W2 L4 211 Flashcards
Need to know intersection and planes and geography of brain,
See slides, I think it will help, probably text too.
Parts of the brain,
Structure and organizTion,
Anatomic regions
Neuraxis
An imaginary line that runs along the length of the CNS
§ Anterior (rostral)
Front end or toward the head
§ Posterior (caudal) Tail end
§ Dorsal ‘(back’) surface
Top of the head and towards the back
§ Ventral (‘belly’) surface
Front surface that faces the ground
§ Lateral
Toward the side
§ Medial
Toward the middle
More useful terms
§ Contralateral
Structures on opposite side of the body
(e.g. left cerebral cortex controls movement of the contralateral hand means that it controls movement of the RIGHT hand.
§ Ipsilateral
Structures on same side of body
(e.g. olfactory bulb sends axons to the ipsilateral hemishere means that the left olfactory bulb sends axon to the left hemisphere and the right olfactory bulb sends its axons to the right hemipshere.
Brain needs protection inlcuding_______and The Meninges are?
§ The brain is encased in a bony skull and floats in a pool of cerebrospinal fluid (CSF).
§ The brain is chemically guarded by the blood-brain barrier.
§ The brain receives a large supply of blood because it is unable to store it’s own fuel.
§ The meninges are the tough, protective connective tissues that surround the brain. a) The dura mater is a outer thick, tough but unstretchable tissue.
b) The arachnoid membrane is the middle soft, spongy layer. It has a weblike appearance.
c) The third layer that sits closest to the brain in the pia mater which comprises
blood vessels.
§ The arachnoid space between is filled with CSF.
The Ventricular System of the Brain
§ The ventricles are interconnected hollow spaces filed with CSF.
§ The lateral ventricles (comprise the first and second ventricle) are the largest.
§ The cerebral aqueduct is a long, tube like structure that connects the third ventricle to the fourth ventricle.
The CSF is produced continuously by the choroid plexus.
§ The CSF is replaced every three hours (the half-life).
§ CSF leaves the fourth ventricle and flows through the subarachnoid space where it is reabsorbed into the blood supply.
Anatomical Divisions of the Brain
Different swellings of the neural tube represent different phases of embryological development.
Telencephalon
Diencephalon
Mesecephalon
Metencephalon
Myelencephalon
Cerebral cortex Basal ganglia Limbic system
Tectum Tegmentum
Cerebellum Pons Medulla Oblongata
SEE THE SLIDES,,,!!!!!
The Forebrain: Cerebral Cortex
The cerebral cortex is highly convoluted with sulci (small grooves), fissures (large or major grooves) and gyri (ridges between sulci or fissures). The convolutions increase the surface area of the cortex.
The cerebral cortex consists mainly of glial cells, axons, dendrites and a high concentration of cell bodies. It is referred to as gray matter.
The white matter (beneath the gray matter) consists of a large concentration of myelinated interconnecting axons.
Central sulcus landmark
Frontal context and parietal distinguished
Sim to lateral fissure defining temporal lobe
The primary sensory areas of the Cerebral Cortex?
The primary sensory areas of the Cerebral Cortex
The primary visual cortex receives visual information, the primary auditory cortex receives auditory information, the insular cortex receives gustatory information and the somatosensory cortex receives information about the body senses
Different regions of the somatosensory cortex receive information from different parts of the body (e.g. feet, hands, fingers).
Cytoarchitectonic analysis (Cellular organisation of the cortex)
Cytoarchitectonic analysis (Cellular organisation of the cortex) The cortex contains up to six cell layers (laminae) § Cell structure and organisation varies between laminae § These laminae vary in density in different parts of the cortex. § The cells vary in size, type, structure and in their connections § These morphological differences relate to functional differences Association
Used to make brain maps, note staining technique,
Area related to numbers
The Forebrain: Limbic System
The fornix is a band of axons that carry signals from the hippocampus to the septum and mammillary bodies. Fornix means arc.
The septum is a midline nucleus attached to the corpus callosum and the fornix. It is connected to the amygdala and hippocampus
The cingulate cortex is a large area of cortex that overlies the corpus callosum. Cingulate means encircling.
The hippocampus (‘or seahorse’) is part of the temporal lobe. It is made up of the cornu ammonis fields (CA1-CA4).
The amygdala is an almond- shaped structure in the temporal lobe. It lies anterior and ventral to the hippocampus. It is made up of several nuclei.
The mammillary bodies are a pair of round bodies on the ventral surface of the brain. They are attached to the anterior arch of the fornix.
The Forebrain: Basal Ganglia
The putamen is a band of axons located in the centre of the caudate. Together, the caudate and putamen have a striped appearance and are know together as the striatum.
The caudate nucleus is located in the centre of the brain. It resembles a C shape with a wide head in the front tapering to a body and a tail at the end.
The Forebrain: Thalamus and Hypothalmus
Allows cortical cortical communication, unidirectional to occipital?
§ The thalamus is a two lobed structure that sits on top of the brain stem.
§ It is divided into several nuclei. Some are sensory relay nuclei; they receive sensory signals relay them to different regions of the cerebral cortex.
§ E.g. the lateral geniculate nuclei of the thalamus receive information from the eye and send axons to the primary visual cortex.
§ Nuclei of the thalamus have widespread cortical projections.
§ The hypothalamus is also made up of several nuclei.
§ These nuclei control feeding, fighting, fleeing and mating.
§ They also control other autonomic and endocrine responses (e.g. drinking and sleeping).
§ Hypothalamic neurons stimulate the pituitary gland which release several hormones in reproductive physiology and behaviour.
The Midbrain: Tectum and Tegmentum
§ The midbrain form the upper part of the brain stem. It comprises the:
1. The tectum (roof) has two pairs of bumps on the dorsal surface called the colliculi. The anterior superior colliculi have a visual function. The posterior inferior colliculi have an auditory function.
2. The tegmentum includes several structures including the rostral reticular formation, the periaqueductal gray, the red nucleus, the substanta nigra. These structures are involved in sleep, arousal, attention, movement and reflexes
The Hindbrain: Cerebellum, Pons and the Medulla Oblongata
• The hindbrain is the most posterior division of the brain. It includes:
1. The cerebellum (known as ‘little brain’) which is convoluted mass of cortex involved in the integration of sensory perception and motor control.
2. The pons which is a large bulge in the brain stem. At its core is the reticular formation that plays an important role in sleep and arousal.
3. Medulla Oblongata is the most caudal part of the brain stem. It also contains a part of the reticular formation and nuclei that control vital functions of respiration and the cardiovascular system
