3 connective tissue membranes that surround & protect the brain

outermost, thickest; tightly attached to periosteum of cranial cavity

subdural space

contains small amount of serous fluid

CSF & blood vessels that supply the brain

Cerebrospinal fluid

CEREBROSPINAL FLUID:

clear, colorless fluid produced in the brain

Functions ot the

CEREBROSPINAL FLUID:

delivery of nutrients and removal of waste, shock absorber

Composition of the

CEREBROSPINAL FLUID:

glucose, proteins, some ions, some white blood cells

superior sagittal sinus

arachnoid granulation (arachnoid villi

fingerlike extensions of the arachnoid mater & subarachnoid space

circulatory pathway of CSF

Hydrocephalus

Circulation of CSF

CSF circulates through the ventricles of the brain & through the central canal of the spinal cord, and it fills the Subarachnoid space.

fingerlike extensions of the arachnoid mater & subarachnoid space

The brain is highly metabolic. What Does that mean?

requires a constant supply of oxygen & glucose to carry out normal functions

Circle of Willis

a circle of vessels (made up of the internal carotid arteries & the basilar artery) formed at the base of the brain

Aneurysm

Embolus

BLOOD BRAIN BARRIER (BBB)

Regulates the movement of materials from the blood into the brain.

BLOOD BRAIN BARRIER (BBB)

Formed by

brain capillaries that are less permeable than other capillaries in the body

Astrocytes

promote formation of tight junctions

The brain consists of 4 major areas:

the brainstem, the cerebellum, the diencephalon & the cerebrum

Brainstem

composed of the

medulla oblongata, the pons & the midbrain

o

; every nerve impulse that passes between the brain and the spinal cord must

pass through the brainstem to allow the body to function normally

Damage to small areas of this region can result in death because various areas are responsible for

Medulla Oblongata

1) Ccontinuous with spinal cord, inferior portion of the brainstem 2) Pathway for sensory (ascending) and motor (descending) nerve tracts 3) Contains nuclei, many of which are

reflex centers



regulates rate & force of heartbeat & blood vessel diameter

adjusts rhythm of breathing

vomiting, coughing, sneezing & hiccupping centers

4) involved with many

occurs.

most of the fibers from the descending (motor) tracts cross over to the opposite side

of the body

Pons

1) Connects the medulla to other parts of the brain 2) Contains ascending & descending tracts & many nuclei (some relay info from cerebrum to cerebellum) 3) Includes the pontine sleep center & the pontine respiratory center

Midbrain

corpora quadrigemina + cerebral peduncles + nuclei

4 mounds on the posterior side (composed of nuclei)

colliculus (plular = colliculi)

2

superior colliculi control?

reflex movements of the eye, head & neck in response to

visual & sensory stimuli

reflex movement of the head in response to

auditory stimuli

make up a major pathway in the CNS

composed primarily of motor tracts originating in the cerebrum & descending into the spinal cord

Nuclei

collections of neuronal cell bodies

L-Dopa (levodopa)

a precursor of dopamine that can cross the BBB

ascending and descending tracts that regulate alertness, balance and posture, and also play a role in the sleep-wake cycle.

Cerebellum

attaches to the brainstem, posterior to the pons

3 large nerve tracts (peduncles) allow for communication between the cerebellum & other areas of

the CNS

(tree of life): unusual arrangement of white & gray matter (resembles a tree)

Purkinje cells: the largest cells in the CNS; inhibitory neurons found in the cerebellar cortex

Cerebellum

3 parts ?

1) flocculonodular lobe (tuft of wool): small, inferior 2) 2 lateral hemispheres (lobes) 3) 1 central

= worm-shaped structure between the cerebellar hemispheres

Cerebellum

involved with controlling muscle movement, muscle tone and balance; also plays a main role in learning motor skills

Diencephalon

Between the brainstem & cerebrum

Includes the

thalamus, hypothalamus & the pineal gland

Thalamus

1) Major

(the principal relay area for sensory input going to the cerebral cortex for interpretation) 2) Also important in learning, awareness; influences mood & actions associated with strong emotions (fear & rage)

Hypothalamus

most inferior area of the diencephlaon 1) Contains many small nuclei 2) Major control center for maintaining

and regulating endocrine function



Centers dealing with rage, aggression, thirst, hunger, feeling of fullness after a meal, body temperature, pleasure, etc.

