Nervous system: The Brain

By: William Maldonado, Francisco Ruiz, Esteban Perez

The Brain ❖ we have about 100 billion neurons ❖ Part of the Central Nervous System

➢ Brain and spinal cord ❖ The CNS Contains:

➢ neurons ➢ neuroglia

- function is to protect and support neurons■ oligodendrocytes - make saltatory conduction possible ■ astrocytes - maintain blood brain barrier■ microglia - do phagocytosis■ Ependymal Cells - help produce cerebrospinal fluid

Function ❖ Awareness of ourselves and of our environment❖ Stream of sensory data❖ Controls muscle movements❖ Secretions of glands❖ Breathing and internal temperature❖ Every creative thought, feeling, and plan is developed by our

brain❖ Neurons record the memory of every event in our lives

Layers of the MeningesFunction is to protect CNSDura mater - outer layer lining skull

-Surrounds and supports dural sinuses carrying blood from the brain to the heart

Arachnoid mater - contains blood vessels. cushions CNS

Subarachnoid space - cerebrospinal fluid protects with central nervous system with cerebrospinal fluid

Pia mater - covers brain cerebrospinal fluid and contains the large blood vessels that supply the brain and spinal

cord.

Spinal cord reflexes - myotatic (stretch) reflex, flexor reflex,

Superficial Brain StructureGrey vs. White matterconvolution = a “wrinkle” on the surfaceGyrus = a region of the cerebrum sulcus = a shallow groove in the cerebrumfissure = a deep groove in the cerebrrumcerebral cortex = the outer few mm of the cerebrum

Brain Development ❖ In utero, the brain starts out as a hollow cylinder in the neutral tube❖ develops sense of touch

❖ At 3 weeks By 3 weeks the neural plate thickens first at the head end of the embryo and folds into the neural tube which will form the brain

and the spinal cord. By 3 weeks, the 3 primary sections of the brain are identifiable. These sections are called the forebrain, midbrain, and hindbrain

Sections of the Brain1. Cerebrum Frontal lobe

Parietal lobe Occipital lobe Temporal lobe Limbic lobe Insular cortex

Function of cerebrum The cerebrum is the center of the of sensory perception, memory, thoughts, judgment, and also the center of voluntary motor activityIt encompasses about two-thirds of the brain mass

Cerebrum cont.Frontal lobe- responsible for conscious thought Parietal lobe- plays an important role in integrating sensory information from various senses

Cerebrum cont.Occipital lobe- responsible for sense of sightTemporal lobe- responsible for senses of smell, sound, and processing of complex stimuli Insular cortex- responsible for pain, and some other senses

Limbic system

2. Limbic system- it supports adrenaline flow, emotion, behavior, motivation, long-term memory, olfaction, our emotional life, and has a large part in the formation of memoriesLocated on both sides of the thalamus, under the cerebrum

Cerebellum3.cerebellum- a region of the brain that plays an important role in motor controlIt is located underneath the cerebral hemispheres attached to the bottom of the brain

Brainstem4. Brainstem- responsible for allowing the nerve connections of the motor and sensory systems from the main part of the brain to the rest of the body It also regulates heart rate, sleeping, breathing, eating, the central nervous system, and helps maintain consciousness

Cranial Nerves- 12 Different Nerves

- Medial

- Motor skills and Senses

OlfactorySmell: Sensory-CN1-branch through cribriform plate-Olfactory mucosa, signal sent to olfactory bulb

OpticVision: SensoryCN2Transfers visual info to the brain.

OculomotorEyelid/Eyeball movement:MotorConnects to eye musclesand relays info from thebrain.

TrochlearControls superior Obliquemoves eye downward andlaterally.Motor

TrigeminalChewing/ face & mouth touchSensory & Motor

3 branches

AbducensTurns eye laterally motor

Connects from pons to lateral rectus muscle

Facialmost facial expressions/secretionsMotor & sensory

Many branches, each targeting a different area.

Vestibulocochlearhearing/equilibrium/sensations Sensory

Cochlea- hearingPeripheral nerves-balance

GlossopharyngealTaste/blood pressure/senses carotidsensory & motormany branches, taste ⅓ of tongue, attaches tostylopharyngeus muscle

Vagus-Slows heart rate-stimulates digestive system-Taste-Senses aortic B.P.Motor & Sensory

Spinal Accessorycontrols trapezius and sternocleidomastoid controls swallowing movementsMotor

Allows movement of head and thoracic.

Hypoglossalcontrols tongue movements.MotorHelps with digestion and the swallowing of food.

ReflexesSensory info normally travels from nerves through the spine to the brain. With reflexes, the action potential loops sooner to give outa mechanical response.Potential harm avoided