EXAM 4 BIO 201

Explain the consequences of a lack of blood flow to the brain

10-second may cause loss of consciousness 1- to 2-minute causes impairment of neural function 4 minutes without blood causes irreversible brain damage

Medulla Oblongata

Begins at foramen magnum of the skull 3 cm extension of spinal cord Ascending and descending nerve tracts Nuclei of sensory and motor Cranial Ns (IX, X, XI, XII)

Compare blood-CSF barrier and blood-brain barrier

Blood brain barrier blood capillaries throughout the brain tissue tight junctions between endothelial cells astrocytes reach out and contact capillaries with their perivascular feet Blood CSF barrier capillaries of the choroid plexus ependymal cells have tight junctions

Pons

Bulge in the brainstem Rostral to the medulla Ascending sensory tracts Descending motor tracts Pathways in & out of cerebellum Cranial nerves V, VI, VII, and VIII

List the components of the forebrain

Cerebrum Diencephalon Hypothalamus Epithalamus

Describe CSF and how it is produced

Clear liquid fills ventricles and canals & bathes its external surface (in subarachnoid space) Brain produces & absorbs about 500 ml/day filtration of blood through choroid plexus

• Define somesthetic sensation

Comes from receptors widely distributed throughout the body touch, pain, pressure, stretch, movement, heat, cold Somatosensory area is postcental

Brain Lesion of Parietal Lobe

Contralateral neglect syndrome unaware of objects or limbs on one side of body

Describe the sensory homunculus

Demonstrates that the area of the cortex dedicated to the sensations of various body parts is proportional to how sensitive that part of the body is

List the components of the brainstem

Diencephalon* Midbrain Pons Medulla oblongata

List and describe the meninges of the brain, as well as all of the layers and spaces that are associated

Dura mater -- outermost, tough membrane outer periosteal layer against bone inner meningeal layer Subdural layer sinuses draining blood from brain supportive structures formed by dura mater falx cerebri, falx cerebelli and tentorium cerebelli Arachnoid mater is spider web filamentous layer Pia mater is a thin vascular layer adherent to contours of brain

Compare and contrast gray and white matter

Gray Matter neuron cell bodies, dendrites, and synapses forms cortex over cerebrum and cerebellum forms nuclei deep within brain White matter bundles of axons forms tracts that connect parts of brain

Describe the location and functions of the reticular formation

Gray matter, pons, midbrain and medulla Regulate balance and posture relays information from eyes and ears to cerebellum Regulates sleep and conscious attention Includes cardiac and vasomotor centers pain modulation Controlling pain

Define habituation

Habituation - ignoring repetitive, inconsequential stimuli injury leads to irreversible coma

Define Language

Includes reading, writing, speaking & understanding words

Describe meningitis - list the signs and symptoms and describe how it is diagnosed

Inflammation of the meninges Bacterial and virus invasion of the CNS by way of the nose and throat Signs include high fever, stiff neck, drowsiness and intense headache and may progress to coma Diagnose by examining the CSF lumbar puncture (spinal tap)

Cerebral Lateralization

Left hemisphere is categorical hemisphere specialized for spoken & written language, sequential & analytical reasoning (math & science), analyze data linearly Right hemisphere is representational hemisphere perceives information more holistically, perception of spatial relationships, pattern, comparison of special senses, imagination & insight, music and artistic skill

Describe the limbic system

Loop of cortical structures surrounding deep brain amygdala, hippocampus, fornix & cingulate gyrus

Describe the basal nuclei and its functions

Masses of gray matter deep to cerebral cortex Receive input from substantia nigra & motor cortex motor control & inhibition of tremors

List the components of the hindbrain

Medulla Oblongata Pons Cerebellum

Cognition

Mental processes such as awareness, perception, thinking, knowledge and memory association areas = 75% of brain integration of sensory and motor information occurs

Cerebellum

Monitors muscle contractions Aids in motor coordination Comparing textures without looking at them Spatial perception and comprehension of different views of three-dimensional objects belonging to the same object Timekeeping center Predicting movement of objects Helps predict how much the eyes must move in order to compensate for head movements and remain fixed on an object Hearing - distinguish pitch and similar sounding words Planning and scheduling tasks Lesions may result in emotional overreactions and trouble with impulse control many children with ADHD have small cerebellums

Diencephalon: Thalamus

Oval mass of gray matter protrudes into lateral ventricle and 3rd ventricle Receives nearly all sensory information on its way to cerebral cortex Relays signals from cerebellum to motor cortex Emotional and memory functions - limbic system

Epithalamus (Pineal Gland)

Pineal gland - secretes melatonin & plays a role in the production of seratonin Habenula -connects limbic system to midbrain

Emotion regions of the brain

Prefrontal cortex controls how emotions are expressed (seat of judgement) Emotions form in hypothalamus & amygdala

