Test 180  (General physiology)

1. Regarding the kidneys: 

a. there are 1.3 millions nephrons in each kidney

b. they produce the aldosterone

c. they receive 12% of the cardiac output when at rest

d. they produce 1.25-dihydroxycalciferol

e. there are more blood flow through the renal cortex than 
    the renal medulla
 

Answera.T   b.F  c.F   d.T  e.T
Aldosterone is secreted by the adrenal cortex. 
The kidneys receive about 1.2 litres of blood
per minute which is about 25% of the cardiac 
output. The blood flow through the renal cortex is about 20 times that of the renal medulla.

2. Aldosterone secretion is controlled by:

a. plasma sodium concentration

b. plasma calcium concentration

c. plasma potassium concentration

d. angiotensin II

e. adrenocorticotrophic hormone (ACTH) 
 

Answera.T  b.F  c.T  d.T  e.T
Aldosterone secretion is controlled by by four main factors:
a. plasma sodium, an increase concentration inhibits the secretion
b. plasma potassium, an increase concentration stimulates the secretion
c. ACTH also increases the secretion.
However, 
d. angiotensin II has the strongest control and its increase strongly stimulate aldosterone secretion.

 
 

3. In pregnancy:

a. the lysozyme in the tear film is increased

b. the intraocular pressure is lower than pre-pregnancy 
    state

c. accommodation is decreased

d. the corneal curvature is decreased 

e. the corneal sensitivity is decreased
 

Answer
a.T   b.T  c.T  d.F  e.T
The increase in lysozyme increases the viscosity of tear.
The reduced IOP is thought to be the effect of the hormones Both beta subunit human chorionic 
gonadotropin and progesterone rise significantly during pregnancy and both have been shown to increase aqueous outflow.
Accommodation is decreased.
The corneal curvature increases during pregnancy.
The reduced in corneal sensitivity during pregnancy 
is thought to be caused by increased corneal thickness due to increased corneal water content.

 

. 4. The following findings are normal in pregnancy:

a. elevated erythrocyte sedimentation rate (ESR)

b. raised serum urea

c. raised serum creatinine

d. elevated white blood cell count

e. elevated alkaline phosphate
 

Answer
a.T  b.F  c.F  d.T  e.T
The urea and creatinine concentration should be normal unless the patient has renal problem. The elevate white blood cell count is caused mainly by neutrophil leucocytosis.
 

5. With regard to cerebral autoregulation:

a. cerebral blood flow is constant over a diastolic blood
    pressure of 60 to 140 mmHg

b. autoregulation is lost during the acute phase of
    subarachnoid haemorrhage

c. it is impaired in hypercapnia

d. it is impaired in hypoxia

e. it is mediated by the sympathetic nervous system
 

Answer
a.F   b.T  c.T  d.T e.F
Cerebral blood flow is constant over the mean systemic blood pressure of 60 to 140mmHg and not just the diastolic or systolic. Autoregulation is lost in area with pathology. It is impaired in hypercapnia and hypoxia. Autoregulation refers to the instrinsic capacity of the blood vessels that control the vascular resistance. 

 

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