The Nervous System

1. The Nervous System

2. Let’s go to the Video!

3. Overview • The Nervous System controls and coordinates all the functions of the body. • The Nervous System consists of two main sub-divisions: • Central Nervous System (CNS) • Peripheral Nervous System (PNS) • The Peripheral Nervous System is divided into two sub-divisions: • Somatic- voluntary • Autonomic- involuntary

4. http://inside.salve.edu/walsh/cns_pns.jpg

5. Structure and Function of the Neuron • Neuron is the scientific name for a Nerve Cell. • Neurons consist of 3 basic structures: • Cyton, or cell body. • Dendrites- receive messages, impulses, and send them to the cell body. • Axons- send messages away from the cell body. • Nerve impulses travel from one neuron to another across synapses, or spaces in between the cells. • The “jumping across” the synapse is facilitated (helped) by chemicals called Neurotransmitters.

6. Dendrites– Branched parts of a neuron that receive impulses from other neurons. Cyton- Contains cytoplasm and the nucleus. Impulses pass through here to the axon. Axon- Single long fiber that carries impulses away from the cell body. A Neuron Parts of the Neuron

8. Myelin Sheath signal direction • Axon coated with insulation made of myelin cells (Fatty, protein substance) • speeds signal • 330 mph vs. 11 mph myelincoating • Multiple Sclerosis • immune system (T cells) attacks myelin coating • loss of signal

9. Synapse Junction between nerve cells • 1st cell releases chemical to trigger next cell • where drugs affect nervous system synapse

10. Types of Neurons Neurons can also be classified by the direction that they send information: ･Sensory (or afferent) neurons: send information from sensory receptors (e.g., in skin, eyes, nose, tongue, ears) TOWARD the central nervous system. ･Motor (or efferent) neurons: send information AWAY from the central nervous system to muscles or glands. ･Interneurons: send information BETWEEN sensory neurons and motor neurons. Most interneurons are located in the central nervous system.

11. Reflexes • Stimulus- a change in the environment. • Response/Reaction- how the body reacts to a stimulus. • ReflexArc- the pathway that an impulse follows to illicit a response to a stimulus.

12. Parts of the Central Nervous System • Brain • Spinal cord

13. What Protects the CNS? Skull and Vertebrae 3protective layers called meninges Dura Mater (outer layer): consists of connective tissues, blood vessels, and nerves. Arachnoid Layer (middle layer): elastic and weblike Pia Mater (inner layer): contains nerves and blood vessels. Cerebrospinal fluid a clear watery liquid separates the middle and inner layers Acts as shock absorber exchange of nutrients between blood and nervous system

14. The Brain • Coordinates body activities • Made up of approximately 100 billion neurons • Uses 20% of bodies oxygen and energy • Divided into three major parts- • the Cerebrum • the Cerebellum • the Brain Stem (Medulla Oblongata, Pons)

15. Cerebrum • Largest part of the brain • Thinking • Memory is stored • Movements are controlled • Impulses from the senses are interpreted.

16. Gray Matter vs. White Matter Gray Matter – Absence of myelin in masses of neurons accounts for the gray matter of the brain – Cerebral Cortex White Matter - Myelinated neurons gives neurons a white appearance – inner layer of cerebrum

17. Cerebrum specialization • Regions specialized for different functions • Lobes • frontal • speech, control of emotions • temporal • smell, hearing • occipital • vision • parietal • speech, tastereading parietal frontal occipital temporal

18. Craniotomy

20. Brain Tumor Surgery

21. Sub-Arachnoid Cyst Removal

22. Cerebral Hemhorrage

23. Subdural Hematoma

24. Brain Worms!

25. Responsible for the coordination of muscles and is the center of balance Cerebellum

27. Center of heart beat, respiration, and other involuntary actions Medulla

28. Other Structures inside the Brain Thalamus– receives messages from sensory receptors; relays information to proper regions of cerebrum Hypothalamus - Regulates hunger, thirst, fatigue, anger, etc… Control of pituitary for endocrine function

