Download Chapter 3 Section 2 - 6th

Chapter 3 Section 1
The Nervous System
- Regulates our internal functions and is involved in how we react to the external world
Two main parts:
1. central nervous system- consists of brain and spinal cord
2. peripheral nervous system- made up of nerve cells that send messages between the
central nervous system and all the other parts of the body
neurons- nerve cells that run through our entire bodies and communicate with each other
Components of Neurons:
1. cell body- produces energy to fuel cell activity
2. dendrites- thin fibers that branch out to receive info. and pass through the cell
body
3. axon- carries messages away from the cell
myelin- white fatty substance that insulates and protects the axon
axon terminals- smaller fibers that branch out at the end of the axon
The Communication Process:
- Messages are sent from axon terminals of one neuron to the dendrites of other neurons
synapse-a junction between the axon terminals of one neuron and the dendrites of another
where messages must cross to be transmitted
Where does the message go?
sensory neurons- nerve cells that carry information received by the senses to the central
nervous system
motor neurons- nerve cells that carry information from the central nervous system to the
muscles and the glands and influence their functioning
Occasionally something happens to disrupt the message-sending process
Examples: car accident, sports injury in which the soft tissue of the brain hits against the
skull
* Guided Practice Activity
Neurotransmitters: Chemical Messengers:
∙Allow messages across synapses by releasing chemicals that are stored in sacs in the
axon terminals; Ex.- release like spray bottle
∙Each transmitter fits into a receptor and is converted to an electric impulse
acetylcholine- neurotransmitter that controls muscles
dopamine- neurotransmitter used in motor behavior
∙deficiency of dopamine plays a role in Parkinson’s disease
The Central Nervous System (CNS)
-Consists of neurons of the spinal cord and the brain
spinal cord- column of nerves that transmits messages between the brain and the muscles and
glands
∙Many of our reflexive actions come without thought through our spinal cords
The Peripheral Nervous System
-Lies outside the central nervous system
-Transmits messages between the C.N. S. and all other parts of the body
Two divisions:
1. Somatic Nervous System-transmits sensory messages to the C.N.S.
- alerts body to changes in position and things like hot/cold
2. Autonomic Nervous System-regulates the body’s vital functions such as
heartbeat, breathing, digestion and blood pressure
A) sympathetic (stress)- activated in action: “fight or flight”, suppressed
digestion
B) parasympathetic (peace)- restored the body’s reserve of energy after an
action has occurred
Chapter 3 Section 2
The Brain: Our Control Center
Parts of the Brain (Divided into 3 sections)
1. Hindbrain-lower portion involved in vital functions such as heart rate, respiration, and
balance
2. Midbrain-involved in vision and hearing
3. Forebrain-front of the brain involved in complex functions such as thought and
emotions
The Hindbrain
medulla- involved with heart rate, blood pressure and breathing
pons- located in front of the medulla and regulates body movement, attention, sleep, and
alertness
cerebellum- rests under the cerebrum and is small, involved in balance and coordination
The Midbrain
∙Located between hindbrain and forebrain, which is involved in vision and hearing
∙Contains part of the reticular activating system, which is important for attention, sleep,
and arousal
- stimulation of this makes us alert
- drugs such as alcohol reduce the activity of the reticular activating system
* Applying Information: write what wakes you and how you respond
The Forebrain
- This allows us to engage in complex thinking
Four key areas of the Forebrain
1. Thalamus- “inner chamber”, critical structure that serves as relay station for
sensory stimulation
2. Hypothalamus- extremely important to behavior and physiological aspects
Also vital for regulation of body temperature, storage of
nutrients and motivation/emotion
3. Limbic System- works with learning and memory, emotion, hunger, sex and
aggression. If it is damaged, a person can recall old memories
but can’t form new ones (50 First Dates)
4. Cerebrum- the part that thinks; it is uniquely human & accounts for 70% of
brain weight
cerebral cortex-outer layer of the brain, which deals with memory,
language, emotions, complex motor functions and
perception
The Cerebral Cortex: What Makes Us Unique
corpus callosum- the structure that connects the two hemispheres of the brain
-This also aids in getting information from one side of the brain to the other
Each hemisphere has four lobes:
1) frontal- motor cortex, body movement
2) parietal-sensory cortex, skin senses
3) temporal- hearing
4) occipital- sight
Association Areas
∙ “executive center” because this shapes information into meaningful things
∙ where we solve problems and make plans and decisions
Language Abilities
-Most people have language functions in left hemisphere of brain
Two Key Areas
1. Wernick’s area- located in temporal lobe, which pieces together sight and
sound
2. Broca’s area- located in frontal lobe, which controls areas of face used for
speaking
Left vs. Right Hemisphere
- “left-brained”: same hemisphere has language, logic, problem-solving and mathematical
computations
- “right-brained”: other hemisphere concerned with imagination, art, feelings, and spatial
relations
- hemispheres still work together
Methods of Studying the Brain
Accidents- study how the brain is connected to psychological functions
Electrical Stimulation of the brain- Jose Delgado used electrical stimulation of the brain
to show how a bull would change its behavioral
patterns. James Olds and Peter Milner used rats to
push levers, which sent electrodes into hypothalamus
stimulating pleasure.
Electroencephalogram (EEG)
- device that records the electrical activity of the brain
- uses electrodes to detect brain waves
Scans
New techniques for examining the brain:
1. CAT (computerized axial tomography)- creates 3-dimensional view of the
brain using radiation
2. MRI (magnetic resonance imagining)- lie in magnetic field and radio waves
cause parts of the brain to give off extra
energy
3. PET (positron emission tomography)- shows the activity of the brain rather
than just a snapshot by injecting
radioactive sugar into the brain
Chapter 3 Section 3:
The Endocrine System
- Consists of glands that secrete substances called hormones into the blood stream
- hormones stimulate growth and reactions such as moods
- hormones are produced in four different glands
1.Pituitary Gland
- size of a pea, but VERY important- “master gland”
- growth hormone regulates growth of muscles, bone and glands
- some hormones affect females in pregnancy and mothering
2. The Thyroid Gland
- produces thyroxin which affects body’s metabolism
- too little thyroxin can result in hypothyroidism- overweight
∙ this in children is called cretinism: stunted growth and
retardation
3. The Adrenal Gland
- cortical steroids increase resistance to stress and promote muscle
development
- adrenaline and noradrenaline are present when stress occurs
4. The Testes and the Ovaries
- produce testosterone, estrogen and progesterone
- testosterone determines male sex in pregnancy
∙ primary sex characteristics- reproduction
∙ secondary sex characteristics- beards
- estrogen fosters primary and secondary sex characteristics
- estrogen and progesterone regulate menstrual cycle
Chapter 4 Section 4:
Heredity: Our Genetic Background
Heredity- the transmission of characteristic from parents to offspring
-vital in traits such as height, hair texture, and eye color
Genes and Chromosomes
genes- basic building blocks of heredity
-23 pairs of chromosomes
3rd chromosome on 21st pairs results in Down Syndrome
Nature vs. Nurture Debate
Nature- What people inherit
Nurture- environment determines how we behave and think
Kinship Studies
-studies on relations
-how much traits are influence by genetics
∙identical twins = 100% same genes
∙parent and full sibling = 50% same genes
∙aunts/uncles = 25%
∙1St cousins = 12.5%
Twin Studies
- Identical twins are more similar traits like shyness, where as fraternal twins are not as
close
Adoptee Studies
- Studies that are done to look at how closely an individual is to a sibling according to
how they were raised