The Brain And Nervous System Flashcards
Define cephalization
-the development of an anterior head where sensory organs and nervous tissues are concentrated
Nerve nets
-loose mesh of neurons found in radially symmetrical animals
Nerve cord
-bundle of nerves which extend from the central ganglia to the rest of the body
Ganglia
-functional clusters of neurons
What is the significance of bilateral symmetry
-body parts are mirror images on the either side of the midline
-organization of the nervous system such as paired nerves linking lobes in brain with specific muscles and receptors allows for sophisticated sensory processing
-Animals: coordinated, rapid movement to hunt prey, escape predators
Differential gene expression at…
-specific times (temporal) and in specific regions(spatially) gave rise to cell differentiation and cell determination(cell fates)
Neural tube
-the precursor of the CNS (brain and spinal cord)
Neural crest
-cells migrate and differentiate into a number of varied cell types
What is example of gene expression during neural tube formation
-cadherins (calcium dependent adhesion molecules)
-transmembrane proteins
-role in cell adhesion, ensures that cells within tissues are bound together
-dependent on Ca2+ to function
What are the main functions of the brain?
-Receive information
-integrate information
-send out information
-store information
-retrieve information
Blood brain barrier
-A separation of circulating blood and cebrospinal fluid (CSF)
-occurs along all capillaries and consists of tight junctions around the capillaries that don’t exist in normal circulation
Endothelial cells in Blood brain barrier….
-restrict the diffusion of microscopic objects(eg bacteria) and large or hydrophilic molecules inot the CSF
-allow the diffusion of small hydrophobic molecules (O2, hormones, CO2)
-cells of the barrier actively transport metabolic products such as glucose across the barrier with specific proteins
What are meninges and what are their function
-layers of connective tissue (membranes) covering the brain and spinal cord
-provide structural support for blood vessels
-serve as a “pad” between brain and skull
What are the three connective tissue layers of meninges
-pia(innermost), arachnoid, dura mater(outermost)
What is cerebrospinal fluid
-clear colorless fluid produced in the choroid plexus (a complex of glial cells-called ependymal cells)
-found in brain and spinal cord
-occupies the subarachnoid space(the space between the arachnoid mater and the pia mater) and the ventricular system
CSF circulates…
-nutrients and chemicals filtered from the blood and removes waste products from the brain
What is the function of CSF
-protect the brain from striking the cranium when the head is jolted
-CSF provides buoyancy and support to the brain against gravity
The buoyancy of CSF protects the brain because
-the brain and CSF are similar in density; this makes the brain float in neutral buoyancy, suspended in the CSF
-this allows the brain to attain a decent size and weight without resting on the floor of the cranium, which would kill nervous tissue
What are the ventricles
-cavities in the brain filled with CSF
-there are four ventricles, two lateral ventricles, the third ventricle, the fourth ventricle
What is a subdural haematoma
-swelling containing blood
-ventricle absorbs shock
Ventricular volume is significantly lower/higher in Alzheimer’s Disease patients compared to age-matched healthy subjects
-higher
What is the forebrain
-forms the cerebrum
-cerebrum has left and right hemispheres
What do the cerebral hemispheres correspond to and what are they connected with
-left cerebral hemisphere responds to sensory signals from the right side of the body and controls movements on right side of body.
-right hemisphere responds and controls movement on left side of body.
-connected by thick axon bundles (the corpus callosum) which enables the exchange of information between the hemispheres
What does the left hemisphere focus on?
-focus on details(such as recognizing a particular face in a crowd); spoken and written language, abstract reasoning math
-Wericke’s and Broca’s areas in left hemisphere
What does the right hemisphere focus on?
-focus on broad background (such as understanding the relative position of objects in space, intuitive thinking, conceptualization, music, art
Define lateralization
-the difference in function between the left and right hemisphere
Cerebral cortex
-outermost thin layer of grey matter (in mammals, comprised of 6 layers of neurons, 2-4mm thick in humans) covering a core of white matter
-convoluted folds to increase surface area
What does grey matter consist of
-neuron cell bodies and dendrites
What does white matter consist of
-axons (many axons have myeline sheaths)
What are the 4 brain lobes of the cerebrum
-frontal lobe, parietal lobe, temporal lobe, occipital lobe
Where is the frontal lobe and what does it control
-front of the brain
-controls executive function
-thinking, organizing, planning, problem solving, memory, Attention, movement
Where is the parietal lobe and what is its function
-sits behind frontal lobe
-deals with perception and integration of stimuli from the senses
Where is the occipital lobe and what is its function
-back of the brain
-vision
Where is the temporal lobe and what is its function
-runs along the side of the brain under the frontal and parietal lobes
-deals with the senses of smell and sound and the formation and storage of memories