Chapter 45 – Chemical Signals in Animals
I.
Hormone  chemical signal that is secreted into body fluids (usually blood), and communicates
regulatory messages __________________ the body; EXTREMELY important in maintaining
homeostasis; produced by the _______________________________ glands and are modified
amino acids, peptides, steroids, etc; carried by the _____________________________ system to
target cells
a. Target Cells  ______________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
i. SO…hormones traveling in the blood stream cause SOME cells to respond …which
causes a specific change (ex. Change in metabolism) while OTHER CELLS just ignore
the signal
II.
An Introduction to Regulatory Systems
a. Body has 2 internal communication systems:
i. ___________________ System = high speed signals; ex. Jerking your hand away from
a flame
ii. Endocrine System = slower communication; ex. Maturation of a ________________;
how fast certain body parts should grow
1. Definition = all of an animal’s hormone secreting cells; the endocrine glands are
________________________ because they secrete the hormones directly into
the body fluids (blood)
a. Exocrine glands = ___________________________________________
__________________________________________________________
__________________________ (ex. Sweat, mucus, digestive enzymes)
b. The endocrine system and the nervous system are very closely related
i. Several chemicals serve as both hormones of the endocrine system and signals in the
nervous systems
1. Ex. Epinephrine
a. Nervous system = _____________________________________
b. Endocrine system = “_____________________________________”
hormone
ii. Each system affects the output of the other
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1. Ex. Breast feeding – uses interdependent nervous and hormonal signals:
a. Suckling = simulates sensory cells and nervous signals in the
hypothalamus then trigger the release of oxytocin from the pituitary
gland; this oxytocin cause the mammary cells to secrete milk
iii. Feedback = COMMON TO BOTH SYSTEMS
1. Positive feedback = _______________________________________________
2. Negative feedback = used the majority of the time; allows hormones to control
_______________________________________
III.
Chemical Signals and Their Modes of Action
a. Local Regulators  affect only ____________________ targets; 3 main types:
________________________, Nitric Oxide, _______________________________________
i. Growth Factors = proteins that stimulate _____________________________________;
they bind to cell surface receptors and stimulate growth and development in the target
cells
1. Name can be misleading because they have a variety of functions:
a. Development of _____________________________________________
b. Affects developing ___________________
c. Enhances the synapse between neurons in the brain
2. The interaction of numerous growth factors regulates cell behavior in
developing tissues
ii. ______________________________________________ = gas; multiple functions;
highly reactive and potentially toxic; triggers change in target cells for a few seconds
and then rapidly breaks down
1. Secreted by neurons = acts as a ______________________________________
2. Secreted by WBC’s = kills bacteria and certain cancer cells
3. Secreted by ________________________________ cells in blood vessels =
causes smooth muscles to relax thus dilating the blood vessels
iii. Prostaglandins (PGs) = ____________________________________; named because
they were first discovered in the components of semen produced by the
_________________________________ gland
1. Most effects deal with the female reproductive system (contraction of the
smooth muscles in the uterus helping sperm get to the egg; induces labor during
childbirth, etc.)
2. Aspirin and Ibuprofen can inhibit the effects of prostaglandins
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b. Most chemical signals bind to PM proteins initiating a _____________________________
pathway
i. Signal Transduction Pathways – 3 parts
1. Reception = ___________________________________________________
_____________________________________________________________
2. Signal Transduction = ___________________________________________
_____________________________________________________________
3. Response = ___________________________________________________
_____________________________________________________________
ii. Most local regulators and hormones have ___________________________________
receptors, and these receptors are usually the first component in the signal transduction
pathway
iii. Different types of cells respond differently, so the ____________________________
_____________________________________________________________________
______________________________________________________________________
______________________________________________________________________
iv. Only small amounts of regulators (ex. Hormones) are necessary because the pathway
triggers enzyme cascades that can greatly amplify the signal
c. Intracellular Receptors
i. Some cells have receptors inside the cell rather than on the PM (usually in the
_____________________________ or ________________________________)
ii. Intracellular signals transduce the signal _______________________ the cell
1. Usually the intracellular receptor is a _________________________________
and the response is changing something using ___________________________
iii. Just like cell-surface receptors, hormones that bind to intracellular receptors can have
different effects on different ____________________ cells within an organism
IV.
