Unit 4 Flashcards
(62 cards)
What does the Diencephalon consist of?
Structures that are crucial for processing sensory information (thalamus)
Structures that are crucial for regulating ANS (hypothalamus)
Structures important for motor control (subthalamus)
Structures important for regulation of biological cycles and resistance against nicotine (epithalamus)
How can the brain be divided according to the prenatal development of the CNS?
Begins as neural tube (hollow tube)
-> develops 3 swellings which become forebrain, midbrain and hindbrain
How can the regions of the brain be further divided in the adult brain?
Prosencephalon: Telencephalon and Diencephalon
Mesencephalon
Rhombencephalon: Metencephalon and Myelencephalon
What does the thalamus consist of, where is it located and what is its role?
Consists of a pair of egg-shaped structures in centre of forebrain (one on each side of third ventricle)
Plays crucial role in processing sensory information detected throughout the body
Where does most of the input from the cortex come from?
The thalamus
What is the only sensory input which bypasses the thalamus?
Olfactory sensory information
What can thalamic nuclei be grouped into anatomically?
Anterior, medial and lateral groups
-> separated by internal medullary lamina (y-shaped thin lamina of white matter)
What does the internal medullary lamina consist of?
Afferent and efferent axons of thalamic nuclei
Where do thalamic nuclei lie?
Some within internal medullary lamina (important for maintaining cortical arousal)
Some in the reticular nucleus
What is the reticular nucleus?
A thin strip of nuclei slightly lateral to the main body of thalamic nuclei
Plays a role in sleep-wake cycles
What are the different types of nuclei present in the thalamus?
Specific nuclei
Non-specific nuclei
Association nuclei
Where are specific nuclei located and what do they do?
In the ventral part of the of lateral group
Receive specific sensory information
Project to specific sensory and motor areas of cortex
The ventral posterior nucleus as a specific nucleus example
Receives somatosensory information from trunk, limbs and head
Sends signal to corresponding parts of primary somatosensory cortex
-> brings information to conscious level
Where do non-specific nuclei lie and what is their task?
Lie in dorsal part of lateral group, as well as all of the anterior and medial groups
Project axons to broadly dispersed areas of cortex (e.g. association areas and limbic system)
What are association nuclei?
Some non-specific nuclei considered association nuclei
Don‘t receive sensory signals, but input from other brain areas
-> sent to different areas of cortex
Thought to have integrative function: bring information of different brain areas together
Whats an example of an association nucleus?
Anterior nuclear group
Receive signals from hypothalamus and projects to the cingulate gyrus (both components from limbic system)
-> involved in control of instinctive drives and emotional aspects of behaviour and memory
What is the limbic system responsible for?
Control and production of emotions
Memory storage
What is retrograde thalamic degeneration?
Lesions in sensory areas of cortex cause corresponding thalamic nuclei to degenerate and lose functionality
What purpose does the hypothalamus serve?
Main controller of ANS
-> capable of influencing behaviours under control of ANS (e.g. feeding, drinking, sleep, wakefulness, temperature regulation and aggression )
Receives information regarding internal state of body
(Can also renew olfactory and gustatory neurones in some cases)
Which are the 2 main sources the hypothalamus receives information about the internal states of the body from?
Neural connections
Signals from circulatory system (e.g. bloodstream)
What types of signals does the hypothalamus receive and process?
Physiological signals (e.g. temperature)
Chemical signals (e.g. blood glucose)
Hormonal signals (e.g. hunger hormones)
=> signals regarding internal state of the body
How does the hypothalamus produce effects on the internal state of the body?
Neural connections
Releasing hormones into bloodstream
The hypothalamus and homeostasis
Hypothalamus performs physiological adjustments to changes in internal and external environments
Example for the influence of the hypothalamus
Temperature receptors in skin and organs detect change in temperature
-> sent to hypothalamus
-> communicates with raphe nucleus in brainstem (controls temperature regulation behaviours