29. Cerebrum Thalamus Pineal gland Hypothalamus Cerebellum Pituitary gland Pons Medulla oblongata Spinal cord Section 35-3

30. The Spinal Cord • Extension of the brain stem • Bundles of neurons that carry impulses from all parts of the body to the brain and from the brain to all parts of your body

31. The Peripheral Nervous System Your brain and spinal cord are connected to the rest of your body by the peripheral nervous system. The PNS is made up of 12 pairs of nerves from your brain called cranial nerves, and 31 pairs from your spinal cord called spinal nerves. Spinal nerves are made up of bundles of sensory and motor neurons bound together by connective tissue. For this reason, a single spinal nerve can have impulses going to and from the brain at the same time. Some nerves contain only sensory neurons, and some contain only motor neurons, but most nerves contain both types of neurons. Somatic and Autonomic Systems The peripheral nervous system has two major divisions. The somatic system controls voluntary actions. It is made up of the cranial and spinal nerves that go from the central nervous system to your skeletal muscles. The autonomic system controls involuntary actions-those not under conscious control-such as your heart rate, breathing, digestion, and glandular functions. These two divisions, along with the central nervous system, make up your body's nervous system. Research Visit the Glencoe Science Web site at tx.science.glencoe.com for more information about the nervous system. Make a brochure outlining recent medical advances.

32. Peripheral Nervous System • Connects body to brain & spinal cord • 12 pairs of nerves from your brain (cranial nerves) • 31 pairs from your spinal cord (spinal nerves) • Bundles of sensory and motor neurons held together by connective tissue • Two divisions • Somatic • Autonomic

33. Divisions of the PNS: Somatic Nervous System • Controls voluntary actions • Made up of the cranial and spinal nerves that go from the central nervous system to your skeletal muscles Autonomic Nervous System • Controls involuntary actions-those not under conscious control-such as your heart rate, breathing, digestion, and glandular functions

34. http://www.christopherreeve.org/Research/Research.cfm?ID=178&c=21http://www.christopherreeve.org/Research/Research.cfm?ID=178&c=21

35. Animals rely on two systems for regulation: Nervous System is a system of nerve cells called neurons. It consists of a central nervous system (brain and spinal cord) and peripheral nerves. Typical responses are fast and short lasting. Endocrine System is a system of ductless glands that secrete hormone into the blood. Hormones travel to target tissues. Typical responses are slow and long lasting. Progesterone Estradiol

36. Human Endocrine Glands Ductless glands transport hormones in the blood Duct glands are exocrine glands that use tubes to carry the secretion (salivary, tears)

37. Pituitary gland and Hypothalamus serve to link the nervous system other glands and metabolic functions.

39. Thyroid and Parathyroid help regulate calcium metabolism Feedback!

40. Goiter: Iodine deficiency and feedback causes the thyroid to enlarge This people have a goiter, a condition that is easily preventable with iodized salt

41. Thyroid regulates metabolism Graves disease: hyperthyroid feedback

42. Pancreas helps regulate blood glucose feedback Insulin from Beta cells reduce blood sugar Glucagon from Alpha cells increase blood sugar

43. THE FIGHT OR FLIGHT MECHANISM • Large amount of adrenaline pumped into the body to put us in a state of increased alertness • Blood is redirected away from the extremities to the large muscles of the body • The heart starts working harder to move the blood to the large muscle groups as quickly as it can • Increase in Respiratory Rate • Release of red blood cells • Release of sugar by liver • Increase in metabolic rate alektorophobia

46. Gonads: Testes and Ovaries produce hormones that regulate secondary sex traits Male sex traits include those changes that occur during puberty Androgens include testosterone feedback

47. feedback Female sex traits include the menstrual cycle and the changes seen during puberty LH and FSH from the pituitary Estrogen and progesterone from the ovary

48. Identify the Glands