Renal system

What percentage of total Cardiac Output (CO) is typically processed by the kidneys?

20-25%

How do the kidneys adjust blood volume?

By either retaining or excreting water.

The kidneys adjust electrolyte concentrations through the processes of _____.

Reabsorption or secretion

Why can the kidneys only manipulate existing quantities of substances rather than creating extra?

They are filtration organs that regulate what is already present in the blood.

Which hormone produced by the kidneys stimulates the production of red blood cells?

Erythropoietin

What is the primary function of the hormone Renin?

It regulates salt retention.

How do the kidneys contribute to the regulation of blood pH?

By regulating the concentration of Hydrogen (H+) ions.

Urine moves from the renal pelvis into which structure to reach the bladder?

The ureter.

Which structure connects the urinary bladder to the outside of the body for urine release?

The urethra.

The _____ is the smallest functional unit of the kidney, comparable to a sarcomere in muscle.

Nephron

Which two major regions of the kidney are covered by the nephrons?

The renal cortex and the renal medulla.

Sequence: Segmental artery → _____ → Arcuate artery → Cortical radiate artery.

Interlobar arteries

Where is the arcuate artery specifically located within the kidney?

On the transition between the renal cortex and the renal medulla.

What is the primary anatomical difference between the renal artery pathway and the renal vein pathway?

The renal vein pathway has no segmental vein.

What are kidney stones primarily composed of?

Crystallized minerals or waste products, most commonly hardened calcium.

Why does dehydration increase the risk of kidney stone formation?

The concentration of minerals becomes too high to dissolve naturally.

Where do large kidney stones typically get stuck, obstructing urine flow?

The renal pelvis.

Alpha blockers used to treat kidney stones target which specific receptors?

alpha-1 Adrenergic receptors.

Which medical treatment uses shock waves to break kidney stones into smaller pieces?

Lithotripsy.

What are the two main functional components of a nephron?

The vascular component (filtration) and the tubular component (urine production).

In nephron diagrams, what color is typically used to represent the vascular portion?

Red or blue.

In nephron diagrams, what color is typically used to represent the tubular portion?

Yellow or tan.

Blood enters the nephron's vascular portion through the _____ arterioles.

Afferent

Blood leaves the glomerulus through which vessels?

Efferent arterioles.

What is the function of the vasa recta in the nephron?

It acts as the junction for exchange between the vascular and tubular sections.

Why is the tubular nephron only a single cell layer in thickness?

To allow for easier diffusion of substances.

Which tubular structure collects filtered fluid directly from the glomerular capillaries?

Bowman's Capsule (or Glomerular Capsule).

What is the next tubular section fluid enters after leaving the Bowman's Capsule?

The proximal tubule.

The Nephron Loop (Loop of Henle) consists of which two tracks?

The descending limb and the ascending limb.

What is the direction of fluid movement in the ascending limb of the Loop of Henle?

Upward.

The _____ is a 'quality control' center created where the ascending track passes the glomerulus.

Juxtaglomerular apparatus

Which hormone system does the juxtaglomerular apparatus use to regulate kidney function?

The Renin-Angiotensin system.

After passing the juxtaglomerular apparatus, fluid travels through the _____ tubule.

Distal

Approximately how many nephrons empty fluid into a single collecting duct?

Up to 8.

Sequence: Collecting Duct → _____ → major Calyx → Renal Pelvis.

Minor Calyx

Concept: Plasma Clearance

Definition: The volume of plasma from which a substance is completely removed per minute.

How does the process of reabsorption affect the rate of plasma clearance?

It reduces plasma clearance by returning substances to the blood.

How does the process of secretion affect the rate of plasma clearance?

It increases plasma clearance by moving substances from capillaries into the tubules.

What physiological rate is calculated using plasma clearance data?

Glomerular Filtration Rate (GFR).

Why is Probenecid sometimes administered alongside penicillin?

To slow down filtration/secretion and allow penicillin to maintain its effect longer.

Why is Inulin used to measure Glomerular Filtration Rate (GFR)?

It is filtered but neither reabsorbed nor secreted.

Scenario: If a substance is filtered but not reabsorbed or secreted, its plasma clearance equals _____.

The GFR.

Scenario: If a substance is filtered and reabsorbed but not secreted, its plasma clearance is _____ than the GFR.

Less

Nearly 100% of which two nutrients are typically reabsorbed from the tubules back into the body?

Glucose and Amino Acids.

The presence of excess glucose in the urine is a clinical indicator of which condition?

Diabetes Mellitus.

Which molecule is injected to measure total renal blood flow?

Para-aminohippurate (PAH).

Scenario: If a substance is filtered and secreted but not reabsorbed, its plasma clearance is _____ than the GFR.

Greater

What would a high concentration of Para-aminohippurate (PAH) remaining in the blood after passing through the kidneys indicate?

Reduced renal blood flow or impaired secretion.

What is the physiological process of contractions that move urine from the kidneys to the urinary bladder?

Peristalsis

The primary muscle responsible for contraction of the urinary bladder is the _____.

Detrusor Muscle

Which branch of the autonomic nervous system primarily controls the detrusor muscle?

Parasympathetic nervous system

Where is the internal urethral sphincter located?

