Urinary/Excretory System Flashcards
4 things the urinary/excretory system includes
Two kidneys
Two ureters
Urinary bladder
Urethra
Urine expelled from body via this system
Urinary/excretory system
Two ductless endocrine glands that have no functional relationship with the urinary system but sit on top of the kidneys
Suprarenal/adrenal glands
Bean-shaped bodies with convex lateral border and concave medial border
Slightly convex anterior and posterior surfaces
Divided into upper and lower poles
Left usually slightly longer and narrower than right
Situated retroperitoneal (behind the peritoneum) and are in contact with the posterior wall of the abdominal cavity
One lying on each side of and in the same coronal plane as L3
Superior aspect lies more posterior than inferior aspect
Each one lies in an oblique plane and is rotated about 30 degrees anteriorly toward the aorta (which lies on tip of the vertebral body)
Right slightly lower than/caudal to left because of the large space occupied by the liver
Supported in a fairly fixed position, partially through the fascial attachments and by surrounding organs
Have respiratory movement of approximately 1 in (2.5 cm) and normally drop no more than 2 in (5 cm) in change from supine to upright position
Kidneys
How long, wide and thick are the kidneys?
Approximately 4 1/2 in (11.5 cm) long, 2-3 in (5-7.6 cm) wide and 1 1/4 in (3 cm) thick
Where are the kidneys located in sthenic, hypersthenic and asthenic habitus?
Normally extend from level of the superior border of T12 to the level of the transverse processes of L3 in sthenic individuals; they’re higher in individuals with a hypersthenic habitus and lower in persons with an asthenic habitus
Outer covering of the kidney, semitransparent membrane that’s continuous with outer coat of the ureter
Renal capsule
Mass of fatty tissue each kidney is embedded in
Adipose capsule
Sheath of superficial fascia that is attached to the diaphragm, lumbar vertebrae, peritoneum and other adjacent structures that the adipose capsule and kidney are enveloped in
Renal fascia
Longitudinal slit on concave medial border of each kidney for transmission of blood and lymphatic vessels, nerves and ureter; expands into body of kidney to form renal sinus
Hilum
Hilum expands into body of kidney to form a central cavity
Fat-filled space surrounding renal pelvis and vessels
Renal sinus
Outer layer of renal tissue
Renal cortex
Inner layer of renal tissue that consists of renal pyramids
Renal medulla
8-15 cone-shaped segments of collecting tubules
Renal pyramids
Extensions of cortex between renal pyramids
Renal columns
Essential microscopic components of the kidneys
Each kidney contains approximately 1 million of these tubular structures
Nephrons
2 things the nephrons are composed of
Renal corpuscle
Renal tubule
Double-walled membranous cup of the renal corpuscle
Glomerular/Bowman capsule
Cluster of blood capillaries in glomerular/Bowman capsule
Formed by a minute branch of the renal artery entering the capsule and dividing into capillaries which turn back, and as the ascend, unite to form a single vessel leaving the capsule
Thin inner wall of the capsule closely adheres to the capillary coils and is separated by a comparatively wide space from the outer layer, which is continuous with the beginning of a renal tubule
Filter for blood, allowing fine particles and water to pass into the capsule
Change from filtrate to urine is caused in part by the water and the usable dissolved substances being absorbed through the epithelial lining of the tubules into the surrounding capillary network
Glomerulus
Vessel entering glomerular capsule
Afferent arteriole
Vessel exiting capsule
After exiting the glomerular capsules, these arterioles form the capillary network surrounding the straight and convoluted tubules, and these capillaries reunite and continue on to communicate with the renal veins
Efferent arteriole
2 parts of the renal corpuscle of the nephrons
Glomerular/Bowman capsule
Glomerulus
Part of nephrons continuous with glomerular capsule in the cortex of the kidney and then travels a circuitous path through the cortical and medullary substances
Renal tubule
3 things the renal tubule becomes
Proximal convoluted tubule
Neuron loop/loop of Henle
Distal convoluted tubule (opens into the collecting ducts)
Converge toward the renal pelvis and unite along their course to form a central tubule within the pyramid
Opens at renal papilla and rains into minor calix
Collecting ducts
Cup-shaped stems arising at the sides of the papilla of each renal pyramid
Each encloses one or more papilla, so there are usually fewer of these than pyramids
Calyces
Beginning branches of calyces (numbering 4-13) that unite to form two or three larger tubes = major
Minor calyces
Unite to form the expanded, funnel-shaped renal pelvis
Major calyces
Wide upper portion lies within hilum and its tapering lower part passes through the lower hilum to become continuous with the ureter (ureteropelvic junction [UPJ])
Renal pelvis
How long are ureters?
10-12 in (25-30 cm) long
Descend behind the peritoneum and in front of the psoas muscle and transverse processes of the L-spine
Convey the urine from the renal pelves to the bladder by slow, rhythmic peristaltic contractions
Supposed to have one on each side, may have two on each side
Ureters
Where are the ureters located?
Pass inferiorly and posteriorly in front of the sacral wing and then curve anteriorly and medially to enter the posterolateral (back/lateral) surface of the urinary bladder at approximately the level of the ischial spine
Musculomembranous sac that serves as a reservoir for urine
Located immediately posterior and superior to pubic symphysis (anterior rectum in males and anterior to vaginal canal in females; apex is anterosuperior aspect and adjacent to the superior aspect of the pubic symphysis)
Varies in size, shape and position according to its content; freely moveable and held in position by the folds of the peritoneum (when empty, located in the pelvic cavity; as it fills, it gradually assumes an oval shape while expanding superiorly and anteriorly into the abdominal cavity)
Adult one can hold approximately 500 mL of fluid when completely full; urge for micturition (urination) occurs when about 250 mL of urine is in the bladder
Ureters enter the posterior wall at the lateral margins of the superior part of its base and pass obliquely through the wall to their respective internal orifices (these two openings are about 1 in (2.5 cm) part when this is empty and 2 in (5 cm) when this is distended; the openings are equidistant from the internal urethral orifice which is situated at the neck of the this)
Urinary bladder
Lowest, most fixed part of the urinary bladder; rests on male’s prostate or female’s pelvic diaphragm
Neck
Triangular area of bladder base between three openings
Two for ureters and one internal urethral orifice
Mucosa over this is always smooth, whereas the remainder of the lining contains rugae when the bladder is empty
Trigone
Conveys urine out of the body
Narrow musculomembranous tube with a sphincter type of muscle at the neck of the bladder
Female: passes along the thick anterior wall of the vagina to the external urethral orifice, which is located in the vestibule about 1 in (2.5 cm) anterior to the vaginal opening
Male: extends from the bladder to the end of the penis
Urethra
What is the length of the urethra in males and females?
Arises at the internal urethral orifice in the urinary bladder and extends approximately 1 1/2 in (3.8 cm) long in females, 7-8 in (17.8-20 cm) long in males
3 portions of the male urethra
Prostatic
Membranous
Spongy
Portion of male urethra that is 1 in (2.5 cm) long; reaches from the bladder to the floor of the pelvis and is completely surrounded by the prostate
Prostatic