Urinary System Flashcards
3 functions of the urinary system:
1) Excretion
2) Elimination
3) homeostatic regulation of blood plasma and solute concentration
5 Homeostatic Functions of Urinary System:
1) Regulates blood volume and blood pressure
2) Regulates plasma ion concentrations
3) helps stabilize pH
4) Conserves valuable nutrients
5) Assists liver in detoxifying poisons
Where is the external urethral sphincter located?
In the urogenital diaphragm
What is the muscle contained in the muscularis layer of the bladder?
Detrusor muscle
3 regions of male urethra:
1) Prostatic
2) Membranous
3) Spongy
Another word for peeing?
Micturition
External Urethral Sphincter voluntary or involuntary?
Its under voluntary control
How much blood flow through the kidneys?
1200 ml per minute
From where does the kidney receive blood from?
Renal Artery
What is the functional unit of the kidney?
The nephron
What branches from the cortical radiant arteries and delivers blood to the glomerulus?
Afferent Arterioles
What two things make up the renal corpuscle?
Bowman’s capsule and the glomerulus
Where does filtration occur in the nephron?
The renal corpuscle.
What receives fluid from many different nephrons, begins in the renal cortex, and carries fluid to the papillary duct?
The Collecting Duct
What kind of nephrons are responsible for most of the kidney’s filtration, and are 85% of all nephrons?
Cortical Nephron
Which kind of nephron has a large descending loop of Henle that descends all the way into the medulla and in which the peritubular capillaries connect to the vasa recta?
Juxtamedullary Nephrons
What’s another name for visceral epithelium cells and what are contained in them?
Podocytes: Pedicles (Little Feet) and Filtration Slits (the finest filters)
What are excluded in the passive filtration process in the glomerulus?
Larger solutes, such as plasma proteins
What is the Glomerular Filtration Rate?
125 mL/min, makes 180 liters of filtrate a day
How does the autoregulation of the Glomerular Filtration Rate (GFR) work?
regulates pressure by changing the diameter of the efferent and afferent arterioles and the glomerular capillaries
How do you increase GFR filtration?
Dilation of afferent arteriole and glomerullar capillaries, and constriction of the efferent arteriole
What are the 3 stimuli that cause JGA to release renin?
1) decreased blood pressure at glomerulus
2) sympathetic innervation of juxtaglomerular cells
3) decreased osmotic concentration at the distal convoluted tubule
What converts Angiotensinogen to Angiotensin I?
Renin
What converts Angeiotensin I to Angiotensin II?
ACE (angiotensin-converting-enzyme)
What are the 5 functions of Angiotensin II?
1) Constricts efferent arterioles of nephron / elevates glomerular pressures and filtration rates
2) reabsorption of Na+ at PCT
3) Stimulates secretion of aldosterone which increases absorption of Na+ in DCT
4) Stimulates thirst
5) triggers release of ADH which stimulates reabsorption of water in DCT
What do the Natriuretic Peptides do?
trigger dilation of afferent and constriction of efferent arterioles.
Elevates glomerular pressures and increases GFR
Decreases reabsorption of Na+
Where does most reabsorption take place?
Proximal Convoluted Tubule >65%
The thin descending loop of Henle is permeable to what?
Water, not solutes
What does the thick ascending Loop of Henle do?
actively absorbs Na+ and Cl, not water or solutes
What is the process called that occurs between the thick and thin loops of Henle involving reabsorption exchange of water and absorption of 2/3 of Na+ & Cl?
Countercurrent multiplication
What happens in countercurrent multiplication concerning ions?
Ion concentration in tubular fluid declines
Main function of DCT?
Selective reabsorption or absorption, making final adjustments in solute concentration and volume of tubular fluid
What is the hormone Aldosterone?
Stimulates synthesis and incorporation of Na+ in the permeable membrane of the DCT and collective duct; reduces sodium lost in urine and retains sodium in blood
What controls volume of water along the DCT and collective duct?
Facultative Water Reabsorption
What is the hormone that causes special water channels to appear in the DCT and collective duct?
ADH (antidiuretic hormone)
What continuously produces at least a small amount ADH?
Hypothalmus
Is the external urethral sphincter voluntary or involuntary?
Voluntary
