‫جامعة بورسعيد‬
‫كلية التمريض‬
Year 2013-2014
Subject: Physiology
2ndTerm
First Year
Date: 16 /6/2014
Total Marks: 50
Time Allowed: Two Hours
Dr. Mona A. Hussain
Model of Answer
Answer All of The Following Questions:
1- Discuss urine formation
A. Glomerular filtration
B. Tubular reabsorption
C. Tubular secretion
D. Excretion
10 marks
4 marks
2 marks
2 marks
2 marks
2- List five functions of the liver
10 marks
1. blood reservoir
2. metabolism
3- synthesis
4- hemostasis
5- storage function
6- Excretion
7- Acid base balance
8- function of non-parenchymal cells
each function 2 marks
3- Discuss the catch-up phenomenon, compensatory growth
and list hormones that control growth. 10 marks
Following a temporary period of stunted growth due to
malnutrition or illness, and given proper nutrition and
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‫كلية التمريض‬
recovery from illness, a child manifests a remarkable growth
spurt (catch-up growth) that brings the child up to the normal
height expected for his or her age.
The mechanism that accounts for this accelerated growth
is unknown. 2 marks
During adult life, a specific type of regenerative growth
known as compensatory growth, can occur in many human
organs. For example, after the surgical removal of one
kidney, the cells of the other kidney begin
to manifest increased cell division, and the kidney
ultimately grows until its total mass approaches the
initial mass of the two kidneys combined. Many
growth factors and hormones participate in compensatory
growth, but the precise signals that trigger the
process are not known.
2 marks
Growth- Thyroid – insulin- estrogen – testosteronecortisol
6 marks
4- Give an account on mechanisms regulate acid base
balance
20 marks
Chemical buffering.
Bicarbonate buffer:
2 marks
Sodium Bicarbonate (NaHCO3) and carbonic acid (H2CO3)
This is the major buffer in (ECF).
Bicarbonate buffer system is the most important buffer in the body
because:4‫ من‬2 ‫صفحة‬
‫جامعة بورسعيد‬
‫كلية التمريض‬
1-it determine the blood ph.
2-its component can be finely regulated ,co2by the respiratory system
and Hco3 by the kidney.
Phosphate buffer: 2 marks
This buffer consists of mixture of basic phosphate (HPO42-) and acid
phosphate (H2PO4- ).
Major intracellular buffer (ICF).
Protein Buffer
2 marks
Proteins in the cells and plasma constitute the most plentiful buffer in
the body because of their very high concentration.
About ¾ of all chemical buffering power of the body is inside the
cells, mostly by the intracellular proteins.
The plasma proteins offer (7-15%) of the buffering power of the
blood.
Hemoglobin is the most important buffer in the blood (35%) of its
buffering power due to its great amount (15 gm.%)
NB:
Chemical buffers in extracellular and intracellular fluids and in bone
are the first line of defense of blood pH . It acts within a fraction of a
second.
Chemical buffering minimizes a change in pH but does not remove
acid or base from the body.
2 marks
Respiratory response:
The respiratory system is the second line of defense of blood pH, acts
within 1-15 minutes.
Normally, breathing removes CO2 as fast as it forms.
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‫كلية التمريض‬
Large loads of acid stimulate breathing (respiratory compensation), which
removes CO2 from the body and lowers the [H2CO3] in arterial blood,
reducing the acidic shift in blood pH.
3 marks
Renal response:
The kidneys are the third line of defense of blood pH. Although
chemical buffers in the body can bind H+ and the lungs can change
[H2CO3] of blood, the burden of removing excess H+ falls directly on
the kidneys.
Hydrogen ions are excreted in combination with urinary buffers.
At the same time, the kidneys add new HCO3 to the ECF to replace
HCO3 used to buffer strong acids.
The kidneys also excrete the anions (phosphate, chloride, sulfate) that
are liberated from strong acids.
The kidneys affect blood pH more slowly than other buffering
mechanisms in the body; full renal compensation may take 1 to 3 days
It is the most powerful mechanism and completely corrects pH.
9 marks
Good luck
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