32 Questions
Which region of the kidney is located outermost?
Renal cortex
What is the function of the renal pyramids?
To collect urine
What is the term for the narrow end of the renal pyramid?
Renal papilla
How many nephrons are found in each kidney?
1 million
What is the term for the capillary beds that reabsorb in the medulla?
Vasa recta
What is the function of the juxtaglomerular apparatus?
To regulate blood pressure
What is the term for the process of forming urine in nephrons and collecting ducts?
Urine formation
What is the term for the cells that produce renin and erythropoietin?
Juxtaglomerular cells
What is the consequence of a low GFR?
Certain waste products may not be adequately excreted
What is one way the body regulates GFR?
By changing the glomerular capillary surface area
What is the effect of constricting the afferent arteriole?
Decreases blood flow into the glomerulus
What system of hormones and enzymes helps control blood pressure?
The renin angiotensin aldosterone system
What is the function of the collecting ducts?
To release urine into the renal pelvis
What is the function of peristalsis in the ureters?
To aid in urine transport
What is the difference in urethral length between males and females?
Males have a longer urethra
What is a unique function of the male urethra?
Is a passageway for sperm cells
What is the main function of the kidneys in regulating blood ionic composition?
Regulating the blood levels of several ions, such as Na+, K+, Ca2+, and Cl-
What is the primary function of the ureters in the urinary system?
To transport urine from the kidneys to the urinary bladder
What is the location of the adrenal glands in relation to the kidneys?
At the top of each kidney
What is the name of the hormone produced by the kidneys that helps regulate calcium homeostasis?
Calcitriol
What is the term for the scientific study of the anatomy, physiology, and pathology of the kidneys?
Nephrology
What is the function of the kidneys in regulating blood volume?
By conserving or eliminating water in the urine
What is the waste product produced by the breakdown of muscle fibers that is excreted by the kidneys?
Creatinine
Where are the kidneys located in the body?
Against the dorsal body wall (retroperitoneal structure)
What is the percentage of glomerular filtrate that returns to the bloodstream via tubular reabsorption?
99-100%
What is the function of the filtration membrane?
To permit the filtration of water and small solutes but prevent the filtration of plasma proteins and blood cells
What is the average glomerular filtration rate (GFR) in males?
125 mL/min
What is the main function of tubular secretion?
To secrete waste materials into the glomerular filtrate
What is the daily volume of glomerular filtrate in adult males?
180 liters
What would happen if the glomerular filtration rate (GFR) is too high?
Needed substances would be lost in the urine
What is the purpose of the glomerular capillaries and podocytes?
To form a leaky barrier for filtration
What is the term for the amount of blood plasma that becomes glomerular filtrate?
Filtration fraction
Study Notes
Urinary System Overview
- The urinary system consists of two kidneys, two ureters, one urinary bladder, and one urethra.
- The kidneys filter blood plasma, return most water and solutes to the bloodstream, and excrete the remaining waste as urine.
Kidney Functions
- Regulation of blood ionic composition (Na+, K+, Ca2+, Cl-)
- Regulation of blood pH (H+, HCO3- levels)
- Regulation of blood volume (conserving or eliminating water in urine)
- Production of hormones:
- Calcitriol (vitamin D) for calcium homeostasis
- Erythropoietin for red blood cell production
- Renin for blood pressure regulation
- Excretion of wastes and foreign substances (ammonia, urea, bilirubin, creatinine, uric acid)
Kidney Structure
- Located against the dorsal body wall (retroperitoneal structure)
- Attached to ureters, renal blood vessels, and nerves at the renal hilum
- Composed of:
- Renal cortex (outer region)
- Renal medulla (inner region)
- Renal pelvis (inner collecting tube)
- Renal pyramid and its overlying cortex
Nephron Structure and Function
- The structural and functional units of the kidneys (1 million in each kidney)
- Responsible for forming urine
- Composed of:
- Glomerulus
- Renal tubule
- Glomerular capsule
- Proximal convoluted tubule
- Loop of Henle (descending and ascending limbs)
- Distal convoluted tubule
- Collecting duct
Renal Vasculature
- Vascular system:
- Afferent arteriole
- Glomerulus
- Efferent arteriole
- Peritubular capillaries (reabsorption in cortex)
- Vasa recta (reabsorption in medulla)
Glomerular Filtration
- The fluid that enters the capsular space is called the glomerular filtrate
- Filtration fraction: the amount of blood plasma that becomes glomerular filtrate
- Daily volume of glomerular filtrate in adults: 150 liters (females) and 180 liters (males)
Glomerular Filtration Rate (GFR)
- The amount of filtrate formed in all renal glomeruli of both kidneys each minute
- Average GFR in adults: 125 mL/min (males) and 105 mL/min (females)
- Regulated by:
- Blood flow into and out of the glomerulus
- Glomerular capillary surface area available for filtration
Urine Collection and Transport
- Collecting ducts release urine into minor calyx → major calyx → renal pelvis → ureter
- Ureters: tubes attaching the kidney to the bladder
- Urinary bladder: smooth, muscular sac that temporarily stores urine
- Urethra: thin-walled tube that carries urine from the bladder to the outside of the body by peristalsis
Urethral Differences between Males and Females
- Length: females (3-4 cm) vs. males (20 cm)
- Location: females (along the wall of the vagina) vs. males (through the prostate and penis)
- Function: females (only carries urine) vs. males (carries urine and sperm cells)
This quiz covers the anatomy and physiology of the urinary system, including the kidneys, ureters, urinary bladder, and urethra.
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