A and P 2- chapter 12-1

what 4 regions do the adult brains have

Cerebral hemispheres

diencephalon

Brain stem

Cerebellum

what 3 sub areas make up the brain stem

midbrain

pons

medulla

what is gray matter

short nonmyelinated neurons and cell bodies

what is white matter

myelinated and nonmyelinated axons

Basic pattern found in CNS:

central cavity surrounded by

gray matter, with white matter

external to gray matter

what are the 3 brain regions

spinal cord

brain stem

cerebral hemispheres

what are the features and changes of pattern of the spinal cord

exhibits this basic pattern; however, pattern changes with ascent into brain stem

what are the features and changes of pattern of the brain stem

has additional gray matter nuclei scattered within white matte

what are the features and changes of pattern of the cerebral hemispheres

(cerebrum) and cerebellum contain outer layer of gray matter

called the cortex

Cerebrum and cerebellum also have scattered areas of gray

matter nuclei amid white matter

what are ventricles

Fluid-filled chambers that are continuous to one another and to central canal of spinal cord

– Filled with cerebrospinal fluid (CSF)

– Lined by ependymal cells (neuroglial cells)

what are the 3 ventricles

lateral ventricle

third ventricle

fourth ventricle

what does the lateral ventricle do

large, paired, C-shaped chambers located deep in each hemisphere

Pair is separated by membranous septum pellucidum

what does the third ventricle do

Each lateral ventricle is connected to the third ventricle

via interventricular foramen

Third ventricle lies in diencephalon

what does the fourth ventricle do

connected to the third ventricle via cerebral aqueduct

Fourth ventricle lies in hindbrain

Continuous with central canal of spinal cor

what are the cerebral hemispheres

form superior part of brain

what are gyri

ridges in brain

what are sulci

shallow grooves in brain

what are fissures

deep grooves in brain

what is longitudinal fissure

separates the two hemispheres in the brain

what divides each hemisphere into lobes

several sulci

into 5 lobes

what are the 5 lobes of the cerebral hemisphere

frontal

parietal

temporal

occipital

insula

what are the first 4 lobes of the brain named after

overlying skull bone

what is the insular lobe

is buried under portions of temporal, parietal, and frontal lobes

what does central sulcus do

separates precentral gyrus of frontal lobe and postcentral gyrus of parietal lobe.

what is the cerebral cortex

the “executive” of the brain

what is site of conscious mind

awareness, sensory perception, voluntary motor initiation, communication, memory storage, understanding

what is the thin 2-4mm of the brain

superficial layer of gray matter

what is the 2-4mm layer on the brain composed of and what is each hemisphere control

Composed of neuron cell bodies, dendrites, glial cells, and

blood vessels, but no axons

Each hemisphere is concerned with contralateral

(opposite) side of body

what are the 3 types of functional areas that the cerebral cortex contains and what do they do

motor- control voluntary movement

sensory- conscious awareness of sensation

association- integrate diverse information

Each hemisphere is concerned with contralateral (opposite) side of body

where is the primary motor cortex located and what does it do

in precentral gyrus of the frontal lobe

Pyramidal cells- large neurons that allow conscious control of

precise, skilled, skeletal muscle movement

what is pyramidal (corticospinal) tracts

formed from long axons

that project down spinal cord

what does the premotor cortex do

Helps plan movements-Staging area for skilled motor activities

Controls learned, repetitious, or patterned motor skills

Coordinates simultaneous or sequential actions

Controls voluntary actions that depend on sensory feedback

what is somatotopy

all muscles of body can be mapped to area on primary motor cortex

what is broca’s area

Present in one hemisphere (usually the left)

Motor speech area that directs muscles of speech production

Active in planning speech and voluntary motor activities

what does the frontal eye field do

controls voluntary eye movements

what are sensory areas of the cerebral cortex and where do they occur

Areas of cortex concerned with conscious awareness

of sensation

Occur in parietal, insular, temporal, and occipital lobe

what are the 8 main sensory areas

Primary somatosensory cortex

Somatosensory association cortex

Visual areas

Auditory areas

Vestibular cortex

Olfactory cortex

Gustatory cortex

Visceral sensory area

what does the primary somatosensory cortex do and where is it located. what is it capable of and what is somatosensory homunculus

Located in postcentral gyri of parietal lobe

Receives general sensory information from skin and

proprioceptors of skeletal muscle, joints, and tendons.

