The Central Nervous System

The Brain• Composed of about 10 billion multipolar

neurons • Divided into three major portions: cerebrum,

cerebellum, and the brain stem• Cerebrum controls sensory and motor functions, higher

mental functions – memory and reasoning (Divided into sections)

• Cerebellum coordinates voluntary muscle activity• Brain stem regulates visceral activities and connects

various parts of the nervous system

Frontal Lobe: Most anterior, right under the forehead.Functions:• How we know what we are doing within our environment

(Consciousness). Controls our emotional response. Controls our expressive language. Assigns meaning to the words we choose. Involves word associations.

• Memory for habits and motor activities. Observed Problems:• Loss of simple movement of various body parts (Paralysis).

Inability to plan a sequence of complex movements needed to complete multi-stepped tasks, such as making coffee (Sequencing). Inability to focus on task (Attending) Changes in social behavior. Changes in personality. Difficulty with problem solving.

• Inability to express language (Broca's Aphasia).

Parietal Lobe: near the back and top of the head.Functions:• Location for visual attention. Location for touch perception.

Goal directed voluntary movements. Manipulation of objects. • Integration of different senses that allows for understanding

a single concept. Observed Problems:• Inability to attend to more than one object at a time. Inability

to name an object (Anomia). Inability to locate the words for writing (Agraphia). Problems with reading (Alexia). Difficulty with drawing objects. Difficulty in distinguishing left from right. Difficulty with doing mathematics (Dyscalculia). Inability to focus visual attention.

• Difficulties with eye and hand coordination.

Occipital Lobes:

Most posterior, at the back of the head.Functions:• Vision Observed Problems:• Defects in vision (Visual Field Cuts). Difficulty with locating

objects in environment. Difficulty with identifying colors (Color Agnosia). Production of hallucinations Visual illusions - inaccurately seeing objects. Word blindness - inability to recognize words. Difficulty in recognizing drawn objects. Inability to recognize the movement of an object (Movement Agnosia).

• Difficulties with reading and writing.

Temporal Lobes:

Side of head above ears.Functions:• Hearing ability Memory acquisition Some visual

perceptions • Categorization of objects. Observed Problems:• Difficulty in recognizing faces. Difficulty in

understanding spoken words. Short-term memory loss. Inability to categorize objects (Categorization). Right lobe damage can cause persistent talking.

• Increased aggressive behavior.

BRAIN STEM Deep in Brain, leads to spinal cord.Functions: • Breathing Heart Rate Swallowing Reflexes to seeing and

hearing (Startle Response). Controls sweating, blood pressure, digestion, temperature (Autonomic Nervous System). Affects level of alertness. Ability to sleep.

• Sense of balance (Vestibular Function). Observed Problems:• Decreased vital capacity in breathing, important for speech.

Swallowing food and water (Dysphagia). Difficulty with organization/perception of the environment. Problems with balance and movement. Dizziness and nausea (Vertigo).

• Sleeping difficulties (Insomnia, sleep apnea).

Brain Stem

• Includes midbrain, pons, and medulla oblongata• Midbrain – several masses of gray matter that serve

as reflex centers = vision reflex and auditory reflex• Pons – relay sensory impulses from peripheral

nerves to higher brain centers• Medulla oblongata – similar to the pons, but also

controls the cardiac center, vasoconstriction and vasodilatation, and respiratory center.

CEREBELLUM

Located at the base of the skull.Functions:• Coordination of voluntary movement Balance and

equilibrium • Some memory for reflex motor acts. Observed Problems:• Loss of ability to coordinate fine movements. Loss of

ability to walk. Inability to reach out and grab objects. Tremors. Dizziness (Vertigo). Slurred Speech (Scanning Speech).

• Inability to make rapid movements.

Diencephalon• Contains the thalamus and hypothalamus and

medial forebrain• Comprised mostly of gray matter• Hypothalamus is important in maintaining

homeostais by regulating:– Secretions that stimulate the pituitary gland– Heart rate– Water and electrolyte balance– Hunger and body weight– Glandular secretions– Body temp– Sleep and wakefulness

Cranial Nerves

Pair of nerves What is does

1. Olfactory smell

2. Optic vision

3. Oculomotor Raise eyelids, move the eye, controls involuntary muscles of the eye, adjusts amount of light into the eyes

4. Trochlear Carries motor impulses to the fifth voluntary muscle of the eye

5. Trigeminal Ophthalmic division = sensory fibers from the surface of the eye, tear glands, anterior scalp, forehead, upper eyelidsMaxillary division = upper teeth, upper gum, upper lipMandibular division = scalp behind ears, skin of jaw, lower teeth, lower gum, lower lip

Pair of nerves What is does

6. Abducens Moves the rest of the eye

7. Facial Taste, anterior two-thirds of tongue, facial expression

8. Vestibulocochlear Vestibular branch = maintain equilibriumCochlear branch = hearing

9. Glossopharyngeal Tongue and pharynx, tonsils, posterior third of tongue

10. Vagus Somatic= Larynx, swallowing, speechAutonomic = heart and smooth muscles

11. Accessory Cranial branch = soft palate, pharynx, larynxSpinal branch = neck muscles

12. Hypoglossal Move the tongue for speaking, chewing, swallowing

The Spinal Cord

Spinal Cord• connected to the brain and is about the diameter of

a human finger • descends down the middle of the back and is

surrounded and protected by the bony vertebral column

• surrounded by a clear fluid called Cerebral Spinal Fluid (CSF), that acts as a cushion to protect the delicate nerve tissues against damage from banging against the inside of the vertebrae

• transmit electrical information to and from the limbs, trunk and organs of the body, back to and from the brain

31 pair of Spinal Nerves

• 8 pair = cervical nerves• 12 pair = thoracic nerves• 5 pair = lumbar nerves• 5 pair = sacral nerves• 1 pair = coccygeal nerves

• Plexuses = nerves are sorted and recombined so that fibers innervate a particular peripheral body part, reach it in the same nerve, even though fibers originate from different spinal nerves

Form complex networks called Plexuses

Spinal NervesThere are four main groups of spinal nerves which exit

different levels of the spinal cord. These are in descending order down the vertebral column:• Cervical Nerves "C" : (nerves in the neck) supply movement

and feeling to the arms, neck and upper trunk. Muscle impulses of the diaphragm (the phrenic nerve)

• Thoracic Nerves "T" : (nerves in the upper back) supply the trunk and abdomen. – Brachial Plexus = deep in shoulders between neck and armpits,

supplies the muscles and skin of arm, forearm, and hand

• Lumbar Nerves "L" and Sacral Nerves "S" : (nerves in the lower back) supply the legs, the bladder, bowel and sexual organs.

• Anterior thoracic spinal nerves do not enter plexus– Enter in the spaces between ribs = intercostal

nerves• Supply the intercostal muscles, upper abdomen wall

muscles – sensory impulses from skin, thorax and abdomen

Brain Dominance

• Brain dominance refers to a preference for using one hemisphere of the brain over the other hemisphere.

• The left hemisphere of the brain is rational, analytical, and verbal.

• The right hemisphere is holistic and intuitive, responsive to visual imagery.

What side of the brain is dominant for you?

Right-brained learners prefer:

• pictures, diagrams, charts, or graphs,

• video, • talking about feelings, • social activities, • music, • attention to the "big

picture," and • creative activities and

projects

Left-brained learners prefer:

• lots of reading, • writing, • assignments involving

reasoning and analyzing, • attention to detail • quantitative methods, • linear, organized approach

to lessons, and • a syllabus showing what will

happen when.