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Bio 137 > Chapter 14 > Flashcards

Chapter 14 Flashcards

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Biology 101 flashcards
1
Q

The development of the nervous system begins with

A

a thickening of the ectoderm called the neural tube

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2
Q

The brain is protected by

A

Cranial bones
Cranial menenges
Cerebrospinal fluid
Pia mater
arachnoid mater
dura mater

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3
Q

Blood flows to the brain via

A

the vertebral and carotid arteries

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4
Q

Blood flows from the brain back to the heart via

A

the jugular veins

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5
Q

Any interuption in oxygen supply to the brain can result in

A

weakening, permanent damage, or death of brain cells

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6
Q

The blood brain barrier

A

protects the brain cells from harmful substances

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7
Q

what is the Neurolemma

A

The outer nucleated cytoplasmic layerof a schwann cell that completel surrounds the myelin sheath.

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8
Q

What does the neurolemma do

A

aids in the regrowth and regeneration of an axon

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9
Q

The brain contributes to homeostasis by

A

receiving sensory input, integrating new and stored information, making decisions, and executing responses through motor activities.

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10
Q

On average, each neuron forms _____ synapses with other neurons.

A

1000

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11
Q

The brain and spinal cord develop from

A

the ectodermal neural tube

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12
Q

primary brain vesicles:

A

prosencephalon, mesencephalon, and rhombencephalon

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13
Q

The prosencephalon (PROS-en-sef′-a-lon), or forebrain, gives rise to ,

A

the telencephalon and diencephalon

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14
Q

rhombencephalon (ROM-ben-sef′-a-lon), or hindbrain, develops into

A

the metencephalon and myelencephalon.

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15
Q

the metencephalon and myelencephalon the telencephalon and the diencephalon are the

A

secondary brain vesicles

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16
Q

The telencephalon (tel′-en-SEF-a-lon; tel- = distant; -encephalon = brain) develops into

A

the cerebrum and lateral ventricles.

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17
Q

The diencephalon (dī′-en-SEF-a-lon) forms

A

the thalamus, hypothalamus, epithalamus, and third ventricle.

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18
Q

The mesencephalon (mes′-en-SEF-a-lon; mes- = middle), or midbrain,

A

gives rise to the midbrain and aqueduct of the midbrain.

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19
Q

The metencephalon (met′-en-SEF-a-lon; met- = after) becomes

A

the pons, cerebellum, and upper part of the fourth ventricle.

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20
Q

The myelencephalon (mī-el-en-SEF-a-lon; myel- = marrow) forms

A

the medulla oblongata and lower part of the fourth ventricle.

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21
Q

The adult brain consists of four major parts:

A

brainstem, cerebellum, diencephalon, and cerebrum

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22
Q

The brainstem is continuous with the spinal cord and consists of

A

the medulla oblongata, pons, and midbrain

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23
Q

Posterior to the brainstem is the

A

cerebellum

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24
Q

Superior to the brainstem is the

A

diencephalon

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25
Q

the diencephalon (di- = through) consists of

A

the thalamus, hypothalamus, and epithalamus.

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26
Q

Supported on the diencephalon and brainstem is

A

the cerebrum (se-RĒ-brum = brain), the largest part of the brain.

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27
Q

The four principal parts of the brain are

A

the brainstem, cerebellum, diencephalon, and cerebrum.

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28
Q

The cranial meninges (me-NIN-jēz)

A

are continuous with the spinal meninges, have the same basic structure, and bear the same names: the outer dura mater (DOO-ra MĀ-ter), the middle arachnoid mater (a-RAK-noyd), and the inner pia mater (PĒ-a or PĪ-a) (Figure 14.2).

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29
Q

the cranial dura mater has two layers;

A

the spinal dura mater has only one. The two dural layers are called the periosteal layer (which is external) and the meningeal layer (which is internal).

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30
Q

there is no ___________around the brain.

A

epidural space

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31
Q

(1) The falx cerebri (FALKS ser-i-BRĒ; falx = sickle)

A

separates the two hemispheres (sides) of the cerebrum.

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32
Q

The falx cerebelli (ser′-e-BEL-ī)

A

separates the two hemispheres of the cerebellum.

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33
Q

The tentorium cerebelli (ten-TŌ-rē-um = tent)

A

separates the cerebrum from the cerebellum.

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34
Q

Cranial bones and cranial meninges

A

protect the brain.

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35
Q

Blood flows to the brain mainly via

A

the internal carotid and vertebral arteries

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36
Q

the dural venous sinuses drain into the internal jugular veins to

A

return blood from the head to the heart

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37
Q

the brain consumes

A

about 20% of the oxygen and glucose used by the body, even when you are resting.

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38
Q

Because virtually no glucose is stored in the brain,

A

the supply of glucose also must be continuous

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39
Q

If blood entering the brain has a low level of glucose,

A

mental confusion, dizziness, convulsions, and loss of consciousness may occur.

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40
Q

The blood–brain barrier (BBB) consists mainly of

A

tight junctions that seal together the endothelial cells of brain blood capillaries and a thick basement membrane that surrounds the capillaries.

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41
Q

The BBB

A

allows certain substances in blood to enter brain tissue and prevents passage to others. Lipid-soluble substances (including O2, CO2, steroid hormones, alcohol, barbiturates, nicotine, and caffeine) and water molecules easily cross the BBB by diffusing across the lipid bilayer of endothelial cell plasma membranes

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42
Q

A few water-soluble substances, such as glucose

A

, quickly cross the BBB by facilitated transport. Other water-soluble substances, such as most ions, are transported across the BBB very slowly.

