Anatomy and physiology of brain stem

Anatomy and physiology

1. ANATOMY AND PHYSIOLOGY OF BRAINSTEM

2. BRAINSTEM Consists of: Midbrain Pons Medulla oblangata . Superiorly continuous with forebrain. Inferiorly continuous with spinal cord. Posteriorly pons and medulla is seperated by fourth ventricle.

3. Midbrain, pons and medulla connected to cerebellum by superior,middle and inferior cerebellar peduncle resp.

4. CRANIAL NERVES EMERGING FROM BRAINSTEM 3 and 4 – midbrain 5-pons 6,7,8-junction of pons and medulla. 9,10,11,12-medulla

5. The tissue in the floor of the aqueduct,between the 3 rd and 4 th ventricles of brain contains ARAS (Ascending Reticular A ctivating System) ARAS: extends throughout the brainstem from the spinal cord to the subthalamus . Determines arousal

6. Damage to ARAS or areas of cerebral hemisphers - disturbance of normal conciousness . If this area is dead- Person will be irreversibly unconcious and apnoeic .

7. Midbrain MIDBRAIN CEREBRAL PEDUNCLE TECTUM TEGMENTUM SUBSTANTIA NIGRA CRUS CEREBRI

8. pons lies between midbrain above and medulla below in front of cerebellum. Include n eu ral pathways that conduct signals from brain down to cerebellum and medulla and that carry signals upto thalamus. Contains nuclei that deals with respiration , swallowing, bladder control , hearing,equilibrium , eye movts . facial sensation , facial expressions e tc .

9. medulla oblangata L ocated in the hind brain anterior to cerebellum. Contains cardiac , respiratory, vomiting and vasomotor centers and thus deals with breathing, heartrate , blood pressure.

10. Functions of brainstem A properly functioning paramedian tegmental area of brainstem-precondition for full consiousness.Enables cerebral hemispheres to work in integrity. Responsible for respiratory drive . Maintenance of blood pressure.

11. All motor output travel through the brainstem. Vision,smell,all the sensory traffic arrives through the brainstem. Mediates cranial nerve reflexes.

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