Module 1 - Introduction to the Central Nervous System Flashcards
What are the 3 primary germ layers in the early embryo?
- ectoderm (develops into neural structures and the epidermis) 2. mesoderm (develops into skin, bone and muscles) 3. endoderm (develops into internal organs)
What kind of brain cut is this?
Coronal
What kind of brain cut is this?
Horizontal
What kind of brain cut is this?
Sagittal
What is the longitudinal fissure?
Located along the midsagittal plane, it separates the two hemispheres
What is the largest lobe?
The frontal lobe
What separates the frontal lobe from the parietal lobe?
The central sulcus
Where is the precentral gyrus? What is it’s function?
In front of (anterior to) the central sulcus, and contains the primary motor areas
Describe the prefrontal association areas
They are concerned with functions such as emotion, motivation, personality, initiative, judgement, ability to concentrate, and social inhibitions.
What is the function of the cingulate gyrus (on the medial surface of the frontal lobe)?
Modulating emotional aspects of behavior
What does the parietal lobe do? (broadly)
Important in regulating somatosensory, language, and spatial oreintation functions
Where is the postcentral gyrus located? What is it’s function?
Behind the central sulcus, in the parietal lobe.
It is the primary somatosensory area of the cortex
What is the primary function of the temporal lobe?
Processing autory information, language, and certain complex functions.
What is the limbic lobe associated with?
Processing complex aspects of learning, memory and emotion
What are the “deep structures” of the brain?
- The basal ganglia
- limbic structures
- white matter
What are the basal ganglia? Where are they broadly located?
The basal ganglia are a group of interconnected, interacting nuclei within the forebrain, diencephalon, and midbrain.
Together, the basal ganglia play a critical role in the initiation and control of voluntary movements
What are the components of the basal ganglia?
forbrain: caudate and lenticular (putamen and globus pallidus) nuclei
diencephalon: subthalamic nucleus
midbrain: substantia nigra
Of what is the forebrain comprised?
Telencephalon and Diencephalon
Of what components is the telencephalon comprised?
- Cerebral hemispheres
- Deep structures
- Thalamus
Of what components is the diencephalon comprised?
- thalamus
- hypothalamus
- subthalamus
What structure is shown in the below image?
subthalamus
What do “projection fibers” do?
project to and from the cortex
What do “commissural fibers” do?
Connec the hemispheres
What do “association fibers” do?
Connect areas within one hemisphere
What is the largest set of commissural fibers?
The corpus callosum
Which is the largest set of projection fibers (ie fibers carrying information to and from the cerebral cortex)?
The corona radiata
What is the diencephalon?
A component of the forebrain, it consists of several sets of paired structures on either side of the 3rd ventrical: the thalamus, the hypothalamus, and the subthalamus
What is the thalamus?
A part of the diencephalon and consisting of 2 “egg-shaped” nuclear masses”
It is critical processing station for all sensory information (except olfactory) on its way to the cortext and plays key roles in processing motor information, in integrating higher order cognitive and emotional information, and regulating cortical activity. The thalamus can be considered the gatekeeper for the cortex.
What is the hypothalamus?
The hypothalamus is structurally part of the diencephalon but functionally part of the limbic system.
It plays key roles in coordinating and integrating endocrine, autonomic, and homeostatic functions.
What is the subthalamus?
The subthalamus is part of the basal ganglia and plays an important role in modulating and integrating voluntary movement and muscle tone.
Together, the midbrain and the hindbrain comprixe what?
The brainstem - the CNS division caudal to the diencephalon
Where are the cranial nerves located and what do they do?
Located in the brainstem, they provide sensory and motor information to and from the head and mediate the senses
What is the most rostral area of the brainstem?
The midbrain
Of what 2 things is the hindbrain comprised?
The pons and the medulla
Of what 5 things is the midbrain comprised?
- A large pair of cerebral peduncles on its anterior surface
- Two pairs of nuclui, the superior and inferior colliculi, on its posterior surface
- The cerebral aqueduct
- The red nucleus
- The substatia nigra
The superior colliculi are involved in visual reflexes
The inferior colliculi are an integrating centre in the auditory pathway
The cerebral aqueduct connects the third and fourth ventricles
The red nucleus and substantia nigra play roles in coordinating motor activity
What is the cerebellum and where is it located?
The cerebellum is an outgrowth of the pons and overlies the fourth ventricle.
The cerebellum has two hemispheres and a central are called the vermis, and its surface is covered by the highly folded cerebellar cortex
How is the cerebellum connected to the brainstem?
By the cerebellar peduncles that carry information to and from the cerebellum.
What is the function of the cerebellum?
The cerebellum has important roles in processing of sensory information and coordination of voluntary motor activity. More recent evidence indicates a role for the cerebellum in cognitive function as well.
How is the cerebellum attached to the brainstem?
By the cerebellar peduncles that carry information to and from the cerebellum
What are two main divisions of the peripheral nervous system?
Somatic and visceral/autonomic
What is the somatic nervous system?
What is the visceral or autonomic nervous system?
Supplies and receives fibers to and from smooth muscle, cardiac muscle, and glands.
What are the 2 divisions of the Visceral or Autonomic Nervous System?
- Parasympathetic division
- sympathetic division
What is the sympathetic division of the ANS?
Important for control of ‘normal’ body functions, e.g., normal operation of digestive system
What is the sympathetic division of the ANS?
Also known as the ‘fight or flight’ division; important in helping us cope with stress
What is the organization of the spinal cord?
A continuous series of posterior rootlets, containing sensory axons, enter the posterior aspect of the spinal cord, and a continuous series of anterior rootlets, containing motor axons, emerge from teh anterior aspect of the spinal cord.
These sensory and motor axons merge together in the spinal nerves.
What do the posterior rootlets contain?
sensory axons
What do the anterior rootlets contain?
motor axons
What do the posterior and anterior rootlets merge to form?
spinal nerves
What is the bulge in the posterior root, just proximal to the point where the spinal nerve forms, known as?
Spinal ganglion - which contains the cell bodies of the sensory nerve fibers
Which two areas within the spinal cord contain increased numbers of motor neurons to supply the arms and legs?
- cervical enlargement
- lumbosacral enlargement
At uts caudal pole, the spinal cord tapers off into the [blank] and ends in the [blank], which anchors the spinal cord to the dorsum of the coccyx.
At uts caudal pole, the spinal cord tapers off into the conus medullaris and ends in the filum terminale, which anchors the spinal cord to the dorsum of the coccyx.