General Affects of the Nervous System

Meniges

3 layers of connective tissue around the brain and spinal cord

layers: Dura mater, subdural space, arachnoid, subarachnoid

Frontal Lobe function

1. Intellectual function and personality

2. Skilled movement

3. Voluntary movement

4. Broca area speech (expression)

parietal lobe

sensation (touch, pain)

occipital lobe

vision

temporal lobe

hearing, smell, comprehension of speech, memory

medulla oblongata

Part of the brainstem that controls vital life-sustaining functions such as heartbeat, breathing, blood pressure, and digestion.

hypothalamus

Autonomic nervous system

Controls body temp, thirst, and hunger

thalamus

sensory sorting and relay center

basal nuclei

coordination and control of body movement

reticular activating system

arousal or awareness

limbic system

emotions

Cranial II

Optic- Vision- Sensory

Cranial V

trigeminal - general sensory eyes, nose, face, oral cavity, teeth, mastication - sensory, motor

Cranial VII

facial - taste, facial expression, salivary glands - sensory, motor

Cranial X

vagus - taste, pharynx, posterior tongue, external ear, visceral sensory, pharynx and soft palate, heart and lungs - sensory, motor

What part of your brain determines LOC

RAS brain stem

Brain stem function and parts

Midbrain: vision, hearing, motor control

Pons: bridge between cerebellum and cerebrum (afferent incoming and efferent outgoing neurons)

Medulla oblongata: vital control center

anterior cerebral artery vs middle cerebral artery

Anterior: supplies blood to the frontal lobe

Middle: supplies blood to the lateral part of the temporal and parietal lobes

basilar artery

supplies blood to the brain stem and cerebellum

posterior cerebral arteries

Supply blood to the occipital lobes.

Broca's area vs Wernicke's area

Broca: expressive speech

Wernicke's: comprehends language, both written and spoken

Supraventricular lesions

Occur in the cerebral hemispheres above the tentorium cerebelli

Leads to specific dysfunction in a discrete area

infratentorial lesion

Located in the brain stem, results in widespread impairment

Glasgow Coma Scale

Eyes, verbal, motor

Max: 15 pts; below 8= coma/intubate

What is the terminal stage of a coma marked by?

loss of all reflexes, fixed and dilated pupils, slow and irregular pulse

vegetative state

loss of awareness and mental capabilities, but brain stem function continues

locked in syndrome

Individual is aware and capable of thinking but is paralyzed and cannot communicate

blinking for yes or no

What determines brain death?

1. Cessation of brain function, including the cortex and brainstem

2. Absence of brainstem reflexes or responses

3. Absence of spontaneous respirations

4. Certainty of irreversible brain damage

What are the two motor responses that occur in someone with severe brain damage?

Decorticate: rigid flexion of the upper limbs; damage to the cerebral hemispheres

Decerebrate: extension that occurs in people with brainstem lesions

How do eye pathways work?

Fibers from the inner half of the retina cross over to the other hemisphere, while the outer half of the retina remains on the same side.

Damage to the left occipital lobe causes what?

loss of the right visual field because the left half of both retinas receives light waves from the right side of the visual field

aphasia

impairment of language, usually caused by left hemisphere damage either to Broca's area (impairing speaking) or to Wernicke's area (impairing understanding).

expressive or motor aphasia site of damage and effect

Site: broca area

Effect: cannot speak or write fluently

receptive aphasia site of damage and effect

Site: Wernicke area, left temporal lobe, prefrontal

Effect: unable to understand written or spoken language

global aphasia site of damage and effect

Site: Broca and Wernicke areas

Effect: cannot express oneself or comprehend language

dysarthria

words cannot be articulated clearly

agraphia

impaired writing ability

alexia

impaired reading ability

agnosia

loss of sensory ability to recognize objects

Tardive Dyskenesia

A neurological disorder characterized by involuntary movements of the face and jaw

Cause: neuroleptic

What is the result of increased intracranial pressure?

Less arterial blood can enter the high-pressure area of the brain, and eventually the brain tissue is compressed

What causes increased ICP?

brain hemorrhage, trauma, cerebral edema, infection, tumors, accumulation of excessive amounts of CSF

What is the earliest sign of increased ICP?

decreased LOC

What are early signs of increased ICP?

severe headache

vommitting

papilledema

What 4 changes in vital signs occur with increased ICP?

1. Cerebral ischemia, which stimulates the Cushing reflex to increase arterial blood supply to the brain

2. Systemic vasoconstriction, which increases BP and forces more blood into the brain to relieve ischemia

3. Baroreceptor response to increased BP and slow the HR

4. Chemoreceptors respond to low CO2 levels and reduce respirations

Summary: increased BP, bradycardia

What 3 visual changes occur with increased ICP?

1. Pressure on the oculomotor nerves affects the size and response of the pupils

2. Blown pupils

3. Droopy eyelid (ptosis)

What is an abnormal level of CSF?

above 14 mmHg

What is the normal color of CSF?

Clear, colorless

What would the CSF look like in increased ICP?

Pink in color and containing erythrocytes, suggestive of hemorrhage.

Yellow CSF means infection

What is herniation?

Displacement of brain tissue due to mass effect or increased intracranial pressure