WARM UP #1 12/14

You are walking alone and someone jumps out at you.

1. List 3 behavioral responses

2. List 3 physiological responses

CH 5 NOTES #112/14

Nervous System

Nervous system:

Our body needs to communicate with its parts to know if there are any changes and to get it back to normal (homeostasis)

PURPOSE:• Sends messages around the

body through nerves

PARTS:

• Brain, spinal cord, nerves

• Nerve cells: neurons

Nervous system and homeostasis1. VOLUNTARY - you control

BEHAVIORAL - Allows you to choose to do something

Part of the brain used – CEREBRUM

EX: running away, talking, jumping, walking, *any movement

HOW IT WORKS - VOLUNTARY

Sensor

Nerves

Spinal cord

Brain – cerebrum

Spinal cord

Nerves

Muscles

DID YOU KNOW?

The right side of your brain controls the left side of your body and vice versa

DID YOU KNOW?

Different parts of the brain control different parts of your body

2. INVOLUNTARY - you don’t control

PHYSIOLOGICAL - Causes your body do something on its own

Part of the brain – BRAIN STEMEVERY SECOND – heartbeat, breathing, blinking, swallowing

(medulla)

WHEN NEEDED: blood pressure changes, temperature, sugar level, pain, goosebumps, digestion, pupil changes, sweat, etc.

QUESTION – BONUS POINTS

1. What does involuntary mean?

2. What part of your brain controls the voluntary?

3. Is physiological voluntary or involuntary?

HOW IT WORKS - INVOLUNTARY

Sensors

Nerves

Spinal cord

Brain – brain stem

Spinal cord

Nerves

Glands or organs

2 divisions of the nervous system to help maintain homeostasis

a. SYMPATHETIC – works in times of stress on your body

“ fight or flight” - makes adrenaline release

Prepares body to survive main priority = brain, heart, lungs, muscles

b. PARASYMPATHETIC – works in times of relaxing; brings your body back to normal

AKA: “rest and digest”

Main priority: digestive; being back to normal

BONUS POINTS

S or P?

1.Heart beats faster

2.Digestion happens

3.Muscles tense up

4.Breath slower

How fast does all this happen?

Around 280 miles per hour!

Feels like it is instant

How does your body know that it needs to do something?

SENSORS – cells that detect changes in our body.

PURPOSE: so your body can respond and go back to homeostasis

REFLEX

A fast reaction to protect the body that skips the brain.

EX: blink, cough, move from hot, flinch, duck sneeze, gag

HOW IT WORKS - Reflex

SensorNervesSpinal cordNervesMuscle movement

NEGATIVE FEEDBACK

Body senses change and it causes it to change back in the opposite direction

EX: heart beats faster - heart beats slower

blood pressure decreases - blood

pressure increases

EX: BLOOD PRESSURE

Increase in blood pressure

Detected by the brain

Message to heart message to arteries decrease dilate

Blood pressure drop back to normal

ENDOCRINE SYSTEM

• Sends messages around the body through chemicals

• Glands – release hormones

• Hormones – chemicals released in blood that cause a reaction in the body

Endocrine system and homeostasis

1. Chemicals will cause your body to respond and maintain homeostasis

EX: sugar balance

water

calcium balance

ph

EXAMPLE

EXAMPLE:

• Blood sugar goes up after a meal

• Pancreas detects the rise and secrete insulin

• Insulin causes the liver and body cells to store the extra sugar

• Sugar back to normal

EXAMPLE:

• Body detect not enough water

• Message to brain

• Pituitary gland releases hormone

• Makes kidney hold onto water; thirsty

• Water balanced