The nerve cell is the basic unit of communication in the vertebrate nervous system. A neuron consists of a cell body with dendrites that receive signals and a long axon that transmits impulses. An action potential is generated when the voltage across the membrane is briefly switched and moves down the axon. Neurotransmitters are released at the synaptic cleft between neurons to transmit signals to the next cell. The nervous system is divided into the central nervous system (brain and spinal cord) and peripheral nervous system. Sensory neurons carry signals to the CNS while motor neurons carry signals away from the CNS to effector cells like muscles.

2. Nerve Cell The nerve cell is the basic unit of communication in the vertebrate nervous system

3. Three Classes of neurons The Neural circuit consists of Sensory neurons receptor for stimulus Interneuron integrate signals Motor neuron transfer signal to effector (muscle)

5. Anatomy of a Neuron Cell body: functional portion Dendrites: short extensions that receive signals Axon: long extension that transmits impulses

6. How does a neuron hold and move info? A neuron at rest has a voltage difference across the plasma membrane called a resting voltage potential An action potential is when this charge across the membrane is briefly switched The action potential moves down the membrane at a rapid pace. Ap can move faster over mylenated portions is called saltatory conduction

9. How does a signal move from one neuron to another? A synaptic cleft divides 2 neurons The AP will not move across the synaptic cleft Neuro transmitters are released by the signal cell to the receiver cell Move by diffusion

10. Types of chemical synapse Acetylcholine: neuromuscular junctions, glands, brain and spinal cord Norepinepherine: affects brain regions concerned with emotions, dreaming

12. Paths of information flow Signals between the brain and spinal cord move to the body regions by nerves Sensory nerves move a signal towards the brain and spinal cord Motor neurons move a signal from the brain or spinal cord to the body

13. Divisions of the nervous System Central nervous system CNS Is the brain and spinal cord Peripheral nervous system PNS all nerves that carry signals to and from the CNS

14. Parts of the PNS Sensory Division carries info to the brain and spinal cord. Motor Division carries info from the brain to the bodies effectors (things that do the work)

15. The Motor division of the PNS has 2 divisions Somatic nerves relay commands to and from skeletal muscle Voluntary control Autonomic nerves send signals to and from smooth muscles Involuntary control Sympathetic Parasympathetic

16. The autonomic divisions Parasympathetic slow down the body activity when the body is not under stress Rest and digest Sympathetic increase overall body activity during times of stress, excitement or danger fight or flight response hormone epinephrine

17. Sympathetic and Parasympathetic Are Antagonistic Work towards the automatic, subconscious maintenance of homeostasis.

19. Components of the CNS Spinal cord 31 pair of spinal nerves Grey matter White matter Controls some reflex actions like bladder emptying Brain parts Hindbrain medulla oblongata cerebellum pons Midbrain Forebrain cerebrum thalamus hypothalamus

20. Other parts of the CNS The two cerebral hemispheres communicate through the corpus collosum left verbal skills right nonverbal skills such as music math, abstract Brain cavities and Canals cerebrospinal fluid surrounds and fills in cavities in the brain Blood Brain barrier- controls what moves into the brain. Will prevent infections.

21. Our state of consciousness The CNS governs sleeping, dozing, daydreaming and full alertness neurons of the reticular activating system control the changing levels of consciousness by releasing serotonin.

22. Limbic system Involved in both memory and emotion. Is involved with behavior. Odors pass through this system and may influence or behavior and emotions.

23. Memory Association is the linkage of information to structural and chemical changes short term- few bits lasts a couple of hours Long term- permanent and limitless The most important info goes rapidly into long term storage memory is stored in a form resistant to degradation Possibly caused by changes in synapses.

24. Tips on studying Concentrate on what you study. Minimize interference. Study takes time. Break material into smaller portions. Rephrase materials in your own words. Test yourself to see what you know.

25. Disorders of the nervous system Trauma Infections Transmission and synaptic defects. Abnormal growth

26. Sensory Reception If a tree falls in the woods with no one to listen does it make a sound?

27. Receptors Are the actual structures that respond to our environment. Each receptor will respond to a different signal. Essentially translators, they translate an energy into one that can be perceived by the brain.

28. Sensory systems consist of Each system has 3 parts 1) sensory receptors. 2) pathway to the brain. 3) region of the brain that recognizes this section.

29. Types of sensory Receptors Chemoreceptors Mechanoreceptors Thermoreceptors Nociceptors Photoreceptors olfaction and taste touch, stretch, hearing, equilibrium radiant energy, infared pain receptors light

30. Sensory Pathways If a receptor is stimulated enough it results in an action potential. The action potential reaches the brain. The stronger the stimulus the greater number of action potentials reach the brain. Sensory adaptation is when the action potentials are reduced by a constant stimulus. Certain receptors will not adapt.

