Brain
Lizette Torres
Mina Yanny
Per. 3
Function of the Brain
• The control network for the body’s functions and abilities
• It is in charge of things your body needs to stay alive
• Tells your body what to do
Layers of the Meninges
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The Dura Mater
The Arachnoid Mater
The Pia Mater
Bone is situated over the meninges followed
by periosteum and skin
Dura Mater
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Outermost, toughest, and most fibrous of the three membranes
Covers the brain and spinal cord
Responsible for keeping in the cerebrospinal fluid
Has two layers
○The superficial: serves as the skull’s inner periosteum
○The deep layer called the meningeal layer which is the
actual dura mater.
Dura Mater Cont.
• Opens at times into sinus cavities,
which are located around the skull.
• Home to meningeal veins.
• It envelops arachnoid mater
• Carries blood from the brain to the
heart.
The Arachnoid Mater
• Middle Layer of the meninges so it is
between the dura mater and pia mater
• Envelops the brain
• Sends processes into the longitudinal and
transverse fissure
• Surrounds nerves
• Forms tubular sheaths for nerves
Arachnoid Mater cont.
The Pia Mater
• Innermost layer of the meninges, closest to
brain
• Composed of fibrous tissue
• Covered on its outer surface by flat cells
thought to be impermeable to fluid.
• Pierced by blood vessels that travel to brain
and spinal cord
• Protects central nervous system by containing
the cerebrospinal fluid
The Brain and its sections
● The brain weighs three pounds
● Has a texture as jelly
● The main parts of the brain are the
cerebrum, cerebellum, brainstem, frontal
lobe, parietal lobe, occipital lobe, and
temporal lobe
● Difference from left and right
● The Neuron forest
The Brains Parts
Brain and sections cont.
Cerebrum
● Largest part of the brain
● Associated with higher brain function
such as thought and action
● For remembering, problem solving,
thinking, feeling and movement
● Has outer layer called cortex, which is
the brains wrinkly surface
Brain and sections cont.
Cerebellum
● Receives information from sensory systems,
spinal cord, and and other parts of the brain
● Regulates motor movements
Brainstem
● Regulates heart rate, breathing, sleeping, and
eating.
● Leads to as the spinal cord
Brain and sections cont.
Frontal Lobe
• Front part of brain
• involved in reasoning, planning, parts of speech,
movement, emotions, and problem solving
Parietal Lobe
• involved in movement, orientation, recognition,
perception of stimuli
Occipital Lobe
• involved in visual processing
Brain and Sections cont.
Temporal Lobe
• involved with perception and recognition of auditory stimuli, memory, and speech
Left & Right of brain
• Left: controls movement on the body’s right side and has logic abilities
• Right: controls movement on the body’s left side and more for creativity
Neuron Forest
• Where the work of the brain goes on in individual cells
• Signals that form memories and thoughts move through
a nerve cell as an electrical charge.
Brain Development
Ectoderm
Neural Plate
Prosencephalon
Telencephalon
Diencephalon
Cerebral cortex Retina of the eye
basal nuclei
Thalamus
Hypothalamus
Mesencephalon
Rhombencephalon
Mesencephalon Metencephalon Myelencephalon
Midbrain
Superior colliculus
inferior colliculus
Pons
Cerebellum
Medulla
Reflexes
• Reflexes are an automatic response to a
stimulus
• maintain homeostasis
• 2 types
– Spinal reflexes
– brain reflexes
Spinal Reflex
• response is mediated by neurons in the spinal
cord
• Action occurs without the awareness of brain
– ex. Kneejerk
Brain Reflexes
• Reflexes mediated by the brainstem
• brain receives information and generates a
response
• ex. movements of the eyes while reading
this sentence
Neurons
• Nerve cell
• transmit information
• 3 types
– motor neuron
– sensory neuron
– interneurons
Sensory Neurons
• Nerve cells that detect changes and send information
• it may activate a motor neuron or another sensory one
• Afferent neurons
Motor Nerves
• Efferent
• They carry signals from the spinal cords to muscles
• They produce movements
interneurons
• They create neural circuits to enable the
communication between motor neurons or
sensory neurons and the central nervous
system
Cranial Nerves
● There are 12 pairs of cranial nerves
● They emerge directly from the brain and the
brain stem.
