Physioex 8.0 Exercise 9 Completed

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Glomerular Filtration
Activity 1:  Effect of Arteriole Diameter on Glomerular Filtration

1.   Compare this data with your baseline data.  How did increasing the afferent arteriole radius affect glomerular filtration rate? >>Increasing the afferent arteriole radius pushed the glomerular pressure, the glomerular filtration rate, and the volume of urine to be higher than the baseline data. Increasing the afferent arteriole radius increased the glomerular filtration rate.  

2.   Under these conditions, does the fluid flow through the nephron? >>No! No urine was collected which indicates no fluid flows through the nephron. 

3.   What is the glomerular filtration rate?
>>The glomerular filtration rate is 0 which means the glomeruli are not carrying out any filtration task.   
4.   How does it compare to your baseline data, and why?  >>The glomerular filtration rate in baseline data is 124.99 which indicate functional glomeruli. The data support the concept that the reduction of the size of the afferent radius will definitely affect the glomerular filtration functions. With significant reduction of the afferent radius, very limited blood can pass through the capillaries and that leaves insufficient fluid to be filtered no any extra water can be produced as urine.       

5.   How did increasing the efferent radius affect glomerular filtration rate?  >> Increasing the efferent radius decreases the glomerular filtration rate. Increasing the efferent radius allows more blood drainage out of the glomerulus and that decreases the amount of blood to be filtered so the glomerular filtration rate will decrease.   

6.   How did decreasing the efferent radius affect glomerular filtration rate?  >> Decreasing the efferent radius increases the glomerular filtration rate. The constriction of the efferent radius will limit blood drainage out of the glomeruli and that requires increasing the glomerular filtration rate. More blood in the glomeruli means more work, so the job has to be done faster.     

7.   Physiologically, what could be the cause of a change in afferent or efferent arteriole radius?  >>The sympathethic impulses largely play major roles in changing the afferent or efferent arteriole radius. The afferent or efferent arteriole radius can dilate or constrict depending on the impulses generated by the sympathetic nerves keeping the autonomic control of blood flow depending on the concentration levels of the body electrolytes and metabolic wastes which are the main basis of blood flow autoregulation. Increased sympathetic impulses will cause afferent and efferent arteriole to vasoconstriction while decreased sympathetic stimulation will facilitate vasodilation. The mechanisms involve various hormones and electrolytes and are largely dependent on the amount of metabolic activity, the extrinsic control mechanism depending on the perfusion needs of the cells, and the vascular resistance generated by the blood pressure. The amount of body fluids and the levels of body wastes definitely play critical physiologic roles that cause changes in the afferent or efferent roles. The effects of drugs play significant roles as well.     

Activity 2:  Effect of Pressure on Glomerular Filtration

1.   As pressure increased, what happened to the pressure in the glomerulus?  >>As pressure increased, the pressure in the glomerulus also increased.

2.   What happened to the glomerular filtration rate? 
>>The glomerular filtration rate kept on increasing with gradual increase of the pressure.  3.   How did the urine volume change? 
>>The urine volume also increased.

4.   How could increased urine volume be viewed as being beneficial to the body? >>With increased urine volume, more filtrates mostly salts which are body wastes will be excreted and that lessens the potential harmful effects of fluid retention and accumulation of unnecessary wastes...
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