The human brain 2

THE HUMAN BRAIN

Human brain

cerebrum

cerebellum

diencephalon

brainstem

a complex organ that is formed from several subdivisions

CerebrumThe location of conscious thought processes and the origin of all complex intellectual functions.

Formed from the telencephalon.

The largest division of the brain.

Also contains a large number of neurons, which are needed for the complex analytical and integrative functions performed by the cerebral hemispheres.

Longitudinal Fissure

Left hemisphere Right hemisphere

Cerebral Hemispheres

Longitudinal fissure – responsible for separating the two hemisphere.

Corpus Callosum (kōr’pŭs kal-lō’sŭm; corpus = body; callosum =hard)- provides the main method of communication between these hemispheres.

Lobes of the Cerebrum

Frontal lobe lies deep to the frontal bone and forms the anterior part of the cerebral hemisphere.

Functions: Higher intellectual functions

(concentration, decision making, planning)

Personality verbal communication voluntary motor control of skeletal

muscles

Parietal lobelies internal to the parietal bone and forms the superoposterior part of each cerebral hemisphere.

Functions:Sensory interpretation of textures and shapesUnderstanding speech and formulating words to express thoughts and emotions (Wernickes’s area)

Temporal lobe Lies inferior to the lateral sulcus and

underlies the temporal bone.

Functions: Interpretation of auditory and

olfactory sensations Storage of auditory and olfactory

experiences

OCCIPITAL LOBE

INSULAa small lobe deep to the lateral sulcus.can be observed by laterally reflecting (pulling aside) the temporal lobe.

Functions:Interpretation of tastememory

Forms the posterior region of each hemisphere and immediately underlies the occipital bone.

Functions: Conscious perception of visual stimuli Integration of eye focusing movements Correlation of visual images with

previous visual experiences

Diencephalon•referred as the “in between brain”

• provides the relay and switching centers for some sensory and motor pathways and for control of visceral activities.

•encloses the third ventricle and connects the cerebral hemisphere to the brainstem.

Three Components of Diencephalon

Epithalamus Left and right ThalamusHypothalamus

Epithalamuspartially forms the posterior roof of the diencephalon and covers the third ventricle.Melatonin – appears to help regulate day-night cycles known as the body’s circadian rhythm.Habenular nuclei – help relay signals from the limbic system to the mesencephalon and are involved in visceral and emotional responses to odors.

refers to paired oval masses of gray matter that lie on either side of the third ventricle.

the principal and final relay point for sensory information that will be processed and projected to the primary sensory cortex.

Thalamus

Hypothalamusthe anteroinferior region of the diencephalon.

Functions:Master control of the autonomic nervous system.Master control of the endocrine systemRegulation of body temperatureControl of emotional behavior Control of food intakeControl of water intakeRegulation of sleep-wake (circadian) rhythms