1. The Central Nervous System
Chapter 8.3
McGraw-Hill Ryerson
Biology 12 (2011)

2. All nerves within the PNS contain a thin membrane called the neurilemma
Neurilemma promotes the regeneration of damaged axons
Grey Matter
Nerves in the brain and spinal cord (CNS)that lack myelin and neurilemma
White matter
Nerves in the brain and spinal cord (CNS) that contain myelin and neurilemma

3. Central Nervous System (CNS)
Contains the nerves of the brain and spinal cord
Function = coordinating center of incoming/outgoing information

4. Central Nervous System (CNS)
Brain is found in the skull & serves as overall control center for the nervous system
Spinal Cord is surrounded by vertebrae and extends down the back of the neck, thorax and abdomen
Center of many reflex actions
Provides a link between sensory and motor nerves
Both are enclosed in 3 protective membranes called the meninge
Space between meninge contains cerebrospinal fluid which protects and cushions the CNS

5. The Brain 3 big regions made up of little parts Forebrain Midbrain
Thalamus: sits at base of forebrain with neurons that connect to various parts of the brain (“great relay station)
Hypothalamus: controls blood pressure, heart rate, body temperature, drives (hunger/thirst), and emotions. Abnormalities is linked to violent, unusual behaviour
Cerebrum: largest part of brain (80% of brain weight) and divided into left and right hemispheres which contain intellect, learning, memory, consciousness, and language
Midbrain
Hindbrain

6. The Brain 3 big regions made up of little parts Forebrain Midbrain
Midbrain: found above the pons in brainstem and is involved in sensory information (eyes, ears, nose) by relaying information between hindbrain and forebrain
Hindbrain

7. The Brain 3 big regions made up of little parts Forebrain Midbrain
Hindbrain
Cerebellum: unconscious coordination of posture, reflexes, body movements, fine/voluntary motor skills, and receives information from specialized sensors (proprioreceptors located within skeletal muscles and joints)
Medulla oblongata: coordinates reflexes and automatic bodily fnctions that maintain homestasis such as heart rate, constriction or dilation of blood vessels, and rate of breathing, swallowing, and coughing
Pons: serves as a relay centre between the neurons of the right and left halves of cerebrum, cerebellum, and rest of the brain

8. The Brain Cerebral cortext split into 4 pairs of lobes
Occipital lobe: receives and analyzes visual information and is needed for recogntion of what is being seen
Temporal lobe: shares in the processing of visual information but its main function is auditory reception
Parietal lobe: receives and processes sensory information from the skin, and helps to process information about the body’s position and orientation
Frontal lobe: integrates information from other parts of the brain and controls reasoning, critical thinking, memory, and personality

9. The Brain
Glial cells: non-neural cells that maintain homeostasis, form myelin, deals with waste materials from neurons, and provide support network and protection in the brain.
Meninges: three layers of tough elastic tissue
Located within skull and spinal column
Directly encloses the brain and spinal cord

10. Blood-brain barrier
A protective barrier formed by glial cells and blood vessels that separates the blood from the central nervous system
selectively controls the entrance of substances into the brain from the blood
Oxygen and glucose are needed by the brain in high and constant supply and enter the brain through special transport mechanisms
Caffeine, nicotine, and alcohol are lipid-soluble so they pass directly through the lipid bilayer of the capillaries in the brain

11. Cerebrospinal Fluid
Dense, clear liquid from blood plasma found in the ventricles of the brain, in the central canal of the spinal cord, and with the meninges
Transports hormones, white blood cells, and nutrients across the blood-brain barrier to cells of the brain and spinal cord
Acts as a shock absorber to cushion the brain

12. Homework
Pg 369 #1, 3, 4, 8, 13,