unit 12
structures protecting the brain
-protecting from trauma bone meninges (membranes) cerebrospinal fluid (watery cushion) -protection from infection and toxicity blood brain barrier
spinal cord
-provides two-wat communication to and from brain -contains spinal reflex centers
limbic system
-structures parts of diencephalon some cerebral structures and encircle brain stem -functions emotions/emotional response memory via hippocampus
reticular activating system
-structures three broad columns running length of brain stem -functions filters out repetitive familiar, or weak stimuli inhibited by sleep centers, alcohol, drugs servers injury results in permanent unconsciousness
meninges
-three layers dura mater arachnoid mater pia mater -functions cover and protect CNS protect blood vessels and enclose sinuses contains CSF -inflammation is called meningitis
Lateralization of cerebral function
right hemisphere -usually dominates for visual-spatial skills, intuition, emotion, and artistic skills
Functional areas of the cerebral cortex
sensory: parietal, insular, temporal, and occipital lobes, conscious awareness of sensation
alzheimers disease
-a neurogenerative disease that results in dementia and emotional changes -causes are hotly debated -associated with amyloid plaques, neurofibrillary tangles -brain shrinkage
medulla oblongata functions
-addition centers regulate vomiting hiccuping swallowing coughing sneezing
white matter fibers tracts connect parts of the CNS to each other
-association fibers connect different parts of same hemisphere -commissural fibers (connect corresponding part of different hemispheres) -projection fibers (connect cortical areas to parts outside the cortex)
blood Brian barrier
-astrocytes are responsible for BBB formation -barrier is much tighter than in capillaries in other parts of body -epithelial tight junctions -controls the chemical environment for the brain -separates brain from blood borne substance water soluble drugs, pathogens, immune cells
brainstem functions
-autonomic behaviors for survival -fiber tracts between higher and lower centers -nuceli associated with 10/12 cranial nerves
medulla oblongata functions
-autonomic reflex center functions overlap with hypothalamus -cardiovascular center adjusts force and rate of heart contraction adjusts blood vessel diameter for blood pressure regulation -respiratory centers generate respiratory rhythm control rate & depth of breathing (with pons)
hypothalamus functions
-body temperature -hunger and satiety -thirst and water balance -sleep-wake cycles -endocrine system control
major sulk of the human brain
-central sulcus separates frontal lobe and parietal lobes -longitudinal fissure separates hemispheres -transverse cerebral fissure separates cerebrum and cerebellum
four major adult brain regions
-cerebral hemisphere -diencephalon -cerebellum -brain stem midbrain pons medulla oblongata
cerebrospinal fluid
-compostion mostly water & electrolytes -functions protects CNS from blows and other trauma nourishes brain and carries chemical signals
diencephalon
-consists of three paired structures 1. thalamus 2. hypothalamus 3. epithalamus -diencephalon encloses the third ventricle
pia mater
-deepest of the meninges -contains many small blood vessels -clings tightly to brain
pons
-fourth ventricle separates pons and cerebellum -relay impulses between motor cortex and cerebellum -nuceli help maintain normal rhythm of breathing
Basal ganglia (basal nuclei)
-group of there nuclei caudate nucleus putamen globus pallidus -functions filter out incorrect or inappropriate response (emotional & motor) starting and stopping slow and stereotypes movements
the human cerium is not smooth
-gyri are ridges on the cerebral surface -sulci are shallow grooves -fissures are deep grooves
choroid plexuses
-hang from roof of each ventricle -clusters of capillaries -lines with ependymal cells -produced and circulate CSF -CSF is replaced every 8 hours
hypothalamus
-inferior to thalamus -contains many nuclei for many tasks -connected to the pituitary gland by the infundibulum
cerebellum
-input from cortex, brain stem and sensory receptors -abor vitae is the treelike pattern of cerebellar white matter -regulates smooth and coordinated movements muscle memory
thalamus
-largest structure of the diencephalon -relay station for input to the cerebral cortex
contusion
permanent neurological damage caused by concussion-related bruising of the brain
medulla oblongata
-joins spinal cord ay foramen magnum -decussation of the pyramidal tracts
brainstem structures
1. midbrain 2. pons 3. medulla oblongata
formation and circulation of CSF
1. produced by choroid plexus of each ventricle 2. flows through ventricles into subarachnoid space 3. flows through subarachnoid space 4. absorbed into dural venous sinuses
neurons are organized topographically in the
primary motor cortex and primary somatosensory cortex
Specific sensory functions are concentrated in brain areas
olfaction (smell) - temporal gustation (taste) - insular vestibular (balance) - insular
concussion
a temporary alteration in brain function following a blow to the head. mild TBI
Functional areas of the cerebral cortex
association: nearby related motor and sensory areas, integrate diverse information
cerebral edema
brain swelling;ong caused by excess fluids. very serious and can cause death on its own
major regions of the cerebrum in cross section
cerebral cortex (gray matter) white matter basal ganglia
flax cerebrium
extension of dura mater into the longitudinal fissure attached to crest Galli
tentorium cerebelli
fold of the dura mater over the cerebellum -in the transverse fissure
five cerebral lobes
frontal lobe insula temporal lobe parietal lobe occipital lobe
arachnid mater
intermediate layer of the meninges subarachnoid space contains CSF and large blood vessels arachnid villi protrude into superior sagittal sinus and permit CSF reabsorption
four ventricles
lateral ventricle cerebral aqueduct fourth ventricle third ventricle
Lateralization of cerebral function
left hemisphere -usually dominates for language, math and logic
four ventricles contain cerebrospinal fluid
lined by ependymal cells that circulate CSF
dura matter
most superficial of the meninges limits excessive brain movements
Functional areas of the cerebral cortex
motor: frontal lobe, control voluntary movement
functional brain systems
networks of neurons that work together but span wide areas of the brain
epithalamus (pineal gland)
the roof of the third ventricle secretes melatonin -regulates sleep-wake cycle
Specific sensory functions are concentrated in brain areas
visual - occipital touch, temp, pressure - parietal auditory - temporal