1. THE BRAIN III. Endocrine System
1. Endocrine System - chemical communication system; a set of glands that secrete hormones into the bloodstream.
Endocrine System - The endocrine system’s glands secrete another form of chemical messengers, hormones, which travel through the bloodstream and affect other tissues, including the brain. When hormones act on the brain, they influence our interest in sex, food, and aggression. Whereas the nervous system is fast, sending messages from eyes to brain to hand in a fraction of a second, the endocrine system sends messages SLOWLY along in the bloodstream, taking several seconds or more to travel from the gland to the target tissue.
Hormones are produced by several different glands. They are the pituitary gland, thyroid gland, the adrenal gland, the testes and ovaries.
Pituitary Gland The pituitary gland is stimulated by the hypothalamus and is responsible for the secretion of many different hormones that affect various aspects of behavior.
Example: Growth hormone regulates the growth of muscles bones, and glands. Children whose growth patterns seem abnormally slow often catch up to others the same age when doctors give them growth hormone.
Thyroid Gland - The thyroid gland produce thyroxin, which affects the body’s metabolism - or its rate of converting food to energy. The production of to little thyroxin can lead to a condition called hypothyroidism. Peel with hypothyroidism often are overweight. For children, too little thyroxin can cause a condition called cretinism, which is characterized by stunted growth and mental retardation.
A. Pituitary Gland - regulates growth & controls other endocrine glands
- called “Master Gland”
B. Thyroid Gland - regulates body’s metabolism by producing thyroxin

2. THE BRAIN
III. Endocrine System continued
C. Adrenal Glands - secrete hormones (epinephrine & norepinephrine) that arouse the body in times of stress.
Adrenal Glands - secrete hormones (epinephrine & norepinephrine) that arouse the body in times of stress. These hormones increase heart rate, blood pressure, and blood sugar, providing a surge of energy. When the emergency passes, the hormones—and the feelings of excitement—linger a while.
Testes and Ovaries - Testes produce testosterone in males. In the prenatal period, testosterone influxes development of the se organs. about six weeks after fertilization, if testosterone is secreted, it stimulates development of male sex organs testosterone is not secreted, then sex organs develop.
Ovaries produce estrogen and progesterone. Estrogen fosters the development of primary and secondary sex characteristics, such as breast enlargement. Progesterone, stimulates growth for pregnancy and together regulate menstrual cycle.
D. Testes & Ovaries - produce testosterone, estrogen, progesterone
Fast Fact - Adrenal Glands release cortical steroids which promote muscle development.

3. THE BRAIN IV. METHODS OF STUDYING THE BRAIN
A. Accidents - See the results of physical brain damage & its affects on
people
Accidents - The oldest way that researchers have been able to see how the brain is related to psychological function is through the study of brain damage and accidents. Brain damage from head injuries can result in loss of vision & hearing, confusion or loss of memory. Loss of large portions of the brain had a small loss of function, yet smaller parts of the brain have had damage and have had a huge loss of function.
Electrical stimulation of the brain. We saw how electric simulation of the motor cortex can cause body movement, but it doesn’t stop there. Some parts of the cerebral cortex that have been stimulated have caused, the hearing of music, or a flashback memory.
Example. They have used rats who had electrodes implanted in their brains to learn about the functions of the hypothalamus. When rats pressed a lever, the electrodes stimulated the portion of the hypothalamus where they were implanted. As it turned out, the rats found this stimulation pleasurable - so pleasurable that the rats would press the lever up to 100 times a minute just to receive the stimulation. In some cases, hungry rats chose electrical stimulation over food.
B. Electrical Stimulation -Electric stimulation of one part of the brain causes specific sensations in the body.

4. THE BRAIN
IV. METHODS OF STUDYING THE BRAIN continued
C. Electroencephalogram (EEG)- a device that records the electrical activity of the brain.
EEG - Electrodes attached to the scalp with tape or pasted detect small amounts of electrical activity called brain waves. Researchers have learned that certain brain wave patterns are associated with feelings of relaxation and with sleep. They use these in sleep analysis, to help diagnose some kinds of psychological disorders and to help locate tumors.
Brain SCANS - CAT - A moving ring passes X-ray beams around and through the head. The density of the brain tissue determines how much radiation is absorbed. Computers measure the amounts of radiation an piece together a 3-d view of the brain that can be seen in a video monitor.
---Developed in the 1970s, CAT (or CT) scanning is a process that combines many 2-dimensional x-ray images to generate cross-sections or 3-dimensional images of internal organs and body structures (including the brain). Doing a CAT scan involves putting the subject in a special, donut-shaped x-ray machine that moves around the person and takes many x-rays. Then, a computer combines the 2-dimensional x-ray images to make the cross-sections or 3-dimensional images.
CAT scans of the brain can detect brain damage and also highlight local changes in cerebral blood flow (a measure of brain activity) as the subjects perform a task.
D. Scans -
• Computerized Axial Tomography (CAT or CT) detect brain damage & measure activity as subjects perform a task.
Fast Fact - Acupuncture is based on the belief that by inserting needles into various parts of the body, they can interrupt pain messages sent to the brain, thus alleviating the pain or treating the illness

5. THE BRAIN IV. METHODS OF STUDYING THE BRAIN continued D. Scans cont. -
• Magnetic Resonance (MRI) - person lies in a very powerful magnetic field & radio waves - More effective than CAT
MRI - The invention of MRI in 1977 was a major breakthrough in imaging technology. Subject is placed on a moveable bed that is inserted into a giant circular magnet. Radio waves then cause parts of the brain to give off extra energy. This energy is measured from multiple angles & is translated by computer into a visual image of the brains anatomy. MRI is more powerful than a CAT scan & can show details more clearly.
Example: MRI is more effective at revealing small injuries & abnormalities in hard to see areas. Unlike PET, MRI does not require the subject to be injected with a tracer substance.
PET Scans- PETs are different from CAT scans & MRI because they show activity of the brain rather than a snapshot of the brain at a given time. Scientists can see the brain actually at work. PETs have been used to see which parts of the brain are most active when we are listening to music, working out a math problem, reading using language or playing chess. So if you raise your hand, the computer will show activity in one area and if you sing a song, another area will light up.
-The person is injected with radioactive sugar or glucose. As the sugar reaches the brain, more of it is used where brain activity is greater. Researchers can watch the glucose go from one area of the brain to another as those areas are working.
(F)MRI – Functional MRI - In an fMRI study, the result is a real-time log of brain activity. It can be frozen at individual frames, such as a highlight of brain activity, or it may be viewed in video form later. Researchers might want to use fMRI to identify the areas of the brain involved in particular responses, for example, while a doctor might order the test to see why a patient can’t perform some cognitive tasks.
fMRI looks specifically at blood flow in the brain and is capable of detecting very small changes. This allows the test to identify when different areas of the brain become active, which can help a doctor or researcher see what a patient’s brain is doing. MRI and fMRI are typically ordered for very different reasons
• Positron Emission Tomography (PET) - Shows activity of the brain in real-time using radioactive sugar
• (f)MRI – combination of PET & MRI.
- real-time log of brain activity

6. PHINEAS GAGE
Students write down the following questions in their notes. Write their answers in complete sentences
What type of scanning device is used to analyze Gage’s brain?
What part of Gage’s Brain was damaged?
How did Phineas Gage change after the accident?
American Scientific Frontiers video clip on Phineas Gage. 8:51 minutes
Mac users click on the black circle to view link to video
Original Link:
Key:
CT Scan
Frontal Lobes or Prefrontal Cortex
Personality, executive decision making, planning, reasoning, inhibiting behavior was changed. No longer Gage, Profane.