Structure and Function of the Brain Flashcards
1
Q
What is the brain?
A
Part of the CNS within the skull cavity
2
Q
What are the three main components of the brain?
A
- Forebrain (from prosencephalon)
- Midbrain (from mesencephalon)
- Hindbrain (from rhombencephalon)
3
Q
What does the forebrain form?
A
- cerebral hemispheres and deep structures
4
Q
What does the midbrain form?
A
Brainstem
5
Q
What does the hindbrain form?
A
- brainstem, pons, medulla and cerebellum
6
Q
Describe the inferior surface of the forebrain
A
ventral surface
7
Q
Describe the anterior surface of the forebrain
A
dorsal surface
8
Q
What is the ventral surface in the brainstem?
A
anterior surface
9
Q
What is the dorsal surface in the brainstem?
A
posterior surface
10
Q
Rostral =
A
- anything toward anterior pole of the forebrain
11
Q
Caudal =
A
- anything toward the inferior pole of the spinal cord
12
Q
Coronal section =
A
- cuts through the brain from superior to inferior
13
Q
Horizontal/axial section =
A
- cuts through the brain parallel to the ground
14
Q
Sagittal Section =
A
- cuts through the brain from anterior to posterior
15
Q
Midsagittal section =
A
separates the two hemispheres
16
Q
Gray matter =
A
- any collection of neuronal cell bodies
17
Q
Describe the gray mater in the brain
A
Found in cortical layer (cortex) on the surface of the forebrain and cerebellum. Large surface area due to grooves (sulci) and ridges (gyri) developing overtime. Can also be found in deep structures of the forebrain, the basal ganglia, and structures of the limbic system
18
Q
White matter =
A
consists of fibre tracts and is found deep to the cortical gray matter in the brain
19
Q
Nucleus =
A
a collection of nerve cell bodies within the CNS
20
Q
What is a collection of nerve cell bodies in the peripheral nervous system?
A
a ganglion
21
Q
How are white and gray matter arranged in the spinal cord?
A
- gray matter is located centrally and surrounded by white matter
22
Q
What is a tract/nerve?
A
a bundle of axons – mostly myelinated and appear white in colour
23
Q
What comprises the forebrain?
A
- Telencephalon and diencephalon
24
Q
Where is forebrain derived from?
A
- Derived from the most rostral parts of the developing neural tube
25
Telencephalon =
* massive cerebrum, which is divided into two cerebral hemispheres
26
What are the gray mater structures deep within the cerebrum?
* Basal ganglia
* Two major limbic system structures (hippocampus and amygdala)
* Underlying white matter
27
Diencephalon =
* thalamus, hypothalamus and subthalamus (all gray matter structures)
28
What are the four lobes of each cerebral hemisphere?
* frontal, parietal, occipital and temporal lobes
29
Ridges =
gyri (gyrus)
30
Grooves or fissures =
sulci (sulcus)
31
Where is the longitudnal fissure located?
* located along the midsagittal plane separates the two hemispheres
32
What does the lateral/sylvian fissure separate?
* separates the temporal lobe from the frontal and parietal lobes
33
What does the parietooccipital sulcus separate?
* is visible on the medial surface of the brain and separates the occipital lobe from the parietal
34
What is the largest lobe of the brain?
frontal lobe
35
What are the boundaries of the frontal lobe?
* Separated from the parietal lobe by the central sulcus and from the temporal lobe by the lateral fissure
36
What part of the brain contains the primary motor areas?
* Precentral gyrus, located anterior to the central sulcus, contains the primary motor areas
37
What are the areas on both the lateral and medial surfaces essenital for regulating in thr frontal lobe?
* surfaces are essential for regulating voluntary motor activity or behaviour and initiating motor behaviour (“deciding” which movements should be performed)
38
Where are expressive or motor aspects of language processsed?
* on the lateral surface of the frontal lobe (primarily dominant (typically left) hemisphere)
39
Association areas of frontal lobe =
prefrontal association areas. Concerned with functions such as emotion, motivation, personality, initiative, judgement, ability to concentrate, and social inhibitions
40
Cingulate gyrus =
* modulating emotional aspects of behaviour
41
What does the parietal lobe regulate?
* Regulates somatosensory, language and spatial orientation functions
42
How is the parietal lobe separated from the frontal, temporal and occipital lobes?
* Separated from the frontal lobe by the central sulcus, from the temporal lobe by the lateral fissure and from the occipital lobe by the parietooccipital sulcus
43
Where is the somatosensory area of the cortex?
* Postcentral gyrus is the primary somatosensory area of the cortex
44
What occurs on the lateral and medial aspects of the parietal lobe?
* Initial cortical processing and perception of touch, pain, and limb position occurs on both the lateral and medial aspects of the parietal lobe
45
Where are receptive or sensory aspects of language processed?
parietal lobe (dominant (left) hemisphere)
46
What mediates complex aspects of spatial orientation and perception, including self-perception and interaction with the world around us?
parietal lobe
47
What is the primary function of the occipital lobe?
processing visual information
48
Where is the visual processing centre located?
medial surface of the occipital lobe
49
How is the occiptal lobe separated from the parietal lobe?
* Separated from parietal lobe the parietooccipital sulcus
50
What does the occiptal lobe mediate?
* Mediates our ability to recognise and see objects
51
What is the main function of the temporal lobe?