Capable of spatial discrimination: identification of body

region being stimulated

Somatosensory homunculus: upside-down caricatures

represent contralateral sensory input from body region

sensory area

what does the somatosensory association cortex do, where is it located and what does it determine

Posterior to primary somatosensory cortex

Integrates sensory input from primary somatosensory cortex

for understanding of object

Determines size, texture, and relationship of parts of objects

being felt

sensory area

what is the primary visual cortex and where is it located

Receives visual information from retinas

located on extreme posterior tip of occipital lobe

visual area

what is the visual association area and where is it located

surrounds primary visual cortex

Uses past visual experiences to interpret visual stimuli

(color, form, or movement) , like the ability to recognize

faces

visual area

what is the primary auditory cortex and where is it located

Superior margin of temporal lobes

Interprets information from inner ear as pitch, loudness, and

location

auditory area

what is the auditory association area and where is it located

Located posterior to primary auditory cortex

Stores memories of sounds and permits perception of sound

stimulus

auditory area

what is the wernicke’s area and where is it located

Located in the temporal lobe of the dominant cerebral

hemisphere

Involved in the comprehension of written and spoken language

auditory area

what is the vestibular cortex and where is it located

Posterior part of insula and adjacent parietal cortex

Responsible for conscious awareness of balance (position of

head in space)

what is the vestibular cortex and where is it located

Medial aspect of temporal lobes (in piriform lobes)

Part of primitive rhinencephalon, along with olfactory bulbs

and tracts

Remainder of rhinencephalon in humans becomes part of

limbic system

Involved in conscious awareness of odor

what is the gustatory cortex and where is it located

In insula just deep to temporal lobe

Involved in perception of taste

what is the visceral sensory area and where is it located

Posterior to gustatory cortex

Conscious perception of visceral sensations, such

as upset stomach or full bladder

what is the prefrontal cortex

most complicated cortical region

Involved with intellect, cognition, recall, and personality.

contains working memory needed for abstract ideas, judgment, reasoning, persistence, and planning.

Development depends on feedback from social environment

what is the multimodal association areas

Receive inputs from multiple sensory areas

Send outputs to multiple areas

Allows us to give meaning to information received, store in

memory, tie to previous experience, and decide on actions.

Sensations, thoughts, emotions become conscious: makes us who we are

what is lateralization of cortical functioning

division of labor between hemispheres

Hemispheres are not identical

what is cerebral dominance

refers to hemisphere that is dominant for language

90% of humans have left-sided dominance

Usually results in right-handedness

In other 10%, roles of hemispheres are reversed

what does the left hemisphere do

Controls language, math, and logic

what does the right hemisphere do

Visual-spatial skills, intuition, emotion, and artistic

and musical skills

how do hemispheres communicate

almost instantaneously via fiber tracts and functional integration

what is basal nuclei, how many in each hemisphere

deep gray matter

one basal nuclei in each hemisphere

Functions of basal nuclei are thought to be what

Influence muscle movements

– Play role in cognition and emotion

– Regulate intensity of slow movements

– Filter out incorrect/inappropriate responses

– Inhibit antagonistic/unnecessary movement

what are parkinson’s and Huntington diseases

disorders of the basal nuclei

what are the 3 paired gray-matter structures that the diencephalon consist of

Thalamus

Hypothalamus

Epithalamus

what is the thalamus

Bilateral egg-shaped nuclei that form superolateral walls of

third ventricle

makes up 80% of diencephalon

what is the function of the thalamus

acts as relay station for information coming into cortex- Sorts, edits, and relays ascending input such as:

Impulses from hypothalamus for regulating emotion

and visceral function

Impulses from cerebellum and basal nuclei to help

direct motor cortices

Impulses for memory or sensory integration

Overall, it acts to mediate sensation, motor activities, cortical

arousal, learning, and memory

what is the hypothalamus and where is it located

Located below thalamus

Forms cap over brain

stem

Contains many important

nuclei

what are mammillary bodies

paired anterior nuclei that act as olfactory relay stations

what is the infundibulum

stalk that connects to pituitary gland

what is the function of the hypothalammus

the main visceral control and regulating center - VITAL to homeostasis

Chief homeostatic controls:

