Transcript Document

•Physiology is the study of the function of organisms
•Psychology challenges us to think of how physiology might
affect our behavior
•Mind Body Problem: Does our mind affect our body? Does
our body affect our mind? Some think that brain=behavior,
therefore if you can understand the brain, then you can
understand behavior.
•Descartes claimed that the pineal gland was the interface
between mind and the rest of the brain. Interactions between
the mind and body are two-way. In perception, the physical
states of the world influence our bodies which influence our
brains which via the pineal gland influence our behavior.
•Are humans and animals the same?
•Most religions say humans are very different than animals and
therefore can not be thought of in the say way.
•Some scientists maintain that humans differ by degree form other
animals as part of a continuum.
•Continuity-humans are more similar than different from other
animals.
•If you give a computer a command it has never encountered
and is not programmed to understand then it will not do the
command--this is same for the human brain. However, over
time the brain can learn this information, but the computer
will never know the command unless it is programmed
differently.
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• Lesion method-cutting part of the brain
Ablation method-destruction of part of the brain
These two types are never used, this is used on animals and not
much in use today. However, humans can be used if they suffered
from an injury.
•Simulation method-electric and chemical simulation which
allows researchers see what stimulation to different parts of the
brain causes. This is in extensive use today.
•EEG(electroencephalgram)- recording technique of the neuron
activity
•Biochemical techniques- used to map neurotransmitters
•MRIs(magnetic resonance imaging) are imaging techniques
which use magnetism
•CAT scans(computer assisted tomography) uses x-rays
•PET scans(position emission tomography) uses the brain’s
metabolic activity
•Basic unit of nervous system
•there are many of them ~10-12 billion in humans
•mostly found in the Central Nervous System ~70%
•Three types of Neurons:
Afferent or Sensory neurons-run from sensory organs to CNS
Efferent of Motor Neurons-run from CNS to muscles
Interneurons or Multipolar neurons-found mostly in the brain and are
connected to other neurons
•Axon- or nerve fiber is a very special part of the neuron, it carries
the information away from the cell in the form of bioelectric signals
also known as nerve impulses.
•In most animals and in humans nerve conduction is electro-chemical
process
Electric occurs within the neuron
Chemical occurs between the neurons
•Depolarization makes it electrical, this is when the membrane
becomes less negative. When the neuron is at rest it is not
conducting an impulse then it is polarized, this is due to the inside of
the membrane is more negatively charged than the outside of the
membrane. The neuron can change from polarized to depolarized by
the movement of Na+ and K+ ions across the membrane.
•Neurotransmitters are biological messenger molecules that carry
information.
•Neurotransmitters communicate across a
synapse in two ways:
1)EPSP (excitatory postsynaptic potential)information is transmitted
2)IPSP (inhibitory postsynaptic potential)transmission is ceased
•Myelin is layers which have a higher proportion of lipids than
other surface membranes. Myelin is wrapped around Schwann
cells.
•There are two functions of
myelin:1.)insulation for the axon 2.)to speed
nerve conduction
•Myelinated axons appear to be whiter,
therefore are called white matter. They are
mostly found in the peripheral nervous
system.
•Unmyelinated axons appear to be gray,
therefore are call gray matter. They are
mostly found in the central nervous system.
This is the concept of how neuron impulse conduction. If a neuron
responds, then it responds completely. Thus, a nerve impulse is
conducted whenever a stimulus of threshold intensity or above is
applied to an axon and all impulses carried on that axon are the
same strength. A greater stimulation causes the rate of the neuron
impulses to increase not the intensity of the impulse. The rate of
the impulses can only be so high, though, due to the refractory
period of the neuron. Each neuron must have a brief refractory
period which is where the threshold stimulus will not trigger
another impulse on an axon.
The central nervous system (CNS) includes the brain and the spinal cord.
The peripheral nervous system is everything else.
The autonomic nervous system is a part of the peripheral nervous
system, and it is the part that regulates functions that run without our
conscious control, such as breathing, heart rate, and digestion.
The brain is made up of neurons.
One organizing principle of the brain is redundancy (different parts of
the brain contribute to solving the same problems)
Another organizing principle is bilateral symmetry (divides the brain into
a right and a left half). Animals that do not show this left-right symmetry
are rare. The brain and body are connected contralaterally (the left side
of the brain controls the right side of the body and vice-versa).
The last organizing principle is evolutionary organization. The areas
nearest to the spinal cord end are the oldest, and the areas furthest from
the spinal-cord end are the newest. The oldest areas are the most
important for survival.
