Unit 2: Nervous System

Wednesday 9-23-09

Reflex Arc

• Reflex = Involuntary Movements to Stimuli– Always happens same way– Always triggered same way– “Arc” = Predictable path message is sent

• Types of Reflexes:– Autonomic– Somatic

Reflex Arc Pathway

1. Receptor notices stimulus

2. Organ is stimulated

3. Sensory Neuron

4. Motor Neuron

5. Reflex

Autonomic Reflexes

• Involuntary Movement of:– Smooth Muscle (digestive)– Cardiac Muscle– Glands

• Examples:– Spit– Sweat– Increased Blood Pressure

Somatic Reflexes

• Involuntary Movement of Skeletal Muscle

• Examples:– Touching a Hot Stove– Knee-Jerk Reflex– Touching a Sharp Object

Brain Hemispheres

• Hemispheres = Different Sides of the Brain– Draw a line straight down the center of your head

(Back Forehead)– YOUR Right = Right Hemisphere– YOUR Left = Left Hemisphere– Right controls Left, Left controls Right

Brain Lobes

• Lobes = Different Regions of Brain

• Each Region has a unique set of functions

• Functions based on which neurons are connected where

• Perpendicular to hemisphere line = Sensory & Motor Division

Frontal Lobe

• Speech Production (Broca’s Area)

• Concentration

• Problem Solving

• Planning

• Voluntary Muscle Control

Parietal Lobe

• Interpretation of speech, sounds, surroundings

• Helps formulate words

• Skin sensations

Temporal Lobe• Interpret sensations

• Visual & Auditory Memory• Hearing function• Ability to learn + connect concepts

• Includes:– Thalamus– Hypothalamus– Pituitary Gland– Limbic System

Stuff In Your Temporal

(Thalamus, Hypothalamus, Pituitary, Limbic)

• Control Body Temperature

• Maintain fluid + ion levels

• Induce sleep

• Regulate hormone secretion

• Limbic = emotions

Occipital Lobe

• Vision

• Combines images to make complete picture

Cerebellum

• Coordinates muscle movement

• Maintains normal muscle tone

• DOES NOT MAKE MUSCLES MOVE!– Makes them move smoothly!

Brain Stem

• Passes info between spinal cord + brain

• Includes:– Midbrain– Pons– Medulla Oblongata

Stuff in Brain Stem

• Fight or Flight responses (based of past)

• Helps with vision + auditory senses

• Maintains Homeostasis – Heartbeat– Breathing rate– Blood pressure– Respiratory + Digestive reflexes