1. Chapters 31 and 34 Nervous and Endocrine Systems
The HUMAN BODY
Chapters 31 and 34
Nervous and Endocrine Systems

2. Chapter 31.1 The Neuron Objectives
Identify the functions of the nervous system
Describe the function of neurons
Describe how a nerve impulse is transmitted

3. NERVOUS SYSTEM Function: Send and receive messages within the body
Respond to stimuli
Systems:
-Central Nervous System
-Peripheral Nervous System
Central nervous system – brain and spinal cord (relays messages, processes information, analyzes information)
Peripheral nervous system – receives information from environment and relays commands from CNS to organs and glands

4. Nerve Cells AKA Neurons
Neuron- basic unit of structure and function of the nervous system
Bundles of neurons form nerves
Neuron – cells that transmit electrical signals (impulses)
Nerves – bundles of neurons; may have only a few neurons or hundreds/thousands of neurons

5. Parts of a Neuron: -Dendrite -Cell Body -Axon
-Myelin sheath (speeds up impulses)
-Axon Terminals
Cell body – largest part of neuron
contains nucleus and much of cytoplasm
most of metabolic activity of cell takes place in cell body
Dendrite – short, branched extensions spreading out from cell body
carry impulses from environment or other neurons TO cell body (like a vein carries blood TO heart)
Axon – long fiber that carries impulses AWAY from cell body
Axon terminals – small swellings at end of axon
Myelin sheath – insulating membrane; impulses jump from node to node, which increases the speed at which impulse travels
Neurons may have dozens of dendrites but usually only axon
SHOW students how impulse travels along neuron; show previous slide to show how neurons connect and impulse travels from neuron to neuron

6. Types of Neurons
Sensory Neurons: Impulse from sense organ to spinal cord/brain
Motor Neurons: Impulse from brain/spinal cord to muscles and glands
Interneurons: Connect sensory and motor neurons
Three types of neurons depending on the direction impulse travels

7. Nerve Transmission Messages are electrical and chemical signals
An electric charge is conducted down a neuron (Dendrite to axon)
Axon is covered in an insulating layer called a myelin sheath to speed up impulses
As it reaches the end of the axon, chemicals (neurotransmitters) are released across the synapse (gap between neurons) to the next neuron
The message continues neuron to neuron
Nerve impulse is similar to flow of electrical current through a metal wire
Nerve transmission begins when neuron is stimulated by another neuron or environment
Impulse travels along the neuron like a row of dominos falling.
Synapse – location at which neuron can transfer an impulse to another cell
at synapse, neurotransmitters are released into the gap b/w neurons; these chemicals transmit the impulse across the gap

8. Nerve Impulse Videos Neurons: Nerve Cells
Describe the path of nerve transmission that allows the batter to hit a ball.
Reflexes
How is a reflex different from the example of the batter hitting a ball in the previous video clip?
Path of nerve transmission that allows batter to hit ball:
Batter senses the ball with eyes (sense organ) that transmits this through sensory neuron to brain
Brain sends message to muscle via motor neuron to allow batter to hit ball
Sensory neurons connect with motor neurons in brain with interneurons
Review also how message transmits from one neuron to another:
dendrite picks up impulse
electrical impulse travels through cell body and down axon
at axon terminal, electrical impulse causes release of neurotransmitters (chemical) that travel across synapse
neurotransmitters picked up by dendrite of next neuron and impulse continues
Reflex different from batter hitting ball:
with reflex the sensory impulse is picked up by sensory neuron and travels to spinal cord
spinal cord immediately sends impulse back to muscle through motor neuron for immediate response
impulse does not go to brain!
brain receives the information AFTER you have responded (by moving)
reflexes protect us by allowing us to respond faster in emergency situations

9. Check-in What is the function of the nervous system?
Send and receive messages and respond to stimuli
Basic unit of structure and function of nervous system
Neuron (nerve cell)
Part of neuron that receives the impulse
Dendrite

