Thalamus The thalamus (from GREEK = bedroom, chamber) Functionally considered as the great sensory gateway to the cerebral cortex

Functions of Thalamus Sensory integration and relay station for all the sensory pathways Except Olfactory Recognition of crude pain Temperature & touch

Influences voluntary movements by receiving impulses from Basal ganglia Cerebellum Participates in maintenance of state of wakefulness & alertness through RAS Role in emotions & recent memory

Brain stem The brain stem is the lower part of the brain, adjoining and structurally continuous with the spinal cord. Parts of brain stem: Pons Medulla oblongata Midbrain

Pons Relays sensory information between the cerebellum and cerebrum. Control of respiration: The apneustic center - lower pons The pneumotaxic center - upper pons

A number of cranial nerve nuclei are present in the pons (from top to bottom): The trigeminal nerve, abducen nucleus, vestibulocochlear nuclei, facial nerve nucleus

Medulla oblongata Function: controls autonomic functions: Respiration Blood pressure Heart rate Reflex arcs Vomiting

Relays nerve signals between the brain and spinal cord Cranial nerve nuclei: The hypoglossal nerve Glossopharyngeal and Vagus nerves.

Reticular formation Diffuse network of fibers Diffuse network of fibers Control physical behaviors Sleep Fatigue Motivation to perform various activities, walking, eating, urination

spinal cord

The spinal cord is an extension of the brain Enclosed in and protected by the bony Vertebral column Main function

Transmission of neural inputs between the periphery and the brain. The peripheral regions of the spinal cord contains neuronal white matter tracts containing sensory and motor neurons. The central region is gray matter that contains nerve cell bodies.

The spinal cord is divided into 31 different segments: 8 cervical segments 12 thoracic segments 5 lumbar segments 5 sacral segments 1 coccygeal segment

Connections between brain and spinal cord The corticospinal or pyramidal tract is a massive collection of axons that travel between the cerebral cortex of the brain and the spinal cord.

Reflexes Receptors in muscle & tendons e.g. knee jerk (L2,3,4 ) Triceps jerk (C 6,7)

General properties of reflexes 1- One way conduction: from presynaptic fibres to postsynaptic neurones (never the opposite direction) 2- Irradiation: strong stimulus produce afferent impulse that irradiate to many segments in Sp. C., (divergence)

General properties of reflexes 4- Reciprocal innervations :reflex contraction of group of muscle is accompanied with inhibition of antagonist muscle 5- Synaptic delay: that is time needed for transmission of an impulse from synaptic knob to postsynaptic neuron.