M4 Cerebrum and Diencephalon Flashcards
is the largest part of the brain
cerebrum
Can be divided into two parts:
- Diencephalon (Central Core)
- Telencephalon (Cerebral Hemispheres)
Cerebrum
Superior surface is concealed by the fornix and is formed by the roof of the third ventricle. This layer consists of an ependymal layer.
Diencephalon
- Lateral surface is bounded by the internal capsule of white matter.
- It consists of nerve fiber that connect the cerebral cortex with the other parts of the brain stem and spinal cord
Diencephalon
- Medial surface is formed in its superior part by the medial surface of the thalamus and its inferior part by the hypothalamus.
- They are separated by hypothalamic sulcus
Diencephalon
4 parts of Diencephalon
- Thalamus
- Subthalamus
- Epithalamus
- Hypothalamus
- The largest part of the diencephalon
- A.K.A “Sensory relay”
- influences mood and registers an unlocalized, uncomfortable perception of pain.
- Ovoid in shape
Thalamus
5 thalamic nuclei
- Anterior Nuclei Group
- Nuclei of the midline
- Medial Nuclei
- Lateral Nuclear Mass
- Posterior Nuclei
- Forms the anterior tubercle of the thalamus
- Bordered by the limbs of the internal lamina
- Receives fibers from mamillary bodies
Anterior Nuclei Group
- Found just beneath the lining of the Third Ventricle and in interthalamic adhesions
- They connect hypothalamus and central periaqueductal gray matter
- The centromedian nucleus connects with the cerebellum and corpus striatum
Nuclei of the Midline
These include most of the gray substance medial to internal medullary lamina; the intralaminar nuclei as well as the dorsomedial nucleus, which projects to the frontal cortex.
Medial Nuclei
- Ventral Anterior Nucleus: connects corpus striatum
- Ventral Lateral Nucleus: projects cerebral motor complex
- Dorsolateral Nucleus: projects to parietal cortex
- Ventroposterolateral Nucleus: relays sensory input from the body
- Ventroposteromedial Nucleus: relays sensory input from face
Lateral Nucleus Mass
- Pulvinar Nucleus: it connects to parietal and temporal cortices
- Medial Geniculate Nucleus: receives acoustic fibers from the lateral lemniscus and inferior colliculus.
- Lateral Geniculate Nucleus: major nucleus for vision.
Posterior Nucleus
- Sensory Nuclei
- Motor Nuclei
- Limbic Nuclei
- Multimodal Nuclei
- Nonspecific Nuclei
5 Functional Nuclear Groups
Includes:
- Ventral posterior group (VPL and VPM)
- Lateral and medial geniculate bodies
- Modifies signals from body, face, retina, cochlea and taste receptors (except OLFACTION)
Sensory Nuclei
Includes:
- Ventral anterior and lateral
- convey motor information from the cerebellum and globus pallidus to the precentral motor cortex.
- Sensory nuclei is also called motor relay nuclei
Motor Nuclei
- Interposed between the mammillary nuclei of the hypothalamus and the cingulate gyrus of the cerebral cortex
- The dorsomedial nucleus receives input from the olfactory cortex and amygdala regions
Limbic Nuclei
Includes:
- pulvinar, posterolateral, and dorsolateral
- have connections with the association areas in the parietal lobe (Sensory)
Multimodal Nuclei
Includes:
- Intralaminar, reticular nuclei and centrum medianum
- No known details
- Some say it relates to cortical motor areas, the caudate nucleus, the putamen, and the cerebellum
Non-specific Nuclei
- Is the most inferior part of the diencephalon
- Plays a central role in the control of body temperature, hunger, and thirst.
