Chapter 3.8 - 3.16 Anatomy of the Nervous System Flashcards
There are three axes to the vertebrate nervous system,what are they?
- Anterior (toward nose end) - posterior (toward Tail end)
- Dorsal (toward the surface of the back or top of the head) - Ventral (toward the surface of the chest or the bottom of the head)
- Medial midline of body) - Lateral (away from midline toward lateral surfaces)
See fig 3.14 on page 64 for reference
What is Gray Matter?
- in inner H-shaped core of spinal cord
- Composed largely of cell bodies and unmyelinated interneurons
What is white Matter?
Composed largely of myelinated axons
What are the five divisions of the brain?
- Telencephalon (cerebral hemispheres)
- Diencephalon
- Mesencephalon (midbrain)
- Metencephalon
- Myelencephalon (medulla)
What is the brain stem?
The stem on which the cerebral hemispheres sit
What is the myelencephalon?
Aka Medulla
- most posterior division of the brain
- composed largely of tracts carrying signals btwn rest of brain & body
- has reticular formation
What is the reticular formation?
Complex network or about 100 tiny nuclei that occupies the central core of the brain stream from the posterior boundary of the myelencephalon to the anterior boundary of th midbrain
What is the metencephalon?
-like myelencephalon, houses many ascending and descending tracts and part of the reticular formation
2 divisions:
1. a bulge called the “pons” on the brain stem
2. The cerebellum (little brain)
What is the cerebellum?
In the metencephalon division
- sensorimotor structure
- large convoluted structure on brain stems dorsal surface
- damage also leads to deficits in decision making and using language
What is the mesencephalon?
Has two divisions:
- Tectum (dorsal surface of midbrain)
- Tegmentum (ventral to the tectum)
What are the two pairs of bumps on the Tectum and what is their function?
- Inferior coliculi (posterior pair)
- auditory function - Superior coliculi (anterior pair)
- visual-motor function
What three structures are found in the Tegmentum (division of the mesencephalon)?
- Periaqueductal gray: gray matter around the cerebral aqueduct
- Substantial Nigra: black substance
- Red Nucleus
What is the cerebral aqueduct?
Duct connecting the third and fourth ventricles
-role in mediating the analgesic (pain-reducing) effect of opioid drugs
What is the diencephalon?
- composed of two structures :
1. Thalamus
2. Hypothalamus
What is the thalamus (structure of diencephalon division)
Large two lobed structure that constitutes the top of the brain stem
-joined by the massa intermedia
What is the hypothalamus? (Structure of diencephalon division)
- located just below the anterior thalamus
- plays important role in regulation of several motivated behaviours (eating, sleeping, sex)
- regulates release of hormones from the pituitary gland
What is th optic chiasm?
Point at which the optic nerves from the eye come together.
-x-shape from crossing nerves (decussate = cross-over)
What is the telencephalon?
- largest division of human brain
- initiates voluntary movement
- interprets sensory input
- mediates complex cognitive processes (ex learning, speaking and problem solving)
What is the cerebral cortex?
Layer of tissue covering the cerebral hemispheres
- mainly composed of small, unmyelinated neurons = appears gray = called gray matter
- deeply convoluted = increase surface area of cerebral cortex
What are fissures? What are Sulci?
Large furrows in a convoluted cerebral cortex are fissures;
Small furrows are called sulci
What are the ridges between the sulci and fissures called?
Gyri (singular gyrus)
What is the longitudinal fissure?
Largest fissure of the cerebral cortex
-almost completely separates the cerebral cortex
What is the Corpus Callosum?
Largest “cerebral commissure” (connecting tracts spanning the longitudinal fissure)
Which two fissures partially divide each hemisphere into four lobes?
The Central Fissure
The Lateral Fissure
What are the four lobes of the cerebral hemispheres?
- Frontal Lobe
- Parietal Lobe
- Temporal Lobe
- Occipital Lobe
What is neocortex?
“New cortex”
- makes up about 90% of the human cerebral cortex
- six-layered cortex of relatively recent evolution
What are four important characteristics of neocortical anatomy?
- Many Cortical neurons are either pyramidal cells or stellate cells
- The 6 layers of neocortex differ in terms of size and density of cell bodies, and relative proportion of pyramidal and stellate cell bodies they contain
- Long axons and dendrites course vertically through the neocortex = columnar organization
- There are variations in the thickness of the 6 layers from area to area
What is the hippocampus?
An important area of the cortex that is not neocortex
- has 3 major layers
- kinda resembles a seahorse shape
- major role in some kinds of memory (ie spatial location)
What is the limbic system?
hypothetical system
-circuit of midline structures that circle the thalamus
-involved in regulation of motivated behaviour: the four F’s
Feeding, fighting, fleeing, fucking
what are Mammillary Bodies?
Structures of the diencephalon division
- often considered to be part of the hypothalamus
- pair of spherical nuclei located on the inferior surface of the hypothalamus just behind the pituitary
What are 6 structures included in the limbic system?
- hypothalamus
- mammillary bodies
- amygdala
- the fornix
- the cingulate cortex
- the septum
What is the amygdala?
- almond-shaped nucleus in the anterior temporal lobe
- involved in emotion - particularly fear
What is he cingulate cortex?
Large strip of cortex in the cingulate gyrus on the medial surface of the cerebral hemispheres
-encircles dorsal thalamus
What is the fornix?
Major tract of he limbic system
-encircles the dorsal thalamus
What is the septum?
Midline nucleus located at the anterior tip of the cingulate cortex
What are the structures of the basal ganglia?
- amygdala (also in limbic system)
- caudate
- putamen
- globus pallidus
What are the basal ganglia involved in?
Performance of voluntary motor responses and decision making