REM Sleep

REM sleep occurs about 5 times a night rapid eye movements under the eyelids vital signs increase EEG resembles awake person dreams and penile erections occur may help sort & strengthen information from memory

Explain what happens in our brain when we are sleeping

Restorative effect brain glycogen levels increase memories strengthened synaptic connections reinforced or eliminated

Define rostral, caudal, cortex, nuclei and tracts

Rostral - toward the nose Caudal - toward the tail Cortex = surface layer of gray matter Nuclei = deeper masses of gray matter Tracts = bundles of axons (white matter

Midbrain

Short segment of brainstem - connects hindbrain to forebrain Contains motor nuclei of 2 cranial nerves for eye movements CN III (oculomotor) and CN IV (trochlear)

Cerebral peduncles

Substantia nigra- dark gray nucleus pigmented with melanin Motor center that relays inhibitory signals to thalamus and basal nuclei preventing unwanted body movement Degeneration of neurons = tremors of Parkinson disease Cerebral crus - connect the cerebrum to the pons Carries corticospinal tracts Tegmentum Dominated by the red nucleus - high density of blood vessels Connections go to and from cerebellum Collaborates with cerebellum for fine motor control

Insula - internal lobe

Understanding spoken and written language, taste and sensory info from visceral receptors

suprachiasmatic nucleus

acts as biological clock to set our circadian rhythym Controlled by hypothalamus, reticular formation, thalamus, and cerebral cortex

Brain Lesion of Temporal Lobe

agnosia - inability to recognize objects prosopagnosia - inability to recognize faces

Brain Waves

alpha: awake & resting with eyes closed beta: eyes open performing mental tasks theta: emotional stress delta: deep sleep

Contrast anterograde and retrograde amnesia

anterograde amnesia -- can not store new data retrograde amnesia -- can not remember old data

Temporal Lobe

areas for hearing, smell, learning, memory, emotional behavior

Explain the function of CSF

buoyancy - the actual mass of the human brain is ~1400g, however the net weight of the brain suspended in CSF = ~25g protection - cushions from hitting inside of skull Chemical stability - rinses away wastes

Compare the volume of the cerebrum and cerebellum

cerebrum is 83% of brain volume cerebellum contains 50% of the neurons

Concussion

damage to brain from blow to head loss of consciousness, visual/equilibrium disturbances

aprosodia

flatless speech

Lesion to Wernicke's

fluent aphasia speech normal & excessive, but makes little sense

Broca's area

generates motor program for larynx, tongue, cheeks & lips

Diencephalon: Hypothalamus

hormone secretion Autonomic NS control thermoregulation food and water intake hunger and satiety sleep and circadian rhythms memory mammillary bodies emotional behavior

Visual association area (occipital lobe)

identify the things we see faces are recognized in temporal lobe

Amygdala

important in emotions

Hippocampus

important in memory

Encephalitis

inflammation of brain due to infection neuronal degeneration, necrosis delirium, seizures, death

Define association areas

interpret sensory information

List the ventricles and canals of the brain

lateral ventricles - inside cerebral hemispheres third ventricle - a single vertical space under corpus callosum cerebral aqueduct - runs through midbrain fourth ventricle - small chamber between pons & cerebellum and is caudal central canal - runs down through spinal cord

Cerebral palsy

muscular incoordination damage to brain during fetal development

Lesion to Broca's

nonfluent aphasia slow speech, difficulty in choosing words entire vocabulary may be 2 to 3 words

Wernicke's area

permits recognition of spoken & written language & communication

Somesthetic association area (parietal lobe)

position of limbs, location of touch or pain, and shape, weight & texture of an object

Brian Lesion of Frontal Lobe

problems with personality inability to plan and execute appropriate behavior

Motor homunculus

proportional to number of muscle motor units in a region (fine control)

Parietal

receives and integrates sensory information

Auditory association area

remember the name of a piece of music or identify a person by his voice

Migraine Headache

severe recurring headaches accompanied by nausea, vomiting, dizziness, light aversion

Special senses

smell, taste, vision, hearing & equilibrium

Anomic aphasia

speech & understanding are normal but text & pictures make no sense

List the stages of sleep

stage 1 is drifting sensation would claim was not sleeping stage 2 still easily aroused stage 3 vital signs change BP, pulse & breathing rates drop reached in 20 minutes stage 4 is deep sleep -- difficult to arouse

Describe the brain barrier system

strictly regulates what substances can get from the bloodstream into the tissue fluid of the brain

Epilepsy

sudden massive discharge of neurons = seizures trauma, tumors, drugs, infections, congenital brain malformation

Locations of special senses

taste is lower end of postcentral gyrus smell is medial temporal lobe & inferior frontal lobe vision is occipital lobe Hearing is superior temporal lobe equilibrium is mainly the cerebellum, but to unknown areas of cerebral cortex via the thalamus

Schizophrenia

thought disorder involving delusions

Occipital Lobe

visual center

Frontal Lobe

voluntary motor functions planning, mood, smell and social judgement