1. Nervous system

2. A. Four Major Functions
Receive input from internal and external environments
Transmit information between nerve cells and brain.

3. 3. Process information

4. 4. Respond to stimuli

5. How it Works
A. Receptors (sensory nerves)sense changes in the internal or external environments.
B. Effectors (motor nerves)carry out the desired response.

6. Sensory input can be in many forms
Mechanoreceptors – sound, pressure, touch,
Chemoreceptors – taste, smell
Photoreceptors- light
Thermoreceptors - Temperature

7. C. The input is converted to a signal and sent to the brain or spinal cord

8. Two main parts of nervous system
1. Central Nervous System (CNS)- includes the brain and spinal cord.

10. 2. Peripheral Nervous System (PNS)- connects the CNS to other parts of the body, and is composed of nerves (bundles of neurons).

11. Two types of cells Neurons and Neuroglial Cells 1. Neurons
Functional unit of the nervous system

12. neuron

13. B. Supporting cells (neuroglial) cells
protect, support and assist the neurons
1. Schwann cells- found in PNS
wrap around nerve fibers
contain myelin- help transmit signals faster
2. Astrocytes-supply neurons with O2 and
nutrients in CNS
3. Microglial- support neurons in CNS
4. Oligodendrocytes- Myelin sheaths in CNS
5. Ependymal cells- forms special ephithelial
tissue around different parts of the brain,
ventricles and spinal cord

14. Schwann cells- found in PNS wrap around nerve fibers contain myelin- help transmit signals faster

15. Astrocytes-supply neurons with O2 and nutrients in CNS

16. Microglial- support neurons in CNS
Support neurons and phagocytize bacterial cells and cellular debris.

17. E. Structure of Neurons Cell body (Soma) Axon Dendrites Nucleus
Synaptic knob
Myelin
Nodes of ranvier

19. F. Types of Neurons
Sensory- Receive and carry information to CNS from internal and external enviro.
Interneurons- found in CNS carry impulses from one area to another
Motor-Carry impulses from CNS to effectors.

20. Nerve Pathways
1. Reflex arc- sensory neuron, to interneuron, to motor neuron

21. reflex arcs include balance, blinking and knee-jerk.

22. 2. Reflex- automatic subconscious response to a stimuli.
3. knee-jerk reflex- patellar ligament
Quadriceps femoris contracts
Helps maintain balance

23. 4. Withdrawal reflex- response to painful stimuli
body part is subconsciously quickly removed from the stimulus

24. Conducts nerve impulses throughout the body.
-impulses are created by a difference in electrical and chemical charges between one side of the cell membrane and the other.

25. 3. Neurotransmitters- send chemical signals from one neuron to another across a synapses
4. Synapses- gap between neurons

28. A. CNS (central nervous system)
1. Spinal Cord:
A.) Located inside the spine

29. B) Relays nerve impulses to & from the brain
C) controls spinal reflexes such as the reflex arc
i. The reflex arc is an automatic, involuntary reaction to a stimulus.

31. B. PNS (Peripheral Nervous System)
A. Two main components of the PNS:
1.) Sensory (afferent) pathways-
- provides input from body (internal and external information) to CNS.

32. 2) Motor (efferent) pathways that carry signals to muscles and glands (effectors) from CNS.
-Autonomic
-Somatic

33. Peripheral nervous system PNS
Sensory division
Motor division
autonomicANS
involuntary
Sensing external environment
Sensing internal environment
Somatic
SNS voluntary
Parasympathetic division
Sympathetic division

34. I. The Somatic Nervous system (SNS)
1. That part of the PNS that includes all nerves controlling the muscular system and external sensory receptors.

35. II.Autonomic nervous system
motor neurons that control internal organs.
muscles in the heart, smooth muscle in internal organs such as the intestine, bladder, and uterus.
Sympathetic
Parasympathetic

37. a. Sympathetic branch of the ANS
sympathetic branch Autonomic NS prepares the body for emergencies:
"fight or flight".
Stimulated by epinepherine

38. b. Parasympathetic branch of the ANS
Returns body functions to normal after they have been altered by sympathetic stimulation.
Stimulated by Norepinepherine

40. 2. Brain (5 Major Regions) A) Brain stem-
Coordinates functions such as breathing, heart rate, & sleep
Contains: midbrain, pons, and medulla oblongata

41. i. Midbrain-
ii. Pons-
iii.Medulla Oblongata- controls visceral activities: cardiac, vasomotor, and respiratory center

42. B. Diencephalon 1. Thalamus
directs messages from spinal cord to correct parts of the brain
Senses Pain

43. C. Hypothalamus Monitors the homeostasis (hunger, thirst, temp., ect.)
Link between nervous & endocrine systems

44. D. Cerebellum
Coordinates muscle activities, balance, equilibrium & posture

45. E. Cerebrum Voluntary (conscious) activity Sensory
Speech, language, memory