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43
Q

proteins and most antibiotic drugs—

A

do not pass at all from the blood into brain tissue. Trauma, certain toxins, and inflammation can cause a breakdown of the BBB.

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44
Q

Cerebrospinal fluid (CSF)

A

is a clear, colorless liquid composed primarily of water that protects the brain and spinal cord from chemical and physical injuries. It also carries small amounts of oxygen, glucose, and other needed chemicals from the blood to neurons and neuroglia

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45
Q

CSF continuously circulates

A

through cavities in the brain and spinal cord and around the brain and spinal cord in the subarachnoid space

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46
Q

CSF contains

A

small amounts of glucose, proteins, lactic acid, urea, cations (Na+, K+, Ca2+, Mg2+), and anions (Cl− and HCO3−); it also contains some white blood cells.

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47
Q

ventricles

A

four CSF-filled cavities within the brain,

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48
Q

There is one lateral ventricle in

A

each hemisphere of the cerebrum.

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49
Q

Anteriorly, the lateral ventricles are separated by

A

a thin membrane, the septum pellucidum

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50
Q

The third ventricle is

A

a narrow, slitlike cavity along the midline superior to the hypothalamus and between the right and left halves of the thalamus.

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51
Q

The fourth ventricle lies

A

between the pons and medulla anteriorly and the cerebellum posteriorly.

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52
Q

The CSF has three basic functions in helping to maintain homeostasis.

A

Mechanical protection
Chemical protection
circulation

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53
Q

Describe the mechanical protection provided by CSF

A

CSF serves as a shock-absorbing medium that protects the delicate tissues of the brain and spinal cord from jolts that would otherwise cause them to hit the bony walls of the cranial cavity and vertebral canal. The fluid also buoys the brain so that it “floats” in the cranial cavity.

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54
Q

Describe the chemical protection provided by CSF

A

CSF provides an optimal chemical environment for accurate neuronal signaling. Even slight changes in the ionic composition of CSF within the brain can seriously disrupt production of action potentials and postsynaptic potentials.

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55
Q

describe how the circulation of CSF contributes to homeostasis

A

CSF is a medium for minor exchange of nutrients and waste products between the blood and adjacent nervous tissue.

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56
Q

Ventricles are

A

cavities within the brain that are filled with cerebrospinal fluid.

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57
Q

The majority of CSF production is from the

A

choroid plexuses

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58
Q

choroid plexuses

A

networks of blood capillaries in the walls of the ventricles

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59
Q

Selected substances (mostly water) from the blood plasma, which are filtered from the capillaries, are secreted by the ependymal cells to produce

A

the cerebrospinal fluid.

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60
Q

Ependymal cells joined by tight junctions

A

cover the capillaries of the choroid plexuses.

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61
Q

Because of the tight junctions between ependymal cells,

A

materials entering CSF from choroid capillaries cannot leak between these cells; instead, they must pass through the ependymal cells.

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62
Q

the blood–cerebrospinal fluid barrier

A

permits certain substances to enter the CSF but excludes others, protecting the brain and spinal cord from potentially harmful blood-borne substances.

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63
Q

The CSF formed in the choroid plexuses of each lateral ventricle flows into the third ventricle through two narrow, oval openings, the

A

interventricular foramina

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64
Q

After CSF enters the third ventricle

A

More CSF is added by the choroid plexus in the roof of the third ventricle. The fluid then flows through the aqueduct of the midbrain (cerebral aqueduct) (AK-we-dukt), which passes through the midbrain, into the fourth ventricle.

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65
Q

CSF enters the subarachnoid space through

A

three openings in the roof of the fourth ventricle: a single median aperture (AP-er-chur) and paired lateral apertures, one on each side.

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66
Q

After the CSF enters the sub arachnoid space

A

CSF then circulates in the central canal of the spinal cord and in the subarachnoid space around the surface of the brain and spinal cord.

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67
Q

Normally, CSF is reabsorbed as rapidly as it is formed by the choroid plexuses

A
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68
Q

Elevated CSF pressure causes a condition called

A

hydrocephalus

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69
Q

CSF is formed from blood plasma by

A

ependymal cells that cover the choroid plexuses of the ventricles.

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70
Q

The brainstem is the part of the brain between

A

the spinal cord and the diencephalon.

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71
Q

The brainstem consists of three structures:

A

(1) medulla oblongata, (2) pons, and (3) midbrain

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72
Q

medulla oblongata (me-DOOL-la ob′-long-GA-ta), or more simply the medulla,

A

is continuous with the superior part of the spinal cord; it forms the inferior part of the brainstem (Figure 14.5; see also Figure 14.1). The medulla begins at the foramen magnum and extends to the inferior border of the pons,

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73
Q

bulges on the anterior aspect of the medulla. These protrusions are called the

A

pyramids

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74
Q

The corticospinal tracts control

A

voluntary movements of the limbs and trunk

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75
Q

Just superior to the junction of the medulla with the spinal cord, 90% of the axons in the left pyramid cross to the right side, and 90% of the axons in the right pyramid cross to the left side. This crossing is called the

A

decussation of pyramids

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76
Q

the decussation of pyramids is why

A

each side of the brain controls voluntary movements on the opposite side of the body.

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77
Q

nuclei

A

a nucleus is a collection of neuronal cell bodies within the CNS.

