Parts of the brain and their functions

what are the three regions of the brain stem

midbrain, pons, medulla oblongata

brain stem function

controls automatic behaviors necessary for survival along with the hypothalamus

the brainstem contains

fiber tracts connecting higher and lower neural centers

where is the midbrain located

between the diencephalon and pons

midbrain structures

cerebral peduncles

cerebral aqueduct

cranial nerve nuclei

corpora quadrigemina

• superior colliculi

• inferior colliculi

substantia nigra

red nucleus

cerebral peduncles

contain descending tracts from cerebral cortex to pons, medulla, and spinal cord

cerebral aqueduct

channel connects 3rd and 4th ventricles

cranial nerve nuclei in the midbrain

III, IV

corpora quadrigemina (tectum)

paired dorsal protrusions

• superior colliculi

• inferior colliculi

superior colliculi

visual reflex centers

inferior colliculi

auditory relay centers

substantia nigra

midbrain nuclei

functionally linked to basal nuclei

red nucleus

midbrain nuclei

relay centers for some descending limb flexion motor pathways

where is the pons located

between midbrain and medulla oblongata

what separates the pons from the cerebellum

the 4th ventricle

what is the pons composed of

conduction tracts that link parts of the brain with one another and with the spinal cord

what major network do some pons nuclei belong to

the reticular formation

what does the reticular formation (including pons nuclei) help regulate

alertness, consciousness, muscle tone, and filtering sensory input

how does the pons contribute to breathing

some pons nuclei help maintain the normal rhythm of breathing

what is the role of the pontine respiratory group

it smooths transitions between inhalation and exhalation and coordinated breathing with activities like speaking and sleeping

overall, what two major functions do pons nuclei support

(1) wakefulness/alertness (reticular formation)

(2) rhythmic breathing

where does the medulla oblongata blend into the spinal cord

at the foramen magnum

what are the pyramids in the medulla

motor tracts from the cortex that cross to the opposite side of the body

what is the main function of the medulla oblongata

autonomic vital reflex center

what vital centers are in the medulla

cardiac center, vasomotor center, and respiratory centers

cardiac center

force and rate of heart contraction

vasomotor center

blood vessel diameter for blood pressure regulation

respiratory centers

generate respiratory rhythm

control rate and depth of breathing (with pons)

what additional reflex centers does the medulla control

vomiting, hiccuping, swallowing, coughing, sneezing

what do the nuclei in the medulla oblongata do

relay sensory info

maintain equilibrium

control vital functions

what does the reticular formation do

sends impulses to cerebral cortex to keep it conscious and alert

helps to regulate muscle tone

filters out repetitive, familiar, or weak stimuli

what is the reticular activating system (RAS)

sensory axons extending from reticular formation

what inhibits the reticular formation

sleep centers, alcohol, drugs

what does severe injury to the reticular formation result in

prolonged unconsciousness (coma)

Where does the cerebellum process input from

cortex, brain stem, and sensory receptors

cerebellum functions

provides precise, coordinated movements of skeletal muscles

plays a major role in balance

how many hemispheres does the cerebellum have

2

what are the 2 hemispheres of the cerebellum connected by

the vermis

each hemisphere of the cerebellum has how many lobes

3 lobes

what is the arbor vitae of the cerebellym

a thin cortex of gray matter with distinctive treelike pattern of white matter

what does the diencephalon consist of

3 paired gray-matter structures that enclose third ventricle

what are the three structures of the dienchephalon

thalamus

hypothalamus

epithalamus

what does it mean that the thalamus consists of “bilateral nuclei that form the superolateral walls of the 3rd nuclei”

the thalamus is made of two groups of nuclei, one in each hemisphere, and together they form the supper side walls of the third ventricle

what connects the left and right thalamus

interthalamic adhesion

what is the thalamus a relay center for

all sensory information (except smell) coming into cerebral cortex

thalamus functions

sorts, edits, and relays ascending input from hypothalamus, cerebellum, and basal nuclei

hypothalamus structure

forms cap over brain stem

forms inferolateral walls of third ventricle

what are the four regions of the hypothalamus

mammillary

tuberal

preoptic

supraoptic

mammillary region + function

contains mammillary bodies

function: role in sensory input, motor control of eating, memory

tuberal region

includes nuclei and infundibulum (stalk that connects to pituitary gland)

