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Lecture 10

BIOB33H3 Lecture Notes - Lecture 10: Renal Corpuscle, Efferent Arteriole, Transitional Epithelium


Department
Biological Sciences
Course Code
BIOB33H3
Professor
Connie Potroff
Lecture
10

Page:
of 2
1
URINARY SYSTEM
(based on Chapter 26)
**Assigned Readings: p.706 (advances in the treatment of renal failure)
Functions:
- water and electrolyte balance (compounds that separate into ions when dissolved in water (eg. Na, K,
Cl, Ca)
- regulating blood volume and blood pressure
- conservation of nutrients
- excretion of toxic nitrogenous compounds (urea and creatine), toxic wastes from bacterial actions and
removal of various drugs taken into the body
ORGANS
KIDNEYS filtration and reabsorption, adrenal cortex and medulla
URETERS transport of urine (to bladder)
BLADDER storage of urine
URETHRA excretion of urine
KIDNEYS
- kidney - RENAL
- positioned against posterior abdominal wall, behind parietal peritoneum (not covered by)
(RETROPERITONEAL)
- right kidney usually lower than left because of large area occupied by right lobe of liver below
- kidney-bean shaped with ADRENAL GLAND S (endocrine glands which produce
CORTICOSTEROIDS) positioned on top
Functions 3 parts:
1. filtration of water and some solutes in blood, move out of glomerulus
2. tubular reabsorption, within tubules, needed solutes and most water moves back in
3. tubular secretion in collecting tubules, solutes move back out
-
- *FIBROUS CAPSULE (renal capsule) composed of dense irregular connective tissue
- blood enters kidneys through RENAL ARTERY
- *kidney has concave medial border called HILUM continuous with internal RENAL SINUS) where
RENAL ARTERY, RENAL VEIN and URETER connect to the kidney
- when sectioned along coronal plane,2 parts: outer RENAL CORTEX (reddish brown and granular in
appearance because of many capillaries present) and inner RENAL MEDULLA (darker and presence
of microscopic tubules and blood vessels give it a striped appearance)
- renal medulla composed of 8-15 RENAL PYRAMIDS (apex called RENAL PAPILLAE) with RENAL
COLUMNS between
- cavity of kidney collects and transports urine from kidney to ureter
- papillae of a renal pyramid projects into depression called MINOR CALYX, several unite to form
MAJOR CALYX, which in turn unite to form funnel-shaped RENAL PELVIS which transports urine to
the ureter
pathway of blood into kidneys renal artery segmental arteries interlobar arteries arcurate arteries
cortical radiate arteries afferent arteriole - GLOMERULUS efferent arteriole peritubular capillaries
venules interlobular veins arcurate veins interlobar veins renal vein
- functional filtration unit of the kidney is the NEPHRON which consists of a RENAL CORPUSCLE
(composed of GLOMERULUS and GLOMERULAR CAPSULE), and RENAL TUBULE consisting of
PROXIMAL CONVOLUTED TUBULE, NEPHRON LOOP (loop of Henle) and DISTAL
CONVOLUTED TUBULE
2
- 2 types of nephrons CORTICAL NEPHRONS short nephron loops near edge or cortex, and
JUXTAMEDULLARY NEPHRONS long nephron loops extend deep into medulla
- *renal corpuscle filters the blood plasma and long renal tubule converts the filtrate to urine
- **capillary network is selectively permeable because of endothelium and cells called PODOCYTES
with cytoplasmic extensions called PEDICELS which line endothelium of capillaries and control flow
of things out of blood supply
- glomerular capsule (Bowman’s capsule) with capsular space is where fluid and waste from blood
collect
- AFFERENT ARTERIOLE brings blood to the Bowman’s capsule and goes into capillary network, and
leaves via the EFFERENT ARTERIOLE
-
- drains into a minor calyx to major calyx then to bladder and out of body through ureter
BLADDER
- located pelvis, sits behind the SYMPHYS PUBIS
- hollow muscular organ
- max volume of bladder 500-600ml (can feel 300ml)
- when full, it projects above the symphys pubis
- lined with transitional epithelium, DETRUSOR a spiral muscle that squeezes and compresses the
bladder
- urinating called MITURITION