chapter 3.6

Question 1

Myelencephalon (medulla)

Answer 1

most posterior division of the brain; composed largely of tracts carrying signals between the rest of the brain and the body.

Question 2

reticular formation (myelecephalon)

Answer 2

complex network of about 100 tiny nuclei that occupies the central core of the brain stem from the posterior boundary of the myelencephalon to the anterior boundary of the midbrain. Nuclei are involved in functions such as sleep, attention, movement, maintenance of muscle tone, and various cardiac, circulatory, and respiratory reflexes.

Question 3

Metencephalon

Answer 3

houses many ascending and descending tracts and part of the reticular formation.

Question 4

pons (metencephalon)

Answer 4

on the brain stem’s ventral surface; bulge created by the tracts.

Question 5

cerebellum (metencephalon)

Answer 5

large, convoluted structure on the brain stem’s dorsal surface; important sensorimotor structure. Cerebellar damage eliminates the ability to precisely control one’s movements and to adapt them to changing conditions. Also produces a variety of cognitive deficits, which suggests that the cerebellum is not restricted to sensorimotor control.

Question 6

Mesencephalon

Answer 6

midbrain

Question 7

tectum (Mesencephalon)

Answer 7

dorsal surface of the midbrain. In mammals, it is composed of two pairs of bumps called the colliculi. In lower vertebrates, the function of the tectum is entirely visual-motor and sometimes referred to as the optic tectum.

Question 8

inferior colliculi (tectum)

Answer 8

posterior pair; auditory function.

Question 9

superior colliculi (tectum)

Answer 9

anterior pair; visual-motor function, specifically to direct the body’s orientation toward or away from particular visual stimuli.

Question 10

tegmentum (Mesencephalon)

Answer 10

ventral to the tectum; contains three structures called the periaqueductal gray, the substantia nigra, and the red nucleus.

Question 11

periaqueductal gray (tegmentum)

Answer 11

gray matter situated around the cerebral aqueduct, which is the duct connecting the third and fourth ventricles. Of special interest because of its role in mediating the analgesic effects of opiate drugs.

Question 12

substantia nigra and red nucleus (tegmentum)

Answer 12

are important components of the sensorimotor system.

Question 13

thalamus (Diencephalon)

Answer 13

large, two-lobed structure that constitutes the top of the brain stem. One lobe sits on each side of the third ventricle, and the two lobes are joined by the massa intermedia, which runs through the ventricle. Visible on the surface are white lamina (layers) that are composed of myelinated axons. Most pairs of nuclei project to the cortex.

Question 14

sensory relay nuclei (thalamus)

Answer 14

nuclei that receive signals from sensory receptors, process them, and then transmit them to the appropriate areas of sensory cortex. Receive feedback signals from the areas they also project to.

Question 15

lateral geniculate nuclei (thalamus)

Answer 15

visual system.

Question 16

medial geniculate nuclei (thalamus)

Answer 16

auditory system

Question 17

ventral posterior nuclei (thalamus)

Answer 17

somatosensory system.

Question 18

hypothalamus (Diencephalon)

Answer 18

located below the anterior thalamus; plays a role in the regulation of motivated behaviors (eating, sleeping, and sexual behavior). Regulates the release of hormones from the pituitary gland.

Question 19

pituitary gland (hypothalamus)

Answer 19

hangs from the hypothalamus on the ventral surface of the brain.

Question 20

Optic chiasm (hypothalamus)

Answer 20

point at which the optic nerves from each eye come together. X shaped because some of the axons of the optic nerve decussate (cross over to the other side of the brain). These fibers are said to be contralateral (projecting from one side of the body to the other) and the nondecussating fibers are said to be ipsilateral (staying on the same side of the body).

Question 21

mammillary bodies (hypothalamus)

Answer 21

pair of spherical nuclei located on the inferior surface of the hypothalamus, behind the pituitary gland.

Question 22

Telencephalon

Answer 22

largest division; mediates the brain’s most complex function: initiates involuntary movement, interprets sensory input, and mediate complex cognitive processes such as learning, speaking, and problem solving.

Question 23

cerebral cortex (telencephalon)

Answer 23

layer of tissue that covers the cerebral hemispheres. Mainly composed of small, unmyelinated neurons and is often referred to as gray matter. Layer beneath the cortex is mainly composed of myelinated axons and referred to as white matter.

Question 24

fissures (telencephalon)

Answer 24

large furrows in a convoluted cortex.

Question 25

sulci (telencephalon)

Answer 25

small furrows in a convoluted cortex.

Question 26

gyri (telencephalon)

Answer 26

ridges between fissures and sulci.