what is the function of the preoptic region

hormone production

body temperature regulation

what is the function of the supraoptic region

nuclei secrete hormones

what is the main overall function of the hypothalamus

it is the main control and regulating center for homeostasis, controlling vital and nonvital reflexes

what systems does the hypothalamus control to regulate homeostasis

it controls the autonomic nervous system (ANS) and the endocrine system

what ANS functions are controlled by the hypothalamus

blood pressure, rate and force of heartbeat, digestive tract motility, and pupil size

how does the hypothalamus participate in emotional responses

it initiates physical responses to emotions as part of the limbic system

what emotional experiences are associated with hypothalamic function

pleasure, fear, rage, biological rhythms, and libido (sex drive)

what body homeostasis parameters does the hypothalamus regulare

body temperature, hunger, satiety, water balance, and thirst

what cycle does the hypothalamus regulate related to consciousness

the sleep-wake cycle (sets the biological clock)

how does the hypothalamus control the endocrine system

it triggers anterior pituitary secretions and produces hormones for the posterior pituitary

what is the epithalamus (in terms of location)

the most dorsal portion of the diencephalon

What does the epithalamus form

the roof of the third ventricle

what does the epithalamus connect

connects limbic system to other parts of the brain

what important structure of the epithalamus contain and where does it extend from

the pineal gland

extends from the posterior border

what hormone does the pineal gland secrete and what cycle does it help to regulate

secretes melatonin

helps regulate sleep-wake cycle

what other name is the cerebrum known as

cerebral hemispheres (right and left)

what structures does the cerebrum consist of

corpus callosum

gyri

sulci

what is the corpus callosum

axons connecting hemispheres of the cerebrum

what are gyri

ridges

what are sulci

shallow grooves

what part of the brain does the cerebrum form

the superior part of the brain

83% of brain mass

what are the five lobes that the sulci divide the cerebrum into

frontal, parietal, temporal, occipital, insula

what are the major sulci of the cerebrum

central sulcus

lateral sulcus

parieto-occipital sulcus

central sulcus

separates frontal and parietal lobes

lateral sulcus

separates frontal and temporal lobes

parieto-occipital sulcus

separates parietal and occipital lobes

what are fissures

deep grooves

what fissures are located in the cerebrum

longitudinal fissure

transverse fissure

longitudinal fissure

separates hemispheres

transverse fissure

separates cerebrum and cerebellum

what are the 3 basic regions of the cerebrum

superficial cerebral cortex of gray matter

internal white matter

basal nuclei deep within white matter

what structures do the basal nuclei include

a caudate nucleus

putamen

globus pallidus

the caudate nucleus and putamen together are called the

striatum

what structures are the basal nuclei associated with

subthalamic nuclei and substantia nigra

what is one motor function of the basal nuclei

they influence muscle movements

how do basal nuclei contribute to cognition and emotion

they are involved in cognitive processes and emotional regulation

what role do basal nuclei play in movement patterns

they regulate the intensity of slow or stereotyped movements

how do the basal nuclei control unnecessary muscle activity

they inhibit antagonistic or unnecessary movements

what are diseases of the basal nuclei

parkinson’s disease

huntington’s disease

what is the limbic system (in terms of structure)

structures on medial aspects of cerebrum and diencephalon

some cerebral structures that encircle the brain stem

in the limbic system, what is the fornix

fiber tract that links the limbic system regions

what other part of the brain does the limbic system interact with

the prefrontal lobes

interaction of limbic system with prefrontal lobes allows for

conscious awareness

emotional reactions

memory

the hippocampus is important in

learning and memory

the amygdala plays a role in

aggression, fear, and anxiety

what does the cingulate gyrus do

connects our actions/behaviors with our emotions

what is the structure of the cerebral cortex

a thin 2-4 mm superficial layer of gray matter

what is the cerebral cortex composed of

neuron cell bodies, dendrites, glial cells, and blood vessels

NO AXONS

what % of mass of the brain is the cerebral cortex

40% of mass of brain

the cerebral cortex is known as the

“executive suite” of the brain