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78
Q

The cardiovascular (cv) center

A

regulates the rate and force of the heartbeat and the diameter of blood vessels

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79
Q

medullary respiratory center adjusts

A

the basic rhythm of breathing

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80
Q

The vomiting center of the medulla causes

A

vomiting, the forcible expulsion of the contents of the upper digestive canal through the mouth

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81
Q

The deglutition center (dē-gloo-TISH-un) of the medulla promotes

A

deglutition (swallowing) of a mass of food that has moved from the oral cavity into the pharynx

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82
Q

Hiccupping is caused by

A

spasmodic contractions of the diaphragm

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83
Q

Just lateral to each pyramid is an oval-shaped swelling called an

A

olive

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84
Q

Within the olive is

A

the inferior olivary nucleus,

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85
Q

the inferior olivary nucleus,

A

receives input from the cerebral cortex, red nucleus of the midbrain, and spinal cord. Neurons of the inferior olivary nucleus extend their axons into the cerebellum, where they regulate the activity of cerebellar neurons. By influencing cerebellar neuron activity, the inferior olivary nucleus provides instructions that the cerebellum uses to make adjustments to muscle activity as you learn new motor skills.

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86
Q

Nuclei associated with sensations of touch, pressure, vibration, and conscious proprioception are located in the posterior part of the medulla. These nuclei are the

A

right and left gracile nucleus (GRAS-il = slender) and cuneate nucleus

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87
Q

The gustatory nucleus (GUS-ta-tō′-rē) of the medulla

A

is part of the gustatory pathway from the tongue to the brain; it receives gustatory input from the taste buds of the tongue

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88
Q

The cochlear nuclei (KOK-lē-ar) of the medulla are part of the

A

auditory pathway from the inner ear to the brain; they receive auditory input from the cochlea of the inner ear

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89
Q

The vestibular nuclei (ves-TIB-ū-lar) of the medulla and pons

A

are components of the equilibrium pathway from the inner ear to the brain; they receive sensory information associated with equilibrium from proprioceptors (receptors that provide information regarding body position and movements) in the vestibular apparatus of the inner ear

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90
Q

the medulla contains nuclei associated with the following five pairs of cranial nerves

A

vestibulocochlear
Glossopharyngeal
Vagus
Accessory XI nerves (cranial portion))
Hypoglossal

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91
Q

Injury to the medulla can be fatal examples of nonfatal medulla injuries include

A

Symptoms of nonfatal injury to the medulla may include cranial nerve malfunctions on the same side of the body as the injury, paralysis and loss of sensation on the opposite side of the body, and irregularities in breathing or heart rhythm.

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92
Q

The pons (= bridge) lies

A

directly superior to the medulla and anterior to the cerebellum

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93
Q

the pons is

A

a bridge that connects parts of the brain with one another

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94
Q

The pons has two major structural components:

A

a ventral region and a dorsal region

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95
Q

The ventral region of the pons

A

forms a large synaptic relay station consisting of scattered gray centers called the pontine nuclei

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96
Q

The dorsal region of the pons

A

contains ascending and descending tracts along with the nuclei of cranial nerves.

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97
Q

Also within the pons is the pontine respiratory group, shown in Figure 23.23. Together with the medullary respiratory center, the pontine respiratory group helps .

A

control breathing

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98
Q

The pons contains nuclei associated with four pairs of cranial nerves.

A

Trigeminal
abducens
facial
vestibulocochlear

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99
Q

The midbrain or mesencephalon extends from

A

the pons to the diencephalon

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100
Q

The aqueduct of the midbrain passes through

A

the midbrain, connecting the third ventricle above with the fourth ventricle below

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101
Q

The anterior part of the midbrain contains paired bundles of axons known as

A

the cerebral peduncles

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102
Q

The posterior part of the midbrain,

A

is called the tectum

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103
Q

the tectum contains four rounded elevations called

A

superior and inferior colloculi

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104
Q

the superior colliculi

A

serve as reflex centers for certain visual activities

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105
Q

the inferior colliculi, are

A

part of the auditory pathway, relaying impulses from the receptors for hearing in the inner ear to the brain. These two nuclei are also reflex centers for the startle reflex, sudden movements of the head, eyes, and trunk that occur when you are surprised by a loud noise such as a gunshot.

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106
Q

The midbrain contains several other nuclei, including the

A

left and right substantia nigra

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107
Q

Neurons that release dopamine, extending from the substantia nigra to the corpus striatum,

A

help control subconscious muscle activities. Loss of these neurons is associated with Parkinson’s disease

108
Q

The midbrain also contains the red nuclei

A

Axons from the cerebellum and cerebral cortex form synapses in the red nuclei which help control muscular movements.

109
Q

other nuclei in the midbrain are associated with two pairs of cranial nerves

A

Oculomotor
Trochlear

110
Q

The broad region where white matter and gray matter exhibit a netlike arrangement is known as the

A

reticular formation

111
Q

The reticular formation

A

extends from the superior part of the spinal cord, throughout the brainstem, and into the inferior part of the diencephalon

112
Q

The ascending portion of the reticular formation is called

A

the reticular activating system (RAS), which consists of sensory axons that project to the cerebral cortex, both directly and through the thalamus.

113
Q

Perhaps the most important function of the RAS is

A

consciousness, a state of wakefulness in which an individual is fully alert, aware, and oriented.

