Mid brain

The midbrain or mesencephalon extends from the pons to the diencephalon and is about 2.5 cm (1 in.)long.
The cerebral aqueduct passes through the midbrain, connecting the third ventricle above with the fourth ventricle below.
The anterior part of the midbrain contains paired bundles of
axons known as the cerebral peduncles.
The cerebral peduncles consist of axons of Corticospinal, Corticopontine, and Corticobulbar tracts, which conduct nerve impulses from motor areas in the cerebral cortex to the spinal cord, pons, and medulla, respectively.
The posterior part of the midbrain, called the tectum, contains four rounded elevations.
Two superior elevations: Superior Colliculi
Two inferior elevations: Inferior Colliculi
The superior colliculi serves as reflex centers for certain visual activities.
Visual activities like, eye movements for tracking moving images (such as a moving car) and scanning stationary images (as you are watching this slide).
The superior colliculi are also responsible for reflexes that govern movements of the head, eyes, and trunk in response to visual stimuli.
The inferior colliculi are part of the auditory pathway, relaying impulses from the receptors for hearing in the inner ear to the brain.
These two nuclei are also reflex centers for the startle reflex, sudden movements of the head, eyes, and trunk that occur when you are surprised by a loud noise such as a gunshot.
The midbrain contains several other nuclei, which includes the left and right substantia nigra.
Neurons that release dopamine, extending from the substantia nigra to the basal ganglia, help control subconscious muscle activities.
Loss of these neurons is associated with Parkinson disease.
Parkinson's disease is a brain disorder that leads to Shaking,
Stiffness, Difficulty with walking, Difficulty with balance, Difficulty with coordination.
Also present are the left and right red nuclei, which look reddish due to their rich blood supply and an iron-containing pigment in their neuronal cell bodies.
Axons from the cerebellum and cerebral cortex form synapses in the red nuclei, which help control some voluntary movements of the limbs.

1. Mid Brain

2. The midbrain or mesencephalon extends from the pons to the diencephalon and is about 2.5 cm (1 in.)long .

3. The cerebral aqueduct passes through the midbrain, connecting the third ventricle above with the fourth ventricle below . Cerebral Aqueduct Mid brain 4 th Ventricle 3 rd Ventricle Lateral Ventricles

4. The anterior part of the midbrain contains paired bundles of axons known as the cerebral peduncles . Fig. 1 Fig. 2

5. The cerebral peduncles consist of axons of Corticospinal , Corticopontine , and Corticobulbar tracts , which conduct nerve impulses from motor areas in the cerebral cortex to the spinal cord, pons, and medulla, respectively.

6. The posterior part of the midbrain, called the tectum , contains four rounded elevations. Two superior elevations: Superior Colliculi Two inferior elevations: Inferior Colliculi Fig. 1 Fig. 2

7. The superior colliculi serves as reflex centers for certain visual activities . Visual activities like, eye movements for tracking moving images (such as a moving car) and scanning stationary images (as you are watching this slide).

8. The superior colliculi are also responsible for reflexes that govern movements of the head, eyes, and trunk in response to visual stimuli .

9. The inferior colliculi are part of the auditory pathway , relaying impulses from the receptors for hearing in the inner ear to the brain. These two nuclei are also reflex centers for the startle reflex , sudden movements of the head, eyes, and trunk that occur when you are surprised by a loud noise such as a gunshot.

10. The midbrain contains several other nuclei, which includes the left and right substantia nigra . Neurons that release dopamine, extending from the substantia nigra to the basal ganglia, help control subconscious muscle activities .

11. Loss of these neurons is associated with Parkinson disease . Parkinson's disease is a brain disorder that leads to Shaking, Stiffness,   Difficulty with walking, Difficulty with balance, Difficulty with coordination.

12. Also present are the left and right red nuclei , which look reddish due to their rich blood supply and an iron-containing pigment in their neuronal cell bodies. Fig. 1 Fig. 2

13. Axons from the cerebellum and cerebral cortex form synapses in the red nuclei, which help control some voluntary movements of the limbs.

14. Quick Revision

15. Mid Brain Location: Superior to pons and inferior to diencephalon

16. Anterior part of Mid brain: Cerebral Peduncles which contains Corticospinal , Corticopontine , and Corticobulbar tracts Posterior part of mid brain: Known as Tectum and contains 4 elevations. 2 superior colliculi: serving as reflex center for serval visual activity 2 inferior colliculi: part of auditory pathway.

17. Substantia nigra : Posterior to cerebral peduncles, contains dopaminergic neurons and having role in controlling subconscious muscle activity Red Nuclei: Next to substantia nigra there is red nuclei involved in voluntary movements of limbs.

18. Thank You