1. Chapter 31- Nervous System
Big Idea: How does the structure of the nervous system allow it to regulate functions in every part of the body?

2. 31.1 The Neuron F(x)s of Nervous System: Collect information
Process information
Respond to environment

3. Peripheral Nervous System (PNS):
Central Nervous System (CNS):
Consists of nerves and supporting cells
Brain and spinal cord, takes info. and delivers it to appropriate part of PNS

4. Neuron f(x):
Neurons transmit nervous system impulses.
Types:
Sensory- Carry messages from sense organs → CNS
Motor-Info. from CNS → to muscles/glands
Interneurons- Process/ send commands to other neurons

5. Cell body-contais nucleus +cytoplasm
Neuron Structure:
Cell body-contais nucleus +cytoplasm
Dendrites- recieve impulses from other neurons, carries through cell body
Axon- Long fiber carrying impulses away from cell body

6. Some axons are surrounded by myelin sheath, which speed impulse movement

7. The Nerve Impulse:
resting state, until large enough stimulus is received from environment or from another neuron. Travels quickly from:
Dendrites → cell body → axon
During impulse resting potential is reversed= nerve impulse= Action potential

8. Impulses move w/ a domino effect.
Threshold= min. stimulus needed to start impulse. All or nothing. If signals are too weak nothing will happen.
Synapse= which impulse travels from one cell to another
Nuerotransmitters= chemicals that carry signals from synapse → cell

9. 31.2 Central Nervous System
Control point of CNS= brain; 3 major areas: cerebrum, cerebellum, and brain stem
Spinal cord connects brain → rest of body

10. Reflex= quick automatic response to a stimulus
-Help protect us
Cerebrum
Largest area of brain. Controls voluntary movement, knowledge, and judgement
Hemispheres connected by tissue called corpus callosum. Each hemisphere manages opposite side of body (=lateralization)

11. (Cerebrum continued)
Outermost layer= cerebral cortex, composed of gray matter. Processes info. from senses, controls movement, thoughts, learning, etc.
Folds in brain=greater surface area
Inner layer= white matter. Bundles of axons, connect to diff. areas of brain

12. Parietal: Reading and speech
Frontal: Decision making, forming plans
Occipital: Vision
Temporal: Hearing and smell

13. Limbic system-
Deep region in brain (amygdala) associated w/ emotions, pleasure, long term memory, fight or flight response

14. Thalamus and Hypothalamus
L: between brainstem and cerebrum
f(x): (Thalamus) receives sensory info. and relays info. to proper region of brain
(Hypothalamus) hunger, thirst, fatigue, anger, regulation of body temperature

15. Cerebellum:
Controls coordination and balance. Familiarizes you w/ coordinated movements.

17. Brain Stem: -3 regions: midbrain, pons, medulla oblongata
-f(x)s: regulates info. from brain → body. Controls breathing, swallowing, blood pressure, swallowing

18. Addiction and the Brain:
Addictive substances cause change in a group of synapses that use the neurotransmitter (NT) dopamine
Dopamine is associated w/ brain’s pleasure centers.

19. -When we find something pleasurable the brain releases dopamine
-When we find something pleasurable the brain releases dopamine. Drugs overflow dopamine, or keep it in system longer.
This overflow of dopamine causes a reduction in dopamine NT. Normal activities no longer produce pleasurable sensations they once did.

20. 31.3 Peripheral Nervous System (PNS)
Sensory portion of PNS transmits info. from sense organs → CNS

22. Type
Responds to
Chemoreceptor
Chemicals
Photoreceptor
Light
Mechanoreceptor
Touch, pressure, vibrations, stretch
Thermoreceptor
Temperature changes
Pain receptor
Tissue injury

23. Somantic nervous system:
Regulates movements under conscious control
Reflex Arc (rapid response):
Sensory receptors pick up stimulus (pick up)
Sensory neurons relay info → spinal cord (relay)
Interneuron processes info. (process)
Motor neuron carries impulse → effector (carry)
Effector (muscle moves) (response)

25. Autonomic nervous system:
f(x): regulates involuntary activities (ex: heart rate, blood pressure (BP), sweat glands, digestion)
Divisions:
Sympathetic: Prepares body for intense activity “fight or flight” response, shuts/slows down activities not related to flee (slow digestion, increase in BP, and energy
vs. Parasympathetic: “Rest and digest” response. Acts opposite of sympathetic, lowers heart rate and BP, stores food

26. 31.4 Senses
Different sensory receptors in the body respond to touch, temperature, and pain.

27. Sensations of taste and smell are the result of impulses sent to the brain by chemoreceptors.
Much of what we taste is a result of smell.
Taste buds detect taste..
Sweet, salty, bitter, sour,
and “umami.” (Savory)

28. Hearing Mechanoreceptors in parts of ear transmit impulses to brain
Main organ of hearing= cochlea
-Cochlea structure= fluid filled portion of inner-ear
- Cochlea f(x)=transmit vibrations to auditory nerve in brain, interpreted as sound

29. Balance Semicircular canals maintain balance Location: Above cochlea
Structure= 3 tiny ½ circle canals. Fluid filled, lined w/ tiny hairs. Change in body position causes bend in hair cells
F(x)= monitor body and head position in relation to gravity

30. outer ear
tympanum auditory ossicles
cochlea
Mechanism of hearing: ______________ funnels sound to hit ___________, which causes the ______________ to vibrate, until it reaches the _______________ which transmits sound to the brain!

31. Vision
-Photoreceptors in eyes transmit impulses to the brain, translates into images

32. Anterior (front) portion of eye
Posterior (back) portion of eye
Cornea:transparent, focuses light
Lens: changes shape to focus
Iris: colored portion, works w/ the pupil to adjust how much light gets in
Retina: contains rods and cones
Filled w/ aqueous humor
Filled w/ vitreous humor

33. Cones: Differentiate colors
In retina photoreceptors convert light into nerve impulses, that go to the brain through the optic nerve.
Contain:
Rods: Light sensitive
Cones: Differentiate colors
blue/black vs. white/gold dress can be explain by different distributions of rods and cones that vary between each individual.