114
Q

The RAS is also active during

A

arousal, or awakening from sleep. Another function of the RAS is to help maintain attention (concentrating on a single object or thought) and alertness. The RAS also prevents sensory overload (excessive visual and/or auditory stimulation) by filtering out insignificant information so that it does not reach consciousness

115
Q

Inactivation of the RAS produces

A

sleep, a state of partial consciousness from which an individual can be aroused.

116
Q

Damage to the RAS, on the other hand, results in

A

coma, a state of unconsciousness from which an individual cannot be aroused.

117
Q

The descending portion of the RAS has connections to the cerebellum and spinal cord and

A

helps regulate muscle tone, the slight degree of involuntary contraction in normal resting skeletal muscles. This portion of the RAS also assists in the regulation of heart rate, blood pressure, and respiratory rate.

118
Q

Even though the RAS receives input from the eyes, ears, and other sensory receptors,

A

there is no input from receptors for the sense of smell; even strong odors may fail to cause arousal.

119
Q

describe the cerebellum

A

The cerebellum, second only to the cerebrum in size, occupies the inferior and posterior aspects of the cranial cavity. Like the cerebrum, the cerebellum has a highly folded surface that greatly increases the surface area of its outer gray matter cortex, allowing for a greater number of neurons.

120
Q

A deep groove known as the transverse cerebral fissure, along with the tentorium cerebelli

A

separates the cerebellum from the cerebrum

121
Q

on the cerebellum

A

The central constricted area is the vermis (= worm), and the lateral “wings” or lobes are the cerebellar hemispheres

122
Q

describe the function of the lobes of the cerebellum

A

The anterior lobe and posterior lobe govern subconscious aspects of skeletal muscle movements. The flocculonodular lobe (flok-ū-lō-NOD-ū-lar; flocculo- = wool-like tuft) on the inferior surface contributes to equilibrium and balance.

123
Q

The superficial layer of the cerebellum,

A

is called the cerebellar cortex, consists of gray matter in a series of slender, parallel ridges called folia

124
Q

Deep to the gray matter of the cerebellum are

A

tracts of white matter called arbor vitae (AR-bor VĪ-tē = tree of life) that resemble branches of a tree.

125
Q

the cerebellar nuclei,

A

are regions of gray matter that give rise to axons carrying impulses from the cerebellum to other brain centers.

126
Q

Three paired cerebellar peduncles

A

attach the cerebellum to the brainstem

127
Q

The superior cerebellar peduncles

A

contain axons that extend from the cerebellum to the red nuclei of the midbrain and to several nuclei of the thalamus

128
Q

The middle cerebellar peduncles

A

are the largest peduncles; their axons carry impulses for voluntary movements from the pontine nuclei (which receive input from motor areas of the cerebral cortex) into the cerebellum.

129
Q

The inferior cerebellar peduncles consist of

A

(1) axons of the spinocerebellar tracts that carry sensory information into the cerebellum from proprioceptors in the trunk and limbs; (2) axons from the vestibular apparatus of the inner ear and from the vestibular nuclei of the medulla and pons that carry sensory information into the cerebellum from proprioceptors in the head; (3) axons from the inferior olivary nucleus of the medulla that enter the cerebellum and regulate the activity of cerebellar neurons; (4) axons that extend from the cerebellum to the vestibular nuclei of the medulla and pons; and (5) axons that extend from the cerebellum to the reticular formation.

130
Q

The primary function of the cerebellum is to

A

evaluate how well movements initiated by motor areas in the cerebrum are actually being carried out.

131
Q

Aside from this coordination of skilled movements, the cerebellum

A

is the main brain region that regulates posture and balance.

132
Q

Damage to the cerebellum can result in an inability to coordinate muscular movements, a condition called

A

ataxia

133
Q

describe the location of the diencephalon

A

It is almost completely surrounded by the cerebral hemispheres and contains numerous nuclei involved in a wide variety of sensory and motor processing between higher and lower brain centers. The diencephalon extends from the brainstem to the cerebrum and surrounds the third ventricle; it includes the thalamus, hypothalamus, and epithalamus. Projecting from the hypothalamus is the hypophysis, or pituitary gland.

134
Q

The thalumus

A

consists of paired oval masses of gray matter organized into nuclei with interspersed tracts of white matte

135
Q

what structure joins the right and left halves of the thalamus in about 70% of human brains.

A

A bridge of gray matter called the interthalamic adhesion (intermediate mass)

136
Q

what divides the gray matter of the right and left sides of the thalamus (Figure 14.9c).

A

A vertical Y-shaped sheet of white matter called the internal medullary lamina It consists of myelinated axons that enter and leave the various thalamic nuclei.

137
Q

the internal capsule,

A

a thick band of white matter lateral to the thalamus

138
Q

The thalamus is

A

the principal relay station for sensory impulses that reach the cerebral cortex from other parts of the brain and the spinal cord.

139
Q

the thalamus contributes to motor functions by

A

transmitting information from the cerebellum and corpus striatum to the primary motor cortex of the cerebrum

140
Q

there are seven major groups of nuclei on each side of the thalamus

A

The anterior nucleus
the medial nuclei
the lateral group
the ventral group
the intralaminar nuclei
The preventricular nucleus
the reticular nucleus of the prethalamus

141
Q

The anterior nucleus

A

receives input from the hypothalamus and sends output to the limbic system (described in Section 14.6). It functions in emotions and memory.

142
Q

The medial nuclei of the thalamus

A

receive input from the limbic system and basal nuclei and send output to the cerebral cortex. They function in emotions, learning, memory, and cognition (thinking and knowing).

