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ANNOUNCEMENTS. LAB PRACTICAL RESCHEDULED: April 28, 29 SECOND EXAM RESCHEDULED: April 22nd Material Covered: Bone, Muscle, Nerve and Circulatory, Lymphatic, and Urinary Systems Conflicts? Exam by appointment: 4/21, 4/23 ** Appointments must be made by 4/17.**
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ANNOUNCEMENTS LAB PRACTICAL RESCHEDULED: April 28, 29 SECOND EXAM RESCHEDULED: April 22nd Material Covered: Bone, Muscle, Nerve and Circulatory, Lymphatic, and Urinary Systems Conflicts? Exam by appointment: 4/21, 4/23 **Appointments must be made by 4/17.** REVIEW SESSION HERE THIS FRIDAY 12:20
ANNOUNCEMENTS Poster Team:Progress report after class Another Great Talk: Robert M. Sapolsky, Stanford University Friday, April 10, at 4PM in ISB 135- Auditorium “Gene Therapy for Psychiatric Disorders:Do Parasites Know More Neurobiology Than We Do?”
*BIOLOGY SENIORS* Join us for lunch! 12 Noon Wednesday, May 13th Lawn, Durfee Conservatory
Podocytes: slit diaphragm bind to basal lamina structural support to high pressure capillaries development of glomerulus Damage to Podocytes---> Excess filtration
Focal segmental glomerulosclerosis (FSGS) NBA superstar Alonso Mourning Families with inherited FSGS - mutations in the ACTN4 gene - encodes α-actinin-4 α-actinin-4: - two identical anti-parallel peptides http://www.bms.ed.ac.uk/research/others/smaciver/Cyto-Topics/alpha%20actinin.htm
Focal segmental glomerulosclerosis (FSGS) Knockout mice that lacked Actn4 expression - severely damaged podocytes - progressive glomerular disease Mutant α-actinin-4 - aggregation rather than pairing - accelerated degradation Mutant α-actinin-4 aggregates in glomeruli Wildtype α-actinin-4 is evenly distributed in glomeruli (2004) A Protein's Role in Progressive Renal Disease. PLoS Biol 2(6): e194
Minimal Change Disease Loss of polyanions in podocyte processes- - effacement - excess filtration - loss of albumin http://www.gamewood.net/rnet/renalpath/ch4.htm
NEPHRON Glomerulus Initial blood filtration - Capillary tuft - Bowman’s capsule Cortical / medullary tubular system • Control of chemical composition of blood • Urine salt concentration
Cortical / Medullary Tubular System Convoluted Tubules - Proximal - Distal Loop of Henle - descending limb - ascending limb Collecting duct
CORTEX MEDULLA
Medullary Pyramid Papilla
Renal Calyx - Minor - Major Transitional Epithelium Renal Pelvis From: Textbook of Renal Pathophysiology, Franklyn Knox; Harper and Row 1978.
Medullary pyramids • Contain tubules and collecting ducts • Base of pyramids: cortex boundary • Tip of pyramids end in papilla • Calyx: spaces collecting urine from papilla that join and drain into ureter
NEPHRON Glomerulus - initial blood filtration Glomerular Filtration Rate - fluid volume filtered from glomerular capillaries into Bowman's capsule / unit time. SecretionReabsorption Creatinine, acids, bases Filtrate water, sodium, glucose Excretion
Reabsorption • Most salt and water reabsorbed across proximal tubules
Proximal Convoluted Tubules Specialized for reabsorption -cuboidal to columnar -apical microvilli/brush border -junctional complex -basal striations -larger diameter -star shaped lumen
Proximal tubule ~65% of H2O, Na, Cl, PO4, glucose, amino acids reabsorbed 1. Na actively pumped out basolateral membrane 2. Na crosses apical membrane via facilitated diffusion 3. Cl and water follow Aquaporin water channels Glucose, amino acids cotransport with Na across apical membrane Small peptides and sugars digested on glycocalyx Proximal Tubule-->Intercellular space-->Peritubular capillaries people.eku.edu/ritchisong/bird_excretion.htm
Loop Henle Descending & Ascending limbs thin and thick segments Vary in epithelium descending thick --> simple cuboidal descending thin --> simple squamous ascending thin --> simple squamous ascending thick --> simple cuboidal Vary in permeability and molecular composition descending thin --> highly permeable to water ascending thin --> impermeable to water Countercurrent multiplier
Countercurrent multiplier: Flow of blood and filtrate are in opposite directions Ascending limb: Impermeable to water Active extrusion of Na => increased osmotic pressure in interstitial fluid Descending limb: Permeable to water • water leaves filtrate Water enters Vasa recta www.nature.com/.../v21/n1/full/ng0199_67.html
Distal convoluted tubule cuboidal, extensive basal and lateral invaginations Na reabsorption K secretion Regulated by ALDOSTERONE Collecting Tubule: Clear cell boundaries, large diameter, more nuclei than proximal Thin Tubule: Simple squamous
Collecting ducts Permeability to water controlled by antidiuretic hormone (ADH), secreted by pituitary gland => insertion of aquaporin channels in apical membrane No ADH, water excretion ADH, water reabsorption www.uic.edu/.../bios100/lecturesf04am/lect21.htm
Collecting Ducts Clear cell boundaries, large diameter, more nuclei than proximal
Diabetes Insipidus Inability of kidneys to conserve water results in frequent urination and pronounced thirst What are the possible causes?
Renal Pelvis ----> Ureter -----> Bladder Mucosa: Transitional epithelium - lamina propria Muscularis: Smooth muscle Longitudinal inner layer Circular outer layer Adventitia
25. URETER
BLADDER http://www.visualsunlimited.com/browse/vu306/vu306638.html
Urethra Epithelium: Female: Transitional----> Stratified Squamous Male: Transitional----> Stratified or Pseudostratified Columnar Stratified Squamous