BIOL111-L8-UrinarySystem

Urinary System Overview

• Course: BIOL111 - 202510

• Figures: Made with BioRender.com unless specified otherwise.

Study Tips

Learning from Test Results

• Evaluate Test Results: Review exam details to identify strengths and weaknesses.

  • Analyze wrong answers: What mistakes were made?

  • Assess right answers: Identify strengths.

• Exam Preparation: Reflect on preparation strategies.

  • What effective material was studied?

  • What elements surprised you?

• Evaluation: Examine each question to implement corrective steps for improved performance.

  • Source: Modified from Usask University Success.

Types of Errors in Exams

Study and Preparation Errors

• Did not study enough material for certain questions.

• Failed to prepare adequately.

Focus Errors or Carelessness

• Ran out of time during the test.

• Confused terms or concepts.

• Misread or misunderstood questions.

Mechanical Errors

• Miswriting or improperly erasing answers on the answer sheet.

• Skipped questions without revisiting them.

Corrective Steps

• Practice predicting possible questions.

• Join study groups for collaborative learning.

• Read through the entire test before starting.

• Allocate time wisely during the exam; take breaks if necessary.

• Seek supplemental help from instructors and attend all review sessions.

• Regularly schedule study sessions and avoid rushing through tests.

  • Source: Modified from Usask University Success.

Correcting Mistakes

• Process of Correction:

  • MCQ: Write out question with the right answer.

  • FIB: Add the correct answers.

  • SA: Fully and correctly respond to questions.

• Integration: Incorporate corrected exams into study guides; research any misunderstood topics.

  • Source: Modified from Usask University Success.

Housekeeping for Exams

• Accommodations: Book necessary accommodations for finals before April 4, 2025.

• Midterm Grades: Curved grades will be factored into final grades (available on URCourses).

• Exam Pickup: Scheduled sessions in Regina and Saskatoon from March 12 through March 25, 2025.

Functions of the Urinary System

• Regulates blood pressure- blood volume

• Eliminates wastes from the body.

• Regulates ions and solutes in blood.

• Forms calcitriol, crucial for calcium balance. Active form of vitamin D. Required for absorption of Ca & P

• Produces and releases erythropoietin, which stimulates red blood cell production. Stimulates erythrocyte production

• Engages in gluconeogenesis during fasting or starvation. Create glucose from non-carbohydrate forms

Kidney Anatomy

• Kidney Locations:

  • T10 to L3 vertebrae region.

  • Left kidney is between T12-T3

  • Adrenal gland sits on top of kidney

• Kidney Structure:

  • Renal Cortex: The outer region of the kidney.

  • Renal Medulla: The inner region.

  • Renal Columns: Connective tissue extensions of the cortex.

    • Divide the kidney into 6-8 lobes

    • They provide frame work for vessels to enter &exit

  • Calyces: Cavities that collect urine.

    • Minor calyx

    • Major calyx

    • Renal pelvis

Blood Flow through Kidneys

• Renal artery branches into smaller vessels.

• Afferent arteriole enters the glomerulus; efferent arteriole leaves it.

• Splits into peritubular capillaries and vasa recta for nutrient and waste exchange.

Nephrons and Their Functions

• Nephron Structure: Functional units of the kidney that modify filtrate into urine. Includes components such as:

• Renal Capuscle-Filter blood plasma based on particle size

• Renal tubule- Secretion & reabsorption

  • Glomerular capsule

  • Proximal convoluted tubule

  • Nephron loop

  • Distal convoluted tubule

  • Collecting tubule and duct.

• Functions of Nephrons:

  • Filtration, reabsorption, and secretion to balance plasma and excrete toxins.

    • Filtration- blood enters glomerulus, forces fluid into nephron

    • Reabsorption- moving nutrients & water back into bloodstream

    • Secretion- moves nutrients & water from capillaries to tubule, from blood to tubular fluid

  • To balance plasma to homeostatic set point & excrete toxins

Filtration Process in Nephrons

• Plasma moves from the afferent arteriole through the glomerulus into the nephron where:

  • Filtrate passes through a filtration membrane created by podocytes and fenestrated glomerular capillaries.

• Regulators of Filtration:

  • Fenestrations, charges in the filtration membrane, and podocyte structures. Filters based on size

  • Membrane charge - Protein embedded within pores are negatively charged

  • Basement membrane - Proteins medium - large based on size

Juxtaglomerular (JG) Apparatus

• Located at the connection of afferent/efferent arterioles and initial DCT (Distal Convoluted Tubule)

• Macula Densa: Monitors fluid composition, especially sodium and chloride concentrations (NaCl) - signalling for renin release

• Granular Cells: Modified smooth muscle cells that regulate blood flow. Can contract or relax- make & release renin

Glomerular Filtration Rate (GFR)

• Defined as the volume of filtrate formed by both kidneys per minute, influenced by hydrostatic and colloid osmotic pressures across the glomerulus.

Nephron Transport Mechanisms

• Substance Reabsorption Details:

  • Glucose, proteins, sodium, water, bicarbonate, calcium, phosphate, potassium, and drugs with their respective transport methods and sites.

• The role of ADH and aldosterone in regulating water and sodium reabsorption is highlighted.

Countercurrent Mechanisms in Nephrons

• Nephron Loop Functionality: Specialized to recover water and sodium.

• Countercurrent Multiplier: Fluids flow in opposite directions, enhancing the concentration of the kidney's interstitial fluid.

• Concentration of Urine: Mechanisms maintaining the osmotic gradient, including urea recycling. AIDS in water recovery

Hormonal Regulation of Fluid Volume

• Hormones:

  • ANP (Atrial Natriuretic Peptide)

  • Aldosterone

  • ADH (Antidiuretic Hormone)

• Each hormone's trigger, action sites, and physiological effects are discussed in detail.

• Baroreceptor detect high BP= high blood volume

  • high APs to CNs= Vasodilation- afferent arteriole

  • High GFR = high urine = low bp

Diuretics

• Overview of what diuretics are and their effect on urine production and blood pressure. Common diuretics include caffeine and alcohol.

• Substances that increase excretion of urine

Renal Failure

• Definition and implications of renal failure, including clinical outcomes and treatment options (dialysis, transplantation).

Characteristics of Urine

• Urine characteristics vary based on hydration, health, and nutrient intake:

  • Normal values for color, volume, pH, presence of proteins, glucose, nitrites, and blood.

Urinalysis

• Uses of urinalysis in detecting renal diseases by analyzing urine composition, tests for blood cells, proteins, etc.

Ureters and Bladder Functions

• Ureters: Transport urine via peristalsis from the renal pelvis to the bladder.

  3 tunics

  • Mucosa - distensible, impermeable to urine

  • Musculauis - smooth muscle

  • Adventitio

• Bladder: Collects, stores urine, composed of detrusor muscle

  • Inner layer- transitional epithelium, allows for fluctuation in volume

  • 1.) Internal splinter- involuntary

  • 2.) external splinter- voluntary, somatic NS, skeletal muscle

Urethra and Urinary Tract Infections (UTIs)

• Urethra's role in urine transport to dispose of waste.

• UTIs: Cause, diagnosis (urinalysis), and common treatments.

• Female- urethra short, only urinary function

• Male - urethralong, urinary & reproductive function

Urination Reflexes

• Micturition coordinated by storage and micturition reflexes, with respective nervous stimulation pathways.

Impaired Urination Conditions

• Incontinence and Retention: Causes and management strategies are discussed.

Practice Questions

• Development of understanding through problem-based queries examining various aspects of renal function and filtration mechanisms.