the brain and cranial nerves

Four main divisions of the brain

Cerebrum diencephalon brainstem cerebellum

Two very important sulci

- central sulcus -lateral sulcus

Diencephalon

-(inter brain) located between the cerebral hemispheres and brain stem -includes thalamus and hypothalamus

Cranial nerves

-12 pairs -four categories -special sensory impulses -General sensory impulses -somatic motor impulses -visceral motor impulses

Techniques used to study the brain

-CT scan (computed tomography) -MRI (magnetic resonance imaging) -gives more views of the brain then CT and may reveal tumors, scar tissue, and hemorrhaging shown by CT -PET scan (positron emission tomography) -visualizes brain in action -electroencephalograph (eeg) -Records electric current given off by brain nerve cells, and used to Study sleep patterns, diagnosed diseases, Help locate tumors, Study drug effects, determine brain death

Cerebrospinal fluid

-Clear liquid that supports nervous tissue and cushions from shock -also carries nutrients to cells and transports waste products from cells -formed in four spaces within the brain called ventricles

Temporal lobe

-Contains auditory, speech comprehension, and all factory areas -contains Wernicke Area(speech comprehension area) if area damaged heyA person will have difficulty understanding the meaning of speech

Cerebral cortex

-Layer of gray matter that covers each hemisphere of the cerebrum (2 to 4 MM thick) -neuronal cell bodies and synapses in this region are responsible for conscious thought, reasoning, an abstract mental functioning's -arranged into folds forming a elevated portions known as gyri and shallow grooves which separate gyri known as sulci (singular sulcus)

Function of the brain

-Sensory information is processed -responses are coordinated -higher functions of reasoning learning and memory occurs

Corpus callosum

-band of white matter -located at the bottom of the longitudinal Fissure -this band is the bridge between right and left hemispheres permitting impulses to cross from one side to the other

Brainstem

-below anterior cerebrum -divided into three sections 1. Midbrain-contains visceral and auditory reflect centers 2. Pons-regulates respiration 3. Medulla oblongata- connects with the spinal cord

Brainstem

-composed of three parts - midbrain - pons - medulla oblongata - these structures connect the cerebrum and diencephalon with the spinal cord

pons

-connecting link between the cerebellum and the rest of the nervous system -regulates some reflexes involving respiration

Frontal lobe

-contains areas for motor and speech -involves areas for memory, problem-solving, and conscious thought -contains broca-the motor speech area (usually found in the left hemisphere) planned sequences of muscle contractions and Tom larynx and soft palate required to form meaningful sentences people with damage to this area are affected by brocus aphasia

medulla oblongata

-contains many myelinated nerve fibers -contains -respiratory center- (Controls the muscles of respiration in response to chemical another stimuli) -cardiac center-(helps regulate the rate and force of the heartbeat -vasomotor center-(regulate contraction of smooth muscles in the blood vessels, controlling bloodflow and Blood pressure) -contralateral (opposite side) Control. (tracs cross)

occipital lobe

-contains visual areas

lateral sulcus

-curves along the side of each hemisphere and separate temporal lobe from the frontal and parietal lobes

Aging

-decreased brain size and weight -decreased speed of information processing -slow movements -diminished memory -reduced blood flow to brain

Ventricles

-four fluid filled spaces within the brain -two lateral -third -fourth -contains choroid plexuses which are a network of ependymal cells and blood vessels which manufacture CSF

hypothalamus

-helps maintain homeostasis by controlling body temperature, water balance, sleep, appetite, and some emotions such as fear and pleasure -under control of sympathetic and parasympathetic divisions of the ANS -influences heartbeat, the contraction and relaxation of blood vessels, and hormone secretion -also contains the pituitary gland

Pia mater

-innermost layer around the brain -attached and nervous tissue of brain and spinal cord and follows contours of the structures -holds blood vessels that supply nutrients and oxygen to the brain and spinal cord

Cerebrum

-largest and most superior part of the brain -divided into left and right hemispheres; subdivided into lobes

The cerebrum

-largest and most superior part of the brain -divided into two hemispheres buy a deep groove called the longitudinal Fissure -each hemisphere is divided into four lobes

central sulcus

-lies between the frontal and parietal lobes of each hemisphere

Arachnoid

-loosely attached to Pia mater by weblike fibers -form space between to meninges where CSF circulates and blood vessels pass-through

Protective structures of the brain and spinal cord

-meninges -cerebro spinal fluid

Dura Mater

-most outer layer -thickest and toughest of the meninges -includes two layers, the outer layer is fused to the cranial bones. Insert these two layers separate to provide venous channels Called Dural sinuses. (drainage of blood coming from bring capillaries)

5 lobes of the cerebral hemispheres

-named after overlying cranial bones - Frontal, parietal, temporal, occipital lobes -fifth Lobe is that insula which is deep in the hemispheres

Parietal lobe

-occupies superior part of each hemisphere -contained in the gyrus of this area is the somatosensory area- where are impulses from the skin such as touch, pain, and temperature I received -contain sensory areas

Cerebellum

-posterior to the brainstem -divided into two hemispheres -cordinator voluntary muscle , maintains balance, and muscle tone

Diencephalon

-sits in the center of the brain between the two hemispheres -contains thalamus and hypothalamus

thalamus

-sort out the impulses and directs them to particular areas of the cerebral cortex

The midbrain

-superior part of the brain stem -four rounded masses of gray matter form the superior part of the midbrain and act as centers for certain reflexes, involving the eye and ear -White matter at the anterior of the midbrain conducts impulses between higher centers of the cerebrum and lower centers of the pons, medulla, cerebellum, and spinal cord

Cerebellum

-three parts -vermis -two lateral hemispheres -has an outer layer of Gray matter an inner portion that is mainly white matter -functions -helps coordinate voluntary muscle -helps maintain balance -helps maintain muscle tone

Memory

Includes -short term memory And -long-term memory

Hypothalamus

Maintains homeostasis, Controls autonomic nervous system and pituitary gland

Thalamus

Sorts and redirects sensory input

Ependymal cells

Specialized neuroglial cells

Meninges

Three layers of connective tissue that surrounds both the brain and spinal cord to form a complex enclosure The three divisions are 1. dura mater 2. Arachnoid 3. Pia mater