143
Q

Nuclei in the lateral group

A

receive input from the limbic system, superior colliculi, and cerebral cortex and send output to the cerebral cortex. The lateral dorsal nucleus functions in the expression of emotions. The lateral posterior nucleus and pulvinar nucleus help integrate sensory information.

144
Q

The ventral anterior nucleus of the thalumus

A

receives input from the basal nuclei and sends output to motor cortex of the cerebrum; it plays a role in movement control

145
Q

The ventral lateral nucleus of the thalamus

A

receives input from the cerebellum and corpus striatum and sends output to motor areas of the cerebral cortex; it also plays a role in movement control

146
Q

The ventral posterior nucleus of the thalamus

A

relays impulses for somatic sensations such as touch, pressure, vibration, itch, tickle, temperature, pain, and proprioception from the face and body to the cerebral cortex

147
Q

The lateral geniculate nucleus (je-NIK-ū-lat = bent like a knee)

A

relays visual impulses for sight from the retina to the primary visual cortex of the cerebrum.

148
Q

The medial geniculate nucleus

A

relays auditory impulses for hearing from the ear to the primary auditory cortex of the cerebrum

149
Q

Intralaminar nuclei of the thalamus (in′-tra-LA-mi′-nar)

A

lie within the internal medullary lamina and make connections with the reticular formation, cerebellum, corpus striatum, and wide areas of the cerebral cortex. They function in arousal (activation of the cerebral cortex from the brainstem reticular formation) and integration of sensory and motor information.

150
Q

The periventricular nucleus of the thalamus

A

forms a thin band adjacent to the third ventricle and has a presumed function in memory and olfaction.

151
Q

The reticular nucleus of the prethalamus

A

surrounds the lateral aspect of the thalamus, next to the internal capsule. This nucleus monitors, filters, and integrates activities of other thalamic nuclei

152
Q

The hypothalamus (hī′-pō-THAL-a-mus; hypo- = under)

A

is a small part of the diencephalon located inferior to the thalamus. It is composed of a dozen or so nuclei in four major regions

153
Q

The four major regios of the hypothalamus are

A

the posterior hypothalamic area (mamillary)
the intermediate hypothalamic area
the anterior hypothalamic area
the preoptic area

154
Q

The mammillary nuclei form two small, rounded projections,

A

the mammillary bodies, that serve as relay stations for reflexes related to the sense of smell.

155
Q

the infundibular stalk (in-fun-DIB-ū-lar = funnel),

A

connects the pituitary gland to the hypothalamus

156
Q

The median eminence of the hypothalamus

A

is a slightly raised region that encircles the infundibular stalk

157
Q

Axons from the paraventricular and supraoptic nuclei form the hypothalamohypophyseal tract (hī′-pō-thal′-a-mō-hī-pō-FIZ-ī-al), which

A

extends through the infundibular stalk to the posterior lobe of the pituitary

158
Q

The preoptic area anterior to the supraoptic region is usually considered part of the

A

hypothalamus because it participates with the hypothalamus in regulating certain autonomic activities. The preoptic area contains the medial and lateral preoptic nuclei

159
Q

the hypothalamus

A

controls many body activities and is one of the major regulators of homeostasis

160
Q

Important functions of the hypothalamus include the following

A

control of the ANS
Production of hormones
regulation of emotional and behavioral patterns
regulation of eating and drinking
control of body temperatureregulation of circadian rythms

161
Q

The hypothalamus releases what two hormones into the posterior lobe of the pituitary

A

oxytocin or antidiuretic hormone

162
Q

hypothalamic hormones released into the anterior lobe of the pituitary

A

releasing hormones and inhibiting hormones

163
Q

Three centers within the hypothalamus that regulate eating and drinking

A

feeding center (promotes eating)
satiety center (Causes a sensation of fullness)
thirst center

164
Q

The suprachiasmatic nucleus (SCN) of the hypothalamus

A

serves as the body’s internal biological clock because it establishes circadian (daily) rhythms (ser-KĀ-dē-an), patterns of biological activity (such as the sleep–wake cycle) that occur on a circadian schedule (cycle of about 24 hours).

165
Q

The mechanism responsible for the internal clock in an SCN neuron is

A

the rhythmic turning on and off of clock genes in the cell’s nucleus, resulting in alternating levels of clock proteins in the cell’s cytosol.

166
Q

The epithalamus (ep′-i-THAL-a-mus; epi- = above),

A

a small region superior and posterior to the thalamus, consists of the pineal gland and habenular nuclei.

167
Q

The pineal gland (PĪN-ē-al = pineconelike)

A

is about the size of a small pea and protrudes from the posterior midline of the third ventricle (see Figure 14.1). The pineal gland is part of the endocrine system because it secretes the hormone melatonin.

168
Q

The habenular nuclei (ha-BEN-ū-lar), shown in Figure 14.7a, are involved in

A

olfaction, especially emotional responses to odors such as a loved one’s cologne or Mom’s chocolate chip cookies baking in the oven.

169
Q

Parts of the diencephalon, are called circumventricular organs (CVOs) (ser′-kum-ven-TRIK-ū-lar)

A

because they lie around the third ventricle.

170
Q

circumventricular organs

A

can monitor chemical changes in the blood because they lack a blood–brain barrier. CVOs include part of the hypothalamus, the pineal gland, the pituitary gland, and a few other nearby structures. Functionally, these regions coordinate homeostatic activities of the endocrine and nervous systems,

171
Q

The cerebrum is the “seat of intelligence.” It provides us with the ability to

A

read, write, and speak; to make calculations and compose music; and to remember the past, plan for the future, and imagine things that have never existed before.