Vertebrate Endocrine System
a. Figure 45.5 pg. 960  Locations of endocrine glands
b. Table 45.1 pg. 961 Major Glands and some of their hormones
c. Tropic hormones  __________________________________________________________
____________________________________________________________________________
d. Hypothalamus
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i. Integrates the endocrine and nervous systems  good example of how they are
structurally related is the ______________________________________ cells located
in the ________________________________
ii. It is part of the ____________________________________
iii. Regulates the _______________________________ Gland
1. Sometimes called the “__________________________ gland” because its
hormones regulate so many other endocrine functions
2. Located at base of the brain
3. It obeys orders from the ________________________________
4. Has 2 discrete parts:
a. Anterior Pituitary (MORE LATER)
i. Secretes hormones directly into blood
ii. Hypothalamus secretes two kinds of hormones:
1. Releasing hormones  __________________________
______________________________________________
______________________________________________
2. Inhibiting hormones  ___________________________
______________________________________________
______________________________________________
b. Posterior Pituitary (MORE LATER)
i. Stores and secretes two hormones
e. Pituitary Gland
i. Posterior Pituitary Hormones  made by hypothalamus but secreted by posterior
pituitary; these hormones act on specific structures rather than affecting other endocrine
glands
1. Oxytocin  acts on muscles of _______________________; induces
contractions during childbirth and causes mammary glands to eject milk during
nursing
2. __________________________________ Hormone  acts on the kidneys;
causes kidneys to increase water retention thus decreasing urine volume; helps
regulate the ______________________________________________________
ii. Anterior Pituitary Hormones 
1. Growth Hormone (GH)  promotes growth directly and also stimulates
growth factors
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a. Human Growth disorders are related to GH production:
i. Too much GH = gigantism
ii. Too little GH = pituitary dwarfism; this can be treated using
growth hormones from cadavers
2. Insulinlike Growth Factors (IGF)  stimulate ___________________ and
_______________________________ growth
3. Prolactin (PRL)  similar to GH; produces a variety of effects in different
vertebrates (so scientists think this is a very old hormone); mammals =
________________________________________________________________
________________________________________________________________
4. Follicle-stimulating Hormone (FSH)  stimulates production of __________
and ________________________
5. Luteinizing Hormone (LH)  stimulates ___________________________
and ______________________________
** Gonadotropins = stimulate the activity of male and female gonads; FSH and LH are
examples
6. Thyroid Stimulating Hormone (TSH)  stimulates the __________________
gland
7. ______________________________________________ Hormone (ACTH)
 stimulates the production and secretion of steroid hormones by the adrenal
cortex (part of the adrenal gland)
8. Melanocyte-stimulating Hormone (MSH)  regulates the activity of
______________________________________________ cells in the skin; has a
role in ________________ metabolism
9. ____________________________________________  body’s natural
opiates; inhibit the perception of pain
f. Pineal Gland
i. Small mass of tissue near the center of the brain
ii. Secretes the hormone _______________________________________, which regulates
functions related to light/dark and seasons marked by changes in day length; related to
biological clock rhythms
g. Thyroid
i. Consists of 2 lobes on the _______________________________
ii. Two closely related hormones:
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1. Triiodothyronine (T3)  causes changes to target cells
2. Thyroxine (T4)  thyroid secretes mainly T4, but the target cells convert it to
T3; this hormone stimulates and maintains metabolic processes
3. BOTH T3 and T4 affect metabolic processes; important in
__________________________________
a. Too much thyroid hormones = hyperthyroidism (_________________
__________________________________________________________
_________________________________________________________)
b. Too little thyroid hormones = hypothyroidism (___________________
_________________________________________________________)
iii. Thyroid has a critical role in vertebrate development and maturation (ex. Human
development), homeostasis (blood pressure, heart rate, muscle tone, digestion)
iv. Calcitonin  ________________________________________________________
h. Parathyroid
i. Found on the surface of the thyroid; function in homeostasis of calcium ions
ii. Parathyroid Hormone (PTH)  ___________________________ calcium levels in
blood; VERY important!