Pineal Gland (pineal body):

gland found posterior to thalamus 1) Very small (pea-sized) endocrine gland that secretes melatonin

(e.g. sleep-wake cycle)

it’s also thought to play a role in controlling the onset of puberty

a. Largest and most prominent portion of the brain b. Composed of 2 hemispheres (right & left), separated by a longitudinal fissure. Each hemisphere has lots of folds & grooves

(sing. Gyrus): folds

(sing. Sulcus): grooves

What is the main purpose of the gyri and sulci?

Cerebral Cortex

outer, gray matter composed of billions of unmyelinated neurons that are associated with higher thinking & performance (e.g. reading, speaking, etc.)

Cerebral Medulla

the white matter inferior to the cerebral cortex (not to be confused with medulla oblongata); composed of nerve tracts that connect the cerebral cortex to other areas of the cortex or other parts of the CNS

Association fibers

connect cerebral cortex areas within the same hemisphere

Commissural fibers

connect one hemisphere to the other

Corpus Callosum

largest bundle of commissural fibers; connects the 2 hemispheres together

Projection fibers

tracts between the cerebrum & other parts of the brain & spinal cord

Within the cerebral medulla, there are clusters of gray matter (mostly collections of cell bodies) called 

_______?

Between the cerebral cortex & the thalamus are 3 very large nuclei collectively called the_______?

Substantia Nigra:

basal nuclei in midbrain

Limbic System FUNCTION?

Plays central role in basic survival functions such as reproduction, nutrition, memory, emotions (aggression, fear, pleasure); it controls visceral functions through the autonomic nervous system and the endocrine system

Limbic System :- composed of?

Made up of regions of the cerebral cortex & diencephalon; includes the

hippocampus

Function of amygdale

Function of hippocampus:

(molecules released by one member of a species that cause a reaction in another member of the same species).

Open head injury,

closed head injury

coup

contrecoup

concussion

contusion

Encephalitis

meningitis

rabies

Merkel's disk

Pacinian corpuscles

Meissner's corpuscles

mechanoreceptors

Chemoreceptors

Thermoreceptors

photoreceptors

nociceptors

Pacinian corpuscles

where are they located?

Pacinian corpuscles

Function?

SENSORY AREAS OF THE CEREBRAL CORTEX

where perception occurs

About midway along the length of the cerebrum, -----------------------

separates the frontal & parietal lobes.

central sulcus

Anterior to the central sulcus

What is the

homunculus?

Size of various regions is related to .........

number of sensory receptors in that area of the body

Primary Sensory Areas of the Cerebral Cortex are

responsible for ..........

perception, localization & identification of the stimulus

Taste Area

inferior end of the postcentral gyrus

Olfactory Cortex

inferior frontal lobe; both conscious & unconscious responses to odor are initiated here

Primary Auditory Cortex

superior temporal lobe

Visual Cortex

occipital lobe

Association Areas

areas of the cerebral cortex immediately adjacent to the primary sensory centers

Association Areas

are involved in the process of ......................

recognition/identification of the stimuli

Association Areas

These areas will

Visual association area

sensory APs in retina reach the visual cortex

the face you may recognize may elicit an emotional reaction

Precentral Gyrus

Primary Motor Cortex

Action potentials originating in this region

Precentral Gyrus

What is

apraxia?

Prefrontal Area

found at the most anterior portion of the brain; this area is involved in motivation, intelligence, abstract ideas, judgment, empathy & conscience; it’s also thought to be the center for aggression

Speech

in most people, the speech area is in the left cerebral cortex

2 major cortical areas involved in speech

in the parietal lobe; sensory speech area

necessary for understanding & formulating coherent speech

inferior frontal lobe; motor speech area

initiates the complex

Aphasia

absent or defective speech or language comprehension resulting from a lesion in the speech area

*Reading a word aloud (seeing the word, then saying it): explain action potential movement

1. APs from retina reach primary visual cortex via CNII (word is seen)

2. Visual Association Area recognizes the word

3. Wernicke’s Area plays a role in understanding the word

4. Association fibers conduct APs from Wernicke’s Area to Broca’s Area; the word is formulated as it will be spoken (the complex movements are initiated)

5. APs are propagated to the Premotor Area, where the movements are programmed

6. Then on to the Primary Motor Cortex, which sends the APs down a descending (motor) tract to the moton neurons of the PNS to the effector muscles for movement to occur in such a way that will result in the word being spoken.

