Nervous System Notes Part 1

Nerve impulses to and from the brain travel as fast as 170 miles per hour.

Ever wonder how you can react so fast to things around you or why that stubbed toe hurts right away? It’s due to the super-speedy movement of nerve impulses from your brain to the rest of your body and vice versa, bringing reactions at the speed of a high powered luxury sports car.

INTERESTING NERVOUS SYSTEM FACTS

The brain operates on the same amount of power as 10-watt light bulbYour brain generates as much energy as a small light bulb even when you’re sleeping.

NOTES – THE CENTRAL NERVOUS SYSTEM (CNS)

• Central Nervous System

• 2 parts 1. brain

2. spinal cord

• Parts of the Brain• BRAINSTEM (4 parts)

1. Medulla Oblongata

• Function: regulation of heart rate, breathing, swallowing, vomit response, coughing, sneezing• all involuntary actions

2. Pons • functions as a bridge between the cerebrum and cerebellum

4. Reticular Activating System (RAS)

• located scattered in the brainstem

• functions in arousing & maintaining consciousness

• damage here results in a coma

3. Midbrain • functions in hearing and visual reflexes

• Cerebellum • processes inputs of cerebral cortex and sensory receptors

• results in smooth, coordinated movements of skeletal muscles• injury results in loss of muscle tone and coordination

• Diencephalon (interbrain)• Thalamus • functions to sort out

all the sensory impulses from the body

• Hypothalamus

• EXTREMELY IMPORTANT in maintaining homeostasis

• What the hypothalamus controls

• Autonomic Control Center

• blood pressure, heart rate, digestive tract, eye pupil (involuntary responses)

• Emotional Responses

• pain perception, pleasure, fear, etc. (limbic system)• body temperature, hunger, thirst, sleep

• endocrine system hormones

• Hypothalamus Disturbances

• body wasting, or obesity, sleep problems, dehydration, emotional imbalances, and more

• The Cerebrum

• Cerebral Cortex • gray matter on the surface of the cerebrum

• enables us to perceive, communicate, remember, understand, appreciate and move voluntarily (consciousness)

• 3 functional areas of the Cerebral Cortex1. Motor Areas • controls movements of

skeletal muscles, speech and eyes

2. Sensory Areas

• conscious awareness of sensations (hot, cold, pressure, pain)

3. Association Areas

• connect different parts of the cortex

• involved in recognizing smells, tastes, etc.

• Examples of Association Areas

• sensory association areas• visual association areas• auditory association areas

• general interpretation area: integrates all incoming signals into a single thought• prefrontal cortex: most complicated part of brain – intellect and complex learning (abstract ideas, judgment, reasoning)

• Cerebral White Matter

• functions to provide communication between cerebral areas

• also provides communication between cerebrum and the rest of the brain

• Brain Disorders (some examples)• Parkinson’s Disease

• deficiency of the neurotransmitter dopamine

• Epilepsy • sudden burst of irregular electrical activity in brain – can lead to seizures, convulsions

• Stroke • blood clot in brain – paralysis appears on side of body opposite to side of brain affected

• Alzheimer’s Disease

• part of cortex shrinks, neurons lost• results in dementia, memory loss, disorientation, loss of body function