1. Chapters 13 & 14 The Central Nervous System: The Brain and Spinal Cord

2. BRAIN

3. The Brain 100 billion neurons 1.6 kg in males/1.45 kg in females (size is not representative of intelligence, only overall average body size) Complexity dictates processing power

4. Major Subdivisions of the Brain 1.Cerebrum 2.Cerebellum 3.Diencephalon –thalamus –hypothalamus 4.Brain stem –midbrain –pons –medulla oblongata Fig. 14-2 No functional area of the brain works alone

5. 1. Cerebrum ~ 80% of the brain’s mass; the thinking center 2 cerebral hemispheres contain 4 distinct lobes: Frontal – motor cortex Parietal – sensory cortex Occipital – visual cortex Temporal – auditory & olfactory cortex Fig. 14-8 Each hemisphere primarily controls the opposite side of the body

6. 2. Cerebellum Coordination of movement Balance and posture

7. 3. Diencephalon (INTERBRAIN) Thalamus - receives sensory inputs and determines which of these signals to forward to the cerebral cortex Hypothalamus - regulates the pituitary gland, body T, food intake, emotion, sleep-wake cycle and memory; controls autonomic functions (heart rate, respiration, blood pressure)

8. Limbic System The “emotional” center, important for perception of pleasure and pain & functions in memory formation Includes hypothalamus, hippocampus (long- term memory formation), amygdala (processing of emotions)

9. 4. Brainstem lowest part of the brain where it connects to the spinal cord Midbrain – processing of visual & auditory data Pons – contains respiratory center Medulla oblongata – relays sensory info to thalamus & other parts of brainstem; controls cardiovascular, respiratory and digestive activities

10. Protection of the Brain Several different mechanisms: Skull & scalp hair Meninges (connective tissue membranes wrapping the CNS) Cerebrospinal fluid (CSF) cushions and nourishes the brain Blood-brain barrier - separation of the CNS from general circulation; composed of the least permeable capillaries; helps to maintain homeostasis in the brain

11. SPINAL CORD

12. Spinal Cord Connects the brain & PNS Located within the vertebral column From brain stem through foramen magnum to second lumbar vertebra (L2), ends as “horse tail”- cauda equina