FORM AND FUNCTION - PowerPoint Presentation

Slide1

FORM AND FUNCTION

THE URINARY SYSTEMSlide2

COMPONENTS

2 Kidneys2

ureters

1 urinary bladder

1 urethraSlide3

FUNCTIONS:

Excretion and filtration

Regulation of blood volume and pressure

Regulation of blood solutes

Regulation of pHRegulation of Red Blood Cell synthesis

Vitamin D synthesisSlide4

Regulation of blood cell synthesis

Production of Erythropoietin (a glycoprotein hormone) by the kidneys controls manufacture of new RBC’s

EPO is banned from use by professional athletesSlide5

The kidneys and Vitamin D

The skin synthesizes inactive Vitamin D and the kidneys convert it to the active form.Slide6

KIDNEY STRUCTURE

Kidneys are fist sized organs

They are located on the posterior abdominal wall on either side of the vertebral columnSlide7

THE NEPHRON

Each kidney is composed of millions of microscopic filtering units known as

nephrons

The

nephron

is the functional unit of the kidney, doing all of the actual workSlide8
Slide9

INTERNAL STRUCTURESlide10

NEPHRON STRUCTURESlide11

FILTRATION

21% of blood pumped by the heart each minute flows through the kidneys

19% of the blood plasma that flows through the capillary bed of the

glomerulus

passes through the filtration membrane into

Bowman’s Capsule, the first part of the

nephron

.

The liquid is called the

filtrate.Slide12

What is in the

filtrate?

The filtrate should contain water, salts, glucose, amino acids, wastes such as urea, vitamins, minerals, drug metabolites, and ions (H+, Na+, and K+)Slide13

FILTRATION

The filtrate

should not

contain blood cells, proteins, or glucose (after initial

rebsorbtion

).

Bowman’s Capsule

GlomerulusSlide14

REABSORPTION

180 liters of filtrate are produced daily!

Plasma volume is only 3 liters so how many times daily is the entire plasma volume filtered?

60 times!

Only 1-2 L of urine are produced daily

Almost all of the water and useful solutes are reabsorbedSlide15

THE PROXIMAL CONVOLUTED TUBULE

Absorbs 65% of water and

NaCl

that passes through

The Na+/K+ pump transports ions from the filtrate into the tubule cells (

simple

cuboidal

epithelium

)

Important substances such as amino acids, glucose, vitamins, and minerals are reabsorbed into the

peritubular

capillariesSlide16

MORE REABSORPTION

The

descending Loop of

Henle

concentrates the filtrate by removing water through

osmosis

This reduces the filtrate volume by another 15%

Urea

is removed by facilitated diffusion

In

the

acsending

loop, the Na+/K+ pump moves Na+ to the interstitial fluid surrounding the loop.Cl- and K+ are moved by

symport

This part of the loop is impermeable to water, so it cannot follow the ions passivelySlide17

LOOP OF HENLESlide18

THE DISTAL CONVOLUTED TUBULE

About 80% of water and 90% of solutes have been removed from the filtrate so far

Helps regulate pH by controlling H+ elimination and retention.

Works with PTH to reabsorb Ca

2+

ions

Further water

reabsorption

is under hormonal control

ADH

-

A

nti-diuretic

H

ormone causes water to leave the filtrate and enter the tubule cellsSlide19
Slide20

When do you need ADH?

Dehydration

Sleeping

Sudden blood loss (aka,

hypovolemic

shock

Vampire

Not a vampireSlide21

NITROGENOUS WASTE

The metabolism of proteins produces nitrogen-based waste products such as ammonia and urea

These two substances can be toxic if they remain in the body.

The kidneys remove them in the distal convoluted tubuleSlide22
Slide23

THE COLLECTING DUCT SYSTEM

It is controlled by hormones like ADH and

Aldosterone

The cells are impermeable to water, so any water in the filtrate remains and is excreted with other wastes as

urine

The Collecting Duct Slide24

What if your kidneys are not working?

DIALYSIS TREATMENTSlide25

The Kidneys at Work

http://www.youtube.com/watch?v=glu0dzK4dbU

http://

www.youtube.com/watch?v=aQZaNXNroVY&feature=related