Worksheet 7J Brain
Draw a flowchart showing the embryology of the brain (and what these areas become)
See paper
What are the meninges? What layers form part of the meninges (add any important characteristics of each)?
Dura- tough layer on the outermost aspect. Also covers the spinal cord. Carries meningeal arteries. Doubled layer (endosteal and meningeal)…dural venous sinus is found in between.
Arachnoid- lines inner surface of dura. Has spider web consistency. Subarachnoid space is between this and the pia mater filled with csf
Pia- covers actual cerebral cortex and supports blood vessels
What is cerebrospinal fluid ? What makes it up? What is its function? Where can you find it?
Cerebrospinal fluid is a fluid that is made up by a choroid plexus ( permeable capillaries and ependymal cells; a type of neuroglial cell). Its functions include cushioning, support, and transport of nutrients, wastes, and chemical messengers. You can find it in every ventricle of the brain as well as the subarachnoid space in the brain and spinal cord.
Lateral ventriclesàinterventricular foramenàthird ventricleàcerebral aqueductàfourth ventricleàmedian & lateral apertures
What is the structural difference between gray and white matter? Functional difference?
Structurally white matter is a collection of myelinated axons and grey matter is a collection of neuronal cell bodies. Functionally, white matter will consists more of tracts that bring information up toward the brain or down toward the body. On the other hand, grey matter usually will process the information received by the white matter. White matter can be found pretty much anywhere deep to the layer of grey matter.
Describe the basic functions of the following areas
Medulla oblongata-contains nuclei of cranial nerves VIII, IX, X, XI, and XII. Has autonomic nuclei for cardiovascular centers and respiratory centers. Has nuclei associated with relay stations for sensory or motor pathways. All information between brain and spinal cord passes through this
Pons- contains nuclei for V, VI, VII, VIII. Has nuclei involved in involuntary control of breathing, also consists of cerebellar peduncles that help communicate with cerebellum. Consists of ascending, descending, and transverse tracts.
Cerebellum- monitors sense of position via proprioceptive information from muscles and joints and equilibrium information from the vestibular system in the ear. Controls postural muscles (erector spinae) and also coordinates movements below consciousness. Balance, posture, and coordination.
Midbrain- contains the corpora quadrigemina which are nuclei that process visual and auditory information. Also consists of the substantia nigra which contains dopamine producing cells involved in regulating fine motor control (less dopamineàparkinsons). Also contains cerebral peduncles which have ascending sensory info to thalamus and descending fibers of corticospinal tracts toward voluntary motor commands. Also has the reticular formation which is involved in maintaining alertness
Diencephalon
Epithalamus: pineal gland is found here. Secretes hormone melatonin, controls circadian rhythms
Thalamus: somatosensory relay station. All sensory input except olfactory is processed through the thalamus on way to primary sensory cortex (parietal lobe)
Hypothalamus: controls several things however the most important have to do with secretion of hormones from the pituitary gland (ADH and oxytocin) and also the autonomic nervous system (heart rate, bp, respiration, and hunger/thirst drives). Also has subconscious control of skeletal muscle contractions (associated with emotions and sexual function)
The cerebrum is divided into 5 lobes. Identify the major functions of the following:
Frontal- high brain functions. Cognition, thinking, personality, emotion, etc. This is also where you find your center for conscious control of skeletal muscles (primary motor cortex, precentral gyrus) “PEC.” Broca’s area for speech production.
Occipital- anything related to vision or visual stimuli is processed here
Temporal- auditory cortex and olfactory cortex. Conscious perception of auditory and olfactory stimuli. Wernicke’s area for speech interpretation.
Parietal- primary somatosensory cortex (postcentral gyrus). Conscious perception of touch, pressure, vibration, pain, temperature, and taste.
Insula- deep to the lateral sulcus. Consists of olfactory cortex and gustatory cortex.
Identify the difference among association tracts, commissural tracts, and projection tracts
Tracts are bundles of myelinated axons that extend from one cortical area to another or that connect areas of the cortex to other regions of the brain.
Association tracts: stay within the same hemisphere. Longitudinal fasciculi connect frontal lobe to other lobes of same hemisphere.
Commisural tracts: interconnect between the two hemispheres. Corpus callosum and anterior commissure. Also the interthalamic adhesion
Projection fibers: link cerebral cortex to diencephalon, brain stem, cerebellum, and spinal cord. All ascending and descending axons must pass through the diencephalon on their way to or from sensory, motor, or association areas of the cerebral cortex. Internal capsule.