1. Regulatory Systems: Nervous and Endocrine Systems

2. Function of Regulation Systems:
regulate the activities of the other systems to make sure homeostasis is maintained
(homeostasis: keeping the internal environment of the body constant; for example, body temperature, blood pressure)

3. Nervous System Uses Electrical signals (impulses) along nerves
Chemical signals (neurotransmitters) to pass the impulse to the next cell

4. Endocrine System Uses: Hormones made in glands
The bloodstream for transmission

5. The NERVOUS SYSTEM

6. Send out motor commands
Nervous system Functions:
Receive Stimulus
Integrate the Input
Send out motor commands

7. Neurons - Functional Units
Neurons (aka nerve cells):
Generate and transmit nerve impulses
Have three main parts:
Cell body – contains nucleus and other organelles
Dendrite – receives impulse from another neuron
Axon – sends impulses to other neurons, muscles or glands
The axons of some neurons have a myelin sheath for protection and faster transmission.

8. The impulse is transmitted:
Neurons
The impulse is transmitted:
Dendrites
Cell body
Axon
Axon terminal
Cell body
Axon
Dendrites
Myelin sheath

9. Types of Neurons
Sensory neurons sense stimuli caused by changes in the internal or external environment
Interneurons integrate signals from different parts of the nervous system
Motor neurons transmit signals to muscles and glands  
Muscles contract
Glands secrete substances

10. Types of Neurons
Sensory Neuron
Interneuron
Motor Neuron

11. The Nerve Impulse
Transmission of nerve impulses depends upon a difference in charge across the cell membrane.
The interior of neurons is more negatively charged compared to the outside
Channel proteins maintain the polarity
This is called its Resting Potential
Sodium ions are concentrated outside of the cell, potassium ions are concentrated inside the cell

12. The Nerve Impulse
The transmission of a nerve impulse is rapid and self-propagating (like dominoes)
The major players:
sodium ions (Na+) usually found outside the cell
potassium ions (K+) usually found inside the cell
sodium protein channels in the cell membrane
potassium protein channels in the cell membrane

13. The Nerve Impulse
The nerve impulse is transmitted along the neuron by reversing the negative charge along the membrane
Inside becomes more positive than outside
This is called the action potential

14. Sodium channels open in part of the membrane and Na+ ions enter the cell
Cell is more negative outside
As Sodium channels close Potassium channels open and K+ ions leave the cell
Cell is more positive outside
Sodium channels open in the area next to the original action potential, passing the impulse along
Sodium-Potassium Pump moves 3 sodium ions out of the cell and 2 potassium ions inside the cell, restoring the original positions of ions

15. The Nerve Impulse Sodium – Potassium Pump is Active transport:
Moving substances across membrane from lower to higher concentration requires cell to expend energy.

16. The Nerve Impulse Saltatory conduction:
Transmission of the action potential in myelated axons (faster than in non myelated axons)

17. The Nerve Impulse Summary:
Resting (no impulse): Inside more negative than outside.
Sodium ions (Na+) move inside through protein channels  makes the inside of the cell less negative  action potential generated
The action potential travels along the axon (like dominoes or in jumps (myelated axons))  nerve impulse
Potassium ions (K+) move outside the cell through protein channels negative charge restored inside the cell
Sodium-Potassium Pump restores positions of ions (sodium out, potassium in)
Until the position of the ions is restored, the nerve can not carry another impulse

18. The Nerve Impulse All or None Principle:
A nerve cell will either fire or not fire – once the impulse begins, it will continue down the cell
Impulse is the same intensity each time
Different strengths of stimuli can be detected by:
a different number of nerve cells that fire
The more cells, the stronger the “message”
the frequency of the repeated impulse
The faster the impulse is repeated, the stronger the “message”

19. The synapse Passing the impulse to the next cell Synapse
vesicles
Terminal end
Synapse
Synapse: gap in between an axon terminal and a dendrite
The neurotransmitters are released into the synapse
At the end of the terminal branches are vesicles with neurotransmitters

20. The synapse

21. The Synapse 1. Nerve impulse reaches axon end
2. Neurotransmitter (NT) released into synapse (exocytosis)
3. Neurotransmitter diffuses across synapse
4. Neurotransmitter binds to receptors in the cell membrane of the next neuron
5. Impulse generated at the next neuron.

22. The Synapse Two examples of NT:
Acetylcholine
Norepinephrine
Certain poisons/drugs interfere with synaptic activity
cause either paralysis or constant stimulation

23. The Nervous System Two main components:
(1) Central Nervous System (CNS): Brain + Spinal Cord
Peripheral Nervous System (PNS): nerves outside the CNS

24. Central Nervous System (CNS)
Functions:
Integrates & interprets sensory impulses
Generates motor impulses.
Consists of the brain and spinal cord
The spinal cord provides communication between the brain and PNS.
The Meninges: three continuous sheets of connective tissue covering the spinal cord and brain

25. Major Areas of The Brain
speech, vision, hearing, thought
Sensory input hunger, thirst, temperature
Balance, posture, coordination
Heart beat, breathing

