The Biological Perspective 89- Dopamine (DA) is associated with Parkinson’s disease and
schizophrenia. - Endorphins are neural regulators that control our pain response.
- Most neurotransmitters are taken back into the synaptic vesicles
in a process called reuptake. - ACh is cleared out of the synapse by enzymes that break up the
molecules.
An Overview of the Nervous System
- 4 Describe how the brain and spinal cord interact and
respond to external experiences.
- The central nervous system consists of the brain and the
spinal cord. - The spinal cord serves two functions. The outer part of the cord
transmits messages to and from the brain, whereas the inner
part controls lifesaving reflexes such as the pain response. - Spinal cord reflexes involve afferent neurons, interneurons, and
efferent neurons, forming a simple reflex arc. - Neuroplasticity refers to the brains ability to modify its structure
and function as the result of experience or injury; researchers are
examining ways to capitalize on this feature to assist individuals
with brain injury or disease.
- 5 Differentiate the roles of the somatic and autonomic
nervous systems.
- The peripheral nervous system is all the neurons and nerves
that are not part of the brain and spinal cord and that extend
throughout the body. - There are two systems within the peripheral nervous system,
the somatic nervous system and the autonomic nervous system. - The somatic nervous system contains the sensory pathway, or
neurons carrying messages to the central nervous system, and
the motor pathway, or neurons carrying messages from the cen-
tral nervous system to the voluntary muscles. - The autonomic nervous system consists of the parasympathetic
division and the sympathetic division. The sympathetic division
is our fight-or-flight system, reacting to stress, whereas the para-
sympathetic division is our eat-drink-and-rest system that restores
and maintains normal day-to-day functioning of the organs.
Distant Connections: The Endocrine Glands
- 6 Explain why the pituitary gland is known as the
“master gland.”
- Endocrine glands secrete chemicals called hormones directly
into the bloodstream, influencing the activity of the muscles and
organs. - The pituitary gland is found in the brain just below the hypo-
thalamus. Among its many functions, it helps us conserve water
and controls oxytocin, a hormone involved in the onset of labor
and lactation. The pituitary also regulates growth hormone and
influences the activity of the other glands.
2. 7 Recall the role of various endocrine glands.- The pineal gland is also located in the brain. It secretes mel-
atonin, a hormone that regulates the sleep–wake cycle, in
response to changes in light. - The thyroid gland is located inside the neck. It controls metabo-
lism (the burning of energy) by secreting thyroxin. - The pancreas controls the level of sugar in the blood by secreting
insulin and glucagons. Too much insulin produces hypoglyce-
mia, whereas too little causes diabetes. - The gonads are the ovaries in women and testes in men. They
secrete hormones to regulate sexual growth, activity, and
reproduction. - The adrenal glands, one on top of each kidney, control the stress
reaction through the adrenal medulla’s secretion of epinephrine
and norepinephrine. The adrenal cortex secretes more than 30
different corticoids (hormones), controlling salt intake, stress,
and sexual development.
- The pineal gland is also located in the brain. It secretes mel-
Looking Inside the Living Brain- 8 Describe how lesioning studies and brain
stimulation are used to study the brain.
- We can study the brain by using lesioning techniques to destroy
certain areas of the brain in laboratory animals or by electrically
stimulating those areas (ESB). - We can use case studies of human brain damage to learn about
the brain’s functions but cannot easily generalize from one case
to another. - rTMS and tDCS are noninvasive methods for stimulating the
brain.
- 9 Compare and contrast neuroimaging techniques for
mapping the structure and function of the brain.
- Different neuroimaging methods allow scientists to investigate
the structure or the function of the living brain. - The electroencephalograph allows researchers to look at the
electroencephalogram (EEG), or electrical activity of the surface
of the brain, through the use of electrodes placed on the scalp
that are then amplified and viewed using a computer. ERPs
allow researchers to look at the timing and progression of cogni-
tive processes. - CT scans are computer-aided X-rays of the brain and show the
skull and brain structure. - MRI scans use a magnetic field, radio pulses, and a computer to
give researchers an even more detailed look at the structure of
the brain. - fMRI allows researchers to look at the activity of the brain over
a time period. - PET scans use a radioactive sugar injected into the bloodstream
to track the activity of brain cells, which is enhanced and col-
or-coded by a computer. SPECT allows for the imaging of brain
blood flow.