10. Check-in
Type of neuron that sends message from sense organ to spinal cord/brain
Sensory neuron
Type of neuron that connects sensory and motor neurons
Interneuron

11. Chapter 31.2 Central Nervous System
Objectives
Discuss the functions of the brain and spinal cord
Discuss the effects of drugs on the brain

12. Central Nervous System
Brain- control center; transmits and receives messages
Cerebrum
Cerebellum
Brain Stem (midbrain, pons, medulla oblongata.)
Spinal Cord- connects brain with rest of the nervous system
CNS like the CPU of a computer
CNS is protected by body:
- skull and vertebrae protect brain and spinal cord
- brain and spinal cord wrapped in 3 layers of connective tissue called meninges
- b/w meninges and CNS tissue is space that is filled with cerebrospinal fluid (shock absorber as well as allowing for xchng of nutrients/wastes
Brain: contains about 100 billion neurons (many of which are interneurons); mass of about 1.4 kg
Cerebrum – largest part; responsible for voluntary or conscious activities of body; intelligence, learning, judgement
right and left sides separated by band of tissue called corpus callosum
right side controls left side of body and vice versa
right side – creativity and artistic ability
left side – analytical and mathematical ability
Cerebellum – second largest part of brain; located at back of skull; responsible for coordination and balance
Brain stem – connects brain and spinal cord; controls important functions like blood pressure, heart rate, breathing, swallowing
- keeps body functioning even when you are asleep or unconscious
- midbrain (uppermost part)
- pons (little lobe)
- medulla oblongata (thicker bump at top of spinal cord)
Spinal cord – 31 pairs of spinal nerves branch off from spinal cord, connecting brain to other parts of body
- certain kinds of information, including many reflexes, are processed directly in spinal cord
- reflex is a quick automatic response to a stimulus

13. Brain function fun! The Brain
7 1/2 minute video clip – have students complete video guide while watching (review the questions at end)
introduction to brain and its power
Brain stem
Cerebellum
Cerebrum and hypothalamus
Cerebral cortex
Parts of cerebral cortex
Hemispheres of brain

14. Addiction and the Brain
Dopamine – neurotransmitter released with pleasurable activities
Addictive drugs cause large release of dopamine (resulting in “high”)
Brain reacts by reducing number of receptors for dopamine  normal activities no longer produce the pleasure they once did

15. Check-in Part of brain that controls balance
Cerebellum
Part of brain that controls heart rate
Brain stem (medulla oblongata)
Part of brain that controls thinking
Cerebrum (frontal lobe)
Part of brain that controls body temperature
Hypothalamus

16. Check-in Neurotransmitter associated with pleasure
Dopamine
Why do addictive drugs create a cycle in which more and more is needed to get the “high”?
Because brain responds to excess dopamine released when they are taken by decreasing the number of dopamine receptors

17. Chapters 31.3 and 31.4 Peripheral Nervous System & Senses
Objectives
Discuss the functions of the sensory division of the peripheral nervous system
Identify the five sense organs and the sensory receptors associated with each
Discuss the functions of the motor division of the peripheral nervous system

18. Peripheral Nervous System
Link between the central nervous system and the rest of the body
Network of nerves throughout the body
*Made of many neurons
Consists of all nerves that are not part of brain and spinal cord
Cranial nerves in the head and neck
Spinal nerves in rest of body

19. Sensory Division
Transmits impulses from sense organs to central nervous system
Uses sensory receptors
Chemoreceptors
Photoreceptors
Mechanoreceptors
Thermoreceptors
Pain receptors
Sensory division: transmits impulses from sense organs to CNS
Sensory receptors (neurons that react directly to stimuli from environment) react to a specific stimulus by sending impulses to other neurons and eventually to CNS
- located throughout body, but concentrated in sense organs (eyes, inner ears, nose, mouth, skin)
Type of receptor Responds to Found in
Chemoreceptors: chemicals nose and taste buds
Photoreceptors: light eyes
Mechanoreceptors: touch, pressure, vibrations, stretch skin, skeletal muscles/ligaments/tendons, inner ears, hair follicles
Thermoreceptors: temperature change skin, hypothalamus
Pain receptors: tissue injury throughout body (except brain)