1. PTH and Calcitonin are ________________________________ hormones and
work together to regulate the calcium levels in the blood (example of
homeostasis); Fig. 45.9 pg. 967
i. Pancreas
i. Secretes bicarbonate ions to balance the pH from the acid chyme in the stomach
ii. ____________________ cells secrete glucagon  signals the liver to release glucose
back into blood stream (_______________________ blood sugar levels); used when
someone has not eaten in a while and blood sugar levels are low
iii. ____________________ cells secrete insulin  signals body cells to take up glucose
from the blood (___________________________ blood sugar levels); used when
someone just ate and blood sugar levels are high
**Insulin and Glucagon are not steroids…they are PROTEIN hormones made of AA’s**
iv. Glucagon and Insulin are antagonistic hormones and work together to regulate the
blood sugar levels in the body; Fig. 45.10 pg. 968
v. Most common endocrine disorder = _________________________________ 
caused by a deficiency in insulin or loss of response to insulin in target cells
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1. Type I diabetes  _______________________________________________
________________________________________________________________
________________________________________________________________
________________________________________________________________
________________________________________________________________
2. Type II diabetes  characterized by deficiency of insulin or reduced
responsiveness in target cells; _____% of diabetics are type II; can usually be
managed by diet and exercise; caused by _______________________ and
__________________________
j. Adrenal Glands
i. Adjacent to kidneys
ii. Two parts:
1. Adrenal _______________________ (outside)
2. Adrenal _______________________ (inside)
iii. Adrenal Medulla  close ties to the nervous system; __________________________
response
1. Epinephrine  sustaining blood pressure (Epi pen when a person is in
anaphylactic shock)
2. Norepinephrine  heart and metabolic rates; acts as a neurotransmitter;
GOOD EXAMPLE of how the endocrine and nervous systems are chemically
related
3. BOTH secreted in response to stress; their release into the blood gives the body
a bioenergetics boost (increasing metabolic rate; effecting target cells; effecting
cardiovascular and respiratory systems = increase stroke volume and rate of
heartbeat)
iv. Adrenal cortex  responds to __________________________ signals rather than
____________________________ signals
1. Glucocorticoids  ___________________________ metabolism; increases
glucose in blood; secreted in response to stress and promotes the synthesis of
glucose from non-carbohydrate substrates (ex. fats and/or proteins)  helps
with long-term environmental issues
2. Mineralocortocoids  helps inflammatory conditions; effects salt and water
balance in kidneys
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3. BOTH help the body deal with LONG TERM stress (whereas epinephrine and
norepinephrine deal with SHORT TERM stress); Fig. 45.14 pg. 971
4. ____________________________ are produced here as well, but their effects
are not well understood; possibly similar to testosterone/ estrogen/ progesterone
k. Gonadal Steroids
i. Controlled by _____________________________________ from the
_______________________ pituitary gland
ii. Produced in both males and females (in different proportions); produced in testes in
males and ovaries in females; general function = affect growth and development and
also regulate reproductive cycles and sexual behavior
iii. 3 major types:
1. Androgens  ex. testosterone; development and maintenance of male
reproductive system; produced in an embryo to turn the fetus into a male instead
of a female; produced during puberty to stimulate secondary sex characteristics
(hair growth, low voice)
2. Estrogens  ex. estradiol; effects the female reproductive system and
secondary sex characteristics in females
3. Progestins  ex. progesterone; prepares and maintains the uterus which
supports the growth and development of an embryo
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Chapter 48 – Nervous Systems
I.