172
Q

The cerebrum consists of

A

an outer cerebral cortex, an internal region of cerebral white matter, and gray matter nuclei deep within the white matter.

173
Q

the cortical region of the cerebrum rolls and folds on itself forming a series of elevated ridges and depressions called

A

grooves

174
Q

the ridges of the cortical region are called

A

cerebral gyri

175
Q

three types of grooves of the cerebral cortex

A
  1. cerebral sulci
  2. interlobar sulci
  3. Cerebral fissures
176
Q

Cerebral sulci (SUL-sī; singular is cerebral sulcus)

A

are grooves that separate neighboring cerebral gyri.

177
Q

Interlobar sulci are

A

grooves that separate the various lobes of the cerebrum.

178
Q

Cerebral fissures are

A

grooves that separate parts of the brain.

179
Q

The most prominent cerebral fissure, the longitudinal cerebral fissure,

A

separates the cerebrum into right and left halves called cerebral hemispheres.

180
Q

Within the longitudinal cerebral fissure between the cerebral hemispheres is the

A

falx cerebri

181
Q

The cerebral hemispheres are connected internally by

A

the corpus callosum (kal-LŌ-sum; corpus = body; callosum = hard), a broad band of white matter containing axons that extend between the cerebral hemispheres at the floor of the longitudinal cerebral fissure

182
Q

The lobes of the cerebrum are named after

A

the bones that cover them: frontal, parietal, temporal, and occipital lobes

183
Q

The central sulcus (SUL-kus) separates

A

the frontal lobe from the parietal lobe.

184
Q

A major gyrus, the precentral cerebral gyrus—located immediately anterior to the central sulcus—

A

contains the primary motor cortex of the cerebrum.

185
Q

the postcentral gyrus

A

contains the primary somatosensory cortex of the cerebrum.

186
Q

The lateral cerebral sulcus separates

A

the frontal lobe from the temporal lobe.

187
Q

The parieto-occipital sulcus separates

A

the parietal lobe from the occipital lobe.

188
Q

the insula,

A

cannot be seen at the surface of the brain because it lies within the lateral cerebral sulcus, deep to the parietal, frontal, and temporal lobes

189
Q

The cerebral white matter consists primarily of myelinated axons in three types of tracts

A
  1. Association tracts
    2 Commissural tracts
  2. Projection tracts
190
Q

Association tracts contain

A

axons that conduct nerve impulses between cerebral gyri in the same hemisphere

191
Q

Commissural tracts (kom′-i-SYUR-al) contain

A

axons that conduct nerve impulses from cerebral gyri in one cerebral hemisphere to corresponding cerebral gyri in the other cerebral hemisphere.

192
Q

Three important groups of commissural tracts are

A

the corpus callosum (the largest fiber bundle in the brain, containing about 300 million fibers), anterior commissure, and posterior commissure.

193
Q

Projection tracts contain

A

axons that conduct nerve impulses from the cerebrum to lower parts of the CNS (thalamus, brainstem, or spinal cord) or from lower parts of the CNS to the cerebrum. An example is the internal capsule, a thick band of white matter that contains both ascending and descending axons

194
Q

Deep within each cerebral hemisphere are nuclei (masses of gray matter) that are collectively termed the corpus striatum (strī-Ā-tum) or basal nuclei

A

Two of the nuclei of the corpus striatum lie side by side, just lateral to the thalamus. They are the globus pallidus (GLŌ-bus PAL-i-dus; globus = ball; pallidus = pale), which is closer to the thalamus, and the putamen (pū-TĀ-men = shell), which is closer to the cerebral cortex

195
Q

Together, the globus pallidus and putamen are referred to as the

A

lentiform nucleus

196
Q

The third nucleus of the corpus striatum is

A

the caudate nucleus (KAW-dāt; caud- = tail), which has a large “head” connected to a smaller “tail” by a long, comma-shaped “body.”

197
Q

The corpus striatum

A

helps initiate and terminate movements, suppresses unwanted movements, and regulates muscle tone.

198
Q

The claustrum (KLAWS-trum)

A

is a thin sheet of gray matter situated lateral to the putamen. It is considered by some to be a subdivision of the corpus striatum. The function of the claustrum in humans has not been clearly defined, but it may be involved in visual attention.

199
Q

The corpus striatum receives input from the

A

cerebral cortex and provides output to motor parts of the cortex via the medial and ventral group nuclei of the thalamus.

200
Q

Other roles of the nuclei of the corpus striatum include

A

They help initiate and terminate some cognitive processes, attention, memory, and planning, and may act with the limbic system to regulate emotional behaviors.

201
Q

Encircling the upper part of the brainstem and the corpus callosum is a ring of structures on the inner border of the cerebrum and floor of the diencephalon that constitutes

A

the limbic system

202
Q

The limbic lobe is

A

a rim of cerebral cortex on the medial surface of each hemisphere.

203
Q

the limbic lobe includes

A

the cingulate gyrus (SIN-gyu-lat; cingul- = belt), which lies above the corpus callosum, and the parahippocampal gyrus (par′-a-hip-ō-KAM-pal), which is in the temporal lobe below. The hippocampus (hip′-ō-KAM-pus = seahorse) is a portion of the parahippocampal gyrus that extends into the floor of the lateral ventricle.

