Nervous system

BRAIN

Questions

Structure of brain

Brainstem

Hindbrain: medulla oblongata, pons, cerebellum

Reticular formation

Midbrain: superior and inferior colliculus

Diencephalon: thalamus, hypothalamus

Subcortical nuclei (Basal nuclei)

Limbic system

Ventricular system

Cranial nerve

BRAIN

unites structures,

which control vital

activity of an

integrated organism

and the higher

nervous formations,

which coordinate the

vital organisms`

processes, provide

adaptive behavior and

mental activity

Brain

Hindbrain

Medulla

oblongata

Pons

Cerebellum

(little brain)

Midbrain

Hillocks (superior

and inferior)

Legs.

Diencephalon

Thalamus

Hypothalamus

Forebrain

•Cerebral

hemisphere;

•Basal

ganglia;

•Limbic

system

(visceral

brain).

Brainstem

Medulla oblongata

Pons

Midbrain

Diencephalon (partially)

The hindbrain is composed of the medulla, the pons, and the cerebellum. The medulla lies next to the spinal cord and controls functions outside conscious

control, such as breathing and blood flow. In other words, the medulla controls essential functions. The pons affects activities such as sleeping, waking, and dreaming. The cerebellum controls balance and coordination of movement.

Damage to the cerebellum impairs fine motor skills, so a person with an injury in this area would have trouble playing the guitar or typing a term paper.

The Midbrain The midbrain is the part of the brain that lies between the hindbrain and the forebrain. The midbrain helps us to locate events in space. It also contains a

system of neurons that releases the neurotransmitter dopamine. The reticular formation runs through the hindbrain and the midbrain and is involved in sleep

and wakefulness, pain perception, breathing, and muscle reflexes. The Forebrain

The biggest and most complex part of the brain is the forebrain, which includes the thalamus, the hypothalamus, the limbic system, and the cerebrum.

ThalamusThe thalamus is a sensory way station. All sensory information except smell-

related data must go through the thalamus on the way to the cerebrum. Hypothalamus

The hypothalamus lies under the thalamus and helps to control the pituitary gland and the autonomic nervous system. The hypothalamus plays an important role in regulating body temperature and biological drives such as hunger, thirst,

sex, and aggression.

Internal structure of a brain

Brainstem

Довгастий мозок

Brainstem

White and grey matters

Grey matter

(In the form of nuclei)

Cortex of Subcortical

Cerebellum nuclei

Cortex of the

big hemispheres

White matter

Conduction tracts

HINDBRAIN

The hind brain is mainly a

continuation of the spinal cord and contains all the ascending and

descending fibers connecting the brain

and spinal cord.

The medulla (as known as the medulla

oblongata) is located at the base of the brain stem

and controls many of the mechanisms necessary

for life, such as heartbeat, blood pressure and

breathing. White and gray substance aren't parted

Clumps of nervous cells are nuclei of cranial

nerves:

XII – Hypoglossal - tongue movement

XI – Accessory - neck and shoulder muscles

X – Vagus - swallowing, taste

IX – Glossopharyngeal - taste, swallowing

VIII – Acoustic (Vestibulocochlear Nerve ) -

hearing, balance

Function of medulla oblongata

Medulla (oblongata)

Vital functions: breathing, heart

rate, digestion

Protective reflexes - vomiting,

coughing, sneezing, elimination of

tears, a winking

Reflexes of alimentary

behavior: digestive juice

elimination, chewing, swallowing,

a suction;

Reflexes of a postur`s changes

- a muscles` tonus

Conduction

Binds a spinal cord to brain

departments

Connections through the

cranial nerves (sensation

and motor nerves for

head) and

parasympathetic nervous

system

Vestibular reflexes:

Static – posture maintenance and equilibriums

of a body at different static positions in a

space

Statokinetic – posture maintenance at change

of rate of movement of a body in space

Vegetative reflexes – locomotor and

secretory activity of an internal at vagus

excitation.

