Ch. 15 11/1/15 4:03 PM

Which hemisphere region is responsible for motor function, responsible for higher thinking, planning, abstract thinking?

Major Brain Structures: Embryonic through Adult  

• In human embryo Brain forms from cranial part of Neural Tube,  undergoes growth in different regions and forms 3 primary brain  vesicles (Forebrain, Midbrain, Hindbrain)

• Forebrain (Separates into two brain vesicles as a newborn) o Telencephalon - which forms the Cerebrum

???? Cerebrum (cerebral cortex)- 13 weeks, by 26 it  

overgrows all other parts of the brain, responsible for  

our ability to function at a higher level than other  

animals, allows us to think creatively, most developed,  

Hypothalamus is responsibe for what?

fastest growing

✂ Right Hemisphere

✂ Left Hemisphere

✂ Longitudinal Fissure – divides right and left  

hemisphere, deep sulci  

✂ Each Hemisphere is Divided into Regions (Frontal  

lobe, Occipital lobe, Parietal lobe, Temporal lobe,  

Insula)  

• Insula – small lobe deep to the lateral  

sulcus, under the temporal lobe  

• Frontal Lobe – responsible for motor  

function, responsible for higher thinking,  If you want to learn more check out What is gender schema theory?

planning, abstract thinking  

• Parietal Lobe – main area of sensory,  

What is cranial never #3?

general sensation (pain, touch, temp.,  

pressure), responsible for sensation of  

taste, participate in recognition of speech

• Occipital Lobe – visual cues, colors, shapes,  

depth perception

• Temporal Lobe – interpretation of audio  

signals, meaning of speech

✂ As the brain grows it becomes folded and forms  

the Gyri and the Sulci in the cerebrum  

• Gyrus - Protruding part, folds of cortical  

tissue

o Pre-central Gyrus - in front of the  

central sulcus, movement, motor  

cortex, responsible for precision of  

muscle contractions, more precise  

movement = more neurons more  

signals to more muscles

o Post-central Gyrus – behind central  

sulcus, interpretation of senses

o Alzheimers Disease – neurons are  

disappearing and gyri become narrow  

and the sulci widen  

• Sulcus - gap between the gyri  

o Lateral Sulcus – deep groove that  If you want to learn more check out What contains each level of maslow’s hierarchy of needs?

separates frontal and parietal lobe  Don't forget about the age old question of What is a hypothesis test?

from temporal lobe

o Central Sulcus – marks the boundary  

with the parietal lobe

✂ When cut the Cerebrum coronally  

• Cerebral cortex Gray matter – cell bodies of  

the neurons, so numerous they want to be  

on the outside because surface area larger  

on the outside, all axons extend in forming  

subcortical white matter

• Subcortical White Matter – axons of neurons  

o Diencephalon - forms the Thalamus, Hypothalamus, and  Epithalamus (only need to know the thalamus and  Hypothalamus) We also discuss several other topics like What are the types of predators?

???? Thalamus – relay station for info travelling to cerebral  cortex, the place that knows where the information has  to process, responsible for awareness of emotional  states  

???? Hypothalamus – responsible for homeostasis (balance)  of temperature, letting you know when you have to eat  (1. Autonomic functions, 2. Produce hormones, 3.  Emotional and behavioral drives, 4. Body Temperature)Don't forget about the age old question of What are the pros and cons of electroencephalography (eeg)?

✂ Contains the pituitary gland – epithelial tissue,

master endocrine gland: stimulate adrenal gland  

and thyroid gland to produce hormones

Other Features of the Cerebrum  

Cerebral Nuclei (also called basal nuclei and mistakenly called the Basal  Ganglia – clusters, paired, irregular masses of gray matter buried deep  within the central white matter in the basal region of the cerebral  hemispheres.  

• Cerebral Nuclei have the following components:  

o Caudate Nucleus - person begins to walk, the neurons in this  nucleus stimulate the appropriate muscles to produce the  pattern and rhythm of arm and leg movements for walking o Amygdaloid body – expanded region at tail of Caudate  Don't forget about the age old question of It is a type of memory that holds information for a brief period of time, what is it?

Nucleus, participates in expression of emotion, control of  

behavior, and development of moods

o Putamen & Globus Pallidus – both are two masses of gray  matter between external surface of insula & lateral wall of  diencephalon, together they form the Lentiform Nucleus

???? Putamen – controls muscle movement at subconscious  level  

???? Globus Pallidus – excites and inhibits activities of the  

thalamus to control & adjust muscle tone  

o Corpus Striatum – the striped or striated appearance of the  internal capsule as it passes by the Caudate Nucleus and  

Lentiform Nucleus  

• Basal Ganglia Disorders  

o Parkinson’s Disease - Stiff frozen limbs and rigid muscles o Hypokinesia = slowness of movement, Comes from dopamine  depletion

o Hyperkinesia - excessive movement, Arises from  

degeneration of caudate nucleus

o Huntington’s Disease (Chorea) - Excessive motion & flailing  limbs

• Midbrain

o Doesn’t change very much

o Posterior Region of Midbrain (aka Tectum) – most posterior  and superior part  

???? Contains Two pairs of sensory nuclei (Superior and  

Inferior Colliculi) collectively called the Corpora  

Quadrigemina or Tectal Plate or Quadrigeminal plate

✂ Corpora Quadrigemina – quick movements of the  

head and neck  

• Superior Colliculus – visually track moving  

objects and control reflexes such as turning  

the eyes and head in response to visual  

stimulus  

• Inferior Colliculus – control reflexive turning  

of the head & eyes in direction of sound

o Anterior Region of the Midbrain (aka Tegmentum) – most  anterior, takes information from cerebrum and cerebellum  and issues commands to erector spinae muscles to maintain  posture while standing, bending at waist, & walking