20. SENSES Vision- eyes Hearing and Balance- ears
Smell and taste- nose and mouth
Touch- skin
Vision – photoreceptors in retina of eye
rods – light but no color; cones – less sensitive, but see color
blind spot – no photoreceptors where optic nerve passes through the back of the eye
Hearing / Balance
hearing: sound vibrations cause eardrum to vibrate; vibrations picked up by ear bones; vibrations of bones cause pressure waves in fluid filled inner ear which cause hair cells in ear to pick up signals which are transmitted to neurons
balance: semicircular canals monitor position of body in relation to gravity
Smell and Taste
Sense of smell – ability to detect chemicals; contributes greatly to sense of taste (try eating while holding nose – much of taste disappears when you cannot smell)
Sense of taste – also chemical detection (by taste buds); taste buds detect salty, bitter, sweet, sour
Touch – all regions of body (amt dependent on # receptors) – most receptors in fingers, toes, face
skin is largest sense organ

21. Optical Illusions Illusions Tour 1: (4) Barrack Obama, (5) color cube
Tour 2: (1) spiral – pretty cool!, (4) white’s illusion, (6) banana cards, (10) corporate ladder
Tour 3: (1) fading color dot – cool!, (3) extreme reading,

22. Motor Division
Transmits impulses from central nervous system to muscles or glands
Somatic nervous system: regulates activities under conscious control
Autonomic nervous system: regulates activities that are automatic or involuntary
Motor division: transmits impulses from CNS to muscles or glands
- somatic nervous system – regulates activities under conscious control (eg., movement of skeletal muscles)
some also involved with reflexes (eg., reflex arc that bypasses brain – spinal cord is interneuron used to connect sensory and motor nerves) and can act with or w/o conscious control
- autonomic nervous system – regulates activities that are automatic or involuntary

23. Check-in Peripheral Nervous System Sensory Division Motor Division
Impulses from sense
organs to CNS
Impulses from CNS
to muscles/glands
Somatic
Autonomic
Conscious control
Involuntary control

24. Check-in Hearing/balance Smell Taste Touch Vision Chemoreceptor
Mechanoreceptor
Pain receptor
Photoreceptor
Thermoreceptor

25. Chapter 34.1 and 34.2 Endocrine System
Objectives
Describe the structure and function of the endocrine system
Identify the functions of the major endocrine glands

26. ENDOCRINE SYSTEM
Function- produce chemical messengers (hormones) from glands to regulate certain body activities
Think about a time when you were startled or frightened. How did you feel?
- rapid heart rate
- shortness of breath
- sweaty palms
These physical reactions are due to nerve and hormone action
We will learn about hormones in this section on the endocrine system, in particular what the major glands do for the human body

27. What are hormones? Glands?
Hormone: chemical messenger
Gland: organ that produces and releases a substance
Exocrine: release substances out of body or into digestive tract
Endocrine: release hormones directly into blood
Endocrine system involves glands that produce hormones
hormones are chemicals released in one part of the body that travel in the bloodstream and affect other parts of the body
hormones bind to chemical receptors on cells – cells that have receptors for a particular hormone are called target cells
Hormones are regulated by feedback mechanisms that function to maintain homeostasis
in general terms, an increase in a substance (hormone) “feeds back” to inhibit the process that produced the hormone in the first place
Glands – an organ that produces and releases a substance
exocrine glands: exo=outside
release substances directly to organs that use them (include those that release sweat, tears, digestive juices)
sweat gland – release sweat to surface of skin
sebaceous gland – release oil (sebum) to surface of skin
salivary gland – release saliva to inside of mouth
endocrine glands: endo=within
release their secretions directly into the bloodstream
We will focus on endocrine glands in this section

