Bio supplemental text notes
Chapter 3: anatomy of the nervous system
General Layout of the Nervous System
Central Nervous System
o Skull and spine
Peripheral nervous system
o Outside skull and spine
Somatic nervous system
Composed of afferent nerves that carry sensory
information from the skin, skeletal muscles joints, eyes,
Efferent nerves that carry motor signals from the
central nervous system to the skeletal muscles
Autonomic nervous system
Regulates internal environment
Composed of afferent nerves that carry sensory
information from internal organs to the CNS
Efferent nerves that carry motor signals from the CNS to
o Afferent(ADVANCE, APPROACH, ARRIVE) goes
o Efferent Nerves
Sympathetic: autonomic motor nerves
that project from the CNS in the
lumbar(small of the back) and
thoracic(chest area) regions of spinal
Parasympathetic: autonomic motor
nerves that project from the brain and
sacral(lower back) region of the spinal
o sympathetic and parasympathetic neurons
project from the CNS and go PART of the way to
the target organs before they SYNAPSE on other
neurons that carry the signals the rest of the way.
o Sympathetic synapse on second-stage neurons at
a large distance, para. Synapse on second-stage
neurons close up.
1. The sympathetic nerves stimulate, organize, and
mobilize energy resources in threatening
situations, whereas parasympathetic nerves act
to conserve energy 2. Each autonomic target organ receives opposing
sympathetic and parasympathetic input, and its
activity is thus controlled by relative leves of
sympathetic and parasympathetic activity
3. Sympathetic changes are indicative of arousal,
whereas parasympathetic changes are indicative
o 12 pairs that project from the brain
o numbered in sequence from the front to back
o purely sensory nerves(olfactory, optic), longest cranial nerve(vagus)
is sensory and motor.
o Disruptions of particular cranial nerve functions provide excellent
clues about the location and extent of tumors and other kinds of brain
Meninges, Ventricles, and cerebrospinal fluid
o The 3 meninges protect the brain and spinal cord
Outer meninx: a tough membrane called the dura mater.
o Inside the dura mater is the arachnoid membrane(weblike)
Beneath the arachnid membrane is the subarachnoid
space(contains large blood vessels and CSfluid)
Innermost meninx, pia mater (adheres to the surface of
Cerebrospinal fluid also protects the brain and spinal cord, it fills the
subarachnoid space, the central canal of the spinal cord, and the cerebral
ventricles of the brain
o Central canal: small central channel that runs the length of the spinal
o Cerebral ventricles: 4 large internal chambers of the brain
2 Lateral ventricles, the 3 ventricle and the 4 ventricle.
o Subarachnoid space, central canal and cerebral ventricles are
interconnected by a series of openings and thus form a single
o Fluid supports and cushions the brain, those missing some fluid
experience headaches and severe pain.
o Produced by the choroid plexuses: networks of capillaries that
protrude into the ventricles from the pia mater
o Excess fluid absorbed by the dural sinuses, into the jugular veins.
o Hydrocephalus: a tumor near the cerebral aqueduct, creates a build
up of fluid in the venticles and causes the brain to expand
o this barrier is a consequence of the special structure of cerebral blood
vessels o cells of the blood vessel walls are tightly packed, thus forming a
barrier to the passage of many moleculesparticularly proteins and
other large molecules.
o The degree to which drugs affect the brain depends on how easily it
can penetrate the barrier.
Chapter 5: the research methods of biopsychology
Methods of visualizing and stimulating the living human brain
X-rays were used, but they’re relatively useless.
o X-ray beam passed through an object then onto a photographic plate.
X-ray is effective in characterizing internal structures that differ
substantially from their surroundings in the degree to which they
o Involve injecting into one compartment of the body a substance that
absorbs x-rays either less than or more than the surrounding tissue.
The injected substance heightens the contrast between the
compartment and the surrounding tissue during x-ray photography.
Cerebral angiography: uses the infusion of a radio-opaque dye
into a cerebral artery to visualize the cerebral circulatory
system during x-ray photography. Useful for locating vascular
damage, and the location of displaced vessels (could indicate a
X-ray computer tomography
o Computer assisted x-ray procedure that can be used to visualize the
brain and other internal structures of the living body. An x-ray tube
projects an x-ray beam through the head to an x-ray detector mounted
on the other side. The tube and detector rotate around the head of the
patient at one level of the brain, taking images as they rotate. The
information of each pic is combined to generate a CT scan of a
horizontal section. Scans of 8 or more levels are combined to create a
Magnetic Resonance imaging
o High-resolution images are constructed from the measurement of
waves that hydrogen atoms emit when they are activated by radio
frequency waves in a magnetic field. Provides high spatial resolution,
and images in 3D.
Positron Emission Tomography
o First to provide images of brain activity rather than structure.
o 2Deoxyglucose is injected into the carotid artery, bc its similar to
glucose, the 2deoxyglucose is rapidly taken up by active cells.
However, it cannot be metabolized SO the areas with glucose are the
areas being activated.
Functional MRI o Produces images representing the increase in oxygen flow in the
blood to active areas of the brain.
o Possible because active areas in the brain take up more oxygen than
they need for their energy requirements, thus oxygenated blood
accumulates in active areas in the brain. Second, oxygenated blood
has magnetic properties.
o BOLD signal: blood oxygen level dependent signal
o Advantages over PET
Nothing is injected
Provides structural AND functional info in one image
Better spatial resolution
Can take 3D images over the entire brain
o Measures changes in magnetic fields on the surface of the scalp tat are
produced by changes in underlying patterns of neural activity,
o Advantage over fMRI
Temporal resolutioncan record fast changes in neural
Trans-cranial Magnetic Stimulation
o Technique for affecting the activity in an area of the cortex by creating
a magnetic field under a coil positioned next to the skull
o Temporarily turns off part of the brain while the effects of the
disruption on cognition and behavior are assessed.
Chapter 6: The Visual System
Light Enters the Eye and Reaches the Retina
If there is no light, there is no vision.
o Animals cant actually see in the dark
Light behaves as particles and as waves
Light: waves of electromagnetic energy that are between 380 and 760
nanometers in length.
Wavelength: plays an important role in the perception of colour
Intensity: plays an important role in the perception of brightness
The pupil and the Lens
o The amount of light reaching the retinas is regulated by the donut
shaped bands of contractile tissue, the irises (eye colour)
o Light enters the eye through the pupil (hole in the iris). The
adjustment of the pupil size in response to changes in illumination
represents a compromise between sensitivity (ability to detect dimly
lit objects) and acuity (ability to see details)
o When the level of illumination is high, the pupils constrict
Image on the retina is sharper and there is a greater depth of
o When illumination is low, the pupils dilate to let in more light, thereby
sacrificing acuity and depth of focus o Behind each pupil is a lens (focuses incoming light on the retina)
When we look at something near, the tension on the ligaments
holding each lens in place is adjusted by the ciliary muscles and
the lens assumes its natural cylindrical shape.
The ability for the lens to refract (bend) light and thus brings
close objects into sharp focus.
When we look at something distant, the lens flattens. The
process of adjusting the configuration of the lenses to bring
images into focus on the retina is called accommodation
Eye position and binocular disparity
o Vertebrates have two eyes because vertebrates have two sides
By having an eye on each side, they can see in every direction
o Humans have eyes on the front so that what is in front can be viewed
through both eyes simultaneously
Important basis to create 3D perceptions
o Your eyes are coordinated so that each point in your visual world is
projected to corresponding points in your two retinas
Your eyes must converge(turn inward). Convergence happens
the most when your eyes are inspecting things that are close.