Physiology Psychology describes or evaluates mechanisms for behavior.
Behavior in its simplest definition is movement. These movements are muscular contractions which are recognizably different, yet performed publicly which makes it easy to study behavior between species.
A species physiology must be compatible to its place in nature to secure survival. .
What are some of these
Identity problem- does ?Brain=behavior?
Continuity problem – what is the relation between humans and animals?
Religious view- human are different kinds of entities
Scientific-human are part of the animal continuum
Mind and Body Problem Important Psychological Issue
The mind and body problem deals with three important philosophical views.
Idealism suggest mental monism or the absence of the physical world. If one believes this he/she is more likely to behave introvertly.
Materialism is the idea that there is no mental. Those who believe this view behave extrovertly.
Epiphenominalism suggest that the mind is a side effect of the brain and the mind holds no power.
Techniques of Studying the Brain
Lesion or Abrasion methods- cutting, severing, or destroying a part of the brain. How does it effect behavior?
Used on animals-Not on humans except after the fact
After WWI many men who had suffered brain injuries were studied.
Stimulation methods -extensively used- electric stimulation, electrode implants.
Stimulation to certain parts of brain have been shown to cause: aggression, submission, and extreme sexual pleasure .
Science Fiction has already explored some concerns of using stimulation to reward or punish humans.
Techniques for Studying the Brain
Chemical Stimulation - A cannula, small tube, is inserted into the brain and crystalline forms of neurotransmitters are introduced.
Recording Technique- Measures the activity of neurons. Recorder is inserted into axon. Electrode stimulates cell’s activity. Example-EEG- electroencephalogram.
Biochemical Technique- used to map out various neurotransmitter systems. Example- How levels of transmitters is linked to depression. Drug therapy can alter these levels.
Imaging Technique- New-Uses forms of energy and computers to create detailed pictures of the brain. Example-MRI (magnetism), CAT Scan (X-rays), and PET Scan (metabolic activity).
Neurons The Basic Unit of the Nervous System
Estimated 10-12 billion or higher!
Large number of neurons= more complex nervous system.
One Neuron can connect to as many as 75 more neurons.
Pyramidal neuron located in
Three Types of Neurons:
Afferent or Sensory- run from sense organs to central nervous system.
Efferent or motor- run from the central nervous system to the muscles.
Interneurons or multipolar- Found within the brain and are multiply connected to other neurons.
Parts of the Neuron
Dendrites - All of the fibrous extensions of the cell body except the axon. They give the Neuron its characteristic shape.
Cell Body - The part of the neuron containing the nucleus, cell membrane and contributing organelles ( endoplasmic reticular, Golgi apparatus, and mitochondria.
Axon - Conducts information from the neuron cell body to the synaptic terminals to trigger synaptic transmission. Axons also transport chemical substances from the cell body to the synaptic terminals.
Myelin - A fatty sheath of insulation that covers larger axons. Not all neurons have myelin.
Synapse - Points of functional contact between axon terminals and other cells.
The Neuron http://faculty.washington.edu/chudler/synapse.html
Within the Neuron
Depolarization- An electrical process
-70 mill volts
When the neuron is resting, not conducting nerve impulses, it is polarized.
The cell is invaded by Na ions and the expulsion of K ions. The electric charge is gone. Depolarization occurs!
A chemical process
When depolarization reaches the terminal buttons, neurotransmitters are released into the synapse.
Either excite or inhibit the following neuron!
Sending neuron-presynaptic neuron
Receiving neuron- postsynaptic neuron.
Parts of the Brain: Frontal Lobe (Forebrain) Location: serendip.brynmawr.edu/bb/kinser/
Four Types of Messengers:
Neurotransmitters : released by terminal buttons of neurons and detected by receptors in the membrane of another cell a short distance away.
Neuromodulators: released in large amounts from the terminal buttons, but diffused throughout part of the brain, affecting many neurons
Hormones: produced by endocrine glands, released into extracellular fluid - stimulate cell receptors on membrane surface or deep within nuclei of cells, including neurons
Pheromones: chemicals released into the environment through sweat, urine, or secretions of special glands. Most receptors in nose of other animals, but may also be detected in skin or other organs
Location - In the anterior most part of the brain (under the forehead)
Determines our consciousness of our environment.
Determines how we initiate and respond to our environment.
Daily decisions in our daily lives.
Controls emotional responses and expressive language.
Two peach-size mounds of folded tissue at the base of the brain
Overlies the pons
The cerebellum ("little brain") has convolutions similar to those of cerebral cortex, only the folds are much smaller. Like the cerebrum, the cerebellum has an outer cortex, an inner white matter, and deep nuclei below the white matter
New skills are learned by trial and error and then coded into the cerebellar memory
Coordinates movement of muscles and joints by synthesizing data from the brain stem, the spinal cord, and another brain areas such as cerebral cortex
The cerebellum fine tunes our motor activity or movement
The hypothalamus is a midline, structure, shaped like a funnel below the thalamus
It connects to the pituitary gland
The hypothalamus has many regulating functions
The autonomic nervous system, emotions and behavior, body temperature, hunger, thirst, sleep-waking cycles
Controls the release of hormones under its control: growth, prolactin, thyroid, corticotropin, and gonadotropins
Regulation of sex hormones, blood pressure, body temperature, water balance, respiration, and food intake, while it also plays a role in regulating complex moods, such as anger, placidity, and fatigue.