Urinary System Flashcards
What is A and what is its structure and function?
Kidney
- S = bean-shaped organ, the size of a fist. Kidneys are retroperitoneal and the right kidney sits more inferior
- F = filter metabolic wastes out of blood to forming urine, secrete erythropoietin (hormone for RBC formation), produce renin (BP regulation), metabolise Vit D to its active form
What is C and what is its function?
Renal artery
- To transport oxygenated blood away from the heart, to the kidney
What is D and what is its function?
Renal vein
- To transport deoxygenated blood from the kidney to the heart
What is B and what is its function?
Medulla
- Regulates concentration of urine
What is A and what is its function?
Cortex
- Outer layer that protects medulla and renal pelvis
What is F and what is its function?
Renal pelvis
- Stores urine before sending it to the bladder via the ureters
Structure and function of a nephron
- S = microscopic structural and functional unit of the kidney
- F = filter blood and reabsorb needed substances into the blood
What is A and what is its function?
Afferent arteriole
- To deliver blood to the glomerulus for filtration
What is B and what is its function?
Efferent arteriole
- To transport filtered blood from the glomerulus back to general circulation (RBC and platelets remain in the blood)
What is C and what is its structure and function?
Glomerulus
- S = tuft of capillaries with small holes
- F = glomerular filtration: high pressure pushes small molecules (e.g. water, salts, amino acids) through the semi-permeable capillary walls and the Bowman’s capsule into the proximal convoluted tubule. Large substances e.g. blood cells and platelets should not pass through the capillary walls.
What is D and what is its structure and function?
Bowman’s capsule
- S = membranous, double walled capsule which surrounds the glomerulus
- F = receives the glomerular filtrate e.g. H2O, NaCl, amino acids, which passes through to the proximal convoluted tubule, NOT blood cells and platelets
What is E and what is its function?
Distal convoluted tubule
- Eliminate excess unwanted substances not already in filtrate e.g. K+, drugs, H+ ions (pH regulation), to form urine which is sent to the collecting duct
What is F and what is its function?
Proximal convoluted tubule
- Selective reabsorption of substances (water, glucose, amino acids, salts) from the glomerular filtrate back into the blood, based on need
NB can be passive or active depending on conc grad
What is G and what is its function?
Ascending loop of Henle
- To reabsorb salts which attract water to regulate blood volume and hence BP
What is H and what is its function?
Descending loop of Henle
- To reabsorb water to regulate blood volume and hence BP (this occurs first since water is more important than salt)
What is I and what is its function?
Collecting duct
- To collect urine from the nephrons and transport it to the renal pelvis
State the 3 steps (in order) of urine formation and where they occur
- Glomerular filtration (glomerulus and Bowman’s capsule)
- Selective reabsorption (proximal convoluted tubule and loop of Henle)
- Tubular secretion (distal convoluted tubule)
Features of healthy urine
- Clear, straw-coloured liquid due to excretion of bile pigments
- Large majority is water with some excreted wastes
What is B and what is its structure and function?
Ureter
- S = tubes consisting of a fibrous outer layer, smooth muscle and mucous membrane that connect the kidneys to the bladder
- F = to transport urine from the renal pelvis (kidney) to the bladder via peristalsis
What is C and what is its structure and function?
Bladder
- S = a distensible muscular sac (can contract and relax) which contains a detrusor muscle (allows it to contract to empty) and transitional epithelium (allows it to expand). Sphincters control the release of urine.
- F = to store urine prior to voiding (urination)
What happens to the bladder as people age?
Bladder capacity and tone decrease, leading to incontinence (leakage of urine) and more frequent micturition (urination)
What is D and what is its structure and function?
Urethra
- S = muscular tube that extends from the bladder to the outside of the body, surrounded by sphincters (male is longer, runs within the prostate gland and transports both urine and semen whereas female is shorter, only transports urine)
- F = to excrete urine from bladder to outside of the body
What are the main functions of the urinary system?
- Filter out waste, toxins and excess water from the blood, and excrete it through urine
- Regulate fluid balance and electrolytes (BP)
- Regulate pH (homeostasis)
- Stimulate RBC production
How does the urinary system help maintain BGL?
If BGL are too high then less glucose will be reabsorbed in the PCT and vice versa if too low
Explain how the respiratory and urinary systems work together to maintain blood pH
- Both work together to remove waste from the body
- Resp system removes CO2 upon exhalation to maintain blood pH
- Urinary system: proximal convoluted tubule absorbs bicarbonate ions back into the blood and distal convoluted tubule secretes H+ ions into the urine
What is osmoregulation?
Process of maintaining a stable water and salt concentration in the blood
Why does water passively follow salt
Because of osmosis: water moves from a high concentration to a low concentration down a concentration gradient (water will be in a high concentration where the concentration of salt is low)
How does water get in and out of our bodies?
- In: food and drinking water
- Out: urine, faeces, sweat, exhaled water vapour
List 4 ways that water balance is regulated
- Thirst response
- ADH (antidiuretic hormone)
- Aldosterone
- ANP (atrial natriuretic peptide)
Describe the thirst response
- Stimulus: insufficient water in blood
- Receptor: osmoreceptors in hypothalamus
- Coordinator: thirst centre in hypothalamus
- Effector: increased thirst, dry mouth sensation to prompt drinking water
- Response: increased water in blood back to WNL
Describe what occurs in terms of ADH production in response to low water levels
- Stimulus: low water levels
- Receptor and coordinator: osmoreceptors in hypothalamus
- Effector: pituitary gland releases ADH which increases permeability of CD and DCT to water, increasing water reabsorption, making urine more concentrated
- Response: increased water in blood back to WNL
Describe what happens regarding the production of ADH in response to high water levels
- Stimulus: high water levels
- Receptor and coordinator: osmoreceptors in hypothalamus
- Effector: ADH release from the pituitary gland is inhibited which decreases permeability of CD and DCT to water, decreasing water reabsorption, making urine less concentrated
- Response: decreased water in blood back to WNL
Describe what happens in terms of aldosterone production in response to high blood pressure
- Stimulus: high BP/water levels
- Receptor: kidney
- Effector: kidney inhibits renin production, so angiotensin is not converted into angiotensin II, leading to vasodilation. aldosterone secretion in the adrenal gland is also inhibited which decreases the permeability of the DCT and CD, decreasing reabsorption of salts which means less water is attracted into the blood.
- Response: decreased BP/water levels back to WNL
Describe what happens to aldosterone production in response to low BP/water levels
- Stimulus: low BP/water levels
- Receptor: osmoreceptors in hypothalamus
- Effector: kidney secretes renin, so angiotensin is converted into angiotensin II, leading to vasoconstriction. aldosterone is secreted by the adrenal gland which increases the permeability of the DCT and CD, increasing reabsorption of salts which attract water into the blood.
- Response: increased BP/water levels back to WNL
Describe what happens to ANP production in response to high BP
- Stimulus: high BP/water levels
- Receptor: stretch receptors in heart
- Effector: ANP (atrial natriuretic peptide) is secreted by the atria of the heart, decreasing the permeability of the DCT and CD, decreasing reabsorption of salts which means less water is attracted into the blood.
- Response: decreased BP/water levels back to WNL
Describe what happens to ANP production in response to low BP/water levels
- Stimulus: low BP/water levels
- Receptor: stretch receptors in heart
- Effector: ANP release (atrial natriuretic peptide) is inhibited by the atria of the heart, increasing the permeability of the DCT and CD, increasing reabsorption of salts which means more water is attracted into the blood.
- Response: increased BP/water levels back to WNL
How to maintain a healthy urinary system
- Urinate after sex to remove bacteria
- Wipe front to back to avoid bacterial transfer (females)
- Change underwear regularly
- Regularly do pelvic floor exercises (specific to urinary system)
Why are UTIs more common in females?
External orifice of the urinary tract is closer to the anal opening > risk of bacteria transfer
Why do we do UA?
It can indicate early signs of medical conditions such as diabetes, kidney disease, liver disease and gives an indication of the body’s ability to remove waste
Pyel/o
Ureter/o
Renal pelvis
Ureter
Vesic/o
Urin/o
Urinary bladder
Urine, urinary tract
Kal/i
Urethr/o
Potassium
Urethra
Cyst/o
Az/o
Urinary bladder
Urea, nitrogen
Cortic/o
Dips/o
Cortex (outer layer of kidney)
Thirst
Ren/o
Nephr/o
Kidney
Acid/o
Glomerul/o
Acid
Glomerulus
Ur/o
Urine, urinary tract
Anuria
Haematuria
Abnormal condition of no urine production
Abnormal condition of blood in the urine
Dysuria
Pyuria
Abnormal condition of painful urination
Abnormal condition of WBC/pus in the urine
Urinary retention
Nocturia
Inability of the patient to empty their bladder
Abnormal condition of excessive urination at night
Oliguria
Urinary frequency
Abnormal condition of low urine production
More frequent voiding than normal
Hypernatremia
Abnormal condition of excessive concentrations of sodium in the blood
Uremia
Polyuria
Abnormal condition of excessive urea levels in the urine
Abnormal condition of excessive excretion of urine
Dialysis
A process in which blood is diverted to an external machine to help filter blood in cases of kidney failure
Hypovolaemia
Nephrosis
Abnormally low blood volume
Disease of the kidney
Albuminuria
Glycosuria
Abnormal condition of protein in the urine
Abnormal condition of glucose in the urine
Enuresis
Diuresis
Abnormal condition of involuntary urination
Abnormal condition of excessive urination