Overview
a. Nervous system is made up of living ________________________
b. Neurons are specialized for the fast transmission of impulses
c. Three major overlapping functions:
i. Sensory Input  ______________________________________________________
_____________________________________________________________________
_____________________________________________________________________
_____________________________________________________________________
ii. Integration  carried out in the CNS (central nervous system; __________________
and spinal cord); input is interpreted and body responds appropriately
iii. ________________________________  conduction of signal from integration center
to the effector cells (muscles or glands that carry out the signal)
iv. Fig. 48.1 pg. 1023
d. Signals are conducted by nerves
i. PNS (peripheral nervous system) = _______________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
ii. Information is communicated by both electrical and chemical signals
e. Neurons (nerve cells)
i. Structural and functional unit of the nervous system
ii. Has a cell body (contains the nucleus) and fiber-like extensions (dendrites and axons)
1. Fig. 48.4 pg. 1025
2. Dendrites
a. Short branched; many per cell body; receive ______________________
information and pass it to the cell body
3. Axons 
a. Long; one per cell body; convey ________________________ messages
from the neuron to other cells
b. Axon hillock – ______________________________________________
__________________________________________________________
c. Covered by ___________________________________ (insulated layer)
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d. ______________________________________ – specialized endings;
relay signals from neuron to other cells by releasing chemical
messengers called neurotransmitters
i. Site of contact between a synaptic terminal and a target cell is
called a __________________________________
1. ___________________________ cell = transmitting cell
2. _________________________________ cell = target cell
f. Simple Nerve Circuits (Reflex Arc)
i. Simplest type of nerve circuit regulates a reflex (automatic response)
ii. Fig 48.3 pg. 1024
iii. Require two types of nerve cells
1. Sensory Neuron  ______________________________________________
______________________________________________________________
2. ___________________________ Neuron  gets info from the sensory neuron;
passes the info to the effector cell (muscle or gland cell)
iv. Interneurons – intervene between ___________________________ receptors and
______________________ cells; organize info to determine most appropriate behavior
v. Ganglion – ____________________________________________________________
______________________________________________________________________
g. Types of Nerve Circuits (3 basic types)
i. One type: Takes info from a single source (ex. eye) and goes to several part of the
brain
ii. Second type: Info from several presynaptic neurons converges at a single postsynaptic
neuron
iii. Third type: Info flows in a circular path; from one neuron to others, then back to the
original source
h. Supporting Cells (called _________________)
i. Help support the nervous system and help it function properly
ii. Originally thought to only have a structural role, but some synaptic interactions do
occur between glia and neurons
iii. In mature CNS, the glia are called __________________________________ – they
provide metabolic and structural support for neurons
10
1. Help form the _________________________________________  restricts
passage of most substances into the brain which controls the extracellular
chemical environment of the CNS
2. ___________________________________ (in CNS) and ________________
cells (in PNS) are glia that form myelin sheaths around the axons of neurons
a. Necessary b/c can’t use regular cell membranes b/c they are made of
lipids which are poor conductors of electrical currents; the myelin works
better
II.
The Nature of Nerve Signals
a. Nerve signals are changes in voltage across the membrane due to movement of ions
b. Membrane Potential  ________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
____________________________________________________________________________
i. __________________________ Potential  membrane potential of an unstimulated
neuron
ii. Can measure membrane potential as a voltage; typical animal cell is –50 to –100 mV
(the negative means the inside of the cell is negative in charge w.r.t the outside)
iii. Differences in membrane potential are sustained by the actions of the ____________
____________________________________________
1. __________ pumped OUT (3 at a time)
2. __________ pumped IN (2 at a time)
3. THEREFORE…outside = ________________; inside = _________________
4. Goes against the gradient, so needs to use energy (ATP) 
____________________ transport
5. Fig. 48.7 pg. 1027
iv. Ion channels are selective for specific ions; so a membrane can have different
permeabilities to different ions
1. They determine WHAT can pass through, but not the RATE
c. Changes in the membrane potential yield nerve impulses
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i. Excitable cells  cells that have the ability to generate large changes in their
membrane potentials (__________________________ cells and _________________
cells)
ii. Changes are made possible by specialized ion channels
1. _________________________ – open all the time (ex. Na/K pump)
2. Gated – open/close in response to a stimuli
a. Chemically-gated ion channels  ______________________________
__________________________________________________________
__________________________________________________________
b. Voltage-gated ion channels  _________________________________
__________________________________________________________
c. Allows only one kind of ion to pass through
iii. Graded Potentials  magnitude of change depends on the strength of the stimulus
(larger stimulus will open more channels)
1. Hyperpolarization – increase in voltage across the membrane
a. Open _______ channel; ________ flows out and causes the inside of the
cell to become more __________________________
2. Depolarization – reduction in the voltage across the membrane
a. Open a _______ channel; ________ flows in and causes the inside of
the cell to become more _________________________
3. Fig. 48.8 pg. 1029
iv. Action Potentials  all or nothing depolarization
1. __________________________________________ causes an action potential
a. Triggered by graded potentials
b. When it reaches a certain point, the ____________________________
(usually 15-20 mV more positive than the resting potential) it causes an
action potential (NERVE IMPULSE!); all or none event
c. Occurs in the ____________________ (not dendrites)
2. HYPERPOLARIZATION does NOT cause action potentials
3. Action Potential Mechanism:
Na+ channels  has 2 voltage
sensitive gates
- one opens quickly to
allow Na+ in (in
response to
depolarization)
- one closes slowly in
response to
depolarization
K+ channels  1 voltage
a. SEE Fig. 48.9 pg. 1030 explains everything perfectly!!