1. Controls autonomic nervous system

Examples: blood pressure, rate and force of

heartbeat, digestive tract motility, pupil size

2. Initiates physical responses to emotions

Part of limbic system: perceives pleasure, fear, rage,

biological rhythms, and drives (love drive)

what are the other everyday functions of the hypothalamus

Regulates body temperature: sweating or shivering

Regulates hunger and satiety in response to nutrient

blood levels or hormones

Regulates water balance and thirst

Regulates sleep-wake cycles- Suprachiasmatic nucleus of thalamus sets our biological clock

Controls endocrine system functions such as:

Secretions of anterior pituitary gland

production of posterior pituitary hormones

what causes a number of homeostatic imbalance

Hypothalamic disturbances

what are some effects from hypothalamic disturbances

Severe body wasting

– Obesity

– Sleep disturbances

– Dehydration

– Emotional imbalances

• Can be damaged by tumors, radiation, surgery or trauma

what does the epithalamus contain, where is it located and what does it do

Contains PINEAL GLAND

Extends from posterior border

– Secretes melatonin that helps regulate sleep-wake

cycle

what are the 3 regions of the brainstem

1. Midbrain

2. Pons

3. Medulla oblongata

what does the brain stem do, what does it contain and what is the structure

Similar in structure to spinal cord but contains nuclei embedded in white matter

Controls automatic behaviors necessary for survival

Contains fiber tracts connecting higher and lower neural center

where is the midbrain located

Located between diencephalon and pons

what are cerebral peduncles and what do they form and what part of the brain are they apart of

two ventral bulges that contain pyramidal motor tracts

– Form pillars that hold up cerebrum

midbrain

what are the cerebral aqueduct and what part of the brain is it in

channel running through midbrain that connects

third and fourth ventricle

midbrain

where are midbrain nuclei

scattered throughout white matter

what is corpora quadrigemina mean and what are the 2 sub catagories

paired dorsal protrusions

superior colliculi

inferior colliculi

what does superior colliculi mean

visual reflex centers

what does inferior colliculi mean

auditory relay centers

what is substantia nigra

functionally linked to basal nuclei

parkinson’s disease is degeneration of this area

what does pons do and where is it located

Located between midbrain and

medulla oblongata

• Relays sensory information to

cerebellum.

• Connects forebrain to

hindbrain.

• Some nuclei help maintain

normal rhythm of breathing

• Helps to regulate sleep/wake

patterns

where is the medulla oblongata located

it blends into spinal cord at foramen magnum

what are the 2 structures of the medulla oblongata

choroid plexus

pyramids

what does the choroid plexus do

capillary-rich membrane that forms cerebral spinal fluid

what does pyramids do

two ventral longitudinal ridges formed by pyramidal tracts from motor cortex

what is the function of the medulla oblongata

Medulla is an autonomic reflex center

– Hypothalamus relays instructions via medulla

what are the 2 functional groups of the medulla oblongata

cardiovascular center

respiratory centers

what do the cardiovascular center do

Cardiac center adjusts force and rate of heart contraction

– Vasomotor center adjusts blood vessel diameter for blood

pressure regulation

what do the respiratory centers do

Generate respiratory rhythm

– Control rate and depth of breathing (with pontine center

what are the 5 other various centers that the medulla oblongata regulate

Vomiting

– Hiccupping

– Swallowing

– Coughing

– Sneezing

what does the cerebellum do and where is it located

Located dorsal to pons and medulla

• Processes input from cortex,

brain stem, and sensory

receptors to provide precise,

coordinated movements of

skeletal muscles

• Also plays a major role in

balance

what does the cerebellum contain

Contains thin cortex of gray

matter with distinctive treelike

pattern of white matter called

ARBOR VITAE

what are the 3 ways the cerebellum fine tunes motor activity

1. Receives impulses from cerebral cortex of intent to

initiate voluntary muscle contraction

2. Receives signals from proprioceptors throughout

body, as well as visual and equilibrium pathways that:

§ Pathways continuously “inform” cerebellum of

body’s position and momentum

3. Cerebellar cortex calculates the best way to smoothly

coordinate muscle contraction

what are the cognitive functions of cerebellum

Neuroimaging suggests that cerebellum plays role in

thinking, language, and emotion

• As it does for motor processes, it may compare actual

output of higher functions with expected output and adjust

accordingly