31. Somatic sensations Touch & Pressure Temperature Pain Muscle sense Mechanoreceptors that respond to changes or constant pressure Increase in temperature causes and increase in AP Respond to intense stimulus on other receptors, cannot be ignored Mechanoreceptors give measurement as to the location of all the muscles and bones in a given moment.

32. Limb position, length and tension How do we know where we are at?

33. Referred pain

34. Taste and Smell Gustation : Taste Receptors located on tongue, roof of mouth, throat and palate Four tastes sweet sour bitter salty Olfaction : smell detect chemicals olfactory bulbs in brain interpret smell smell is often combined with emotion

35. Taste Taste Bud 25 cells Taste hairs project into mouth Hairs contain receptors Categories Sweet Sour Salty bitter

36. Hearing Acoustical receptors detect vibrations The ear In the organ of corti loudness is determined by The total number of cells that are stimulated Pitch depends on frequency of vibration

38. Balance Vestibular apparatus Closed system of fluid filled sacs Contain otoliths that detect changes in orientation as well as acceleration Overstimulation of the hair cells of the vestibular apparatus results in motion sickness

39. Vestibular apparatus

41. The Eye

42. Structure of the eye Outer sclera (white) (is all the way around) Cornea (clear) Pupil (opening to the back) Lens (transparent) Retina (back side has photoreceptors and support material) Fovea has highest concentration of photoreceptors.

43. Regulating light amount The iris adjusts to amount of light entering the eye. The lens goes through accommodation to adjust lens curvature (as we age the lens cannot buldge enough to focus on a close object)

44. Light must reach the sensors by going through neurons. Outermost layer is pigmented to absorb light not absorbed by the sensors Photoreceptors are in middle layer Translucent neurons and ganglions are on top of the photoreceptors.

45. Production of Action Potentials by Rods and Cones Within these cells flattened disks contain photopigment When this protein absorbs light it changes conformation, if enough are activated they cause an action potential. Rods contain rhodopsin and are most sensitive to dim light Cones contain different pigments

46. Rods and Cones Bright light tends to use more cones, 300x more sensitive Dim light uses Rods and Rhodopsin, it is broken apart by light and must be remade (hence the 5-10 minute wait to see in darker areas)

47. Signaling to visual perception Photoreceptors are in the retina When rods or cones are stimulated they send a signal to the brains visual cortex. In the brain the final interpretation makes sense of sight

48. Problems with the Eyes Retinal detachment: retina separates form choroid Cataracts: lens becomes opaque Color blindness: Inability to distinguish colors, is a genetic disease, lacks specific types of cones

50. The Endocrine system The oldest method of control is using a signal molecule that moves from one part of the body to the other

51. The Endocrine System Regulates Salt and water balance Blood pressure Stress responses Digestion Cellular metabolism Production of RBC’s Growth and development

52. Location of Endocrine Glands

53. Hormones and other signal molecules Hormones : molecules secreted by glands into the blood that move to a nonadjacent target Neurotransmitters : act on a directly adjacent cell Local signaling molecule : act quickly and degrade quickly Pheromones : secreted by glands and target cells in other organisms

54. Signaling Mechanisms Requirements Cells that secrete the signal molecule are either within a gland or nervous tissue The signal molecule Steroid hormone (fat soluble will move through the plasma membrane) Non steroid hormone (peptides and other molecules must bind to a receptor on the cell) Target cell

55. Target cell activities Different hormones activate different cellular response mechanisms No all cells have receptors for all hormones: Three possible hormones A cell with a single receptor on it Does not bind, No reaction Good fit rx occurs

56. Characteristics of the Endocrine system Each hormone acts only on certain cells Cells respond only when they have receptors Is slower than nervous system control Endocrine and nervous system to interact with one another.

57. Interaction of Endocrine System and Nervous System

59. Negative Control using Hormones

60. The pancrease an endocrine and an exocrine gland Glucagon: raises blood sugars, release of stores and AA metabolism Insulin: lowers blood sugars opposes glucagon Somatostatin: inhibits secretion of the above enzymes

61. Bracketing using hormones

62. Regulation of Blood Calcium concentration Increase Calcium Parathyroid Hormone: removes calcium and phosphate from bone, increase absorption, retention of calcium in kidneys Decrease of Calcium Calcitonin

65. Oxytocin and nursing, a cascade of events At the end of pregnancy, Estrogen rise. Uterus produces more oxytocin receptors Fetus produces oxytocin, starts a cycle of material production of oxytocin Oxytocin is a part of the neuroendocrine reflexes and will help in the smooth muscle contractions which cause the release of milk.