1. 8.3 The Central Nervous System
UNIT 4
Chapter 8: The Nervous System and Homeostasis
Section 8.3
8.3 The Central Nervous System
CNS = structural and functional centre for the entire nervous system.
-the site of neural integration and processing.
Myelinated neurons form white matter, which forms the inner region of some areas of the brain and the outer area of the spinal cord.
Unmyelinated neurons form grey matter. The grey matter is found around the outside areas of the brain and forms the H-shaped core of the spinal cord.
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2. The Central Nervous System
UNIT 4
Chapter 8: The Nervous System and Homeostasis
Section 8.3
The Central Nervous System

3. The spinal cord is protected by the meninges and the bony vertebrae.
UNIT 4
Chapter 8: The Nervous System and Homeostasis
Section 8.3
The Spinal Cord
The spinal cord extends out of the skull from the brain and downward through a canal within the backbone.
Sensory and motor nerves are found within the spinal cord. It is also the primary reflex centre. The tissues are protected by cerebrospinal fluid, soft layer tissues, and the spinal column (vertebrae). Injury to the spinal cord can result in paralysis.
The spinal cord is protected by the meninges and the bony vertebrae.

4. The Brain UNIT 4 The brain is protected by the skull and the meninges.
Chapter 8: The Nervous System and Homeostasis
Section 8.3
The Brain
The brain is protected by the skull and the meninges.
The brain is divided into 3 general regions:
hindbrain
midbrain
forebrain
Three layers of tissue, called the meninges, surround and protect the brain and spinal cord.

5. The Hindbrain: Coordination and Homeostasis
UNIT 4
Chapter 8: The Nervous System and Homeostasis
Section 8.3
The Hindbrain: Coordination and Homeostasis
A – cerebellum: involved in unconscious coordination of posture, reflexes, body movement, and fine voluntary motor skills
B – medulla oblongata: coordinates automatic bodily functions that maintain homeostasis, including heart rate and breathing
C – pons: relay centre between right and left halves of the brain

6. Midbrain: Processing Sensory Input
UNIT 4
Chapter 8: The Nervous System and Homeostasis
Section 8.3
Midbrain: Processing Sensory Input
D – midbrain: processes information from the eyes, ears, and nose and controls skeletal muscle movement

7. Forebrain: Thought, Learning, and Emotion
UNIT 4
Chapter 8: The Nervous System and Homeostasis
Section 8.3
Forebrain: Thought, Learning, and Emotion
E – thalamus: connections btw the forebrain & hindbrain
F – hypothalamus: regulates body’s internal environment, (ie. behaviour, blood pressure, heart rate, body temperature, hunger, thirst)
G – cerebrum: divided into right and left cerebral hemispheres; each contain centres for intellect, learning, memory, consciousness, and language

8. The Blood-Brain Barrier
UNIT 4
Chapter 8: The Nervous System and Homeostasis
Section 8.3
The Blood-Brain Barrier
The blood-brain barrier is formed by glial cells and blood vessels. It separates the blood from the CNS and selectively controls the entrance of substances into the brain from the blood.
The brain requires a constant supply of oxygen and glucose. Both of these substances can cross the blood-brain barrier through special transport mechanisms.
Lipid-soluble substances (caffeine, nicotine, alcohol) have rapid effects on brain function because they are able to pass directly through the barrier.
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9. The Blood-Brain Barrier
UNIT 4
Chapter 8: The Nervous System and Homeostasis
Section 8.3
The Blood-Brain Barrier

10. Cerebrospinal Fluid UNIT 4
Chapter 8: The Nervous System and Homeostasis
Section 8.3
Cerebrospinal Fluid
-A dense, clear liquid derived from blood plasma.
-It transports hormones, white blood cells, and nutrients across the blood-brain barrier to the cells of the brain.
-Shock absorber; circulates between 2 layers of the meninges (the arachnoid and pia mater).

11. The Structure and Function of the Cerebrum
UNIT 4
Chapter 8: The Nervous System and Homeostasis
Section 8.3
The Structure and Function of the Cerebrum
Each half of the cerebrum contains a mass of white matter and a thin, outer covering of grey matter called the cerebral cortex. The cerebral cortex is responsible for language, memory, personality, vision, conscious thought, and emotion.
The right and left halves (the cerebral hemispheres) are linked by the corpus callosum. The corpus callosum sends messages from one hemisphere to another.
The folds on the cerebral cortex increase the surface area of grey matter in the cerebrum.

12. UNIT 4
Chapter 8: The Nervous System and Homeostasis
Section 8.3
The Cerebrum
Cognitive functions originate from both right-brain (right cerebral hemisphere) and left-brain (left-cerebral hemisphere) components. However, some functions have a dominant hemisphere:
the right-brain is associated with holistic and intuitive thinking, visual-spatial skills, and artistic abilities
the left-brain is associated with sequential and logical ways of thinking, and linguistic/mathematical skills

13. The Cerebral Cortex UNIT 4 Four lobes:
Chapter 8: The Nervous System and Homeostasis
Section 8.3
The Cerebral Cortex
Four lobes:
occipital lobes: receive and analyze visual information
temporal lobes: share some visual processing but mainly process auditory information
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14. The Cerebral Cortex UNIT 4
Chapter 8: The Nervous System and Homeostasis
Section 8.3
The Cerebral Cortex
parietal lobes: receive and process sensory information from the skin
frontal lobes: integrate info and controls critical thinking, memory, personality, and fine motor skills. Each side of the frontal lobes controls muscles on the opposite side of the body.