BIOL126 Lecture Notes - Lecture 5: Urobilinogen, Vascular Permeability, Malabsorption
8 Jun 2018
School
Department
Course
Professor
Renal System
o Urinary tract
• Urine passes along the CD through renal pelvis, to ureters and then to urinary
bladder for storage until eliminated via urethra
o Ureters
• Muscular tubes that use peristalsis to move urine to bladder
o Bladder
• Hollow, muscular distensible organ in pelvic cavity
• Stores urine before voiding
o Urethra
• Exit tube from body
• Male
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▪ 20cm
▪ Passage of semen and urine
• Female
▪ 4cm
▪ Passage of urine only
• Describe the structure of the kidneys and explain the roles of the tubular and vascular
components
o Location
• Retroperitoneal - T12 to L3
• Superior lumbar of posterior abdominal wall
• Adrenal glands lie superior to each kidney
o Functions
• Water balance (water homeostasis) and blood/plasma volume
• Maintains ECF osmolarity and concentration of most ECF ions (e.g. Na+, K+, Cl-,
Ca2+, H+, HCO3-)
• Acid-base balance (pH maintenance) - loss of H+ and HCO3- in urine
• Calcium regulation (activation of vitamin D to active hormone calcitriol)
• Blood pressure maintenance (renin production) which maintains kidney
function
• Anaemia correction (secretion of EPO in response to reduced renal O2 levels
and a drop in RBC numbers)
• Protein catabolism (for gluconeogenesis in BGL homeostasis)
• Excretion - filtration and removal of toxins (drugs, metabolic wastes e.g. urea,
uric acid, creatinine, bile pigment)
o Kidney physiology
• Maintenance of the composition of the extracellular fluid:
▪ ECF volume
▪ Electrolyte composition
▪ Osmolarity
• Homeostatic regulation
• Also kidneys are the main route for eliminating potentially toxic metabolites
and foreign compounds from the body (min 500mL urine/day)
o Kidney structure
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• Nephron
▪ Functional unit of the kidney
▪ Approximately 106 nephrons per kidney
▪ Blood filtered to excrete wastes, and toxins and retain/adjust nutrients,
ions and water
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Document Summary
Stores urine before voiding: urethra, exit tube from body, male, 20cm, passage of semen and urine. Female: 4cm, passage of urine only, describe the structure of the kidneys and explain the roles of the tubular and vascular components, location, retroperitoneal - t12 to l3, adrenal glands lie superior to each kidney. Superior lumbar of posterior abdominal wall: functions, water balance (water homeostasis) and blood/plasma volume, maintains ecf osmolarity and concentration of most ecf ions (e. g. na+, k+, cl-, Ca2+, h+, hco3: acid-base balance (ph maintenance) - loss of h+ and hco3, calcium regulation (activation of vitamin d to active hormone calcitriol, blood pressure maintenance (renin production) which maintains kidney. Summarise the processes involved in the formation of urine: filtration, secretion and reabsorption: glomerular filtration, tubular reabsorption, tubular secretion, glomerular filtration. Filtrate and plasma have the same osmolarity and composition except: cells and most large proteins don"t get filtered in health, tubular reabsorption.
