1. The Nervous System  Nerves  neural “cables” containing many axons  part of the peripheral nervous system  connect the central nervous system with muscles, glands, and sense organs  Sensory Neurons  neurons that carry incoming information from the sense receptors to the central nervous system

2. The Nervous System  Interneurons  CNS neurons that internally communicate and intervene between the sensory inputs and motor outputs  Motor Neurons  carry outgoing information from the CNS to muscles and glands  Somatic Nervous System  the division of the peripheral nervous system that controls the body’s skeletal muscles

3. The Nervous System  Nervous System  the body’s speedy, electrochemical communication system  consists of all the nerve cells of the peripheral and central nervous systems  Central Nervous System (CNS)  the brain and spinal cord  Peripheral Nervous System (PNS)  the sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body

4. The Nervous System Central (brain and spinal cord) Nervous system Autonomic (controls self-regulated action of internal organs and glands) Skeletal (controls voluntary movements of skeletal muscles) Sympathetic (arousing) Parasympathetic (calming) Peripheral

5. THE NERVOUS SYSTEM zCentral Nervous System zPeripheral Nervous System ySomatic yAutonomic xSympathetic xParasympathetic

6. Central Nervous System (CNS) zComprised of the brain and the spinal cord, considered to be the command center of the body. zSpinal cord deals with reflex or involuntary actions. yInjuries can produce paralysis of limbs. The higher the site of the damage, the more severe the injury.

7. CNS Con’t. zCommon reflex know as the “knee- jerk”reflex. yTested by tapping just below the knee, causing the lower leg to suddenly jerk forward. xOften used as part of a clinical neurologic exam. zThe BRAIN is required for all voluntary movements.

8. Central Nervous System The Spinal Cord and Reflexes Simple Reflex

9. The Peripheral Nervous System  Autonomic Nervous System  the part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart)  Sympathetic Nervous System  division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations  Parasympathetic Nervous System  division of the autonomic nervous system that calms the body, conserving its energy

10. Peripheral Nervous System (PNS) zConnects the CNS with the rest of the body through nerves zCarries incoming messages to your brain and outgoing signals to your body’s muscles and glands. zIncludes the Somatic Division and the Autonomic Division zExample: As you cross a busy street, your PNS will notice the auditory sounds of cars and the visual patterns of oncoming traffic. Your brain assesses the situation and tells your body that danger may be lingering, so you cross the street with caution.

11. The Somatic Division of the PNS zAllows communication with the outside world. zCarries information to the CNS and sends voluntary signals to your muscles. zFor example: if you smell a food that gives you an arousal, your muscles are then induced to eat the food.

12. Autonomic Nervous System (ANS) (Part of the PNS)…Two Parts…. Sympathetic Nervous System: Division of the ANS that arouses the body, mobilizing its energy in stressful situations. Activation of the Sympathetic Nervous System results in an increase in respiratory and heart rates, dialation of the pupils. “Flight-or-Fight” response allows you to either attack or flee from a situation.

13. Autonomic Part II: zParasympathetic Nervous System: yPart of ANS that allows a person to return to a calm and collected state after arousal from the sympathetic nervous system.

14. The Nervous System  Autonomic Nervous System  the part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart)  Sympathetic Nervous System  division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations  Parasympathetic Nervous System  division of the autonomic nervous system that calms the body, conserving its energy

15. Autonomic Nervous System (ANS) Sympathetic NS “ Arouses ” (fight-or-flight) Parasympathetic NS “ Calms ” (rest and digest)

16. The Nervous System  Neural Networks  interconnected neural cells  with experience, networks can learn, as feedback strengthens or inhibits connections that produce certain results  computer simulations of neural networks show analogous learning InputsOutputs Neurons in the brain connect with one another to form networks The brain learns by modifying certain connections in response to feedback

17. The Endocrine System The Endocrine System is the body’s “slow” chemical communication system located in the lower half of the brain. Communication is carried out by hormones synthesized by a set of glands. For example, it allows us to sense thirst or hunger.

18. Hormones Hormones are chemicals synthesized by the endocrine glands that are secreted in the bloodstream. Hormones affect the brain and many other tissues of the body. For example, epinephrine (adrenaline) increases heart rate, blood pressure, blood sugar, and feelings of excitement during emergency situations.

19. The Main Gland: The Hypothalamus zLinks the nervous and endocrine system by receiving signals and propagating the endocrine response. zLocated in the lower half of the brain.

20. Pituitary Gland Is called the “master gland.” The anterior pituitary lobe releases hormones that regulate other glands. It is under control of the hypothalamus. The posterior lobe regulates water and salt balance.

21. Pituitary Gland and the Hormones it releases… zOxytocin: Contraction of uterus; breast milk let-down. zAntidiuretic hormone: Water retention in kidneys. zGrowth hormone: Stimulates growth. zProlactin: Stimulates milk production from mammary glands.

22. Con’t. zFollicle stimulating hormone: Stimulates production of ova and sperm. zLuteinizing hormone: Stimulates ovaries. zThyroid Stimulating hormone: Stimulates the thyroid.

23. Pineal Gland zSmall peanut shaped gland near the center of the brain. yReleases melatonin, which maintains sleep- wake cycle and other circadian rhythms.

24. Thyroid & Parathyroid Glands Regulate metabolic and calcium rate. Thyroid: near the trachea Parathyroid: on the surface of the thyroid gland.

25. Thyroid Gland and the hormones it releases… zTriiodothyronine and thyroxine: Stimulates metabolism zCalcitonin: Lowers calcium level in bloodstream; stimulates bone construction

26. Parathyroid gland releases… zParathyroid hormone: Raises blood calcium.

27. Adrenal Glands Adrenal glands consist of the adrenal medulla and the cortex. The medulla secretes hormones (epinephrine and norepinephrine) during stressful and emotional situations, while the adrenal cortex regulates salt and carbohydrate metabolism.

28. The Pancreas… zLocated near the kidneys. Contains specialized cells called Islets of Langerhans that secret hormones. yInsulin: Lowers blood glucose yGlucagon: Raises blood glucose

29. The Adrenal Glands zLocated on top of the kidneys zIn an emergency, secretes hormones that cause an increase in heart rate, blood pressure, and sugar levels, while simultaneously reducing blood flow to the digestive system. yNorepinephrine and Epinephrine: Causes fight- or-flight response to emergency situations; stimulates metabolism.

30. Gonads Sex glands are located in different places in men and women. They regulate bodily development and maintain reproductive organs in adults.

31. Gonads and the hormones they release… zTestes yReleases Androgens: Promotes sperm formation and secondary male characteristics. zOvaries yReleases Estrogens: Stimulates uterine lining and secondary female characteristics. yReleases Progesterone: Stimulates uterine lining growth; maintains pregnancy.