Test 55  (general physiology)
1. Cerebral blood flow is increase in: 
a. chronic anaemia 

b. inhalation of 5% carbon dioxide 

c. seizures 

d. inhalation of hyperbaric oxygen 

e. raised intracranial pressure 

2. The following are true about the sodium channels: 

a. they are made up of polypeptide chains 

b. have the highest densities at the nodes of Ranvier 

c. open in response to depolarization 

d. remain open as long as depolarization is maintained. 

e. blocked by tetrodotoxin 


3. The cerebral blood flow: 
a. is increased by hypercapnia 

b. is increased by hypoxia 

c. accounts for 15% of the total cardiac output 

d. is increased if isoflorane is used during general 

e. is controlled mainly through the autonomic system 

4. The blood-brain-barrier: 

a. contains the foot processes of astrocytes 

b. contains endothelial cells with tight junction 

c. allows transport in one direction only ie from the 
    vascular system into the brain 

d. does not allow diffusion of water 

e. contains more mitochondria in the endothelial than those 
    found elsewhere. 


5. The following are true about the antidiuretic hormone: 
a. it is produced by the anterior pituitary gland 

b. it reduces the cardiac output 

c. it increases the renal absorption of sodium 

d. it decreases the release of ACTH 

e. it increases the peripheral resistance 

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