???? Red Nucleus

???? Substantia Nigra (“Black substance”) – make a lot of  

dopamine (which affects brain processes that control  

movement, emotional response, and ability to  

experience pain and pleasure)

???? Cerebral Peduncles – most anterior  

• Hindbrain – divides in two vesicles  

o Pons – brainstem nuclei and respiratory centers responsible  for proper rhythm of respiration, houses sensory and motor  cranial nerve nuclei for the trigeminal (CN V), abducens (CN  VI), and facial (CN VII) cranial nerves.

o Medulla Oblongata – brainstem nuclei, respiratory & cardiac  control centers (stimulates things like heart rate speeding up  and monitoring of normal functions of the heart)

o SEPARATE YET CONNECTED Cerebellum – responsible for  coordination of movement, balance, equilibrium, skilled  

movement, diseases produce “ataxia”  

Brain and Cranial Nerves

• 2 sets of 12 Cranial nerves, they are paired 12 on left and 12 on  right  

o Cranial Nerve I: Olfactory – bipolar neurons in nasal  cavity, carries smell  

???? Olfactory Bulb forms cable like structure that travels  into the brain that carries the smell to the temporal  

lobe for interpretation  

o Cranial Nerve II: Optic – receptors are cones and rods that  are sensitive to colors and intensities/shades, info travels  through optic nerve and cross the optic chiasm so part of  what left eye sees the right eye see and vice versa. Allows us  to form 3D image, interpreted in the Visual Cortex  

(occipital lobe)

o Cranial Nerve III: Oculomotor – responsible for eye  movement, movement originates in Frontocerebral lobe  specifically in the prefrontal gyrus  

???? Stimulates the  

✂ Superior Rectus

✂ Medial Rectus

✂ Inferior Rectus

✂ Inferior Oblique  

o Cranial Nerve IV: Trochlear – Superior Oblique, eye  o Cranial Nerve V: Trigeminal – all general sensation from  the head, sensory: skin of face, forehead, teeth, lips, gum,  (touch, pain), Motor: muscles of mastication

o Cranial Nerve VI: Abducens – lateral rectus is the muscle  activated by these nerves, eye  

o Pneumonic = [LR6(SO4)]AO3 for what the optic nerves innervate, cranial nerve 6 moves the Lateral Rectus muscle  (abduction of the eye, eyes going outwards), Superior Oblique  is innervated by cranial nerve 4, All Other- the ocular motor  nerve moves all others (inferior oblique, medial, inferior, &  superior rectus)

o Cranial Nerve VII: Facial – Sensory: taste to anterior 2/3  of tongue, motor: muscles of facial expression, parietal lobe is  where taste is recognized

???? Bell’s Palsy – inflammation of facial nerve, paralysis of  CN VII (facial nerve), loss of motor to muscles of facial  expression, stapedius muscles, taste anterior 2/3  

tongue  

o Cranial Nerve VIII: Vestibulocochlear – nerve responsible  for hearing and balance, sensory: vestibular portion = sense  of balance, sensory: cochlear portion = sense of hearing  

o Cranial Nerve IX: Glossopharyngeal – provides pathway  for taste to travel, sensory: taste to posterioe 1/3 of tongue,  motor: pharyngeal muscles (swallowing)  

o Cranial Nerve X: Vagus – wanders away from the cranium,  provides mixed stimulation for and from the thorax and entire  abdominal cavity, Sensory: to pharynx, ear canal, visceral  organs in thorax & abdominopelvic cavity, Motor: pharyngeal  muscles and visceral organs in thorax & abdominopelvic  cavity

o Cranial Nerve XI: Accessory Nerve – motor innervation,  provides stimulation to sternocleidomastoid and trapezius  o Cranial Nerve XII: Hypoglossal – Motor: to tongue muscle,  originates in pre-central gyrus  

• Cranial Meninges – connective tissue covering the brain o Dura Mater – superficial outermost, tough protective layer  “tough mother”  

???? Dural Folds  

✂ Falx Cerebri- Double layer of the dura mater  

inside of the longitudinal fissure

✂ Falx Cerebelli – double layer of dura that  

separates right and left hemisphere of cerebellum  

✂ Tentorium Cerebelli - Double layer of dura mater  

between cerebellum and cerebrum  

✂ Superior Sagittal Sinus – formed by dual layer of  

dura  

o Arachnoid Mater – beneath the dura mater, spiderweb looking  layer  

o Pia Mater – “Delicate mother”

o The space between the pia and arachnoid is filled with  cerebrospinal fluid, the cells producing this are the glial cells,  fluid provides suspension for the brain and a sort of  

protection  

• Ventricles of the Brain – fluid filled cavities within the brain, don’t  contain any neurons don’t respond to sensation, lined by glial cells  (ependymal cells) that are cuboidal epithelial cells  

o Lateral Ventricles – fluid produced in both right and left  ventricle

o Third Ventricle – narrow space, from here the fluid flows  posteriorly under brain and brain stem into fourth ventricle  o Fourth Ventricle – in the posterior under the cerebellum,  pathway from third to fourth is called cerebral aqueduct

o Flow of Cerebrospinal Fluid (CSF)  

???? Made by choroid plexus (exists in lateral ventricles)  

???? Exits ventricles via arachnoid granulations  

HOMEWORK TABLE 15.7

Responsible for the roman numerals of the cranial nerves, names,  functions (not the parasympathetic association)

National Geographic Link for testing ourselves not for studying  Exam NOT next Thursday but following Tuesday (November 10)