At the beginning of the urethra.

Under what physical condition does the internal urethral sphincter normally open?

When it is stretched.

How does the control of the external urethral sphincter differ from that of the internal sphincter?

The external sphincter is under voluntary control via motor neurons.

What is the natural state of the external urethral sphincter when not actively being inhibited?

Closed or contracted.

In the process of urination, the clinical term for the act of voiding the bladder is _____.

Micturition

What event during bladder filling triggers the initial urge to urinate?

The stretching of the detrusor muscles.

Which occurs first: the urge to urinate or the stretching open of the urethral sphincters?

The urge to urinate.

What is the primary function of the Guarding Reflex?

To override micturition and prevent involuntary urination while the bladder fills.

During the Guarding Reflex, what happens to the parasympathetic nerves controlling the bladder?

They become inhibited to allow the detrusor muscle to stretch.

How do motor neurons contribute to the Guarding Reflex?

They activate to keep the external sphincter closed.

The Micturition Reflex is alternatively known as the _____ reflex.

Voiding

Which two structures primarily oversee the Micturition Reflex?

Stretch receptors and detrusor muscles.

What change in parasympathetic activity occurs when the bladder reaches maximum stretch during the voiding reflex?

The parasympathetic system becomes stimulated.

How do motor neurons respond during the Micturition Reflex to allow urination?

They become inhibited, causing the external sphincter to relax.

Which higher brain regions are responsible for controlling the Guarding and Voiding reflexes?

The Frontal Cortex and the Insula.

Concept: Urinary Incontinence

Definition: The involuntary loss of bladder control.

What specific type of incontinence is triggered by coughing, sneezing, or laughing?

Stress incontinence.

In males, what medical condition is a common cause of urinary incontinence?

Prostate issues.

What is the physiological hallmark of an Overactive Bladder (OAB)?

Loss of control over the detrusor muscle, leading to uncontrolled contractions.

Which clinical test involves filling the bladder with warm fluid to measure pressure and compliance?

Cystometric test.

List the three main systems that regulate acid-base balance in the body.

The chemical buffer system, the pulmonary system, and the kidneys.

What is the primary limitation of the H2 CO3 HCO3- chemical buffer system?

It cannot resist acidity changes over the long term.

How does the pulmonary system contribute to the removal of acid from the body?

By eliminating CO2.

Why are the kidneys considered the most effective line of defense against acidity despite being the slowest?

They can physically remove H+ ions from the body.

Which three substances are the primary tools used by the kidneys for acid-base regulation?

Hydrogen, Bicarbonate, and Ammonia.

In the nephron, Hydrogen (H+) ions are filtered and secreted but are never _____.

Reabsorbed

How does the kidney's handling of Bicarbonate (HCO3-) change in response to high blood acidity (high H+)?

Bicarbonate reabsorption increases to act as a buffer.

Under normal homeostatic conditions, what percentage of filtered bicarbonate is reabsorbed in the proximal tubule?

Up to 90%.

What is the minimum pH limit below which the nephrons can no longer produce urine?

pH 4.5

Why must the kidneys utilize Ammonia (NH3) and Phosphate (PO4) rather than relying solely on Bicarbonate for urinary buffering?

Bicarbonate is mostly reabsorbed for use in the blood and lungs, leaving the urine unbuffered.

By what mechanism does Ammonia (NH3) buffer the urine?

It absorbs H+ to become Ammonium (NH4+).

From which biological molecules is Ammonia derived as a by-product?

Proteins and amino acids.

How many Hydrogen molecules can a single Phosphate (PO4) molecule absorb?

Up to three.

What is the general physiological effect of diuretics on blood volume and pressure?

They decrease both blood volume and blood pressure.

Why are patients on low-sodium diets and diuretics often prescribed aldosterone blockers?

To prevent excessive potassium loss (often alongside potassium supplements).

Concept: Acute Renal Failure

Definition: Kidney dysfunction occurring rapidly over the course of hours or days.

Which renal condition is characterized by inflammation of the glomerulus and impaired filtration?

Glomerulonephritis

What are the two common primary causes of Glomerulonephritis?

Infections or autoimmune disease.

Define renal insufficiency.

The state where nephrons are damaged or destroyed.

Which medical procedure serves as an 'artificial kidney' to remove wastes from the blood?

Dialysis

Concept: Hemodialysis

Definition: The process of passing blood through dialysis fluid to remove metabolic wastes.

How many times per week is dialysis typically required for patients with renal failure?

3 to 4 times a week.

The _____ reflex involves the activation of motor neurons to keep the external sphincter closed during bladder filling.

Guarding

Which diuretic type acts specifically on the thick ascending limb of the loop of Henle?

Loop diuretics

Where do Thiazide diuretics primarily exert their effect in the nephron?

The distal convoluted tubule.

Carbonic anhydrase inhibitors primarily target which section of the nephron?

The proximal convoluted tubule.

What is the function of Potassium-sparing diuretics in the collecting duct?

To promote sodium excretion while preventing potassium secretion.

The urge to urinate initiates _____ the sphincters are forced open by stretching.

Before

Which clinical condition might result from childbirth or aging in females?

Urinary incontinence.