1. CNS Notes
Parts of the Brain

2. CNS = BRAIN + SPINAL CORD
The spinal cord connects the CNS to the PNS via nerves that travel through a canal inside the backbone
Sensory neurons carry impulses from the sensory receptors in the periphery to the brain
Motor neurons carry impulses from the brain to the effectors (muscles, glands, organs)
The spinal cord is also the primary reflex centre – allowing the body to react quickly to potentially dangerous situations

3. Spinal cord Contains white matter and grey matter
White mattermyelinated nerve fibres from sensory and motor neurons
Grey matternonmyelinated interneurons

4. Brain protection Cranium = skull
Cranium and mandible of documented 17 year old.
Manner of death was two gunshot wounds, and cranium shows classic entrance and exit wounds.
From Maxwell Museum, Albuquerque, NM.

5. Brain protection – con’t
Meninges
3 membranes surrounding the brain
Make up the blood-brain barrier – allow a separation of blood in the brain – although some substances do cross (ie alcohol, caffeine, nicotine, heroin, other lipid-soluble substances)

6. Brain injury
Why do we wear helmets?

8. Brain Forebrain Midbrain Hindbrain
Primary cortical areas-receive signals from receptors on the body’s periphery
Association areas-coordinate and process sensory input from different receptors

9. Forebrain Cerebrum Thalamus Hypothalamus Olfactory bulbs
Largest, most developed part of the brain
Thalamus
Coordinates and interprets sensory information and directs to appropriate part of cerebrum
Hypothalamus
Coordinates nerve and hormone functions; directly connected to pituitary gland; maintains internal equilibrium
Olfactory bulbs
One in each hemisphere; process information about smell

10. Hypothalamus Influences HR, BP, resp. rate,
Autonomic regulatory center
Influences HR, BP, resp. rate,
GI motility, pupillary diameter.
Emotional response
Involved in fear, loathing, pleasure
Drive center: sex, hunger
Regulation of body temperature
Regulation of food intake
Contains a satiety center
Regulation of water balance and thirst
Regulation of sleep/wake cycles
Hormonal control
Releases hormones to the pituitary gland

11. Pituitary gland A gland that lies just beneath the hypothalamus
Divided into anterior and posterior pituitary
Responsible for the production of many different hormones

13. Cerebrum Divided into two hemispheres; left and right
Right side: visual patterns and spatial awareness
Left side: verbal skills
Further subdivided into 4 lobes (frontal, temporal, occipital, parietal)
Cerebral cortex: outer layer of the cerebral hemispheres
Grey matter
Deep folds increase surface area
Corpus Callosum
Nerve tract that joins the two cerebral hemispheres; allows communication between the two sides

14. Scientists believe that epilepsy is caused by an overload of neurological electrical activity – so the corpus callosum is sometimes cut in an epilepsy patient to prevent the seizures from spreading from one hemisphere to the other.

15. Lobes of the Cerebrum Frontal Temporal Parietal Occipital
Motor areas control voluntary muscles
Temporal
Sensory areas associated with vision and hearing
Parietal
Sensory areas associated with touch and temperature
Association areas linked with emotions and interpreting speech
Occipital
Sensory areas associated with vision
Association areas interpret visual information

16. Sensory Areas Found in the parietal, occipital, and temporal lobes.
Parietal lobe
Temporal lobe
Occipital lobe

17. Motor Area Frontal Lobe
Controls fine motor movements – but innervation is not equal – some parts of the body have a larger proportion of the motor area devoted to them than others
Contains large neurons which synapse on skeletal muscles
Allow for voluntary motor control

18. Midbrain 4 spheres of grey matter
Relay centre for some eye and ear reflexes

20. Hindbrain Cerebellum Medulla oblongata Pons
Largest section of hindbrain
Controls limb movements, balance and muscle tone
Medulla oblongata
Connects the peripheral and central nervous systems
Joins spinal cord to cerebellum
Responsible for involuntary muscle action
Pons
Part of brain that bridges the cerebellum and medulla, acts as a relay station

21. Cerebellum Has 2 primary functions: 2nd largest region of the brain.
10% of the brain by volume, but it contains 50% of its neurons
Has 2 primary functions:
Adjusting the postural muscles of the body
Coordinates rapid, automatic adjustments, that maintain balance and equilibrium
Programming and fine-tuning movements controlled at the subconscious and conscious levels
Compares motor commands with sensory info from muscles and joints and performs any adjustments to make the movement smooth

24. Your Turn Read pg 430 and discuss questions 1-3 with a friend
Complete questions 1-4 & 8 on pg. 432