26. Cerebrum Two hemispheres a core of grey matter covered by white matter
an outer grey layer (cerebral cortex).
Four lobes
Frontal
Parietal
Occipital
Temporal

27. Lobotomy: destruction of the prefrontal cortex:
Treatment for a wide range of mental illnesses including schizophrenia, clinical depression, and various anxiety disorders.
Phineas Gage (1848)

28. Peripheral Nervous System (PNS)
Functions: Carry sensory impulses from receptors to CNS
Carry motor impulses from CNS to muscles and glands.
Composed of nerves
(bundle of axons)

29. (ganglion = collection of cell bodies)
Peripheral Nervous System (PNS):
The bundled axons make up the nerves of the PNS
Cell bodies of neurons are found in the CNS or in ganglia present in the PNS
(ganglion = collection of cell bodies)

30. Peripheral Nervous System
Divided into Two main Sections:
The Somatic system
the nerves that convey sensory information to the CNS
the motor nerves that transmit impulses to muscles
voluntary control as well as involuntary reflexes
The Autonomic system
involuntary control of glands, cardiac muscle, and smooth muscle.

31. Reflex Arc
Involuntary response, or reflexes, can be mediated by the brain or the spinal cord.

32. Anatomy of the Human Ear
pinna
Hammer
(Malleus)
Anvil (Incus)
Stirrup (Stapes)

33. Anatomy of the Human Ear
Outer Ear:
Pinna – visible part of ear:
composed of cartilage
presence on both sides of the head allows us to localize the source of sound from the front vs. the back.  
External Auditory Canal: the tube through which sound travels to the eardrum.
Tympanic membrane (eardrum):
between the outer and middle ear
transmits sound waves to middle ear

34. Anatomy of the Human Ear
Middle Ear
Eustachian tube (auditory tube)
connects the middle ear to the back of the nose
equalizes the pressure between the middle ear and outside air.
Ossicles:
Hammer - (malleus)
passes vibrations from the eardrum to the anvil.
Anvil - (incus)
passes vibrations from the hammer to the stirrup
Stirrup - (stapes)
U-shaped bone that passes vibrations from the stirrup to the cochlea.
smallest bone in the human body. 

35. Anatomy of the Human Ear
Inner ear
Cochlea
spiral-shaped, fluid-filled structure
lined with cilia (tiny hairs)
move when vibrated and
cause a nerve impulse to be generated.
Semicircular Canals –
three loops of fluid-filled tubes
attached to the cochlea
help maintain sense of balance.
Auditory Nerves –
carry electro-chemical signals from the inner ear (the cochlea) to the brain.

36. The spiral organ of the cochlea
To cochlear nerve

37. Sound Waves to Nerve Impulses
Air pressure waves in the ear canal (sound energy) causes...
Ear drum motion (vibrational energy), which causes...
Motion of the ossicles (vibrational energy), which causes...
Inner ear fluid pressure waves (vibrational energy), which causes…
Nerve impulses within the cochlea, which are then carried via a series of nerve connections to the portion of the brain that perceives "sound," the auditory cortex (electrochemical energy.)

38. Anatomy of the Eye

39. Anatomy of the Eye Sclera "the white of the eye" Conjunctiva
is the tough, opaque tissue that serves as the eye's protective outer coat
Completely surrounds eye 
Conjunctiva
thin, transparent tissue that covers the outer surface of the eye. 
begins at the outer edge of the cornea, covers the visible part of the eye, and lines the inside of the eyelids
nourished by tiny blood vessels that are nearly invisible to the naked eye.  

40. Anatomy of the Eye Cornea Pupil
transparent, dome-shaped window covering the front of the eye
a powerful refracting surface
provides 2/3 of the eye's focusing power
Pupil
black, circular opening in the center of the iris. 
opens and closes
regulates the amount of light entering the eyeball

41. Anatomy of the Eye Iris Lens Colored part of the eye
controls light levels inside the eye similar to the aperture on a camera. 
embedded with tiny muscles that dilate (widen) and constrict (narrow) the pupil size. 
Lens  
focus light onto the back of the eye

42. Anatomy of the Eye Vitreous Retina
thick, transparent substance that fills the center of the eye
composed mainly of water
comprises about 2/3 of the eye's volume
gives it form and shape
Retina
Very thin layer of tissue lining the inner part of the eye
captures the light rays that enter the eye
light impulses are then sent to the brain for processing, via the optic nerve.

43. Anatomy of the Eye Choroid Optic nerve Lies between retina and sclera
composed of layers of blood vessels that nourish the back of the eye.
Optic nerve
transmits electrical impulses from the retina to the brain. 

44. Vision Humans have binocular vision
Eyes see slightly different angles
Allows for depth perception
Two types of photoreceptors in retina
Rods: very sensitive, night vision
Cones: detect bright light, colors, detail

45. Light Waves to Nerve Impulses
Light energy passes through the pupil
Lens focuses light on photoreceptors in the retina
Photosensitive pigments are split and release energy
Electrochemical signal generated
Intermediate cells in the retina integrate signals
Signal is passed on to the optic nerve
Nerve impulses sent to the brain for processing into an image