Upload
aku-karachi
View
187
Download
3
Tags:
Embed Size (px)
Citation preview
Neural and Hormonal Regulation of GFR
Neural Regulation of GFR:
When the blood pressure increase the sympathetic nerve fibers release nor epinephrine which causes constriction of blood vessel thus decreasing GFR.
Hormonal Regulation of GFR:
Two hormones, Angiotensin II reduce GFR and atrial natriuretic peptide (ANP) increase GFR
Substance Filtered Reabsorbed Urine
Water 180 liter 178 liter 1-2 liter
Protein 2 g 1.9 g .1 g
Sodium ion 579 g 575 g 4 g
Chloride ion 640 g 633.7 g 6.3 g
Bicarbonate ion 275 g 274.9 g 0.03 g
glucose 162 g 162 g 0 g
urea 54 g 24 g 30 g
Potassium ion 29.6 g 29.6 g 2 g
Uric acid 8.5 g 7.7 g .8 g
Creatinine 1.6 g 0 g 1.6 g
Substances filtered reabsorbed and excreted in urine
Tubular Reabsorption and SecretionReabsorption: Normally 99% of filtered water is reabsorbed Solutes that are reabsorbed include glucose, amino acid,
urea and ion such as sodium, potassium, calcium, chloride, bicarbonate and phosphate.
Secretion: Substance that are secreted include: hydrogen ion,
potassium, ammonium ion, creatinine and certain drugs. Two important outcomes of Tubular secretion:
Secretion of H- ion help to control body PH Secretion of other substance eliminate them from the body
Reabsorbtion and secretion in the PCT 65% of Na+ is reabsorbed 65% of H2O is reabsorbed
65% K+
100% Glucose 100% amino acid 50% Cl-
90% of filtered bicarbonate (HCO3-)
Secretion: Variable amount of H+ NH4- and urea and a small
amount of Creatinine is secreted in the PCT.
Reabsorbtion and Secretion in the LOH
Reabsorbtion: 25% Na+
15% H2O
20-30 % K+
35 % Cl-
10-20% HCO3-
Secretion:
Variable amount of urea is secreted in the LOH
Hormonal Regulation of Tubular Reabsorbtion and Tubular Secretion
Angiotension II Aldosterone Antidiuretic hormone Natriuretic peptide Parathyroid
Antidiuretic hormone
ADH (antidiuretic hormone) makes collecting ducts more permeable to water, it helps produce concentrated urine
-efferent arterioles
Effect of aldosterone on DCT and Collecting Duct
BP causes angiotensin II formation angiotensin II stimulates adrenal cortex adrenal cortex secretes aldosterone aldosterone promotes Na+ reabsorption Na+ reabsorption promotes water reabsorption water reabsorption urine volume BP drops less rapidly
Effect of atrial natriuretic factor (ANF)
BP stimulates right atrium Atrial walls stretches atrium secretes ANF ANF promotes Na+ and water excretion BP drops
Ureters• Tubes that convey urine from kidney to the urinary bladder• 25-30 cm long and 3mm in diameter• Start from pelvis, enter into pelvic cavity and passes obliquely
through the posterior wall of the bladder
Structure consists of three layers of tissue Outer fibrous tissue Middle smooth muscle layer Inner mucosa lined with transitional epithelium
Functions:• Propel urine from kidney into the bladder by peristaltic contraction of
smooth muscle layer• The wave of contraction occur in minor calyces• Peristaltic wave occur several time per minutes and send little spurts
of urine into bladder.
Urinary bladder:
It is a reservoir for urine whose size and position vary, depending on the amount of urine it contain
Lie in the pelvic cavityStructure:• Roughly pear shaped structure but more oval when
filled with urine.• The posterior surface is called base and the point
where the bladder open into urethra is called neck• The superior surface of the bladder is covered by
peritoneum• Posteriorly bladder is surrounded by uterus in female
and rectum in male
Outer loose connective tissue layer
Mucosa Middle smooth muscle and elastic tissue
rugae
Trigone NeckUrethral sphincter
The bladder wall composed of three layers
1. Outer layer of loose connective tissue containing blood, lymph vessels and nerve
2. The middle layer consists of inter-lacing mass of smooth muscle fibers and elastic tissue. These are called Detrusor muscle. It contracts to empty urine
3. The mucosa lined with transitional epithelium When the bladder is empty the inner layer is arranged in
folds or rugae which disappear when bladder is full The total capacity of bladder is more then 600 ml and
awareness of desire to urinate is initiated at 300-400ml The three orifices of the bladder wall form a triangle or
trigone.
• The upper two pore is the opening of ureter and the lower one is the urethra
• At the site where the urethra emerge is a thick smooth muscle layer called urethral sphincter.
Reflex control of micturition when conscious effort cannot override the reflex action..
• http://highered.mheducation.com/sites/0072507470/student_view0/chapter26/animation__micturition_reflex.html
Control of micturition after bladder control is established