Lecture 26: Anatomy and Physiology II(urinary system) Flashcards
What are the functions of the kidneys?
- regulates composition and volume of extracellular fluid
- removes metabolic waste from blood and combines with excess water, electrolytes to form urine
- secretes erythropoietin hormone for red blood cell production
- secretes renin enzyme to maintain blood volume and blood pressure
- processes 180 L of filtrate daily
-filters entire plasma volume around 60x a day
-entire plasma volume is filtered every 22 minutes
-only less than one percent of fluids leaves body as urine
What is erythroproietin?
Hormone for red blood cell production
What is included or is the structure of the kidneys?
- hilum
- renal sinus
- renal medulla
What is the hilum?
The concave part of the kidney where it is the entrance/exit for blood vessels, nerves, lymphatic vessels, and ureter
What is the renal sinus?
It is the hollow chamber of the kidney
What is included in the renal medulla?
- renal pyramids
What is included in the renal pyramids
- renal papillae
What are renal pyramids in the renal sinus?
The striated conical tissue which is around 8 lobes
What is the renal papillae in the renal pyramids?
The small projections into minor calyx. Also, there are parallel bundles of urine collecting tubes
What is the renal medulla?
The middle part of the kidney
What is the renal cortex?
The granular shell around renal pyramids
What are renal columns in the renal cortex?
Cortex tissue that separates medulla
What are nephrons?
The functional unit of the kidney
How are the nephrons separated?
- renal corpuscle
- renal tubule
- collecting duct
What is the renal corpuscle composed of?
- glomerulus
- glomerular capsule
What is glomerulus in the renal corpsucle?
The tangled cluster of blood capillaries or the “glom” which is the ball of yarn
What is the glomerular capsule?
It surrounds the glomerulus and is Bowman’s capsule
What are some features of renal corpuscle?
- glomerulus
- glomerular capsule
What are some features of the renal tubule?
- proximal convoluted tubule
- loop of henle
- distal convoluted tubule
What is the loop of Henle
- descending limb of the nephron loop
- ascending limb of the nephron loop
What is the glomerular filtration?
The glomerular capillaries filter blood plasma
What are some features of glomerular filtration?
- Afferent(incoming) arteriole is larger than efferent(outgoing) arteriole
- blood pressure is greater for blood entering glomerulus
- blood plasma is filtered into glomerular capsule
- filtration rate is affected by constriction/dilation of blood vessels and plasma colloid pressure
- only molecules smaller than 3 nm pass freely through such as water, glucose, amino acids, nitrogenous waste. Also, blood cells or protein in urine indicated pathology
What is tubular reabsorption?
Renal tubules return dissolved material back to peritubular capillaries.
What is the process of tubular reabsorption?
- sodium ions is moved back by active transport
- water diffuses passively by osmosis
- Almost all water and sodium ions are reabsorbed
- Other chemicals reabsorbed: glucose, creatine, amino acids, urea, bicarbonate, potassium
What is tubular secretion?
Peritubular capillaries allow material to be transported to renal tubules such as drugs, histamine, hydrogen ions, ammonia, potassium, urea, creatine, and hormones
What is aldosterone?
It stimulates distal convoluted tubule to reabsorb sodium. Where the sodium moves into bloodstream and water follows
What is angiotensin II?
It stimulates secretion of aldosterone
What is antidiuretic hormone?
It increases water reabsorption by distal convoluted tubule
What is diabetes?
Continuous high blood sugar over time
What are the features of diabetes?
- kidney reach threshold of glucose reabsorption, excess glucose in nephron tubule
2.high osmotic pressure in nephron tubule inhibts water reabsorption
- increased urine output, dehydration, increased thirst, fruity odor in urine
What is involved in regulating blood volume?
- aldosterone
- angiotensin II
- Antidiuretic hormone
What is diuretic?
The process where it enhances urine output such as alcohol that inhibits aldosterone or caffeine that inhibits Na+ reabsorption, increases glomerular filtration(increased heart rate and blood flow)
What is the chemical composition of urine?
- Water: 95%
- urea
- uric acid
- creatinine
What is urea?
Breakdown of amino acids
What is uric acids?
The breakdown of nucleic acids
What is creatinine?
The breakdown of creatine used by skeletal muscles
What is the composition of urine color?
urobilin
What is urobilin?
The urochrome or the yellow pigment from destruction of heme
What are abnormal signs in urine?
- cloudy: bacteria
- food pigments: beets
- bile pigments
- blood
What is the pathway of urine elimination?
- nephron
- collecting duct
- renal papillae
- minor calyx
- major calyx
- renal pelvis
- ureter
- urinary bladder
- urethra
What is the ureter?
Lined with smooth muscle to move urine by peristaltic waves to urinary bladder
What is the urethra?
The tube from urinary bladder to outside the body
What is the urinary bladder?
The hollow organ that stores urine
What is the trigone?
The floor of urinary bladder that has 3 openings where 2 is the ureter and entrance and 1 urethra which is the exit
What is the detrusor muscle?
The smooth muscle of bladder that has the bladder walls, internal urethral sphincter, and is involuntary
What is mictruition?
The process that expels urine from urinary bladder
What is the process of urine elimination?
- stretch receptors stimulated as bladder fills
-triggers mictruition reflex - detrusor muscle contracts rhythmically
-sensation of urgency - urge begins as bladder fills to 150mL, but capacity is 600 mL
- Passed 300 mL, sensation intensifies and bladder wall contracts more powerfully
- Once contractions are strong enough, internal urethral sphincter is forced open
- External urethral sphincter (voluntary relaxes and bladder empties