* Important for processing auditory information, language, and certain complex functions
52
How is the temporal lobe separated from the frontal, parietal and occiptal lobes?
* Separated from the frontal and parietal lobes by the lateral fissure and the occipital lobe by a line that can be drawn as an extension as the parietooccipital sulcus
53
What occurs in the superior temporal gyrus?
* area where our ability to both hear and interpret what we hear is processed
54
What is the key area located on the lateral surface of the temporal lobe?
* functions for perception of language
55
What comprises the limbic lobe?
A ring of cortex on the medial surface, the cingulate and parahippocampal gyri
56
What is the function of the limbic lobe?
* This area of cortex overlies and is interconnected with structures in the limbic system and is important in processing complex aspects of learning, memory and emotion
57
What are the basal ganglia?
* Group of interconnected, interacting nuclei with the forebrain, diencephalon, and midbrain
58
What are the forebrain components of the basal ganglia and where do they lie?
* lie deep within the cerebral hemispheres and include the caudate and lenticular (putamen and globus pallidus) nuclei
59
What is the nucleus in the diencephalon?
subthalmic nucleus
60
what is the nucleus in the midbrain?
* substantia nigra
61
What is the critical function of the basal ganglia?
initiation and control of voluntary movements
62
What are the functions of the limbic structures of the forebrain?
* Consists of interconnected interacting structures that provide a neuroanatomical substrate for drive-related, motivated and emotional behaviours and play a role in learning and memory
63
What are the deep forebrain structures of the limbic system?
thalamus and amygdala (located in the temporal lobe)
64
What do association fibres interconnect?
interconnect various cortical regions within the same hemisphere
65
What do commissural fibres connect?
* reciprocally connect areas of cortex in one hemisphere with corresponding areas of cortex in the opposite hemisphere
66
What is the largest commissural fissure?
* corpus callosum – interconnects the two hemispheres
67
What is the largest set of projection fibres?
= corona radiata, which is bunded into the internal capsule as it passes through the cerebrum and contains all the fibres travelling between the cortex, the deep forebrain structures and the spinal cord
68
What is contained within the diencephalon?
* Several paired structures on either side of the third ventricle
69
What is the largest structure within the diencephalon and what is its function
* Largest structure = thalamus
* Two “egg-shaped” nuclear masses
* Critical processing station for all sensory information (except olfactory) on its way to the cortex and plays key roles in processing motor information, in integrating higher-order cognitive and emotional information, and regulating cortical activity
70
How does the structural and functional aspects of the hypothalamus differ?
* structurally part of diencephalon but functionally part of the limbic system
71
What is the function of the hypothalamus?
* Key roles in coordinating and integrating endocrine, autonomic and homeostatic functions
72
What is the role of the subthalamus?
* Important role in modulating and integrating voluntary movement and muscle tone
73
What is the function of the brainstem?
* provides the conduit through which all ascending and descending information between the brain and the spinal cord travels
74
What is the function of the cranial nerves?
* provide sensory and motor information to and from the head and mediate special senses à achieved through activity of reticular formation nuclei. Diffuse nuclei run primarily along the midline of the brainstem
75
What additional aspects are organised and intergrated in the brainstem?
* Aspects of cardiovascular and respiratory function, cortical arousal, and consciousness are organised and integrated in different areas of the brainstem
76
What do the midbrain and hindbrain comprise?
the brainstem
77
What is the most rostral area of the brainstem? And how is it characterised?
Midbrain
* Characterised by the large pair of cerebral peduncles on its anterior surface and two pairs of nuclei, superior and inferior colliculi, on its posterior surface
78
What do the descending corticospinal tracts mediate?
* voluntary motor activity travels through the cerebral peduncles
79
Superior colliculi =
in the rostral midbrain are involved in visual reflexes
80
Inferior colliculi =
* in the caudal midbrain, are a major integrating centre in the auditory pathway
81
What is the function of the Cerebral aqueduct
* connecting the third and fourth ventricles is found in the posterior area of the midbrain. Important internal structures of the midbrain include the red nucleus and the substantia nigra – roles in controlling motor activity
82
What does the pons consist of?
* consists of bundles of descending, longitudinal corticospinal fibres, and transverse pontocerebellar fibres. Carry information from the pontine nuclei to the opposite cerebellum through the middle cerebellar peduncles (arise off the lateral surface of the basal pons)
83
What is located on the posterior surface of the pons?
* Posterior surface consists of the fourth ventricle and rostrally the superior cerebellar peduncles – containing primary cerebellar efferents, which form most of the roof of the fourth ventricle
84
What is the function of olivary nuclei?
modualting motor activity
85
What is the caudal portion of the medulla characterised by?
* characterised by pyramids on its anterior surface and prominent sensory tracts, the **fasciculus gracilis** and **fasciculus cuneatus**, on its posterior surface. The pyramids cross, forming the **decussation of the pyramids**, in the caudal medulla. The fourth ventricle narrows to form the central canal of the spinal cord.
86
What is the central area of the cerebellum called?
vermis
87
How is the cerbellum attached to the brainstem?
* Attached to the brainstem by cerebellar peduncles – carry information to and from the cerebellum
88
What is the function of the cerebellum?
* Important role in processing sensory information and coordination of voluntary motor activity
89
What is the outgrowth of the pons and overlies the fourth ventricle?
the cerebellum
