UNIT 7 – Human Biology

LT 6.10.6SWBAT describe and compare the main functions of human body systems and

organs

Before we begin

What do you

fear the most?

How do you

respond to your

fear?

Hook

• http://www.youtube.com/watch?v=5yGJGTjV2WE

The nervous system and the endocrine system provide the means by which organ systems communicate.

J – TPS (Justify – Think Pair Share)

• What happens when you touch something extremely hot? How do you react? Why?

J-TPS (Justify –Think Pair Share)

THINK PAIR

SHARE

The body’s communication systems help maintain homeostasis

• A stimulus is something that causes a response.– Responses can be:

• Chemical• Cellular• Behavioral

– The nervous and endocrine systems respond to stimuli.

What is homeostasis?

Think• What stimuli cause your body to sweat and cause

your pupils to shrink?THINK BOX

• The nervous system controls thoughts, movement, and emotion.

• The endocrine system controls growth, development, and digestion.

The nervous and endocrine systems have different methods and rates of

communication

• The nervous system works quickly.

• It uses chemical and electrical signals.

• The nervous system allows us to respond to pain.

spinal chord

nerves

spinal chord

nerves

• The nervous system is divided into:–The Central Nervous System (CNS) and–The Peripheral Nervous System (PNS)

The endocrine system works more slowly

– only chemical signals– signals move through bloodstream – physically unconnected organs

receptor

target cell

not a target cell

bloodstream

hormone

Think• Which system, the endocrine or the nervous,

controls the rate at which you blink? Explain.THINK BOX

Check your understanding

• Both the nervous and the endocrine systems allow you to1. analyze thoughts2. respond to stimuli3. control growth4. react at the same rate

Check your understanding

• The nervous and endocrine systems respond to 1. receptors2. changes3. messages4. stimuli

Check your understanding

• The endocrine system controls growth, development1. emotions2.digestion3. thoughts4. movement

Check your understanding

• Which activity is most likely controlled by the nervous system? 1. Growth2. response to pain3. changes in body chemistry4. development

Check your understanding

Why is the nervous system able to respond so quickly to a stimulus?

1. The nervous system responds only to certain simple stimuli

2. Messages don't have to travel first to the brain3. All parts of the nervous system are physically

connected in a network4. Chemical signals travel quickly in the body.

Check your understanding

• Which type of neuron relays signals from the central nervous system to the muscles?1. sensory neuron2. interneuron3. motor neuron4. specialized support cell

Hook

• http://www.youtube.com/watch?v=8dbDJzDV1CM

The nervous system is composed of highly specialized cells

IBE – JTPS What do you notice about these cells?

J-TPS (Justify –Think Pair Share)

THINK PAIR

SHARE

A neuron has three parts

1. cell body has nucleus and organelles

1 Cell body

2. dendrites receive impulses

3. axon carries impulses

2 dendrites

3 axon

• Electrical impulses (messages) are carried from the axon terminal across the synapse to the dendrite of the next neuron

Neurons never physically touch (The Synapse)

• Neurotransmitters (chemical message signals) are primarily found in the synapse between neurons

Motor neurons pass messages to muscles

IBE – JTPS How do your neurons react when in the morning your alarm clock buzzes?

J-TPS (Justify –Think Pair Share)

THINK PAIR

SHARE

The Resting Neuron  • When a neuron is resting (not transmitting a

message), the outside of the cell is more positive and the inside of the cell is more negative.

• An action potential is a moving electrical chemical message called an impulse.

• This occurs because:– Positive sodium ions (Na+) rush into the axon.

The action potential (the active neuron)

– The neuron returns to the at rest position (negative inside) when potassium ions (K+) leave.

When an action potential reaches the axon terminal, a chemical signal passes between neurons.

– Vesicles release neurotransmitters into the synapse.

– Neurotransmitters stimulate the next cell

The Synapse

Revisit IBE – JTPS How do your neurons react when in the morning your alarm clock buzzes?

Check your understanding

• Which part of this neuron carries messages to the cell body?1. axon2. dendrites3. nucleus4. terminals

Check your understanding

An electrical impulse moving down an axon is called a(n)

1. automatic function2. neurotransmitter3. action potential4. feedback loop

Check your understanding

• Thoughts, movements, and some life processes are controlled by the1. nervous system2. endocrine system3. muscular system4. circulatory system

Check your understanding

• Thoughts, movements, and some life processes are controlled by the1. nervous system2. endocrine system3. muscular system4. circulatory system

Check your understanding

• The structure that carries impulses in a neuron's cell is called a(n)1. axon2. vesicle3. synapse4. dendrite

Check your understanding

• What is a neuron's resting potential?1. the quantity of electrical impulse a cell generates2. the number of positive particles outside a cell3. the diffusion of ions inside of the cell4. the difference in charge across the cell membrane

Check your understanding

• What part of a neuron receives messages?1. the axon2. the dendrites3. the cell body4. the synapse

http://www.youtube.com/watch?v=U0NpTdge3aw