*Repeating a word you’ve heard: explain action potential movement

1. APs from cochlea reach the Primary Auditory Cortex via CN VIII

2. APs then proceed to the Auditory Association Area

3. APs are then sent to Wernicke’s Area …

4. Association fibers conduct APs from Wernicke’s Area to Broca’s Area; the word is formulated as it will be spoken (the complex movements are initiated)

5. APs are propagated to the Premotor Area, where the movements are programmed

6. Then on to the Primary Motor Cortex, which sends the APs down a descending (motor) tract to the moton neurons of the PNS to the effector muscles for movement to occur in such a way that will result in the word being spoken.

Left hemisphere more involved in ......

spoken and written language, numerical and scientific skills & reasoning

Right hemisphere

musical & artistic awareness, space perception, insight, imagination

ELECTROENCEPHALOGRAM (EEG)

a record of brain activity

4 types of waves defined by frequency. what are they?

Alpha waves

Beta waves

Theta waves

Delta waves

observed in a normal person who is awake but in a quiet, resting state with the eyes closed

fast activity; seen during intense mental activity

slow activity; abnormal in normal awake adults, but perfectly normal in children up to 13 years old and in sleep; also seen in adults w/ certain brain disorders or who are experiencing frustration

the lowest frequency; occurs in deep sleep, in infants, and in patients w/ severe brain disorders

There are 4 stages of sleep and the brain wave patterns vary during these stages: what are they?

1. stage 1

beta waves

What does REM stand for?

During which stage do we dream?

infarction

if there is a disruption in blood flow (and, thus, oxygen) to an area of the brain, those brain cells that aren’t being supplied will die

Hemorrhagic stroke and

Ischemic stroke

Hemorrhagic stroke

results from bleeding of arteries

Ischemic stroke

results from blockage of arteries

thrombus

clot that develops in place within an artery

embolism

plug composed of a detached clot, a gas bubble or other foreign body

Alzheimer’s Disease

a severe type of mental deterioration, usually affecting older people 1. Loss in the number of neurons in the cerebral cortex

(fragments of degenerating nerve fibers that are normally broken down in healthy brains) 3. Symptoms: intellectual deficiency, memory loss, short attention span, moodiness, disorientation, irritability

special senses

have ......

highly localized and very specialized receptors that provide specific information about the environment.

Which of our senses are considered "special senses?"

OLFACTION: sense of ___________

The stimuli for olfaction are ......

odorants

, or odor molecules.

both

both

OLFACTION: sense of ___________

The stimuli for olfaction are

,

Chemoreceptors located at the ---------------------

The axons of the olfactory neurons collectively make up the ---------------

the axons pass through the holes of the 

Olfactory Bulbs

the axons pass through the holes of the

________________

olfactory tracts carry the sensory information to the

_________

what are the

3 Areas of the olfactory cortex

Lateral olfactory area

medial olfactory area

intermediate olfactory area

Lateral olfactory

associated with the conscious perception of smell

responsible for visceral & emotional responses to odors

feedbacks

to the olfactory bulb

Gustation:

sense of _______________

Taste buds

chemoreceptors that detect tastants

what are the

4 types of papillae

Vallate

Fungiform

Foliate

Filiform

The taste buds are composed of ________________

nonsensory cells and 50 sensory cells called

gustatory

There are

?

sour

salty

bitter

sweet

Umami

The perception of taste is also affected by additional elements. What are three things that affect taste?

Texture

smell

olfation

Facial nerve # 7

Glossopharyngeal nerve # 9

Vagus nerve # 10

Fiberous

Vascular

Nervous

Fibrous Tunic consist of____________

sclera & cornea

Sclera

outer, white layer of the posterior 5/6 of the eye

structural support (thanks to the dense connective tissue – collagen & elastin)

attachment point for the extrinsic muscles

avascular

Cornea

continuous with the sclera, but makes up the anterior 16 of the eye

allows entry of light into eye

avascular, but highly innervated

convex (so it bends, or refracts, the light)

What characteristics make the cornea easy to transplant?

its easy to access

avascular

Vascular Tunic consists of ___________

Choroid coat

posterior part of the vascular tunic

highly vascular

darkly pigmented (thanks to melanocytes)

Ciliary body or muscle

anterior part, around the lens

) alter the shape of the lens during focusing

hold the lens in place

secretes aqueous humor

__________

____________

Nervous Tunic

Pigmented retina

Pigmented retina

outer, single layer of pigmented epithelial cells (absorb excess light)

Sensory retina

inner portion containing photoreceptors & relay neurons

Photoreceptors

specialized receptors stimulated to produce APs in response to light;