The brain is divided into a left and a right half, and those halves are
connected by a fibrous band of tissue called the corpus callosum. The
corpus callosum serves as a bridge for information from one half of the
brain to the other. Although the two halves are physically similar, they
function differently.
Bilateral symmetry is the symmetry
everybody is aware of, and to many people this
is symmetry itself. Bilateral symmetry occurs
when two halves of a whole are each other's
mirror images. It is also called mirror symmetry.
The left hemisphere: Is in charge of language functions and logical
thought. Speech, song, and writing are all examples of left hemisphere
functions; however, functions such as speech and song are controlled by
different areas in the left hemisphere.
The right hemisphere: Is responsible for such things as the
perception of rhythm, spatial-relation skills, and abstract or intuitive
thought. The right hemisphere is less controlled by logic.
*There are some people who show the opposite pattern of hemispheric
specialization. Those people have language functions in the right
hemisphere, and rhythm, spatial relation skills, and abstract/intuitive
thought in left hemisphere.
The medulla is the first part of the hind brain from the spinal cord. The
medulla contains the centers that regulate breathing and heart rate. That
is why damage to the medulla is usually fatal.
The pons are the next brain area up from the spinal cord. The pons are
centers that control wakefulness and alertness.
The reticular formation contains information. It is a small tube that is
inside the larger tube of the brain stem. Within are many axons, which
communicate with the body.
The cerebellum is the first big bump on the brain. Its main job is the
control of gross motor function.
Pons: Controls paradoxical sleep
Medulla: Controls vital functions
(breathing, heart rate, and respiration)
Spinal Cord: Mediates spinal reflexes,
receives sensory information (afferent),
transmits motor information (efferent)
The inferior colliculus is responsible for reflexive responses to auditory
stimuli. It controls your response to loud noises; although sometimes
you can control your response.
The superior colliculus controls visual reflexive stimuli. It is responsible
for making you look at bright lights and other things.
Together, the inferior and superior colliculus make up the colliculi.
Also called the cortex, or neocortex.
The newest and largest part of the brain.
A great deal of the surface has no function that can be determined.
Those surface areas are called associative areas, and are probably
responsible for a great deal of our cognitive capacity.
The cortex is divided up into five lobes. The four lobes on the surface are
the frontal, parietal, occipital, and temporal. The fifth lobe is underneath
the surface lobes, and is called the limbic lobe or limbic system.
The frontal lobe: The frontmost portion, this area controls motor
functions or movements. Also, it controls higher order functions,
planning, thinking, and worrying. The body parts being controlled are
mapped onto this portion of the cortex. Some parts, such as the hands
and lips, receive more brain tissue than other parts, such as the torso.
The parietal lobe: This area monitors sensory information and body
awareness. The body parts here are also mapped onto the sensory areas
of this parietal lobe, but that map is not exactly like the one mentioned
above.
The temporal lobe: Receives sensory input from the ears. Sounds
are analyzed and interpreted as language.
The occipital lobe: Receives sensory input from the eyes. It analyzes
and interprets visual stimuli. The analysis and interpretation of vision is
extremely complex and accounts for the largest percentage of the brain's
activity.
The limbic lobe: Also called the limbic system. This is the ancient
cortex, sometimes called the paleocortex. The neocortex has taken over
most of the limbic system's original functions. Now, the limbic system
primarily controls emotional behaviors and memories.
Brain power evolves because there is a need for it. Some environments
require all of it for us to survive and reproduce.
Evolutionary changes are constrained by physical and temporal factors.
Going up the evolutionary chain, we see more bumps or convolutions
(folds) on the brains of the “higher” evolved animals.
Animal brains are laid out horizontally, but the human brain is laid out at
nearly a right angle. When humans evolved into creatures that walked
upright, our heads rotated forward and the brain had to follow. Making
the head bigger might have been a solution, but the size of the human
female's birth canal put a constraint on that. The brain got bigger, the
head stayed about the same size, and the brain folded up to fit inside the
size of the head.
This is an integrating system (a system that helps to organize behavior
and physiology).
This system uses ductless glands that are specialized tissues that secrete
hormones directly into the bloodstream. Hormones are fairly simple
chemicals that are absorbed by other tissues, known as target sites, and
then used by those tissues.
Endocrine action includes physical growth and the menstrual cycle. In
humans, physical growth is mediated by a somatotrophic hormone
(growth hormone) and it ceases to work during adulthood. During
adolescence, growth hormone and the sexual hormones combine to
produce the adolescent synergistic growth spurt. A synergism is when
two or more elements combine to produce a greater effect. Synergistic
effects also happen when certain drugs are taken.