AP- Chapter 20, Central Nervous System.

Subarachnoid space

contains shock absorbing cerebral spinal fluid (CSF) 

Motor Area

Functional organization of the cerebral cortex.

• Broca’s Area: left hemisphere, movement of mouth for speech (motor speech area)

• Primary Motor Area: voluntary actions of skeletal muscles on the opposite side of the body

Celebellum

Second largest portion of brain (“Little Brain”)

Three functions of the cerebellum:

• With the cerebral cortex produces skilled muscle movements

• Controls posture

• Controls skeletal muscles to maintain balance

Injury to cerebellum causes: ataxia, hypotonia, tremors, and disturbances in gait

Thalamus

• oval shaped mass of grey matter

• A large number of axons conduct impulses to thalamus from the spinal cord, brainstem, and cerebrum

• Major relay station for sensory impulses on way to cerebral cortex

Main functions of the thalamus

• Major relay station for sensory impulses to cerebral cortex, filters out insignificant info

• Emotions- Associates sensory impulses with pleasant/unpleasant feelings

Hypothalamus

• Inferior to thalamus

• Six major functions (survival and enjoyment):

  • Control of the autonomic nervous system

  • Production of hormones

  • Regulate emotional and behavior patterns (together with limbic system)

  • Regulation of eating and drinking

  • Control of body temperature

  • Regulation of circadian rhythm

Association areas

• Somatosensory Association Area.

• Visual Association Area.

• Wernicke’s Area.

• Frontal Association Area.

Somatosensory Association Area

Permits you to determine the exact shape and texture of an object by feeling it, recognize and object (paperclip vs. pencil) by feeling it

Visual Association Area

Relates present and past visual experiences and can recognize and evaluate what you have seen before (ex. a spoon is for eating soup, spoons have many shapes, sizes)

Wernicke’s Area

The left hemisphere, allows you to understand the meaning of the spoken word (sensory speech area)

Frontal Association Area

Concerned with the makeup of a person’s personality, intellect, complex learning abilities, foresight, reasoning, conscience, intuition, mood, planning for the future.

• damage leads to a person becoming rude, moody, unable to anticipate the consequences of rash/reckless behavior.

Pons

• Superior to the medulla oblongata.

• Pons=bridge

  • connects different parts of the brain with one another.

• Pneumotaxic center- respiration, signaling inspiration after expiration

Medulla oblongata.

Most inferior, enlarged extension of the spinal cord just above foramen magnum.

• Vital center (Vital Reflexes)

• Non-Vital Center (Non vital reflexes)

Vital center (Vital Reflexes):

• Cardiovascular center-regulates the rate and force of the heartbeat

• Vasomotor center-regulates the diameter of blood vessels

• Respiratory center-adjusts the basic rhythm of breathing

Non-Vital Center (Non vital reflexes)

• vomiting, coughing, sneezing, swallowing, hiccupping

Limbic system

• Sometimes called the “emotional brain” because plays primary role in emotions.

  • Examples: pleasure, pain, affection, fear, anger

• Amygdala-reward and fear center of the brain, social function such as mating

• Hippocampus-required for the formation of long-termed memories

• Functional organization of the cerebral cortex

Cerebrum

• largest and uppermost.

• The Cerebral Cortex: Right and left hemisphere, and corpus callosum.

• Lobes of the cerebrum (named after the bones which surround them):

  • Frontal lobe

  • Parietal lobe

  • Temporal lobe

  • Occipital lobe

Left hemisphere

• logic, details, facts, words, language

Right hemisphere

perception of auditory material (music), tactual perception, perceiving and visualizing spatial relationships

Corpus callosum

• white matter connecting the two hemispheres.

• its function is to facilitate communication between the left and right hemispheres of the brain.

Sensory areas

• Primary somatosensory area-receives impulses from touch, proprioception, pain, itching, tickling,

• Primary visual area- receives impulses to convey information for vision.

• Primary auditory area-receives information for sound and is involved in auditory perception.

• Primary gustatory area-receives impulses for taste and is involved in gustatory perception and taste discrimination.

• Primary olfactory area- receives impulses for smell and is involved in olfactory perception.

CSF – cerebrospinal fluid

• Located in the ventricles of the brain and the subarachnoid space, surrounding the brain and spinal cord.

• Clear, colorless liquid composed primarily of water that protects brain and spinal cord from chemical and physical injuries. Carries small amount of O2, glucose, ions; about 3-5oz in adult

Sensory location – dorsal nerve root

carries only sensory information (dorsal root ganglion).

Motor location – ventral nerve root

carries only motor information.

Parkinson disease

• degeneration of neurons in the substantia nigra.

• Lack of dopamine- this inhibits the excitatory effects of acetylcholine.

• Restrains output of muscle signals.

• Causes rigidity, tremors, shuffling gait, forward tilting of trunk.

Dementia

• Degenerative diseases that cause destruction of neurons.

• Alzheimer’s disease- Form of dementia; lesions develop in the cortex in middle to late adult years

Cerebral palsy

• Damage to motor areas of brain tissue during birth

• Causes: Trauma, lack of oxygen, poisons.

Huntington disease

• Inherited disease characterized by involuntary, purposeless movements.

• Body produces a protein in the brain that prevents normal function

• Progression to severe dementia and death.

CVA – cerebrovascular accident

• Stroke.

• Hemorrhage from or cessation of blood flow through cerebral blood vessels.

• Destruction of neurons in the brain; oxygen supply is stopped

Poliomyelitis

• Destroys anterior horn motor neurons.

• Produces flaccid paralysis.