1. Central Nervous System

2. The Brain 2 hemispheres and 4 major portions one of the largest organs (3 lbs) contains approximately 100 billion neurons made up of gray matter (cell bodies) and white matter (axons with myelin)

4. Brain Stem: medulla oblongata, pons, and midbrain Medulla oblongata –Cardiac center- regulates heartbeat –respiratory center – rate, rhythm, and depth of breathing –vasomotor center – regulates dilation of blood vessels –other: swallowing, coughing, sneezing, hiccupping, vomiting

5. Brain Stem: medulla oblongata, pons, and midbrain Pons : “bridge” –connects medulla oblongata to midbrain –transmits impulses from the cerebrum to the cerebellum Midbrain –controls reflexive movements of head and eyes in response to visual stimuli –controls reflexive movements of head and trunk in response to auditory stimuli

7. Diencephalon Thalamus –central relay station for sensory impulses (except smell) –interpretation center for pain, temperature, light touch, pressure

8. Diencephalon Hypothalamus –body temperature –water balance –control of hunger and body weight –control of movements and glandular secretions of the stomach and intestines –production of hormones that stimulate the pituitary gland to secrete other hormones –sleep and wakefulness –limbic system (emotional (experiences & expression), memory)

10. Cerebellum coordinates but does not initiate voluntary motor action coordination maintains posture/balance damage to the cerebellum will likely result in tremors, inaccurate movement of voluntary muscles, loss of muscle tone, loss of equilibrium Pons important because relays info between cerebrum (movement) and cerebellum (coordination)

12. Cerebrum many raised folds called gyri the deep grooves are called sulci consists of 2 hemispheres connected by nerve fibers called the corpus callosum has four lobes: frontal, parietal, temporal, occipital provides higher order mental functions interprets sensory impulses and initiates voluntary muscular movements stores memory and uses it for reason intelligence and personality stem from cerebral activity

13. Lobes of the Cerebrum Frontal –primary motor area for upper and lower limbs –Broca’s area – (SPEECH) coordinates tongue, mouth, and larynx for speech –movement of the eyes and eyelids –higher intellectual processes like problem solving. Parietal –Receives and sends out sensory input (Senses); temperature, touch, pressure, pain in the skin –understanding speech and using words to express feelings and thought

14. Lobes of the Cerebrum Temporal –hearing –interpreting sensory experiences, visual scenes, music and patterns Occipital –vision –combining visual experiences with other sensory experiences; recognition

16. Meninges found between bone and soft tissue of the nervous system; cover and protect brain and spinal cord –dura mater “tough mother”- outer most covering –arachnoid mater “spider” - middle layer Well Vascularized – therefore main site of blood brain barrier. –pia mater “ delicate”- inner layer

18. Blood Brain Barrier BLOOD-BRAIN BARRIER capillary walls in brain contain more densely packed cells (called astrocytes) and have a continuous basement membrane This protects the brain by keeping toxins out and protecting brain from a direct rise in temperature (fever). Some substances permeable through barrier: –Water- Carbon dioxide- Glucose –Insulin- Alcohol- Heroin- Nicotine Some substances impermeable to the barrier: –Hydrogen ions- Proteins- Antibiotics Other characteristics of blood brain barrier: Trauma can destroy it and lead to brain injury Keeps out many useful drugs; researchers are developing ways to attach drugs to molecules that can cross the barrier

20. Spinal Cord column of nerve tissue that starts in the medulla oblongata and runs down the vertebral column consists of 31 segments; each associated with a pair of spinal nerves contains a core of gray matter that roughly resembles a butterfly with its wings spread or a flattened H; surrounded by white matter conveys sensory impulses from PNS to the brain and conducts motor impulses from brain to PNS