b. ________________________________ – Na+ and K+ channels closed
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c. _____________________________ – some stimulus opens Na+
channels; it reaches threshold potential, and therefore more Na+
channels open triggering an action potential
d. _____________________________ - because Na+ channels are open
and K+ channels are closed, the inside of the cell becomes more positive
e. ______________________________ – Inactivation gates close the Na+
channels and the K+ channels open; K+ leaves the cell and the inside
becomes more negative than the outside
f. _____________________________ – K+ gates remain open because
they are slow, but the Na+ gates are closed; resting state is restored very
quickly (hyperpolarization happens for a millisecond)
4. Because both gates of the Na+ channel are closed, if another stimulus arrives
during this period, it is unable to trigger a change (inactivation gates had not had
time to open back up yet)  called __________________________ period
(neuron is insensitive to depolarization)
5. It is the _________________________________________________________,
not their ______________________________, that codes for a stimulus
intensity in the nervous system
6. Action potentials propagate themselves along an axon (like tipping over the first
of a long line of dominoes)
a. Factors that affect the speed of the action potentials (how fast they go
along the axon):
i. Diameter of axon (larger diameter  faster transmission)
b. Saltatory conduction  ______________________________________
__________________________________________________________
i. Fig. 48.11 pg 1032
7. Communication between cells occurs at __________________________
a. Synapses – _________________________________________________
__________________________________________________________
__________________________________________________________
__________________________________________________________
b. Electrical Synapses
i. Allows action potentials to spread from presynaptic cell to
postsynaptic cell via gap junctions
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ii. Not as common as chemical synapses
c. Chemical Synapses
i. Very common
ii. Chemical synapses are called
____________________________; they separate presynaptic
cell from postsynaptic cell
1. The cleft prevents an action potential from going directly
from the pre to the postsynaptic cell
2. A series of events converts the ___________________
signal of the action potential arriving at the synaptic
terminal into a _________________________ signal
that travels across the synapse, where it is converted
back into an __________________________ signal in
the postsynaptic cell. (electrical signal  chemical
signal  electrical signal)
iii. Fig. 48.12 pg. 1033
iv. Structure of a Chemical Synapse
1. __________________________________ (intracellular
messengers) are held in the tip of the presynaptic axon
2. Action potential releases these neurotransmitter
molecules into the synapse (the action potential
depolarizes the membrane)
3. The postsynaptic membrane has special receptors for
neurotransmitters
a. Neurotransmitter binds  opens ion channels
(________________________ gated!) –
postsynaptic membrane is either hyperpolarized or
depolarized (depending on __________________)
b. Neurotransmitter is removed quickly
(_______________________________________)
 therefore the effect is brief and precise
c. NOTE: nerve impulses can only transmit ONE
way
v. Excitatory Synapse vs. Inhibitory Synapse
14
1. BOTH 
a. Graded potentials
b. The electrical impact on the postsynaptic cell
decreases with the distance away from the
synapse
2. Excitatory 
IPSP and EPSP
counter each others
chemical effects
a. Allows _______ in and ______ out (more
permeable to Na+, so more of that is allowed in)
b. Inside of cell becomes ___________________ =
DEPOLARIZES the plasma membrane (gets it
closer to the action potential)
c. Excitatory Postsynaptic Potential (EPSP)  the
name for the whole process that uses an excitatory
synapse
3. Inhibitory  NO ACTION POTENTIAL!
a. _________ out and _______ in (higher
permeability to K+)
b. Inside of cell becomes _________________ =
HYPERPOLARIZE the plasma membrane
c. Inhibitory Postsynaptic Potential (IPSP)  the
name for the process that uses an inhibitory
synapse
vi. Summation
1. Several synaptic terminals working simultaneously on the
same postsynaptic cell can have an additive effect 
summation!