Question 27

longitudinal fissure (telencephalon)

Answer 27

largest of the fissures and almost completely separates the cerebral hemispheres.

Question 28

cerebral commissures (telencephalon)

Answer 28

tracts spanning the longitudinal fissure that direct connect the cerebral hemispheres.

Question 29

corpus callosum (telencephalon)

Answer 29

largest cerebral commissure.

Question 30

central fissure and lateral fissure (telencephalon)

Answer 30

both fissures partially divide each hemisphere into four lobes: frontal lobe, parietal lobe, temporal lobe, and occipital lobe.

Question 31

precentral gyri (telencephalon)

Answer 31

found in frontal lobe.

Question 32

postcentral gyri (telencephalon)

Answer 32

found in parietal lobe.

Question 33

Superior temporal gyri (telencephalon)

Answer 33

found in temporal lobe.

Question 34

Occipital lobe (telencephalon)

Answer 34

rely on visual input to guide out behavior and the occipital cortex and large areas of adjacent cortex perform this function.

Question 35

Parietal lobe (telencephalon)

Answer 35

the postcentral gyrus analyzes sensations from the body (e.g. touch), whereas the remaining areas of the cortex in the posterior parts of the lobe play roles in perceiving the location of both objects and out own bodies and in directing out attention.

Question 36

Temporal lobe (telencephalon)

Answer 36

the superior temporal gyrus is involved in hearing and language; the inferior temporal cortex identifies complex visual patterns; and the medial portion of the temporal cortex is important for certain kinds of memory.

Question 37

Frontal lobe (telencephalon)

Answer 37

the precentral gyrus and adjacent frontal cortex have a motor function, whereas the frontal cortex anterior to motor cortex performs complex cognitive functions, such as planning response sequences, evaluating the outcomes of potential patterns of behavior, and assessing the significance of the behavior in others.

Question 38

neocortex (telencephalon)

Answer 38

90% of human cerebral cortex; six-layered cortex.

Question 39

(1) neocortex

Answer 39

neurons are into two categories:
Pyramidal cells – large multipolar neurons with pyramid-shaped cell bodies, a large dendrite called an apical dendrite that extends from the apex of the pyramid straight toward the cortex surface, and a very long axon.
Stellate cells – small star-shaped interneurons (short axon or no axon).

Question 40

(2) neocortex

Answer 40

The six layers differ from one another in terms of the size and density of their cell bodies and the relative proportion of pyramidal and stellate cell bodies that they contain.

Question 41

(3) neocortex

Answer 41

Many long axons and dendrites course vertically through the neocortex. The basis of its columnar organization: neurons in a given vertical column of neocortex often form a mini-circuit that performs a single function.

Question 42

(4) neocortex

Answer 42

Variation in the thickness of the respective layers from area to area.

Question 43

hippocampus (telencephalon)

Answer 43

three major layers; located on the medial edge of the cerebral cortex as it folds back on itself in the medical temporal lobe. Plays a major role in some kinds of memory, particularly memory for spatial location.

Question 44

limbic system (telencephalon)

Answer 44

circuit of midline structures that circle the thalamus. Involved in the regulation of motivated behaviors (fleeing, feeding, fighting, sexual behavior). Include the amygdala, fornix, cingulate cortex, septum, mammillary bodies, and the hippocampus.

Question 45

amygdala (limbic)

Answer 45

almond-shaped nucleus in the anterior temporal lobe. Involved in emotion.

Question 46

cingulate cortex (limbic)

Answer 46

large strip of cortex in the cingulate gyrus on the medicals surface of the cerebral hemispheres; encircles the dorsal thalamus.

Question 47

fornix (limbic)

Answer 47

major tract of the limbic system, also encircles the dorsal thalamus.

Question 48

septum (limbic)

Answer 48

midline nucleus located at the anterior tip of the cingulate cortex.

Question 49

basal ganglia (telencephalon)

Answer 49

includes the amygdala. Plays a role in the performance of voluntary motor responses. Pathway that projects to the striatum from the substantia nigra of the midbrain is associated with Parkinson’s disease when it deteriorates.

Question 50

Caudate (basal)

Answer 50

sweeping out of each amygdala; tail-like. Forms an almost complete circle; in its center, connected to it by a series of fiber bridges, is the putamen.

Question 51

Striatum (basal)

Answer 51

includes the caudate and the putamen.

Question 52

Globus pallidus (basal)

Answer 52

pale circular structure. Located medial to the putamen, between the putamen and the thalamus.

Question 53

Nucleus accumbens (basal)

Answer 53

medial portion of the ventral striatum. Thoughts to play a role in the reward effects of addictive drugs and other reinforcers.