anatomy week 11
ventricles
CSF is formed in four spaces within the brain
IX Glossopharyngeal
Carries impulses from tongue, pharynx. Controls swallowing, stimulates parotid
VIII vestibulocochlear
Carries sensory impulses for hearing and equilibrium from inner ear
I olfactory
Carries smell impulses from receptors in the nasal mucosa brain
II optic
Carries visual impulses from the eye to the brain
Epilepsy
Chronic disorder involving an abnormality of the brain's electrical activity with or without apparent changes in the nervous tissue Dilantin causes gingival overgrowth
Cerebrospinal Fluid
Clear liquid that circulates in and around the brain and spinal cord. -Supports nervous tissue, cushions shocks -Carries nutrients to the cells and transports waste products from the cells. -Flows through the brain and flows out into the subarachnoid space Much of the fluid is returned to the blood through projections called the arachnoid villi in the dural sinuses.
III oculomotor
Contraction of eye movement
XI Accessory
Controls muscles to neck and larynx
XII Hypoglossal
Controls tongue muscles
X Vagus
Longest cranial nerve; supplies most organs in thoracic, abdominal cavities. Carries motor impulses to larynx, pharynx
The Cerebellum
Made up of three parts; The middle portion (vermis) and two lateral hemispheres. -Coordination of voluntary muscles. -Maintenance of balance. -Maintenance of muscle tone.
VII facial
Mostly motor. Controls facial expression movements, some taste sensations
Cerebrovascular Accident (Stroke)
Stroke is by far the most common kind of brain disorder Most common caused is a blood clot that blocks the flow to an area of the brain tissue Cerebral Hemorrhage or rupture of a blood vessel Risk factors diabetes, HBP, smoking, excess alcohol consumption and arterial wall damage
The lateral sulcus
which curves along the side of each hemisphere and separated the temporal lobe from the frontal and parietal lobes.
IV trochlear
Supplies one eyeball muscle
Lateral ventricles
are the largest, located in the two cerebral hemispheres. Their extensions into the cerebrum are called horns. These ventricles communicate with a midline space, the third ventricle by means of foramina.
The Medulla Oblongata
: appears white on the outside, internally it contains collections of cell bodies (gray matter) called nuclei or centers. -The three to remember are: Respiratory, the cardiac and the vasomotor.
Meninges
: three layers of connective tissue that surround the brain and spinal cord. dura, arachnoid, pia mater
Alzheimer Disease
A brain disorder resulting from unexplained degeneration of the cerebral cortex and hippocampus Causes severe intellectual impairment with mood changes and confusion Changes in the brain occur before noticeable signs are seen. These changes are a build up of an abnormal protein amyloid and a tangling of neuron fibers that prevent communication between cells
Parkinson Disease
A progressive neurological condition characterized by tremors, rigidity of limbs and joints, slow movement and impaired balance The part of the brain that produces the neurotransmitter dopamine Main therapy is administration of L-dopa
fourth ventricle
A small canal called the cerebral aqueduct, extends through the midbrain into the fourth ventricle
Limbic System
-is located between the cerebrum and the diencephalon. This system is involved in emotions and behaviour. -The hippocampus functions in learning and the formation of long term memory. It includes regions such as the reticular formation, a network that governs wakefulness and sleep.
Choroid plexus
: A vascular network in each ventricle that forms CSF by filtration of the blood and by cellular secretion.
Pia mater
: The innermost layer Attached to the nervous tissue of the CNS. Holds blood vessels that supply oxygen, nutrients to brain, spinal cord
Arachnoid
: The middle layer Loosely attached to the deepest layers by way of web like fibers.
Dura mater
: The outermost layer Thickest and the toughest layer Inside the skull, the dura mater splits in certain places to provide venous channels, called dural sinuses. Two layers in brain, one in spinal cord
Hydrocephalus
An abnormal accumulation of CSF within the brain May result from overproduction or impaired drainage of the fluid Increase pressure from fluid build can squeeze the brain against the skull and destroy brain tissue Treatment involves shunt to drain CSF fluid
cerebral hemisphere
Each cerebral hemisphere is divided into four lobes, named for the underlying bones. -Frontal, parietal, occipital, temporal -A fifth small lobe (insula) is located deep within each hemisphere that cannot be seen. -Outer nervous tissue of the cerebral hemispheres is gray matter that makes up the cerebral cortex. -Responsible for conscious thought, reasoning and abstract mental functions. -The cortex is arranged in folds called gyri. Gyri are separated by many sulci (shallow grooves)
Encephalitis
Inflammation of the brain Symptoms include fever, vomiting and coma Some infectious agents that can cause this are rabies virus, HIV, West Nile virus, poliovirus
Meningitis
Inflammation of the meninges, the coverings of the brain and spinal cord -Usually caused by a bacteria that enter through the -ear, nose or throat or are carried by the blood -Meningococcus is responsible for epidemics among people living in close quarters Some viruses cause meningitis Headache, nausea, vomiting and stiff neck Lumbar puncture to exam CSF
Functions of the Cerebral Cortex
Receives and analyzes nerve impulses. Particular functions are localized in the cortex of each lobe
VI abducens
Sends impulses to an eyeball muscle
V trigeminal
Sensory nerve of the face, head. Three branches: that transport sense impulses from eye, upper jaw and lower jaw.
Brain Stem
connects the cerebrum and the diencephalon with the spinal cord. -Upper portion = midbrain -Below that, is the pons connecting the midbrain with the medulla. The medulla oblongata connects the brain with the spinal cord.
Temporal lobe
contains the auditory area for interpreting impulses from the ear and the olfactory area.
Frontal Lobe:
contains the motor area which directs movement. Contains two areas important in speech.
Parietal lobe
contains the sensory area. Impulses from skin (eg. touch, pain, temperature) are interpreted. Estimation of distance, size and shape
The occipital lobe
contains the visual area, interpreting impulses from the retina of the eye.
The Midbrain
forms the forward part of the brain stem. Four rounded masses of gray matter, hidden by the cerebral hemispheres form the upper part of the midbrain. -These masses act as relay centers for certain eye and ear reflexes. The white matter at the front of the midbrain conducts impulses between the higher center of the cerebrum and the lower centers of the pons, medulla, cerebellum and spinal cord.
Corpus callosum
is a band of white matter located at the bottom of the longitudinal fissure. -This band acts a bridge between the right and left hemispheres, permitting impulses to cross from one side of the brain to the other
Cerebellum
is connected with the cerebrum, brain stem and spinal cord by means of the pons.
cerebrum
largest part of the brain (anterior portion ) -Divided into right and left cerebral hemispheres by a deep groove called the longitudinal fissure.
The central sulcus
lies between the frontal and parietal lobes of each hemisphere at right angles to the longitudinal fissure.
The Pons
lies between the midbrain and the medulla in front of the cerebellum. Important connecting link between the cerebellum and the rest of the nervous system. -Certain reflex actions (i.e. as in breathing) are integrated in the pons.
The hypothalamus
maintains homeostasis by controlling body temperature, water balance, sleep, appetite and some emotions. -The ANS is under control of the hypothalamus
dienccephalon
the area located between the cerebral hemispheres and the brain stem. -Includes the hypothalamus and the thalamus.
thalamus
two parts of the thalamus form the lateral walls of the third ventricle. sorts out the impulses and directs them to particular areas of the cerebral cortex.