human brain

The Human Brain

Part I:

Lobes, the Cerebral Cortex, and Cortical Regions of the Brain

Cerebrum -The largest division of the brain. It is divided into two hemispheres, each of which is divided into four lobes.

Cerebrum

Cerebrum

Cerebellum

Cerebral Cortex

Cerebral Cortex

Cerebral Cortex - The outermost layer of gray matter making up the superficial aspect of the cerebrum.

Cerebral Features:

• Sulci – Small grooves dividing the gyri– Central Sulcus – Divides the Frontal Lobe from the Parietal Lobe

• Fissures – Deep grooves, generally dividing large regions/lobes of the brain

– Longitudinal Fissure – Divides the two Cerebral Hemispheres

– Transverse Fissure – Separates the Cerebrum from the Cerebellum

– Sylvian/Lateral Fissure – Divides the Temporal Lobe from the Frontal and Parietal Lobes

• Gyri – Elevated ridges “winding” around the brain.

Gyri (ridge)

Fissure

(deep groove)

Sulci (groove)

Longitudinal Fissure

Transverse Fissure

Sylvian/Lateral Fissure

Central Sulcus

Specific Sulci/Fissures:

Lobes of the Brain (4)

•Frontal•Parietal•Occipital•Temporal

Lobes of the Brain - Frontal• The Frontal Lobe of the brain is located deep to the Frontal Bone of the skull.

• It plays an integral role in the following functions/actions:

- Memory Formation- Emotions- Decision Making/Reasoning

- Personality

Investigation (Phineas Gage)

Lobes of the Brain - Parietal Lobe

• The Parietal Lobe of the brain is located deep to the Parietal Bone of the skull.

• It plays a major role in the following functions/actions:- Senses and integrates sensation(s)

- Spatial awareness and perception(Proprioception - Awareness of body/ body parts in space and in relation to each other)

Lobes of the Brain – Occipital Lobe

• The Occipital Lobe of the Brain is located deep to the Occipital Bone of the Skull.

• Its primary function is the processing, integration, interpretation, etc. of VISION and visual stimuli.

Lobes of the Brain – Temporal Lobe

• The Temporal Lobes are located on the sides of the brain, deep to the Temporal Bones of the skull.

• They play an integral role in the following functions:

- Hearing-Organization/Comprehension of language

- Information Retrieval

Lobes and Structures of the BrainB.

A.

C.

D. E.

F.

G.

Lobes and Structures of the Brain

B. A. (groove)

C. (groove) D. E.

F.

G.

B. Frontal Lobe

G. Parietal Lobe

F. Occipital Lobe

D. Temporal Lobe

A. Central Sulcus

(groove)

E. Transverse Fissure

C. Sylvian/Lateral Fissure

Cortical Regions

A.

B.

C.

D.E.

F.

G.

H.

I.

J.

K.

Brain structureBrain structure

Cerebrum

cerebellumhypothalamu

s

Pituitary glandmedullabrain functions

Spinal Cord • Runs through the

vertebral canal(neural canal)

• Extends from foramen magnum to second lumbar vertebra

• Regions– Cervical – Thoracic – Lumbar– Sacral– Coccygeal

• Gives rise to 31 pairs of spinal nerves– All are mixed nerves

Cranial Nerves• 12 pairs• Emerge from brain

• Supplied to different parts of head

• Sensory, motor, or mixed

Spinal nerves• 31 pairs• Emerge from spinal cord

• Connected to different body parts

• All are mixed nerves

•The organs (the "viscera") of our body, such as the heart, stomach and intestines, are regulated by a part of the nervous system called the autonomic nervous system (ANS).

•The ANS is part of the peripheral nervous system and it controls many organs and muscles within the body.

The ANS is most important in two situations:

• In emergencies that cause stress and require us to "fight" or take "flight" (run away)

• In non emergencies that allow us to "rest" and "digest."

• Eye, ear, nose, skin and tongue• Enable the body to detect the various changes in the surroundings

• Important link between external and internal environment

• Makes body irritable and sensitive

• Largest organ• Epidermis and dermis• Dermis has receptors1) Pacinian corpuscle-

pressure

2) Merkel’s disk and Meissner corpuscle - touch

3)End organ of Krause - cold

4) Ruffini’s organ- warmth

• Two parts- external nose and nasal cavity

• Nasal cavity has mucous membrane on top side

• Molecules dissolve in the mucous and stimulate olfactory receptor cells

• Olfactory nerve carries impulses to the brain

• Organ of taste• Has gustatory receptors or taste buds

• chemicals in the food dissolve in saliva and stimulate these receptors.

• Four regions,a)Back – bitterb)Tip – sweetc)Sides – salt and sour