1. Nervous & Endocrine Systems Honors Biology Semester One Mrs. Williams

2. How Organ Systems Communicate  Importance of cell membrane; what makes it up?  Phospholipid bilayer  Carbohydrates  Proteins  What serves as a cell identifier?  Carbohydrates  Read pg. 84…then think, pair, share the following question:  HOW DOES THE CELL MEMBRANE HELP CELLS COMMUNICATE?

3. How Organ Systems Communicate  We’ll look at the nervous and endocrine systems through the lens of cells communicating  What is homeostasis?  Maintenance of a stable internal environment  For that maintenance to occur, the body must  Generate, deliver, interpret, and act upon messages  That’s the job of the nervous and endocrine systems

4. Nervous System  Physically connected network of cells, tissues, and organs that controls thoughts, movements, and simpler life processes  Works quickly and controls immediate processes such as heart rate and breathing  Divided into two parts:  Central nervous system (CNS)  Peripheral nervous system (PNS)

5. Special Cells  Neurons  Store information and carry messages within the nervous system and between other body systems  3 parts to the neuron:  1. Cell body  2. Dendrites  3. Axon

6. Neuron Drawings  You and your partner will draw a LARGE neuron on your table with chalk  Label and be able to explain the function of the following parts of the neuron:  1. Cell body  2. Dendrites  3. Axon  4. Myelin Sheath (the function of this may take a little looking for…)

7. Three Types of Neurons  1. Sensory neurons  Detect stimuli and transmit signals to the brain and spinal cord  2. Interneurons  Compose the brain and spinal cord  Receive signals from sensory neurons and relay them within the brain and spinal cord  3. Motor Neurons  Pass messages from the nervous system to other tissues in the body, such as muscles

8. So…  How does a neuron’s shape allow it to send signals across long distances?

9. How Signals are Sent  Figure 29.4, page 878  Join with another table and use your neuron drawings to explain how a signal is transmitted between two neurons based on Fig. 29.4  Include the following terms in your explanation:  Action potential, synapse, terminal, neurotransmitters

10. The Senses  Your group will summarize – in 50 words or less – the following senses with regards to cell communication:  1’s: Vision (pg. 881)  2’s: Hearing (pg. 882)  3’s: Smell & Taste (pg. 882/883)  4’s: Touch, Temperature & Pain (Pg. 883)

11. Investigation…  With your partner, quickly do the lab on pg. 884 in your textbook  FOLLOW DIRECTIONS CAREFULLY  When you’re done, answer questions 1 & 2 at the bottom of the page

12. Central and Peripheral Nervous Systems  These systems work together to help you interpret stimuli and respond appropriately

13. Central Nervous System  Includes the brain and the spinal cord  Composed of interneurons that interact with other nerves in the body  Receives, interprets, and sends signals to the peripheral nervous system

14. Peripheral Nervous System  Collection of nerves that connect the CNS to all of the organ systems  Uses sensory neurons to detect internal and external stimuli  Uses motor neurons to carry signals from the CNS to other parts of the body

15. CNS – The Brain  Has more than 100 billion neurons  Protected by three layers of connective tissue called meninges with fluid in between each layer  Composed of three main structures:  Cerebrum  Cerebellum  Brain Stem

16. Cerebrum  Interprets signals from the body and forms responses such as hunger, thirst, emotions, motion, and pain  Divided into the right and left hemispheres  Right hemisphere processes stimuli received by the left side of the body  Left hemisphere processes stimuli received by the right side of the body

17. Cerebrum  Outer layer is the cerebral cortex  Interprets information from sensory organs and generates responses  As thick as a pencil, but is folded to increase surface area  Unfolded, it would cover the area of a typical classroom desk  Can hold more than 10 billion neurons  Divided into lobes  See Fig. 29.10 on page 887

18. Cerebellum  Coordinates movements  Helps maintain posture and balance  Automatically adjusts the body to help you move smoothly  Positioned below and behind the cerebrum

19. Brain Stem  Connects the brain to the spinal cord  Controls the most basic activities required for life such as breathing and heartbeat  Divided into three major parts  Midbrain  Controls some reflexes  Pons  Regulates breathing and passes signals between the brain and spinal cord  Medulla Oblongata  Connects the brain to the spinal cord and controls basic, life-sustaining functions

20. CNS – The Spinal Cord  Spinal column consists of vertebrae, fluid, meninges, and spinal cord  Spinal cord  Ropelike bundle of neurons about as wide as your thumb  All signals that go to or from the brain pass through the spinal cord (why spinal cord injuries often result in paralysis)

21. Reflex Arcs  Spinal cord controls involuntary movements called reflexes  Nerve pathways that only need to cross two synapses before producing a response  Response is quick because the signal never has to travel up the spinal cord  See Fig. 29.12 on page 889

22. Peripheral Nervous System  Includes 12 pairs of nerves in the head and 31 pairs of spinal nerves  Most nerves contain axons from both sensory and motor neurons that carry info to and from the CNS  PNS made up of a sensory and motor system  Sensory systems collects info about the body and its surroundings  Motor system triggers voluntary and involuntary responses within the body

23. Peripheral Nervous System – Categories Somatic Nervous System  Regulates all of the movements over which you have voluntary control  Connects CNS to target organs Autonomic Nervous System  Controls involuntary movement/ response  Helps maintain homeostasis

24. Autonomic Nervous System - Categories Sympathetic Nervous System  Prepares body for action and stress  “Fight or flight” response  Contracting and dilating blood vessels cause changes that improve your physical movement and abilities and allow you to think quickly Parasympathetic Nervous System  Calms the body  Helps body conserve energy  Lowers blood pressure and heart rate  Active when the body is relaxed

25. Endocrine System

26.  Makes chemical signals – hormones - that help the body grow, develop, and maintain homeostasis  Some of the chemicals control processes such as cell division, cell death, and sexual development  Some chemicals help maintain homeostasis by affecting body temperature, alertness, or salt levels

27. Hormones  Chemical signals made by the endocrine system in glands  Glands are found throughout the body and release hormones into the bloodstream  Hormones only interact with cells that have specific membrane receptors  These are called the target cells  Hormones belong to one of two categories  Steroid hormones  Nonsteroid hormones

28. Steroid vs. Nonsteroid Hormones  Steroid hormones are:  Made of cholesterol, a type of lipid  Nonsteroid hormones are:  Present in three different types  Made up of one or more amino acids

29. Hormone Action  Read Fig. 29.19 on page 897  Talk with your table partner about the differences between actions of steroid and nonsteroid hormones  Be prepared to share…

30. Major Glands  Hypothalamus  Pituitary gland  Thyroid gland  Thymus  Adrenal gland  Pancreas  Gonads  Fig. 29.20 on page 899

31. Importance of the Hypothalamus  The nervous and endocrine systems connect to each other at the base of the brain  The hypothalamus acts as part of both systems  As part of the CNS, it receives, sorts, and interprets information from sensory organs  As part of the endocrine system, it produces releasing hormones that affect tissues and other endocrine glands  What are ‘releasing hormones’?  Hormones that stimulate other glands to release their hormones

32. Hypothalamus  Many of the releasing hormones affect the pituitary gland  The pituitary and hypothalamus are connected by a series of short blood vessels, so hormones can be passed quickly back and forth between the two  Read the example on page 900  How does this relate to cell communication?

33. Illness Due to Hormonal Imbalance  Read page 901  Why do hormonal imbalances affect the entire body?  *You don’t need to know about specific illnesses caused by hormonal imbalances