The nervous system

1. The nervous system CNS, PNS, and the brain

2. Central Nervous System (CNS) • Consists of the spinal cord and the brain • Both covered with a protective membrane called meningens • Impulses are received at the spinal cord and the brain via the PNS- initiates voluntary motor control

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4. Peripheral Nervous System (PNS) • -Lies outside the central nervous system • -Contains cranial and spinal nerves that send signals to and from the CNS

6. Somatic vs. Autonomic System • Somatic system – includes nerves that take stimuli from PNS to the CNS and motor commands from the CNS to the skeletal muscles. • Voluntary responses • Autonomic System • Regulates activity of smooth muscle and glands • Divided into the sympathetic and parasympathetic divisions

7. Sympathetic Division • Neurons arise from the middle of the spinal cord • Involved with “fight or flight” responses that are important during emergency situations. • If you need to fend of a foe or flee from danger, your muscles need a quick supply of glucose and oxygen. • To accomplish this, the sympathetic division accelerates the heartbeat and dilates the bronchi, but inhibits the digestive tract. • The neurotransmitter released during this is norepinephrine (NE)

8. Parasympathetic Division • Involves a cranial nerves and nerves that arise from the bottom of the spinal cord • Promotes all internal responses associated with a relaxed state. • Causes the pupil of the eye to contract, promotes digestion of food and slows down the heartbeat • The neurotransmitter released during this is acetylcholine (Ach)

10. http://www.youtube.com/watch?v=J968Wco1u0s

11. The Brain

12. Medulla Oblongata • -Lies between the spinal cord and the PONS • -Regulates heartbeat, breathing, and blood pressure • -Reflex center for vomiting, sneezing, swallowing, and coughing

13. Cerebellum • -Separated from the brainstem • -Passes on both sensory and motor information • -Maintains normal muscle tone, posture and balance • -Makes sure all skeletal muscles function together for smooth and coordinated movement (like playing the piano or swinging a baseball bat)

14. Thalamus • -Integrates sensory information • -Serves as a central relay station for impulses travelling up to the cerebrum • -Involved in higher mental functions such as memory and emotion

15. Hypothalamus • -The integrating center for the autonomic system • -Also helps maintain homeostasis • Regulating hunger, sleep, thirst, body temperature and water balance • -Controls the pituitary gland

16. Pituitary Gland • -Located on the hypothalamus • -An endocrine gland • Secretes hormones involved with growth, blood pressure, breast milk production, body temperature, ect. • -Hormonal secretion controlled by the hypothalamus

17. The Cerebrum • -Largest portion of the human brain • -Has two halves connected by the corpus callosum • -Highest center to receive sensory input and carry out integration before commanding voluntary motor response • -Works with other parts of the brain to regulate activities • -Carries out higher thought processes required for learning, memory, language and speech