Human brain hemispheres

The cerebral hemispheres are the highest level of the Central Nervous System. They are like two mushroom caps bulging of the left and right front end of the brain stem, as shown in Figure 1 at the right. They control the activity of the lower levels, directing the overall plan and direction of behavior.

Figure 2 at the left represents the left cerebral hemisphere in humans. It shows four of the five lobes (the limbic lobe is on the inner surface) and the location of the primary sensory and motor areas.

Figure 3 at the right shows the variation among species in size of the cerebral hemispheres Compared to the rest of the brain, the hemispheres have undergone by far the greatest changes in the evolution. In fishes and amphibia (frogs, salamanders, etc.), they are little bumps on the brain stem. In mammals the hemispheres have expanded enormously to cover the front end of the brain stem. They are the largest in primates and cetaceans (whales, dolphins). The human cerebral hemispheres are about 3 times larger than the chimpanzee's. In humans, the hemispheres make up about 2/3 of the whole brain, hiding the front half the brain stem.

Figure 4 at the left is a cross section through the cerebral hemispheres, showing their internal structure. The outer surface of the hemispheres, colored pink in Figure 4, is called the cerebral cortex (Greek for rind), which is filled with cell bodies and dendrites, and synaptic connections from axons. The cortex contains about half of all neurons in the human brain and serves as the highest level of brain function. It is essential for the highest levels of mental and behavioral functions. Underneath the cortex are the axons connecting each cortical area with other parts of the brain. The underlying axon area is a creamy white and is called white matter Because it is full of cell bodies, etc., the cortex looks darker and is called grey matter.

  • Primary areas, one for each major sense and one for motor control. They are most directly connected to the input from the senses and output to the motor system.
  • Sensory and motor association areas, several for each major sense and for motor control. These are involved in perceptual and motor organization.
  • Higher order association areas, one on the back half of the brain and one in the front. These are essential for mental functions, like language that do no depend on one particular sense.

The inside of the cerebral hemispheres contain several large, interconnected clusters of cell bodies called the basal ganglia. These link sensory parts of the cerebral cortex to its motor parts, and connect the motor parts to brain stem and spinal cord.

You might also like

Biology Control & Co-ordination part 18 (Human Brain: CNS
Biology Control & Co-ordination part 18 (Human Brain: CNS ...
The Human Brain Dr Vishal Indla Part 2
The Human Brain Dr Vishal Indla Part 2
027 The 3 parts of the brain stem and their functions
027 The 3 parts of the brain stem and their functions
The Human Brain Dr Vishal Indla Part 1
The Human Brain Dr Vishal Indla Part 1
Learning Resources Learning Resources Cross-section Brain Model
Toy (Learning Resources)
  • Explore the human brain through hands-on investigation; learn new terminology, location, and complexities with this labeled cross-section model
  • One half is labeled with the parts of the brain, and the other has letters only for testing purposes; parts are differentiated by color for easy identification
  • An Activity Guide is included with detailed information about the human brain and how it functions
  • Completed model can be used as a display or demonstration in classrooms to identify and learn the parts of the brain
  • Includes 2-piece, clearly identified, soft foam model, and Activity Guide
  • Model measures 5 in diameter
  • Winner of 3 awards
  • Ideal for ages 7+
TEDCO Toys EIN-O's Human Brain Box Kit
  • Learn about basic body structures.
  • This kit contains Ein-o s I Know Guide and a detailed 3D model of the human brain.
  • Enjoy!
Learning Resources Learning Resources Human Body Model
Toy (Learning Resources)
  • Explore the organs of the human body and their functions in this 3-D model
  • Easy-to-assemble richly detailed miniature plastic model
  • 31-piece torso model includes: brain, skull, heart, rib cage, lungs, liver, stomach, pancreas, kidneys, intestines, spine, structural body parts, stand, Fact Guide...
  • Measures 4½ H when assembled
  • Winner of 3 awards
  • Ideal for ages 8+
Colore Electric Pencil Sharpener For Colored / Graphite Lead Pencils - Battery / USB Powered Professional Sharpener - Great School & Office Supplies For Teacher, Kids and Adults - FREE Core Sharpener
Office Product (Colore Art)
  • FREE BONUS: One Extra Core Sharpener. Professional grade white electric sharpener with dual powering options: USB Powered (included USB cord) or 4 AA Battery Operated...
  • PERFECT GIFTS as educational supplies for teachers, high school teens, college art students, artists, boys and girls that just loves to sketch and draw a lot. Great...
  • NO MORE MANUAL Pencil Sharpener - Sharpening your color or graphite pencils with this pencil sharpener efficiently in just a few seconds without the hassle of breaking...
  • LIGHTWEIGHT AND PORTABLE Electric Sharpener with maximum efficiency and easy to use. Simply put your pencil into the sharpener s mouth opening for a few seconds...
  • HIGH QUALITY Automatic Pencil Sharpener best designed for everyone and applicable in home, school and office use. We are so confident that you ll love your pencil...
Jaguar Educational The Human Brain Poster Series - 5 Poster Set. Brain Facts, Brain Structure, Brain Health and Safety, Brain Functions and Brain Neurons.
Home (Jaguar Educational)
  • 5 Plain Paper Posters in the Series. (Also available Laminated).
  • Printed at Highest Resolution on Quality Paper.
  • Each poster measures 18 x 24
  • Each poster them features key illustrations and facts.
  • Also available in LAMINATED version, sold under a separate Amazon listing.


Do humans only use 10% of their brain for actual psychological processes? | Yahoo Answers

No, it's *all+ used for sub-conscious processing and autonomic care and functioning of the body.

Copyright © . All Rights Reserved