urinary system Flashcards
what are the functions of the urinary system
- Filter blood
- Regulate blood volume
- Regulate concentration of blood solutes
- Regulate pH of extracellular fluid
- Regulate blood cell synthesis
- Synthesis in the active form of vitamin D
what is the external anatomy of the kidney
renal capsule, perirenal fat, renal fascia, hilum
what is the internal anatomy of the kidney
cortex, medulla, calyces, renal pelvis, ureter
what is the functional unit of the kidney
nephron
what are the parts of the nephron
i. Renal corpuscle
ii. Proximal convoluted tubule
iii. Loop of henle
iv. Distal convoluted tubule
v. Collecting ducts
What is the order of urine formation in the nephron?
Nephron, renal pelvis, ureters, urinary bladder, urethra
Name the 3 processes by which urine formation is categorized
1.golumlar Filtration
2.Tubular reabsorption
3.Tubular secretion
What is filtrate
it is the pre form of urine, but when it exists the body it is called urine
- Filtration pressure determines
the amount of filtrate formed
What is the glomerular filtration rate
The volume of filtrate formed by both kidneys per min
what is the bowmans capsule
- Enlarged end of the nephron
- Indented to form a double-walled chamber
- Surround glomerulus
what is the glomerular capillary
- Network of capillaries
- Blood enters afferent arteriole
- Exits efferent arteriole
what is a podocyte
these wrap around the glomerular capillaries
what is the main function of the juxtaglomerular apparatus
Releases renin which regulates blood pressure
- main site of renin production
Juxtaglomerular cells
ring of smooth muscle that lines the afferent arteriole entering bowmans capsule, Secretes renin which is important in regulation of blood pressure
Macular densa
specialized tubule cells of the distal convoluted tubule, responds to changes in the sodium chloride levels in the distal convoluted tubule
Which part of the nephron is involved during tubular reabsorption
Peritubular capillaries
Major site of reabsorption
proximal convoluted tubule
How do solutes transport through the nephron during the reabsorption
Solutes are transported by active transport and co transport
how is water get transported
through osmosis
ascending loop of Henle in tubular reabsorption
impermeable to water but still permeable to solutes
- The water stays in the filtrate
- Not allowing water or solute to pass through
descending loop of Henle in tubular reabsorption
water exits osmosis and solutes enter
- Permeable to water (squamous cells)
- Additional 15% of filtrate volume is reabsorbed
How does diabetes impact filtrate volume? In other words, do diabetes patients produce higher volume of filtrate or lower volume of filtrate?
- People with diabetes cannot reabsorb 100% of glucose because the concentration of glucose in the filtrate exceeds the capacity of transporters. Not enough transport proteins to take enough glucose back
- Glucose in the filtrate draws water into the convoluted tubule which increases filtrate volumes
What is tubular secretion
Solutes are secreted from the blood into the filtrate
where does tubular secretion take place in the nephron
distal convoluted tubule
Give examples on what types of solutes or substances can be secreted directly into filtrate?
Urea, creatinine, sulfates, phosphates and nitrates
Renin-angiotensin-aldosterone
Stimulated by low blood pressure. Changes of the blood pressure will send signal to juxtaglomerular cells to secrete an enzyme aldosterone.
ADH
Stimulated by decreased blood pressure or increased blood osmolality.
What are the 2 common substances that can affect ADH release? What happens if ADH is blocked?
Caffeine and alcohol
glomerular filtration
movement of substances from the blood within the glomerelus into the capsular space
tubular reabsorption
tubular secretion