Functions of medulla oblongata

Importance

Maintenance of a constancy of structure of internal medium – a homeostasis (activity of vital centers)

Association of segments of a spinal cord

Regulation of work of a spinal cord

Realization of difficult forms of adaptive reactions of an organism to environment

Medulla oblongata and pons

Reticular formation (RF) – special formation – a net of

nervous fibers in brainstem and hindbrain

Functions:

Maintenance of interaction of ascending and

descending pathways of a brain

Coordination of an organism functions.

Reticular formation of brainstem

System of nervous cells of the various form and the sizes

with a lot of processes which intertwine and form a lot

of contacts

Functions of RF

Specifies

Breath regulation

Regulation of hard

activity

Regulation of a

vascular tonus etc.

Unspecifies

Regulation of

level of functional

activity of brain

departments

(activation or

inhibition)

Regulation of breath`s

center (pneumotaxic

center influences

depth and frequency

of breath)

The vascular center

The respiratory center

Activation of neurons of a

spinal cord

Functions

RF of medulla oblongata

Pons (the "bridge")

Structure

Cranial nerves:

V - Trigeminal

VI – Abducent

VII - Facial

VIII – Acoustic(VestibulocochlearNerve )

Many nerves cross over from one

side of the body to the other

Contains (within the medulla and

pons) the reticular formation and

raphe system

Ascending reticular

formation: sends output to

cerebral cortex and controls

arousal and attention

functions

raphe system: axons to the

forebrain

increasing/decreasing

readiness to respond to stimuli

Pons

Pons connects medulla oblongata to mesencephalon peduncles

Functios

Control ConductionVestibular reflexes, which Ascending and descending nervous ways -

regulate a tonus of muscles, fibers which bridge cerebellum

including mimic hemispheres themselves and a cortex

of the big brain

Cranial nerves:

VII – Facial - taste, facial expressions

VI – Abducent - eye movements

V – Trigeminal - facial sensations, chewing

Cerebellum

Cerebellum

Cerebellum bonds with CNS

Cerebellar peduncle

Inferior with medulla Superior with midbrain

oblongata and spinal cord and hypothalamus

Middle with

pons and across it

with an motor zone of a cortex

Function of cerebellum

Coordination of muscle slow movements

Control of a body position

Fine motor skills

Maintaining balance, posture, and equilibrium

Muscle tone control: equilibrium, forces of

muscular contraction

Vegetative functions:

Influence on the work of cardiovascular, respiratory,

digestive and other systems

Influence on a metabolism

Midbrain

Midbrain (structure)

Peduncles

Substantia Red

nigra nucleus

Mesencephalic

tegmentum

(Quadrigeminal plate)

Superior Inferior

colliculus colliculus

Functions of midbrain (the center of

regulation of support of normal position of a

body)Quadrigeminal plate – the organization of rough visual and

acoustical reflexes on visual and acoustical irritation

Superior colliculus – the primary visual centers,realization of visual reflex reactionsMovement of head

Movement of eyes

Change of a lumen of a pupil

Accommodation change

Inferior colliculus – the primary acoustical centers

Movement of head

Movement of auricle

Tension of the tympanic membrane, auditory ossicles

Red nucleus – regulation of a muscular tonus of the

planned adjustable movement and pose maintenance

– inhibition of a motor activity of a spinal cord

Substantia nigra (Contains melanin)

Regulation of certificates of chewing, swallowing

Maintenance of exact movements of fingers of arms

Regulation of plastic tonus

Cranial nerves

IV – Trochlear - eye movements

III – Oculomotor - eye movements, eyelid opening

DiencephalonThe center of sensory, movement and vegetative reactions

of an organism

Structure of diencephalon

Thalamus Hypotalamus

(optic thalamus) (subthalamic

Cranial nerve region)

II Optic - vision

Structure of Brain

Тhаlаmus

The highest subcortical center of the afferent

information from all external and internal receptors

which perceive irritation except the olfactory.

