Feb17Lec - Feb 17th lecture overview and transcription. I...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Feb 17 th lecture overview and transcription. 1 I Am What I Do Not Eliminate: The excretory system; How waste leaves my body (ppt Clicker Ques. ) Answer = Last Time: how nutrients and oxygen enter your blood stream & fuel the activities of all your cells. Today: how the kidneys filter the blood and produce a hormone that stimulates red blood cell formation in the bone marrow. The following summarizes the function of your excretory system. Also use Rand’s ppts to help you answer the questions he’s posted in relation to this lecture – this will show you the main point you need to understand for the prelim. SUMMARY of The Excretory System ~ Human Excretory System - the system consists of a pair of kidneys and ureters, a urinary bladder, the urethra, and the blood vessels of the renal circuit. The kidney consists of an outer cortex, an inner medulla, and a renal pelvis. The cortex contains the filtering units called nephrons . The nephron is composed of a spherical capsule called the Bowman's capsule followed by a long tubule. The renal artery branches into smaller arterioles; each arteriole (called an afferent or incoming arteriole) enters the Bowman's capsule and branches to form a structure called the glomerulus (a capillary bed composed only of artery); the arteriole leaving the capsule is called the efferent arteriole; this branches into the peritubular capillaries, a fine network of arteries and veins covering the rest of the nephron; this drains into the renal vein. The Bowman's capsule leads to the proximal convoluted tubule which leads to a section of the nephron called the loop of Henle , then the distal convoluted tubule and finally to the collecting duct. Note: the afferent arteriole forms a passing connection with the distal convoluted tubule called the juxtaglomerular complex, important in sodium re-absorption. The collecting duct drains to the renal pelvis (note: there are thousands of nephrons in each kidney ) where urine collects. The urine then drains down the ureter to the urinary bladder for temporary storage. It finally passes out of the body through the urethra. The Work of the Nephron : A variety of transport processes, from force filtration to passive diffusion, occur along the nephron and a variety of substances are transported (see Randy’s ppts). Here we will examine what occurs in each part of the nephron. A) Bowman's capsule - blood entering this region is under very high pressure; it comes directly from the aorta leaving the heart. The blood is forced into the tiny vessels of the glomerulus and materials are forced out by force filtration (crude, but it works). Water, salts, glucose, urea, and
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Feb 17 th lecture overview and transcription. 2
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This document was uploaded on 11/09/2010.

Page1 / 6

Feb17Lec - Feb 17th lecture overview and transcription. I...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online