Anatomy
Where exactly are the kidneys located?
Posterior on the abdominal walls
Lateral to vertebral column
Both only partially protected by rib cage
List the functions/processes of the Urinary System
Filtering of Blood!
Filtrate is converted into Urine
Elimination of Metabolic waste, hormones & drugs
Regulation of Ions, Acid Base Balance & BP
You are planning to visit Denver Colorado on a trip with friends. How will your kidneys play a role in allowing your body to adjust to the higher elevation?
The Production and release of erythropoietin
• Higher elevation can cause lower blood oxygen
When released, this causes your red bone marrow to increase RBC production
True or False? The Kidneys are innervated by both divisions of the ANS
True!!
Though the effects of the PNS are unknown (innervation from Cranial Nerve x) , the SNS functions to decrease urine production during times of stress (innervation from T10-T12)
Why is the right Kidney 2cm inferior to the left Kidney?
Positioning due to accommodate the location of the Liver.
Liver is on right upper abdominal region, therefore the right Kidney is lower to make space.
What 2 Ions are secreted & reabsorbed to regulate the acid base balance? What are each's effect on Blood pH?
H+ Ions = the reabsorption into the bloodstream increases acidity and lowers blood pH
HCO3- (bicarb) = the reabsorption into the bloodstream increases alkalinity and raises blood pH
A man is stranded on an island and has to GREATLY ration his food supply. Through which process will his kidneys engage in to prevent hypoglycemia?
Gluconeogenesis, without proper nutrition (in instances of starvation or prolonged fasting) the kidneys will create glucose from non-carb sources
think gluco-NEO-genesis, creation of sugar from new sources
What is ANP? What is its affect on BP & the kidneys?
Peptide hormone released from cardiac muscle cells in response to stretch of atria in heart.
Increases GFR >>> Increases Urine production >>> Decreases Blood volume >>> Decreases BP
What is the name of the medial, concave surface of the kidney where vessels, nerves and ureter connects?
The Hilum
What is the functional unit of the Kidney & what does it consist of?
Consists of a Renal Tubule & Renal Corpuscle
How do the Kidneys function to regulate Blood pressure?
The secretion or reabsorption of water & ions.
The RAAS system (Renin-Angiotensin- Aldosterone)
There are 2 forms of Nephrons. What are the differences between them & which one makes up the majority?
Cortical Nephrons- Corpuscles oriented closer to renal cortex. Nephron loop is much shorter and barely passes through Medulla * 85% of nephrons belong to this category *
Juxtamedullary Nephrons- Renal corpuscles are oriented to the cortico-medullary junction (hence name) much longer nephron loops pass into medulla
*Longer loop of Jm Nephrons allows for Na+ concentration gradient
Where is the Fibrous Capsule? What is its significance?
External surface of kidney (think capsule = encloses kidney)
Maintains its structure and acts as a protective barrier to trauma and pathogenic microbes
* Dense Irregular Connective tissue + Adipose Connective tissue (cushions)
Describe the composition of Urine. Rank them from largest portion of Urine to smallest.
Can they be reabsorbed secreted or both?
Water (about 90-95%) secreted & reabsorbed
Salts - secreted & reabsorbed
Urea - produced from protein breakdown (secreted & reabsorbed)
Uric Acid - produced from nucleic acid breakdown in liver (secreted & reabsorbed)
Creatinine - produced from creatinine metabolism in muscle (Only secreted)
Renal autoregulation consists of what 2 controls for BP and GFR maintenance? Which is dominant?
Myogenic response: Contraction or relaxation of smooth muscle of afferent arteriole in response to stretch
* more dominant, low BP = dilation >>> more blood flow
Tubuloglomerular feedback mechanism
• “Backup system” to increased blood pressure
• If glomerular blood pressure increased
• Amount of NaCl in tubular fluid also increased
• Detected by macula densa cells in juxtaglomerular apparatus
• Results in further vasoconstriction of afferent arteriole
Explain why there might be Glucose present in a person's urine
If the transport maximum for Glucose is reached and the levels of Glucose exceeds the availability for carrying, it is excreted into the Urine
Hyperglycemia >>> Glucose into the Urine (Glucosuria)
A common symptom for Diabetes M
Starting at the Minor Calyx, what is the pathway of Urine through the kidney and out the body?
Minor calyx >>>major calyx >>> renal pelvis >>> ureter >>> urinary bladder >>> urethra >>> out of body
What 4 major structures/organs comprise the Urinary System? What are their functions?
Kidneys, filter blood + Remove waste products and convert filtrate into urine
• Ureters, transport urine>> From kidneys to urinary bladder
• Bladder - Stores as much as 1 L urine
• Urethra: eliminates urine from body(from bladder to external)
Describe the difference between filtration, reabsorption and secretion
Glomerular filtration- movement of substances from blood within Glomeruli >>> into capsular space (filtered inside Glomerulus)
Tubular Reabsorption- movement of substances from tubular fluid >>> back into the blood (reabsorbed into blood)
Tubular Secretion- movement of substances from blood >>> into tubular fluid (secreted into tubule)
What is the "Blood pressure" inside the Glomerulus and what 2 other pressures oppose it?
Glomerular hydrostatic (blood) pressure (HPg)
pushes out water + ions out of Glomeruli >>> ino capsular space
opposed by
Blood colloid osmotic pressure (OPg)
pressure by dissolved solutes that "sucks" fluid back into Glomerulus
Capsular hydrostatic pressure (HPc)
Pressure in glomerular capsule due to filtrate that barriers the movement of additional fluid into the Glomerulus