Physiology2 // Dr Faisal Mohammed
Lecture 5 , spring 2020
Done by Dina Alzyoud , Checked by Hyfaa Zreqat .
Questions ( students asked ) :
1- Since olfaction is the only order that reaches cerebral cortex directly
(without passing the thalamus ) so ; why people die because of
suffocation( ) during their sleep ?
Answer : in the above case , suffocation happened due to CO poisoning ,
and
wakes people . death because of CO poisoning happens because CO has
200 times higher affinity to hemoglobin than O2 , and because of fact that
dissolved O2 in plasma
response to increased CO .
NOTE: during co poisoning , the respiratory center in the medulla
obolongata will not be stimulated because there are no change in the (O2 ,
CO2) partial pressure.
odors to house gases .
2- When damage happens to spinal cord at level of decussation which side of
*
body will be affected ?
Answer : it depends on nature of the damage , whether it is complete or
partial damage .
Complete : both sides become paralyzed
Partial : could be ipsi/contralateral based on whether the cut happened
before or after decussation .
Cerebellum :
Over view:
- It is located posterior to cerebrum , in posterior cranial fossa which is a
strategic position because all tracts that go up and down pass through
cerebellum.
- It is divided into lobes , each lobe has specific function ( details about
lobes and their functions are excluded )
- Cerebellum ,like cerebrum, has a topographic representation of our
motor system ( muscles ) .
1
, Note : every part of brain ( thalamus , bas s
a topographic representation .
Functions of cerebellum :
1- Coordination of movements
2- Regulate posture and balance
3- Smoothening of movements
4- Prediction of movements
5- Memory for skilled movements
Explanation for Cerebellar functions :
Motor system pathway :
On past , they thought that cerebellum has no function
because it descending tracts ( there is no
cerebelluspinal pathway .
Cerebellum runners
integrates with cerebrum or thalamus to control
our movements .
In order to move your hand : motor commands from cerebral
cortex > corticospinal tract > motor neuron .
But ; motor orders from cerebral cortex are never exact and
have errors .
Movements done in response to cerebral orders are called
tremor movements .
This is tremor during action , or intention
tremor , because you have the intention for
movement .
2
Lecture 5 , spring 2020
Done by Dina Alzyoud , Checked by Hyfaa Zreqat .
Questions ( students asked ) :
1- Since olfaction is the only order that reaches cerebral cortex directly
(without passing the thalamus ) so ; why people die because of
suffocation( ) during their sleep ?
Answer : in the above case , suffocation happened due to CO poisoning ,
and
wakes people . death because of CO poisoning happens because CO has
200 times higher affinity to hemoglobin than O2 , and because of fact that
dissolved O2 in plasma
response to increased CO .
NOTE: during co poisoning , the respiratory center in the medulla
obolongata will not be stimulated because there are no change in the (O2 ,
CO2) partial pressure.
odors to house gases .
2- When damage happens to spinal cord at level of decussation which side of
*
body will be affected ?
Answer : it depends on nature of the damage , whether it is complete or
partial damage .
Complete : both sides become paralyzed
Partial : could be ipsi/contralateral based on whether the cut happened
before or after decussation .
Cerebellum :
Over view:
- It is located posterior to cerebrum , in posterior cranial fossa which is a
strategic position because all tracts that go up and down pass through
cerebellum.
- It is divided into lobes , each lobe has specific function ( details about
lobes and their functions are excluded )
- Cerebellum ,like cerebrum, has a topographic representation of our
motor system ( muscles ) .
1
, Note : every part of brain ( thalamus , bas s
a topographic representation .
Functions of cerebellum :
1- Coordination of movements
2- Regulate posture and balance
3- Smoothening of movements
4- Prediction of movements
5- Memory for skilled movements
Explanation for Cerebellar functions :
Motor system pathway :
On past , they thought that cerebellum has no function
because it descending tracts ( there is no
cerebelluspinal pathway .
Cerebellum runners
integrates with cerebrum or thalamus to control
our movements .
In order to move your hand : motor commands from cerebral
cortex > corticospinal tract > motor neuron .
But ; motor orders from cerebral cortex are never exact and
have errors .
Movements done in response to cerebral orders are called
tremor movements .
This is tremor during action , or intention
tremor , because you have the intention for
movement .
2
