- outside of the peritoneum (retroperitoneal)
- Is ventral to the 1st few lumbar vertebrae
- The right kidney is slightly more cranial and is more firmly attached
- is lateral the the aorta and the posterior vena cava
Renal
of, relating to, in the region of, the kidneys
the shape of most kidneys
bean
the shape of bird kidneys
3 lobed
shape of bovine kidney
multi lobed
the shape of a horse kidney
heart
Where is peri-renal fat located?
outside the kidney capsule
sometimes completely envelops the kidney (bovine)
what does peri-renal fat do?
protects
insulates
what is often called suet?
peri-renal fat
what are the 5 external renal structures
- anterior pole
- posterior pole
- capsule
- hilus
- renal artery and vein
anterior pole
external structure
cranial
rounded end of the kidney
posterior pole
external structure
caudal
rounded end of the kidney
Capsule
external structure
- tough, white connective tissue covering
- maintains the kidney shape
- when cut, the kidney tissue pops/bulges out
Hilus
external structure
- medial border of the kidney
- concave depression
- entrance for blood vessels and ureters (where everything enters and exits)
Renal artery
external structure
- derived from the aorta
- enters the kidney at the hilus
- more cranial
- smaller in diameter and stiffer
Renal vein
external structure
- joins the posterior vena cava
- exits the kidney at the hilus
what are the 4 major divisions of the kidney
- Cortex
- medulla
- renal pelvis
- renal papilla
cortex
internal division of the kidney
- is the outer/peripheral layer of the kidney
what 4 things does the cortex contain
most of the nephron:
1. glomerulus
2. bowman’s capsule
3. proximal convoluted tubule
4. distal convoluted tubule
loop of Henle is not in the cortex
Medula
internal division of the kidney
- pyramid shaped with the base towards the cortex and apex towards the hilus
what is the medula subdivided into?
Outer medulary zone
inner medulary zone
outer medulary zone
dark red
contains the loop of Henle and the collecting tubules
where is the loop of Henle located
outer medulary zone
inner medulary zone
lighter (tan-cream)
only contains the collecting tubules
Renal pelvis
internal division of the kidney
- is the expanded part of the ureter in the kidney
- receives the formed urine from the collecting tubules
varies with species
horse and sheep renal pelvis
the collecting tubules open into a lengthwise ridge
pig and primate renal pelvis
papillae empty into calyces (which open to the renal pelvis)
what don’t cows have
a renal pelvis
renal papilla
-the apex of papilla
- the point at which urine enters the minor calyx or pelvis
what are the 7 internal renal structures
- nephron
- glomerulus
- bowman’s capsule
- proximal convoluted tubule
- loop of hele
- distal convoluted tubule
- collecting tubule
Nephron
Internal renal anatomical structure
- the microscopic unit of structure and function in the kidney
- includes both the filtering and secretory part of the kidney
glomerulus
Internal renal anatomical structure
- capillary tuft, interposed during and arteriole
afferent arteriole: into
efferent arteriole: exiting
Bowman’s capsule
Internal renal anatomical structure
aka glomerular capsule
- expanded blind end of the nephron called the proximal convoluted tubule
renal corpuscle
Internal renal anatomical structure
glomerulus + Bowman’s capsule
proximal convoluted tubule
Internal renal anatomical structure
- longest and most winding of tubules
- cells lining the tube are columnar or cuboidal
- function is reabsorption
Loop of Henle
Internal renal anatomical structure
- descends into the medula and back up to the junction of the inner and outer medulla
where is the greatest concentration of urine found?
at the bottom of the U
What is the descending limb of the loop of Henle responsible for?
- reabsorption of water, sodium, chloride ions
- passive
- countercurrent exchange mechanism
describe the ascending limb of the loop of Henle
- impermeable to water and solutes
- active transport moves sodium and chloride into the peritubular space increasing their concentration
- this increase in concentration draws more water from the descending limb
distal convoluted tubule
- shorter
- less convoluted
collecting tubules
- The last part of the nephron
- arched at first then straight
- begins in the cortex, ends in the medula
- join to form a single papillary duct, opening to the papilla
tubular reabsorption
- process where glomerular filtrate substances are carried from the lumen of the tubules, across the lining of the cells, into the surrounding blood capillaries (peritubular capillaries)
- occurs in the PCT, loop of Henle
- due to the need by the body for certain substances to be retained
passive reabsorption
diffusion
osmosis
no energy required
active reabsorption
active transport
requires energy
filtration
- plasma moves from arteries into the nephron
- renal capsule
reabsorption
- select components to move from capillaries into the nephron
- passive and active
- PCT, the loop of Henle
secretion
- final few select components move from capillaries to the nephron
- active transport
- DCT
ureters
- muscular tubules (smooth muscle)
- internal transportation of urine (renal pelvis to urinary bladder)
- active process of peristalsis
enters the urinary bladder at an oblique angle (to prevent urine reflux) - transitional epithelium
urinary bladder
- hollow
- wall thickness varies with fullness
- peritoneum covers the cranial part
- trigone
urethra
- from the base of the urinary bladder to the ischial arch of the pelvis and enters the reproductive tract at the junction between the vagina and the vulva in females and in males it continues to the end of the penis
- transitional epithelium lining
micturition
urinating
- is both voluntary and involuntary
- is stimulated by the stretching of the bladder wall
- the brain can cause voluntary suppression of micturition
glomerulus filtrate composition
water
amino acids
glucose
small proteins
minerals
wastes
The main components of urine
- Fluids
- wastes: UREA, CREATININE, nitrates, uric acid, phosphates
- any substance that exceeded the threshold level
renal hormones
renin
erythropoietin
anti-diuretic hormone
renin
- glycoprotein-enzyme
- produced in the kidney (by juxtaglomerular cells)
- acts on angiotensinogen (changes into angiotensin l, ll, lll
- angiotensin lll: constricts blood vessels (increasing BP), acts on adrenal glands to release hormone aldosterone which circulates in the blood of the kidney, and acts on tubules to increase the reabsorption of sodium ( helps increase BP)
erythropoietin
- hormone/glycoprotein
- produced in the glomerulus in response to decreased oxygen levels in the afferent arterioles
- released into the bloodstream
- stimulated bone marrow to increase RBC creation
- corrects hypoxia by increasing oxygen-carrying capacity
anti-diuretic hormone
- secreted by the hypothalamus in response to intracellular osmolarity
diuretics
-any drug and or substance that will enhance the output of urine
what are the 3 types of diuretics
xanthines
osmotic pressures diuretics
enzyme blocking substances
glomerulonephritis
ANY inflammatory condition involving both the glomerulus and the tubules
nephritis
inflammation of the tubular part of the nephron including the proximal and distal convoluted tubule and loop of Henle
hydronephrosis
- fluid accumulation
- usually from obstruction of the ureter, causing a non-inflammatory condition in the nephron
- results in swelling of the ureter(s) and renal pelvis(es) and accumulation of urine in the kidney/nephrins
cystitis
inflammation of the urinary bladder wall
- often idiopathic
uremia
excess of urea, creatinine, and other nitrogenous end protein metabolism in the blood
- smells sweet
- seen in renal failure /disease
urinary calculi/uroliths
stones in the urinary tract
urolithiasis
condition of having urinary calculi/uroliths
cystoliths
uroliths in the bladder
nephroliths
uroliths in the kidney
FLUTD
feline lower urinary tract disease
- production of crystals and blood in the cat bladder, often results in frequent and painful urination
- obstructed male cats
- multifactor and can be idiopathic
pyelonephritis
infection of the upper UT, specifically the kidney
- more acute
- may also have fever, vomiting, kidney pain