Psych 255-lecture 3

What are the three layers of the meninges?

• dura mater

• arachnoid membrane

• pia mater

Describe the dura mater

layer of matter softer than the skull and acts as a bag but does not tightly grip the brain and spinal cord

• encloses the brain and spinal cord in a loose sac

Describe the arachnoid membrane

A layer with spider web like quality that clings directly to the brain

• ultrathin layer of delicate connective tissue that follows the brain’s contours

Describe the pia mater

The thinner/more delicate layer directly attached to the brain

• moderately tough membrane of connective tissue that clings to the brain’s surface

What is the subarachnoid space?

The space between the brain is filled with CSF

What is the importance of CSF?

cushions the brain so that it can move or expand slightly without pressing on the skull 

What is encephalitis?

Infection of the brain caused by a number of different viruses or microorganisms

What is the gyrus?

Bumps on the brain’s surface

What is the cerebral cortex?

The brain’s outer layer

What are sulci?

cracks on the brain’s surface

what are longitudinal fissures?

fissures that run from anterior to posterior and separates left and right hemispheres

What are lateral fissures?

Fissures that run along the sides of the brains

• separates the temporal lobe from the frontal lobe and the parietal lobe

What are central fissures?

Separates the frontal lobes from the parietal lobes

What are the cerebral arteries?

• arteries that feed blood to the brain

• emerge from the neck and wrap around the outside of the brainstem, cerebrum, and cerebellum finally penetrating the brain’s surface

What are the there major arteries that send blood to the brain?

• Anterior cerebral artery (ACA): irrigates the anterior portion of the brain

• Middle cerebral artery (MCA): irrigates the middle of the brain, slightly in the frontal , parietal, and much of the occipital lobe

• Posterior cerebral artery (PSA): extensive branching to irrigate the temporal and occipital lobe

What is gray matter composed of?

predominantly composed of cell bodies and blood vessels 

What is the function of neurons within gray matter?

these neurons collect and modify information before sending it along

What is white matter composed of?

predominantly composed of axons, nerve fibers covered by myelin sheaths

gray matter surrounds white matter in the _____

brain

White matter surrounds gray matter in the ______

spinal cord

What is the function of white matter?

forms long distance connections between and among some of the brain’s neurons

what are the lateral ventricles?

two wing shaped cavities that contain CSF

what is the choroid plexus?

A network of blood vessels that line the ventricles and produce the CSF that fills the four ventricles

What is the corpus callosum?

the major area of white matter connecting the two hemispheres using nerve fibers

What is the function of the corpus callosum?

Allows the two hemispheres to communicate

What is a tract?

A connection of nerve fibers in the brain and spinal cord

What is a nerve?

A bundle of fibers outside the CNS

Where is CSF created?

Created in the ventricles

What is the function of CSF?

• Suspends the brain making it buoyant so that it allows the mass of the brain to seemingly be reduced by 1/3rd

• also absorbs shock

• has regulated chemical content to provide an optimal environment for the brain to function

What are the four component parts of the corpus callosum?

• Splenium

• body: majority of the corpus

• genu: the region that bends

• rostrum: the region found beneath the genu

What is the function of the brainstem?

• it recieves afferent signals from the body and sends efferent signals out to the spinal cord

• responsible for most life sustaining behavior

What are the four components of the hindbrain?

• pons

• medulla

• cerebellum

• reticular formation

What is the function of the hindbrain?

Controls motor functions

What is the reticular formation?

A net like mixture of gray and white matter with nuclei that function in stimulating the forebrain

What is the function of the medulla?

Regulates essentials such as heart rate and breathing and contains structures that control many vital functions

What is the most distinctive feature of the hindbrain?

cerebellum

What is the function of the cerebellum?

• Primarily muscle control including balance and movement

• also plays a role in cognitive functions

What are the functions of the pons?

• Acts as a relay station: a system that carries messages from the brain and spinal cord back and forth

• contains structures that control many vital functions

What are the two major regions of the midbrain?

• tectum

• tegmentum

What are the two components of the tectum?

• superior colliculi

• inferior colliculi

What is the function of the superior colliculi?

handles visual information processing coming from the optic nerve

What is the function of the inferior colliculi?

handles auditory information processing coming from the auditory pathways

What kind of information does the tectum process?

Sensory information

What kind of information does the tegmentum process?

Motor information

What is the periaqueductal gray matter?

gray matter made up of cell bodies that surrounds the cerebral aqueduct

What is the function of red nucleus?

• controls limb movements

• involved in motor movement but not directly

What is the function of the substantia nigra?

• nuclei involved in motor movements particularly walking

What are the two components of the diencephalon?

• thalamus

• hypothalamus

What is the function of the diencephalon?

• integrate sensory and motor information on its way to the cerebral cortex

What is the function of the thalamus?

• organizes and integrates sensory information traveling to the cerebral cortex from all sensory systems

• recieves information then sends it to the correct area of the spinal nerve or cortex

What is the major function of the hypothalamus?

plays a key role in regulating hormones in the pituitary gland and ensures the correct levels of hormones and the correct feedback loops