Grey matter consist of 40 nuclei

Classification of nuclei by character

of influence on a cerebrum

Specific

Process and transition

visual, movement,

tactile, gustatory

signals to definite

associative zones of a

cerebrum.

Nonspecifies

Excitation diffusively

propagates in

hemispheres. Creation

of the general activity

of a cerebrum for

consciousness

maintenance.

Kinds of specific nuclei

Switching - send the tactile, temperature,

painful, gustatory, acoustical, visual

information to a certain lobe of a cortex;

Associative – receive impulses from

switching and send to frontal, temporal area

of a cerebrum;

Impellent – switching of signals from a

cerebellum, basal a ganglion in a motor lobe

of a cerebrum.

Function of thalamus

Receive and estimation of the information from

sense organs;

Allocation and transfer to a cortex of the most

important information;

Regulation of emotional behavior;

The center of painful sensitivity;

Coordination of difficult movement functions (a

suction, chewing, swallowing, laughter) with

vegetative processes.

Hypothalamus

• The center of regulation of vegetative functions

which provide homeostasis support, regulation

of functions of vegetative, endocrine and

somatic systems.

• Grey matter consist of 32 (50 pars) nuclei

Function of hypothalamus The center of sympathetic and parasympathetic nervous

systems (forward and back nuclei);

Regulation of endocrine system;

Thermoregulation (back nuclei);

The centers of saturation, hunger, thirst;

The center of regulation of a dream, wakefulness;

Synthesis of hormones: a vasopressin, oxytocin

(supraoptic nucleus), liberins, statins

Metabolism regulation (middle nucleus);

Synthesis peptides – enkephalins, endorphines;

Formation of motivations together with limbic system;

Correcting of deviations of a homeostasis by means of

nervous and humoral mechanisms

Subcortical nuclei (Basal nuclei)

Are located in the middle of the big

hemispheres, between front parts and an

diencephalon

Subcortical Brain Structures

(Basal nuclei)

Basal nuclei

Globus pallidus Nucleus caudatus Amygdala

The big neurons – the beginning Striated body (Alternating of

to axons which come to an end in white and gray substance)

nucleus of midbrain and diencephalon

(substantia nigra, red nucleus) Fine neurons and which axons

go to globus pallidus and substantia

Rough reactions nigra

Movements of extremities

Alimentary behavior Receives eisodic impulses from a

Difficult movements (walking, run) sensory lobe of a cortex,

Difficult mimic movements nonspecific nucleus of a

thalamus, substantia nigra

- through an diencephalon regulates vegetative functions and carries out instincts

- storing of difficult impellent programs

Striated body

Nucleus caudatus

Brake or exciting

influence on

subcortical

structures;

Muscle tonus.

Amygdala

The organization of

alimentary behavior;

- Meal search;

- Capture and

mastering.

Breath regulation,

sulivation.

Limbic systemIt is located in a depth of an average surface of hemispheres.

Limbic system

Functions:

Participation in regulation of vegetative functions(especially digestion);

Participation in regulation of congenital behavioralreactions;

Formation and regulation of emotions;

Formation and memory implication;

Homeostasis maintenance;

Control of reactions referred on self-preservation andkind conservation; Integration of the olfactoryinformation (I pair olfactory nerves);

Control of the referred behavior;

Coordination of vegetative and somatic reflexesaccording to an emotional condition (anger, pleasure,a sexual inclination, alarm).

Ventricular systemThe brain is not a solid organ. There are

fluid-filled cavities within the brain called

ventricles. The ventricles are important in

providing nourishment to the brain. The

ventricular system produces and

processes cerebrospinal fluid – a clear,

watery substance that flows around the

brain and helps cushion and protect it.

Cranial nerve

LITERATURE

Anatomy and physiology. - The

McGraw−Hill, Companies, 2003