If you have ever browsed this site, you may have encountered this video/song about the brain I posted many years ago ago. Since then I have been meaning to find out more about the most complex organ of the human body.
There are four basic regions to the brain, each of which may be composed of different structures. The evolutionary development of our brain maps well to other vertebrates’ brains which were thought to have evolved at earlier points in history.
The simplest brains belong to our oldest evolutionary ancestors (early fish and amphibians) and we share more features with our more recent ancestors (birds).
Brain
The human brain is the central organ of the human nervous system, and with the spinal cord makes up the central nervous system. The brain consists of the cerebrum, the brainstem and the cerebellum. It controls most of the activities of the body, processing, integrating, and coordinating the information it receives from the sense organs, and making decisions as to the instructions sent to the rest of the body. The brain is contained in, and protected by, the skull bones of the head. [Wikipedia]
The most primitive part of your brain - controls breathing and other basic functions
Part of the brain stem
Part of the brain stem
Part of the brain stem
Gathers information from sensory organs
Regulates your metabolism and controls adrenalin releases from the pituitary
Produces hormones to control growth and blood pressure
The little brain. Involved in motor function and emotional control involving pleasure and fear
Fluid-filled chambers
Runs along the base of the trench that divides the two halves of the brain
Smell, language, memory, speech - it is the largest part of the brain so it does a lot
Frontal lobe
Parietal lobe
Occipital lobe
Temporal lobe - missing from diagram
Brain Stem
This is the bit that is responsible for all the really basic functions of the brain. It is similar in structure to the brains of modern reptiles which appeared on the evolutionary tree many millions of years ago. The brain stem controls things like breathing and blood pressure. It consists of the midbrain, pons and medulla.
Limbic System
This is the next oldest bit of the brain and consists of four distinct regions.
Thalamus – information from the sensory organs (although not smell) go here before being distributed to higher regions of the brain
Hypothalamus – there are various involuntary functions of the body such as release of hormones (eg adrenalin) and feelings of thirst or hunger that are part of the autonomic nervous system, controlled by the hypothalamus
Amygdala – important for visual learning and memory but also involved in emotion and fear
Hippocampus – this is important for turning short-term memory into long-term memory but it is also involved in some emotional behaviour too
Cerebellum
Moving forward on the evolutionary scale, the “little brain” is involved in muscular control and balance.
Cerebrum
The cerebrum is the folded outer region of the brain. It consists of four lobes.
Frontal lobe – involved in reasoning, planning and problem solving
Parietal lobe – responsible for recognition, perception of stimuli, movement
Occipital lobe – associated with visual processing
Temporal lobe – this region processes auditory information and speech
Questions…
- Of which organ system is the brain a member?
- Name another human organ system and one of its constituent organs.
- Name a hormone other than adrenalin
- What are the five classes of vertebrate?
- Suggest a characteristic that all amphibians share.
- What is the name of the fluid that fills the ventricles and surrounds the brain?
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