Chapter

14

The Brain and Cranial Nerves

The cranial nerves CN I CN II CN III CN IV CN V CN VI CN VII CN VIII CN IX CN X CN XI CN XII Olfactory Optic Occulomotor Trochlear Trigeminal Abducens Facial Accoustic Glossopharyngeal Vagus Spinal Accessory Hypoglossal On Old Olympian Towering Tops A Finn And German Viewed Some Hopps

A Quick brain overview

cerebrum cerebral hemispheres neural cortex (gray matter) gyri ridges sulci depressions fissures fig. 14-1

Brain landmarks cerebrum conscious thoughts sensations intellect memory complex movements

fig. 14-1 cerebellar hemispheres coordinates complex muscle actions cerebellum

thalamus relay, process sensory info fig. 14-1 hypothalamus emotions, autonomics, hormones pituitary gland midbrain process visual hearing info pons fiber tract medulla oblongata autonomics, etc.

embryology brain: tube wall cavity

embryology five brain vesicles: telencephalon diencephalon mesencephalon metencephalon myelencephalon cerebrum thalamus mid cerebellum/pons medulla ob.

embryology five brain vesicles: all hollow fluid-filled spaces ventricles with CSF (cerebrospinal fluid)

brain ventricles: telencephalon diencephalon mesencephalon metencephalon myelencephalon lateral v third v cerebral aqueduct fourth v fourth v

fig. 14-2 third fourth cerebral aqueduct third fourth

ventricles (and central canal of the spinal cord) are all connected to each other all filled with CSF

brain is surrounded by: 1.bones of cranium 2.meninges

dura mater arachnoid mater pia mater 3.CSF

inside and around outside

CSF cushion brain/spinal cord supports brain transport nutrients/wastes produced by lining of cavities circultates in and around brain

blood supply to brain neural tissue does not have reserves of glucose, O 2 etc., has a very good blood supply internal carotid arteries vertebral arteries

blood supply to brain CVA (stroke) blood supply to part of the brain is cut off tissue begins to die infarction

blood supply to brain blood-brain barrier restrict access to neural tissue of most molecules capillary endothelial cells tight junctions astrocyte foot processes

astrocytes fig. 12-4

A&P Jeopardy What is a nucleus ?

The cellular organelle containing the DNA What is a nucleus ?

A collection of NCB in the CNS (nerve cell bodies) What is a ganglion ?

A collection of NCB in the PNS

review cranial nerves brain name and number 5 vesicles and fates CSF in and around CNS good blood supply to brain blood / brain barrier nucleus vs. ganglion

The Brain medulla oblongata autonomic reflexes cranial nerve nuclei relay stations

medulla oblongata all info brain spinal cord passes through

medulla oblongata autonomic reflexes heart rate heart contraction strength peripheral blood flow respiration rate

medulla oblongata motor nuclei for cranial nerves: CN IX, X, XI, XII muscles of pharynx, neck, back viscera

medulla oblongata sensory nuclei for cranial nerves: CN VIII from inner ear

medulla oblongata relay stations: nucleus gracilis nucleus cuneatus solitary nucleus olivary nucleus somatic sensory visceral sensory somatic motor

pons links cerebellum with… …everything else lots of tracts passing through

pons cranial nerve nuclei motor: CN V, VI, VII jaw and some face muscles sensory: CN VIII vestibular cochlear nuclei

cerebellum adjust postural muscles of body fine-tune motor movements

fig. 14-7

Purkinje cells in cortex each one can receive input from up to 200,000 synapses input from: proprioception visual tactile balance auditory

fig. 14-7

ataxia (lack of order) a disturbance in muscular coordination physical damage stroke drugs (EtOH)

mesencephalon corpora quadrigemina superior colliculi inferior colliculi

mesencephalon corpora quadrigemina superior colliculi relay for visual reflex center for eyes, head, neck response to bright light

mesencephalon corpora quadrigemina superior colliculi inferior colliculi relay for visual auditory reflex center for head, neck, trunk response to loud noise

mesencephalon tegmentum red nucleus control arm position and background muscle tone substantia nigra regulates basal nuclei

mesencephalon headquarters of RAS

diencephalon epithalamus pineal gland melatonin thalamus relay info to basal nuclei and cerebrum hypothalamus control and integration hormones, emotions d/n

diencephalon thalamus R & L separated by third v.