- Holds the pituitary gland via the infundibulum
Hypothalamus
- Optic chiasm
- Tuber cinereum
- Mammillary bodies
- Infundibulum
- Medial Hypothalamic area
- Lateral hypothalamic area
Hypothalamus
- Eating
- Autonomic Function
- Body Temperature
- Water Balance
- Anterior Pituitary Function
- Circadian Rhythm
- Expression of Emotion
7 parts of Hypothalamus
- Lateral hypothalamus: evoked eating behavior
- Ventromedial Nucleus: stops hunger and inhibits the feeding center when a high blood glucose level is reached after food intake.
- Damage to feeding center of Ventromedial nucleus may lead to anorexia (loss of appetite)
Eating
evoked eating behavior
Lateral hypothalamus
stops hunger and inhibits the feeding center when a high blood
glucose level is reached after food intake
Ventromedial Nucleus
- Posterolateral and Dorsomedial areas: function as a sympathetic activating region
- Anterior area: parasympathetic activating region.
Autonomic Nervous System
- Related to autonomic response
- A fall in body temperature, for example, causes vasoconstriction.
- A rise in body temperature results in sweating and cutaneous vasodilation.
- hypothalamic set point: <37C
Body Temperature
Osmoreceptors in hypothalamus influence vasopressin secretion within the posterior pituitary
- Stimulated by blood osmolarity
- Thirst Center: located near the supraoptic nucleus.
Water Balance
in hypothalamus influence vasopressin secretion within the posterior pituitary
Osmoreceptors
Failure of Osmoreceptors or damage to posterior pituitary (vasopressin) leads to Diabetes Insipidus where there is polyuria and polydipsia
Water Balance
The functions of the body such as temperature, corticosteroid levels, oxygen consumption are influenced by light intensity changes that have a circadian (day-to-day) rhythm
Circadian Rythm
It is involved in the expression of rage, fear, aversion, sexual behavior, and pleasure.
Expression of emotion
Landmarks:
- Subthalamic Nucleus
- Body of Luys
Subthalamus
- Is a small area superior and posterior to the thalamus
- Houses the pineal gland
Epithalamus
- Influences the onset of puberty
- play a role in controlling some long-term cycles that are influenced by the light-dark cycle via Melatonin.
- Melatonin:rises in darkness and falls during the day.
- Plays an important role in the regulation of reproductive function
Pineal Gland
rises in darkness and falls during the day
Melatonin
- is the largest part of the brain
Cerebrum
2 parts of the Cerebrum
Diencephalon and Telencephalon
the crests of the cortical folds
gyrus
furrows of the brain
sulcus
just like sulci but only deeper
fissures
why is the presence of gyri and sulci in a pattern that is relatively constant from brain to brain?
Easy to identify cortical areas that fulfills specific functions
- aka sylvian fissure
- separates the frontal and parietal lobe
Lateral Cerebral fissure
- aka circuminsular fissure
- separates the insula and separates it from the adjacent frontal, parietal, and temporal lobes
Circular Sulcus
separates the left and right hemispheres
Longitudinal Cerebral Fissure
- fissure of rolando
- separates the frontal lobe from the parietal lobe
Central Sulcus
Separates the parietal lobe from the occipital lobe.
Parieto-occipital fissure
Begins on the medial surface of the hemisphere near the occipital pole and extends forward to an area slightly below the splenium of the corpus callosum
Calcarine fissure
Is a large bundle of myelinated and unmyelinated fibers
Corpus Callosum
Serves to integrate the activity of the two
hemispheres and permits them to communicate with each other
Corpus Callosum
Found below the cingulate gyrus
Corpus Callosum
is the largest of the interhemispheric
commissures and is largely responsible for coordinating the activities of the two
cerebral hemispheres.
Corpus Callosum
Anterior part of Corpus C.
Genu
Posterior part of Corpus C.
Splenium
Involved in:
- Motor ,Initiative judgment, abstract
reasoning, creativity, and socially appropriate behavior (inhibition of
socially inappropriate behavior)
Frontal lobe
are phylogenetically newest and
the most uniquely “human”.
Initiative judgment, abstract
reasoning, creativity, and socially appropriate behavior