204
Q

the dentate gyrus is a component of the limbic systemthat

A

lies between the hippocampus and parahippocampal gyrus.

205
Q

The amygdala (a-MIG-da-la; amygda- = almond-shaped) is part of the limbic system that is composed of several groups of neurons located close to the tail of the caudate nucleus.

A
206
Q

The septal nuclei is part of the limbic system

A

located within the septal area formed by the regions under the corpus callosum and the paraterminal gyrus (a cerebral gyrus).

207
Q

The mammillary bodies of the hypothalamus

A

are two round masses close to the midline near the cerebral peduncles. they are components of the limbic system

208
Q

Two nuclei of the thalamus, the anterior nucleus and the medial nucleus, participate in

A

limbic circuits

209
Q

The olfactory bulbs

A

are flattened bodies of the olfactory pathway that rest on the cribriform plate. they are components of the limbic system

210
Q

The fornix, stria terminalis, stria medullaris, medial forebrain bundle, and mammillothalamic tract (mam-i-lō-tha-LAM-ik)

A

are linked by bundles of interconnecting myelinated axons. They are all a part of the limbic system

211
Q

The limbic system governs

A

emotional aspects of behavior.

212
Q

The limbic system is also involved in

A

olfaction and memory

213
Q

One portion of the limbic system, the hippocampus, is seemingly unique among structures of the central nervous system—

A

it has cells reported to be capable of division.

214
Q

Specific types of sensory, motor, and integrative signals are processed in

A

certain regions of the cerebral cortex

215
Q

sensory areas

A

receive sensory information and are involved in perception, the conscious awareness of a sensation;

216
Q

motor areas control

A

the execution of voluntary movements

217
Q

association areas deal with

A

more complex integrative functions such as memory, emotions, reasoning, will, judgment, personality traits, and intelligence.

218
Q

Sensory association areas

A

integrate sensory experiences to generate meaningful patterns of recognition and awareness.

219
Q

a person with damage in the ___________ visual cortex would be blind in at least part of his visual field, but a person with damage to a visual ____________ area might see normally yet be unable to recognize ordinary objects such as a lamp or a toothbrush just by looking at them.

A

Primary
association

220
Q

Important sensory areas of the cerebral cortex

A

primary somatosensory cortex
primary visual cortex
primary auditory cortex
gustatory cortex
olfactory cortex

221
Q

The distorted somatic sensory map of the body within the somatosensory cortex is known as the

A

sensory homunculus

222
Q

The primary somatosensory cortex allows you to

A

pinpoint where somatic sensations originate, so that you know exactly where on your body a stimulus is coming from

223
Q

The primary visual cortex,

A

located at the posterior tip of the occipital lobe mainly on the medial surface (next to the longitudinal cerebral fissure), receives visual information and is involved in visual perception.

224
Q

The primary auditory cortex,

A

located in the superior part of the temporal lobe near the lateral cerebral sulcus, receives information for sound and is involved in auditory perception.

225
Q

The primary somatosensory cortex is located

A

directly posterior to the central cerebral sulcus of each cerebral hemisphere in the postcentral gyrus of each parietal lobe. It extends from the lateral cerebral sulcus, along the lateral surface of the parietal lobe to the longitudinal cerebral fissure, and then along the medial surface of the parietal lobe within the longitudinal cerebral fissure.

226
Q

The gustatory cortex,

A

located in the insula, receives impulses for taste and is involved in gustatory perception and taste discrimination.

227
Q

The olfactory cortex,

A

located in the temporal lobe on the medial aspect, receives impulses for smell and is involved in olfactory perception.

228
Q

Particular areas of the cerebral cortex

A

process sensory, motor, and integrative signals.

229
Q

Motor output from the cerebral cortex flows mainly from

A

the anterior part of each hemisphere

230
Q

The four motor areas of the cerebral cortex

A

The primary motor cortex
The premotor cortex
Brocas area
The frontal eye field

231
Q

Electrical stimulation of any point in the primary motor cortex causes

A

contraction of specific skeletal muscle fibers on the opposite side of the body.

232
Q

The primary motor cortex is located

A

in the precentral gyrus of the frontal lobe

233
Q

The distorted muscle map of the body within the primary motor cortex

A

is called the motor homunculus.

234
Q

The premotor cortex is located

A

immediately anterior to the primary motor cortex.

235
Q

The premotor cortex

A

sends impulses to the primary motor cortex that plan movements that cause specific groups of muscles to contract simultaneously or sequentially.

236
Q

Broca’s area (BRŌ-kaz) is located

A

in the frontal lobe close to the lateral cerebral sulcus

237
Q

From Broca’s area,

A

nerve impulses pass to the premotor regions that control the muscles of the larynx, pharynx, and mouth. The impulses from the premotor cortex result in specific, coordinated muscle contractions. Simultaneously, impulses propagate from Broca’s area to the primary motor cortex. From here, impulses also control the breathing muscles to regulate the proper flow of air past the vocal cords. The coordinated contractions of your speech and breathing muscles enable you to speak your thoughts.

238
Q

The frontal eye field is located

A

partially in and anterior to the premotor cortex and superior to Broca’s area.