28. Glands of Endocrine System
Head Region:
-Pituitary: controls other glands
-Pineal Gland: regulates sleep and wake cycle, along with other basic functions
-Hypothalamus: controls secretions of the pituitary gland (link between endocrine and nervous system)
Pituitary – bean sized structure that dangles on a slender stalk of tissue at the base of the skull (located below the hypothalamus in the brain)
divided into an anterior and posterior part
produces a great many hormones that control other glands
produces growth hormone that affects how tall you will grow
Pineal gland
Hypothalamus – part of the brain above and attached to the posterior pituitary gland
controls the secretions of the pituitary gland

29. Glands of the Endocrine System
Neck Region:
-Thyroid: regulates metabolism (rate at which food is turned into energy)
-Parathyroids: maintains homeostasis in blood calcium levels
Thyroid gland – located at base of neck and wrapped around the upper part of the trachea
produces a hormone (thyroxine) that regulates metabolic rate (rate at which food is turned into energy)
Parathyroids – four glands found on back surface of thyroid gland
work with the thyroid gland to regulate the amount of calcium in the blood
Thymus gland – located in front of chest; large in childhood and shrinks in adulthood
helps certain WBC develop and play their part in body’s defenses

30. Glands of the Endocrine System
Abdominal Region:
-Adrenals: helps body prepare for and deal with stress (fight or flight)
-Pancreas: Releases insulin and glucagon to regulate level of glucose in blood
Adrenal glands – located on top of the kidneys
produce the “fight or flight” response to stress by releasing epinephrine and norepinephrine
increase heart rate, blood pressure, and blood flow to muscles
cause air passages to open wider (allow for increase flow of oxygen)
stimulate release of extra glucose into blood stream
Pancreas – located behind the stomach
produces insulin (stimulates cells in the liver and muscles to remove sugar from blood and store as glycogen or fat) and
glucagon (stimulates the liver to break down glycogen and release glucose back into the blood)
insulin is released after eating as blood glucose levels rise (to bring it down)
after 1-2 hours, blood glucose levels drop and glucagon is released to bring blood glucose level back up
Diabetes mellitus – when pancreas fails to produce or use insulin properly
Type 1: autoimmune disorder; usually begins in childhood (before age 15)
little or no secretion of insulin
must follow strict diet and take daily injections of insulin
Type 2: most commonly begins after age 40
low or normal amounts of insulin produced, but cells not able to use it properly (interaction b/w insulin and insulin receptors inefficient)
early stages – controlled by diet and exercise

31. Glands of the Endocrine System
Reproductive Region:
-Ovaries (females): produce eggs and estrogen to create female characteristics
-Testes (males): produce sperm and testosterone to create male characteristics
Gonads – body’s reproductive glands
produce gametes (egg or sperm) and sex hormones
Female – ovaries
produce eggs (gametes)
produce estrogen: required for egg development and female physical characteristics (development of reproductive system, widening of hips, development of breasts)
produce progesterone: prepares uterus for arrival of developing embryo
Males – testes
produce sperm
produce testosterone: required for normal sperm production and development of male physical characteristics (growth of facial hair, increase in body size, deepening of voice)

32. Check-in Controls the pituitary gland Regulates metabolism
Hypothalamus
Regulates metabolism
Thyroid
Regulates sleep/wake cycle
Pineal
Controls other glands
Pituitary

33. Check-in Produces eggs and estrogen
Ovary
Helps deal with stress (fight or flight)
Adrenal
Maintain blood calcium levels
Parathyroid
Regulates blood glucose/sugar levels
Pancreas

34. Citations
Neurons: Nerve Cells. Cochran, 1993. Video Segment. 23 April 2011. <
Reflexes. Cochran, 1993. Video Segment. 23 April 2011. <
The Brain. Cochran, 1993. Video Segment. 23 April 2011. <