Class Notes (838,541)
Canada (510,933)
Brock University (12,137)
Biology (1,633)
BIOL 2P93 (93)
Lecture

Control of ECF Volume III (Sodium Balance)

2 Pages
55 Views
Unlock Document

Department
Biology
Course
BIOL 2P93
Professor
Jenny Janke
Semester
Fall

Description
Control of ECF & Composition III Sodium Balance I. Regulation of ECF volume & composition a. Glomerular-tubular balance—small changes in GFR won’t have large effects on Na excretion b/c renal tubules compensate for changes in GFR by proportional changes in Na reabsorption b. Physical Factors—changes in concentration of solutes (osmolarity) or volume, may be monitored by sensors i. Hydrostatic pressure differences—↑volume => ↑GFR (more “push”) ii. Oncotic pressure differences—as [H2O] ↓, [proteins] ↑ => ↑reabsorption c. Hormonal Factors—released in response to GFR change or diff. rates of substance reabsorption Segment Hormone Effect Proximal Tubule Angiotensin ↑ NaCl reabsorption (vasoconstriction) TAL/ DCT / CCT Aldosterone ↑ NaCl reabsorption Distal/Collecting Atrial Natriuretic ↓ NaCl reabsorption (↑GFR => Duct Factor (ANF) ↑excretion) i. Renin-Angiotensin System 1. ↓BP => macula densa cells signal J-G cells →release renin → converts angiotensinogen to angiotensin I →at lungs, angiotensin converting enzyme (ACE) converts angiotensin I to angiotensin II →↑BP in several ways: 1) stimulates ADH release, 2) stimulates aldosterone release, 3) promotes vasoconstriction 2. Aldosterone— a. Synthesized/released in zona glomerulosa cells of adrenal cortex b. Fxn: ↑NaCl reabsorption in DCT/ Collecting ducts by ↑ transcription of proteins that ↑ Na channel activity c. Regulation: ↑[Na]plasma => ↓ aldosterone secretion i. ↑[K] & ↑[ACTH] =
More Less

Related notes for BIOL 2P93

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit