1. Chapter 15: The Brain! Lesson Objectives:
To describe the gross structure of the brain and the functions of the cerebrum, cerebellum, medulla oblongata and hypothalamus

2. Brain teasers – what do you see?

3. Stare at the dot for a few seconds, then move your head closer to it!

4. What does the brain ideally look like?
Of course, really the brain is dynamic and individually variable…
- information on Brain Anatomy!

5. The brain is an expanded extension of the spinal cord
Brain structure
Cerebrum (left and right cerebral hemispheres) linked by corpus callosum
The brain is an expanded extension of the spinal cord
It contains ventricles containing CEREBRO-SPINAL FLUID (continuous with the spinal cord)
Consists of myelinated (white areas) and unmyelinated (grey areas) neurones

6. Brain structure – annotate!
Ventricle containing cerebro-spinal fluid (secreted by the meninges)

7. Right versus left Cerebrum
Verbal
Non-verbal

8. The cerebrum – highly folded area
Parietal lobe
Sensory area
Motor area
Frontal lobe
Contains an area involved with planning actions and movements
Occipital lobe
Corpus callosum – links the two cerebral hemispheres
A large association area in the parietal and occipital lobes is involved in determining body position
NOT SHOWN – Temporal lobe!

9. The cerebrum – highly folded area
NOT SHOWN –
Amygdala (‘almonds’) - coordinates the action of the autonomic and endocrine systems as well as a role in emotions
Hippocampus (‘seahorse’) – role in memory (making new memories)
Limbic system (part of) – emotions and memory

10. Studying the brain … BRAIN SCANS
CAT scan (computer assisted tomography)
Uses X-rays to find out about the tissues in the brain
Put many ‘slices’ of the brain together to create a 3D image!

11. Studying the brain … BRAIN SCANS
CAT scan (computer assisted tomography)

12. Studying the brain … BRAIN SCANS
PET Scan (positive emission tomography)
•Inject radioactive material (labelled 2-deoxyglucose)
Respiring cells take this up and use it in glycolysis (phosphorylate it)
It cannot be metabolised further or removed from the cell
•Scan to detect the decay of the material (half-life)
More metabolically active regions of the brain take up more 2-deoxyglucose.
Give patient injection and then give them a stimulation or get them to think about something

13. Studying the brain … BRAIN SCANS
PET Scans

14. Studying the brain … BRAIN SCANS
MRI (magnetic resonance imaging)
Used to find out which parts of the brain are active at different times
Computer-controlled equipment measures the magnetic field from Haemoglobin in different regions of the brain
Oxyhaemoglobin has a smaller magnetic effect than deoxyhaemoglobin
Areas with high activity have a greater level of oxyhaemoglobin

15. Two association areas in the left hemisphere - language
Broca’s aphasia
Wernicke’s aphasia

16. The Cerebellum Cerebellum – folded surface
Controls movement and posture – responsible for balance, coordination, eye movement and fine manipulation
Receives impulses from ears, eyes, stretch receptors in muscles and other parts of the brain
Integrates information and uses it to coordinate skeletal muscle contraction

17. The Brain Stem Mesencephalon (midbrain) Medulla oblongata
Links the brain and spinal cord
Coordinates and controls involuntary movements (breathing, heartbeat etc.)
Pons – conducts signals from the cerebrum to the cerebellum and medulla as well as sensory signals to the thalamus

18. Diencephalon - the interbrain
Hypothalamus
Links the nervous system to the endocrine system via the pituitary
Size of an almond in humans!
Controls body temperature, hunger, thirst, fatigue, anger and circadian cycles (autonomic nervous system)
Thalamus (left and right)
Believed to process and relay sensory info. selectively to cerebral cortex
The links with the cortex may be linked with consciousness
Regulates sleep and wakefulness (damage leads to a coma!)

19. Phineas Gage (1823-1860) was a railroad construction foreman
Studying the brain …
Frontal lobe damage:
Phineas Gage ( ) was a railroad construction foreman
An 1848 explosion
forced a steel tamping
rod through his head
Others said he was
“…no longer Gage…”
3.2 cm diameter rod!
Went through his head from bottom to top and landed approx. 30 metres behind him!