Test 23 ( general physiology )

1. The following signs occur in ipsilateral interruption of the cervical sympathetic trunk:

a. pupillary dilatation

b. enophthalmos

c. ptosis

d. vasodilatation in the skin of the face

e. decreased lacrimation

answera.F   b.T   c.T    d.T    e.F
Interruption of the cervical sympathetic trunk leads to Horner's syndrome and the signs include:
partial ptosis
small pupil
enophthalmos
Paralysis of the vasoconstrictor nerve supply leads to vasodilatation in the skin of the face.
Lacrimation is under the control of the parasympathetic pathway.

2. The hypothalamus contains cells which are sensitive to:

a. PO₂

b. arterial blood pressure

c. [H+]

d. TSH (thyroid-stimulating hormone) concentration

e. plasma volume

answera. F   b.F   c.F   d.T   e.F
Cells sensitive to :
PO₂ is found in the peripheral chemoreceptors
Arterial blood pressure in the carotid sinuses and aortic arch
[H+] in the medulla
Blood volume in the atrium.

3. The axons of the Purkinje cells in the cerebellar cortex:

a. terminate in excitatory synapses

b. terminate in cerebellar nuclei

c. terminate in the spinal cord.

d. form the main efferent pathway from the cerebellar cortex

e. influence contralateral movements.

answera.F   b.T   c.F   d.T   e.F
They terminate in cerebellar nuclei and have inhibitory synapses.
They influence the ipsilateral movements.

4. The joint position sense of the right leg is impaired in damage of:

a. the superior colliculi

b. the cerebellum

c. the thalamus of the right

d. the post-central gyrus of the left cerebral hemisphere

e. the right dorsal column in the thoracic region.

answera.F   b.F   c.F   d.T   e.T
The superior colliculi and the cerebellum are not concerned with the joint position sense.
The dorsal column contains the fibres responsible for joint position sense and the fibres ascend uncrossed. There the joint position sense in the right leg is impaired if there is damage to the dorsal column on the right in the thoracic region.
The ascending paths decussate (cross the midline) in the brain stem and the thalamic relay is contralateral to the peripheral innervation. The post-central gyrus is in the somatosensory receiving area of the cortex and is connected with the contralateral periphery.

5. The lateral spinothalamic tract:

a. carries fibres which terminate in the thalamus

b. contains mainly the second-order neurones. 

c. carries fibres that carry information on temperature and pain

d. contains nerve fibres from receptors on the ipsilateral side of the body

e. half of the fibres terminate in the cerebellum.

answera.T   b.T   c.T   d.F   e.F
The fibres are crossed and the cerebellum receives mainly the porpioceptive sensation.

 

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