● They exchange information between the brain
and the body parts
○ some bring information from sense organs
and others control muscles
Olfactory nerve
• First cranial nerve
• A sensory nerve
• It carries the sensory information for smell
• Capable of regeneration
Optic Nerve
• a sensory motor
• Transmits visual information from the retina
to the brain
• ex . brightness perception, contrast
Oculomotor Nerve
• It is a motor nerve
• It controls most of the eye’s movements
– ex. maintaining the opening of an eye lid and
pupil constriction
Trochlear nerve
• It is a motor nerve
• It innervates a single muscle
• the superior oblique muscle of the eye
• It has the smallest number of axons
Trigeminal nerve
• it is a sensory and a motor nerve
– sensation in the face
– chewing and biting
• divided in 3 branches
– ophthalmic, maxillary and mandibular
Abducens nerve
• somatic efferent nerve
• motor nerve
• controls the movement of the lateral rectus
muscle of the eye
Facial nerve
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both motor and sensory nerves
It emerges from the brain stem
Responsible for facial expressions
it also supplies sensation information
– taste sensation
vestibulocochlear nerve
• It is a sensory nerve
• it transmits sound and equilibrium information from
inner ear to brain
• it consists of cochlear nerve and vestibular nerve
glossopharyngeal nerve
• both sensory and motor nerve
– carries afferent sensory and efferent motor information
• several functions
– receives general sensory fibers
– receives special sensory fibers
– receives visceral sensory fibers
Vagus nerve
• both motor and sensory nerve
• it supplies motor parasympathetic fibers to all
organs except adrenal glands
• it controls few skeletal muscles
Accessory nerve
• motor nerve
• provides information about the spinal cord, trapezius and other
surrounding muscles.
• provides muscle movement of the shoulders and surrounding
neck.
Hypoglossal nerve
• it is a motor nerve
• innervates movement of the tongue
– controls movement required for speech,
swallowing and food manipulation.
Spinal Nerves
• 31 pairs of spinal nerves
• organized and divided into 4 regions
– Cervical
– Thoracic
– Lumbar
– Sacral
• provide communication between body parts and cns
• they split into 3-4 branches
– Dorsal branch
– Ventral branch
– Visceral branch
– Meningeal branch
• 2 roots
– posterior
– anterior
Cervical nerves
• 8 pairs
– C1 - C8
• emerge from corresponding vertebrae
• they innervate the sternohyoid, sternothyroid
and omohyoid muscles
Thoracic nerves
• 12 pairs
– T1 - T12
• originate from corresponding vertebra
• they communicate with parts of chest or
thorax and abdomen
Lumbar nerves
• 5 pairs
– L1 - L5
• emerge from lumbar vertebrae
• they supply many muscles
– ex. Gluteus medius muscle and gluteus
minimus
Sacral nerves
• 5 pairs
– S1 - S5
• start inside the vertebral column and exit the
sacrum
• they supply the hip, thigh and foot
Works Cited
Patricia Anne Kinser, “Brain Structures and Their Functions.” Serendip Studio. Paul Grobstein, 5
September 2012. Web. 21 April 2015.
<www.serendip.bryanmawer.edu>
Alzheimer’s Association, “3 Main Parts of the Brain.” Alzheimer’s Association. 2011. Web. 19 April
2015.
<www.alz.org/braintour>
“Arachnoid Trabeculae.” Encyclopedia Britannica. 9 September 2010. Web. 19 April, 2015.
<www.en.wikipedia.org/arachnoidtrabeculae>
Michelle Watnick, ”Nervous System II.” Hole’s Human Anatomy and Physiology. Fran Schreiber,
2007. Book. 18 April 2015.