a. Temporal Summation  ___________________
________________________________________
________________________________________
________________________________________
b. Spatial Summation  ______________________
________________________________________
15
________________________________________
________________________________________
c. Fig. 48.14 pg. 1036
d. Neurotransmitters
i. Same neurotransmitter can produce different effects on different
types of cells (depends on the ___________________________)
ii. Major neurotransmitters  Table 48.1 pg. 1037
1. Acetylocholine – most common; can be either inhibitory
or excitatory
2. Biogenic Amines – derived from ___________________
a. Epinephrine & Norepinephrine (excit and inhib)
b. Dopamine (generally excit)
c. Serotonin (generally inhib)
3. Amino Acids –
Sleep, mood,
attention,
learning
a. GABA (gamma aminobutyric acid) – found at
most inhibitory synapses; creates IPSP (increases
Cl- permeability)  no action potential
b. Neuropeptides – short chains of ______________
i. Substance P – excit. Signal; mediates
perception of pain
ii. Endorphins – decreases perception of
pain; emotional effects
e. Gas signals of Nervous System:
i. Ex. Nitric Oxide and Carbon Monoxide
ii. Used as local regulators
iii. Gasses not stored; cells make them on demand
16
III.
Evolution and Diversity of Nervous Systems
a. Great Diversity in organization of new systems
i. Lack nerve systems (sponges)
ii. Nerve nets (cnidarians)
iii. Cephalization
1. Nerve cords (planarians)
2. Clearly defined CNS….etc.
b. Fig. 48.15 pg. 1039
IV.
Vertebrate Nervous System
a. CNS – _____________________________________________; develops from the _________
____________________________________________________________________________
b. PNS – everything else; transmits information to and from the CNS and regulates the internal
environment of the organism
c. Cerebrospinal Fluid – made in the ____________________ by filtering the
________________; fills the spaces in the _________________________________________
i. Function – to act as a _____________________________________
d. White Matter – _________________ covered in myelin
e. Gray Matter – _____________________ and __________________________ axons
f. PNS – Peripheral Nervous System
i. Cranial Nerves – start in the ____________________; innervate head and organs of
upper body
ii. Spinal Nerves – Start in __________________________; innervate rest of body
iii. Division of PNS with respect to FUNCTION: Fig. 48.17 pg. 1041
1. ________________________ Division  incoming neurons
2. ________________________ Division  outgoing neurons
a. Somatic Nervous System – carries signals to __________________
muscles; mainly reacts to external stimuli
b. Autonomic Nervous System – regulates internal environment by
controlling ______________________ and ___________________
muscles; consists of 2 parts that act on our bodies with opposing effects:
i. _____________________________  ACTIVE
1. Arousal/energy; heart beats faster
2. Uses ________________________ as neurotransmitter
ii. _____________________________  INACTIVE
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1. Calming/ conserving energy; emphasis on selfmaintenance functions
2. Uses _________________________ as neurotransmitter
iii. Fig. 48.18 pg. 1041
g. Embryonic Development of the Brain
i. Bulges from the nerve cord from the forebrain, midbrain, and hindbrain
1. Forebrain  cerebrum, diencephalons (thalamus, hypothalamus, epithalamus)
2. Midbrain  midbrain
3. Hindbrain  pons, cerebellum, medulla oblongata
ii. Fig. 48.19 pg. 1042
iii. Fig. 48.20 pg. 1043
h. Brainstem (aka “_____________ brain”)
i. 3 parts:
1. __________________________________  controls automatic, homeostatic
functions (ex. breathing, swallowing, digestion, heart and blood vessel activity)
2. Pons  also helps control automatic functions (ex. regulate breathing centers in
the medulla)
3. Midbrain  acts as projection center; sends coded sensory information to parts
of the forebrain
ii. Major Functions: _______________________________________________________
______________________________________________________________________
______________________________________________________________________
iii. Reticular Formation –
1. Fig. 48.21 pg. 1044
2. System of neurons that passes through the brainstem
3. RAS (reticular activating system)  regulates sleep/ arousal
a. Selects what information reaches the cerebral cortex; more input the
cortex receives, the more awake/aware the person is
i. Cerebellum
i. Develops from the _______________________________ (hindbrain)
ii. Functions in __________________________________; muscle actions; involved in
learning and remembering motor responses
iii. Balance, hand-eye coordination
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j. Thalamus / Hypothalamus
i. Develops from diencephalons (forebrain)
ii. _______________________________ – produces cerebrospinal fluid
iii. _______________________________ – main input center for sensory information