5 groups of nuclei anterior medial ventral posterior lateral

diencephalon thalamus anterior part of limbic system (later, emotions/motivation)

diencephalon thalamus medial connect emotional centers of hypothalamus with frontal lobes of cerebrum

diencephalon thalamus ventral info from basal nuclei to motor areas of cerebrum relay senses to cerebrum

diencephalon thalamus posterior integrate, relay sensory information to cerebrum LGN visual MGN auditory

diencephalon thalamus lateral feeback loops with limbic s emotions integration of senses

fig. 14-9

diencephalon hypothalamus below thalamus optic chiasm mamillary bodies infundibulum

fig. 14-10

diencephalon hypothalamus subconscious control of skeletal muscle (facial expression with emotions)

diencephalon hypothalamus control autonomic centers of medulla and pons heart rate, bp, resp, digest

diencephalon hypothalamus coordinate nervous and endocrine systems

diencephalon hypothalamus produce two hormones ADH antidiuretic hormone Oxytocin smooth muscle contraction

diencephalon hypothalamus produce emotions/drives hunger, thirst

diencephalon hypothalamus Coordinate Voluntary and Autonomic functions Take out a sheet of paper for a surprise 300 point quiz… increased heart rate, breathing, etc.

diencephalon hypothalamus regulate body temperature by controlling blood flow to the skin

diencephalon hypothalamus controls circadian rhythms

Early April Poster session (Centrum) Also other Biology seminars

The limbic system nuclei and tract along border of cerebrum and diencephalon functions: establish emotional states link conscious with unconscious facilitate memory storage/recall a “motivational system”

The limbic system limbic lobe of cerebrum (1) cingulate gyrus dentate gyrus parahippocampal gyrus

gyri conceal hippocampus (2)

learning long-term memory

fig. 14-11

fig. 14-11

The limbic system amygdaloid body (3) interface between limbic cerebrum sensory systems regulate heart rate (sym) link emotions/memories

The limbic system fornix fiber tract between hippocampus and hypothalamus

table 14-7

The cerebrum largest region of brain conscious thoughts intellectual functions processing of sensory and motor info surface is gray matter cerebral cortex

The cerebrum hemispheres (R and L) separated by longitudinal fissure divided into lobes

fig. 14-12

The cerebrum hemispheres (R and L) receive/send info to opposite side of body have different functions

The cerebrum white matter fibers association interconnect - same side commissural interconnect R and L projection fibers to other structures

label corpus callosum fig. 14-13

The cerebrum basal nuclei several nuclei caudate nucleus lentiform nucleus globus pallidus putamen

fig. 14-14

The cerebrum basal nuclei subconscious control of skeletal muscle tone coordination of learned movements

The cerebrum basal nuclei inhibited by dopamine from the substantia nigra if s.n. is destroyed or dopamine levels decline… basal nuclei are overactive… increase in muscle tone…

The cerebrum basal nuclei …Parkinson’s disease difficulty starting muscle movements

fig. 14-12

table 14-8

The cerebrum primary motor cortex frontal lobe pyramidal cells (UMN) piano analogy primary sensory cortex parietal lobe touch, pain, pressure, taste, vibrations, temp.

(if thalamus relays it)

fig. 14-15

mapping

The cerebrum other “sense” cortex visual auditory olfactory gustatory occipital temporal temporal frontal

fig. 14-15

The cerebrum association areas interpret incoming information

fig. 14-15

The cerebrum association areas interpret incoming information e.g., visual association area associate visual symbols with object C A R =

The cerebrum association areas interpret incoming information visual association area someone with damage here would “see” the symbols “C A R” but would have no idea that they mean something

The cerebrum premotor cortex coordination of learned movements repetition programs in “patterns” of stimulation back to the piano analogy

The cerebrum integrative centers receive lots of information direct extremely complex motor activities, analytical functions, … some centers are restricted to one side hemispheric lateralization

The cerebrum integrative centers for example: general interpretive center (aka Wernicke’s area; left side) receives input from all sensory areas

The cerebrum integrative centers for example: general interpretive center (aka Wernicke’s area; left side) damage affects ability to interpret what is seen and heard sit here

fig. 14-15b

The cerebrum integrative centers for example: speech center (aka., Broca’s area; left side) coordinates activity of pharynx, tongue, cheeks, jaw, lips, etc.,

The cerebrum integrative centers for example: prefrontal cortex receives and coordinates input from all association areas performs abstract intellectual functions, predicting consequences

The cerebrum integrative centers for example: prefrontal cortex generates feelings of frustration, anxiety, tension… severe its’ connections and remove those feelings

The cerebrum integrative centers for example: prefrontal cortex prefrontal lobotomy “cure” mental patients

The cerebrum hemispheric lateralization each hemisphere has specific functions not done by the other side

fig 14-6

The cerebrum Monitoring brain activity directly stimulate areas behavioral changes with injury Phineas Gage PET scan, MRI’s

The cerebrum Monitoring brain activity electrical activity: EEG (electroencephalogram) (brain waves)

The cerebrum Monitoring brain activity electrical activity: different wave patterns alpha beta theta delta

fig 14-17

normal resting adult concentration, stress children, frustrated adults deep sleep, injury

The cerebrum Monitoring brain activity electrical activity: seizure: temporary, drastic changes in electrical activity of cerebrum

epilepsy clinical conditions caused by a seizure

epilepsy and cutting corpus callosum split brain