Exam 2 (Ch. 5-7 & 9) Flashcards
Maturation of the Vertebrate Brain
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How the brain develops in infant.
What are the five stages in the development of neurons?
Proliferation, Migration, Differentiation, Myelination, and Synaptogenesis
What is proliferation?
Production of new cells/neurons in the brain that primarily occurs early in life.
(Cells tend to divide, but some will remain where they are or become neurons that migrate to other locations)
What is migration?
Movement of newly formed neurons and glia to their eventual locations (chemical trails)
What is differentiation?
Forming of the axon and dendrites that gives the neuron its distinctive shape
What is myelination?
Process by which glia produce the fatty sheath (myelin sheath) that covers the axons of some neurons.
(Myelin speeds up transmission of neural impulses. First occurs in spinal cord, then hindbrain, midbrain, and forebrain. Occurs gradually for decades)
What is synaptogenesis?
Final stage for formation of synapse between neurons
(Occurs throughout life, slows significantly later in lifetime, explains why babies sleep 12-16 hours a day)
The Brain and Experience
The brain doesn’t develop just because of genetics. The brain also develops because of a person’s experience, which is greatly responsible for the growth of brain.
What is the cornea?
Helps the eye to focus light in order to see clearly. Located in the front of the eye.
What is the lens of the eye?
Focuses light rays on the retina. Located in the front of the eye.
What is the pupil?
Controls how much light is let into the eye
What is the iris?
Colored area of eye & controls pupil
What are rods and cones?
Responds to color and bright light. Rods are most abundant in periphery of eye. Cones are most abundant in and around the fovea.
What is the blind spot of the eye?
It has no receptors. Located in the back of eye
What are bipolar cells in the eye?
The only neurons that connect the outer retina to the inner retina
What are ganglion cells of the eye?
They convey info from other retinal neurons to the rest of the brain
What is the optic nerve?
Consists of axons of ganglion cells that band together and exit through the back of the eye (at the blind spot) and travel to the brain
What is the fovea?
Central portion of the retina that allows for acute & detailed vision
How does the eye convert light to electrochemical signals?
First, light passes through the cornea.
Some of this light enters the eye through an opening called the pupil. The iris controls how much light the pupil lets in.
Next, light passes through the lens. The lens works together with the cornea to focus light correctly on the retina.
When light hits the retina, special cells called photoreceptors turn the light into electrical signals.
These electrical signals travel from the retina through the optic nerve to the brain. Then the brain turns the signals into the images you see.
What is color vision?
Visible light is a portion of the electromagnetic spectrum.
Perception of color is dependent upon the wavelength of light, so it is different for each person.
Red & yellow are the easiest colors to see, while blue & violet are the hardest.
What is color blindness? (Also known as color vision deficiency)
Impairment in perceiving color differences (colors not seen are typically red & green).
This happens when at least one cone doesn’t work.
It’s caused by genetics and typically found on the “X” chromosome, so it’s more common in males.
What is the pinna?
Structure of flesh and cartilage attached to each side of head that helps us locate source of sound. A part of the outer ear