going to cerebrum and main output center for motor information leaving the cerebrum
iv. Hypothalamus – important in homeostatic regulation
a. Source of hormones
b. Body’s _____________________________
c. Regulates hunger/thirst
d. Role in sexual/mating behaviors; fight or flight; pleasure/rage
2. __________________________ Rhythms 
a. Regular, repeated rhythmic behaviors (sleep/ wake)
b. Controlled internally (biological clock!) partially…also relies on
external signals (ex. light)
c. Squirrel experiment – Fig. 48.23 pg. 1046
k. Cerebrum
i. Most highly developed structure of the mammalian brain
Left Side  adept at language,
math, logic, serial sequences of
information
Right Side  pattern recognition,
space recognition, spatial
relations, nonverbal, emotions
ii. Divided into left and right hemispheres
1. Each hemisphere consists of:
a. Gray matter (cerebral cortex) – covering
b. White matter – internal part
c. Basal nuclei – found deep within the white matter; important in planning
and learning movement sequences
iii. Cerebral Cortex (“gray matter”)
1. Largest and most complex part of the mammalian brain
2. Evolved a lot through evolution
3. ________________________________ – 6 layers of tissue outside of the
cortex; unique to mammals
iv. Right half of brain controls the functions of the left side of the body; left half controls
the right side
1. Corpus callosum – _________________________________________________
________________________________________________________________
________________________________________________________________
v. Each side of the cerebrum has 4 lobes:
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1. Frontal, Parietal, Temporal, Occipital
2. Fig. 48.24 pg. 1047
3. Primary motor cortex and primary somatosensory cortex
form the boundary between the frontal lobe and parietal lobe
a. Motor Cortex  sends commands to _________________________
b. Somatosensory Cortex  gets and integrates signals from touch, pain,
pressure and temp receptors throughout the body
c. Fig. 48.25 pg. 1048
4. ____________________________ Lobe  speech, motor cortex, emotions
5. ____________________________ Lobe  somatosensory cortex, taste,
speech, reading, touch, pain, pressure, temp
6. ____________________________ Lobe  smell, hearing
7. ____________________________ Lobe  vision
vi. If one part of the brain gets damaged early in development, it can cause redirection of
its functions to another area
vii. Language and Speech
1. Processed by multiple areas of the cortex (ex. ___________________ area –
frontal lobe; _____________________________ area – temporal lobe)
viii. Emotions
1. Due to ______________________ lobe and ______________________ system
2. Limbic System  forms a ring around the brainstem; composed of
hippocampus and the olfactory cortex
a. Responsible for emotions (laughing, crying, feeding, aggression,
sexuality)
b. Fig. 48.27 pg. 1050
3. Amygdala  ____________________________________________________
________________________________________________________________
________________________________________________________________
________________________________________________________________
a. Interesting note: frontal lobotomies, which disrupt the frontal lobes and
limbic system, used to be performed to treat severe emotional disorders
ix. Memory and Learning
1. Short term memory (frontal lobe)  released if memory is ________________
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2. Long term memory (limbic system, hippocampus)  if info is pertinent; goes
from short term to long term with repetition (“practice makes perfect”)
3. Skill memory  ex. ________________________, _____________________,
etc; once learned, it is hard to unlearn (bad habits are hard to break!)
4. Long-term depression (LTD) – _______________________________________
________________________________________________________________
________________________________________________________________
________________________________________________________________
5. Long-term ____________________________ (LTP) – enhanced responsiveness
to an action potential; so…single action potential has much greater effect on the
postsynaptic cell then before
l. Research may lead to new cures to CNS injuries/ diseases
i. ____________ can’t repair itself
ii. Nerve Cell Development
1. Neurons develop by cell to cell communication, control of gene expression, and
genetic basis
2. Axons grow to target cells and use molecular signals to direct them (don’t grow
in a straight line)
3. Sequence and time of development are important – therefore it is hard to
replicate
4. Scientists are trying to get axons to regrow using different combinations of
proteins
iii. Neural Stem Cells
1. In adults, new cells are found in the _________________________________
(memory/ learning)
2. Function of the new stem cells = unclear!
3. Issues with stem cell research  what can we use as a source?!?!
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