239
Q

Association areas of the cerebral cortex include

A

somatosensory association area
visual association area
Facial recognition area
auditory association area
orbitofrontal cortex
Wernickes area
common integrative area
the prefrontal cortex

240
Q

The somatosensory association area is located

A

just posterior to and receives input from the primary somatosensory cortex as well as from the thalamus and other parts of the brain

241
Q

The somatosensory association area

A

permits you to determine the exact shape and texture of an object by feeling it, to determine the orientation of one object with respect to another as they are felt, and to sense the relationship of one body part to another. Another role of the somatosensory association area is the storage of memories of past somatic sensory experiences, enabling you to compare current sensations with previous experiences.

242
Q

The visual association area, is located

A

in the occipital lobe

243
Q

the visual association area

A

receives sensory impulses from the primary visual cortex and the thalamus. It relates present and past visual experiences and is essential for recognizing and evaluating what is seen.

244
Q

The facial recognition area, is located

A

in the inferior temporal lobe,

245
Q

the facial recognition area

A

receives nerve impulses from the visual association area. This area stores information about faces, and it allows you to recognize people by their faces.

246
Q

The auditory association area,

A

is located inferior and posterior to the primary auditory cortex in the temporal lobe, allows you to recognize a particular sound as speech, music, or noise.

247
Q

The orbitofrontal cortex,

A

is located along the lateral part of the frontal lobe, receives sensory impulses from the olfactory cortex. This area allows you to identify odors and to discriminate among different odors. During olfactory processing, the orbitofrontal cortex of the right hemisphere exhibits greater activity than the corresponding region in the left hemisphere.

248
Q

Wernicke’s area (VER-ni-kēz) (posterior language area),

A

a broad region located in the left temporal and parietal lobes, interprets the meaning of speech by recognizing spoken words.

249
Q

The regions in the right hemisphere that correspond to Broca’s and Wernicke’s areas in the left hemisphere also contribute

A

to verbal communication by adding emotional content, such as anger or joy, to spoken words.

250
Q

The common integrative area

A

is bordered by somatosensory, visual, and auditory association areas. It receives nerve impulses from these areas and from the gustatory cortex, the olfactory cortex, the thalamus, and parts of the brainstem. This area integrates sensory interpretations from the association areas and impulses from other areas, allowing the formation of thoughts based on a variety of sensory inputs. It then transmits signals to other parts of the brain for the appropriate response to the sensory signals it has interpreted

251
Q

The prefrontal cortex is

A

an extensive area in the anterior portion of the frontal lobe that is well developed in primates, especially humans.

252
Q

The prefrontal cortex is concerned with

A

the makeup of a person’s personality, intellect, complex learning abilities, recall of information, initiative, judgment, foresight, reasoning, conscience, intuition, mood, planning for the future, and development of abstract ideas.

253
Q

although the two hemispheres share performance of many functions, each hemisphere also specializes in performing certain unique functions. This functional asymmetry is termed

A

hemispheric lateralization.

254
Q

At any instant, brain neurons are generating millions of nerve impulses. Taken together, these electrical signals are called

A

brain waves.

255
Q

electroencephalogram EEG

A

a record of a patients brain waves that is gathered by placing electrodes on the scalp

256
Q

Four types of brain waves

A

Alpha Waves
Beta Waves
Theta Waves
Delta Waves

257
Q

Alpha waves.

A

These rhythmic waves occur at a frequency of about 8–13 cycles per second. (The unit commonly used to express frequency is the hertz [Hz]. One hertz is one cycle per second.) Alpha waves are present in the EEGs of nearly all normal individuals when they are awake and resting with their eyes closed. These waves disappear entirely during sleep.

258
Q

Beta waves.

A

The frequency of these waves is between 14 and 30 Hz. Beta waves generally appear when the nervous system is active—that is, during periods of sensory input and mental activity.

259
Q

Theta waves. .

A

Theta waves (THĀ-ta) have frequencies of 4–7 Hz. These waves normally occur in children and adults experiencing emotional stress

260
Q

Delta waves.

A

The frequency of these waves is 1–5 Hz. Delta waves occur during deep sleep in adults, but they are normal in awake infants. When produced by an awake adult, they indicate brain damage.

261
Q

A concussion (kon-KUSH-un) is

A

an injury characterized by an abrupt, but temporary, loss of consciousness (from seconds to hours), disturbances of vision, and problems with equilibrium.

262
Q

chronic traumatic encephalopathy (CTE).

A

It is a progressive, degenerative brain disorder caused by concussions and other repeated head injuries and occurs primarily among athletes who participate in contact sports such as football, ice hockey, and boxing as well as combat veterans and individuals with a history of repetitive brain trauma

263
Q

The signs and symptoms of TBI

A

range from mild to moderate to severe, depending on the extent of brain damage. A person with mild TBI may remain conscious or lose consciousness. Among other signs and symptoms of mild TBI are headache, slurred speech, confusion, lightheadedness, dizziness, blurred vision, tinnitus, fatigue, sleep disturbances, memory loss, behavioral or mood changes, and difficulty with memory, concentration, attention, and thinking.

264
Q

A brain contusion (kon-TOO-zhun) is

A

bruising due to trauma and includes the leakage of blood from microscopic vessels. It is usually associated with a concussion. In a contusion, the pia mater may be torn, allowing blood to enter the subarachnoid space.

265
Q

A laceration (las-er-Ā-shun) is

A

a tear of the brain, usually from a skull fracture or a gunshot wound. A laceration results in rupture of large blood vessels, with bleeding into the brain and subarachnoid space. Consequences include cerebral hematoma (localized pool of blood, usually clotted, that swells against the brain tissue), edema, and increased intracranial pressure.

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