Key Area 2.6

Maintaining stable body conditions

Starter Activity: 2 Minutes thinking time.Discuss with your partner, what do you knowabout the nervous system in the body?

Can you come up with 3 facts about the nervous system?

Facts-

The nervous system contains the brain, spinal cord and nerves.

The human brain is made of about 100 billion cells.In humans the right side of the brain controls the left side of

thebody and vice versa.The brain weighs approximately 3lbs (1-1.5kgs). We have about 600 miles of nerves in our bodies.

Nervous System

Learning Intention: Research the nervous system and how it responds to environmental changes

Success Criteria: Show an understanding of the nervous system structure and how the reflexes work

Nervous System

• The nervous system controls the bodies functions.

Breathing Heart Rate Digestion

Thoughts Memory

Movement Balance Temperature

What does it control?

Nervous system

• The nervous system is split up into the Central Nervous System and the Peripheral Nervous System.

• The Central Nervous System (CNS) is made up of the brain and spinal cord.

• Spinal cord

Nervous system

Brain

Spinal Cord

Nerves

This diagram shows the structure of the bodies nervous system.

•Watch the video in the link and answer the questions on page 3 and 4 about the Nervous system

Nervous system

• The way in which the neurones carry the information is known as a nerve impulse.

• These nerve impulses travel very quickly. (up to 100 m/s)

• This allows someone to receive information and respond in a fraction of a second.

• Neurons

Nervous System• Nerve impulses are so fast so they can help us

survive! This is known as our reflexes.

• A reflex can be described as an automatic, protective response to a harmful stimulus.

Reflexes• Reflexes are design to respond to a situation without

us having to think about it. Why?

• What happens when we touch a hot surface?• A stimulus (heat) is detected and causes an impulse

to be carried by the nerves from the skin to the spinal cord.

• Another impulse is then sent via another nerve to the muscles of the arm.

• You respond by pulling your hand away to prevent burning.

Reflexes• This response is automatic and difficult to suppress.

• Stimulus not sent via the brain to save time.

• Some other examples of reflexes are sneezing, coughing, blinking.

Receptors

Learning Intention: Investigate the density of touch receptors in the skin

Success Criteria: Investigation in to touch receptors. Show an understanding of the Homunculus model.

Starter Activity1. Name the parts of the central nervous system.Brain and spinal cord.

2. What is a reflex action?An automatic, protective response to a harmful stimulus.

3. Name to thing that our nervous system controls.Breathing rate, heart rate, memories, logical thinking,emotions, movement, balance.

4. Give an example of a reflex action.Coughing, sneezing, blinking.

What do you think this is?

Senses

• As we have discovered nerves control a range of functions that our body can do.

• Sensitivity to touch is a major factor that helps us balance, move and stay safe.

• If blindfolded could you find your way around the classroom?

• How would you move about?• Would you have to feel your way around the

room?

Homunculus• We can demonstrate our sensitivity to touch by

using a model known as a homunculus.Each part of our body has different levels of sensitivity.

The model shows how a human might look if their body was in proportion to the number of sensory neurones that controlled it.

The bigger it is the more sensitive it is!!

Activity 2: Sensitivity Practical

• Around the room there are 5 boxes• Place a blindfold on and place your hands

in the boxes. Can you guess what the objects are?

Touch Receptors

• The touch receptors on the surface of your skin pick up information and pass it along sensory neurones to your brain to be interpreted.

Homeostasis

Learning Intention: To investigate homeostasis and understand two common examples.

Success Criteria: Show an understand of the process of homeostasis and the bodies reaction to changes in its environment

Starter

• How many words can you make with the letters from:

HOMUNCULUS

Homeostasis• Homeostasis- is the process by which we can

control our bodies internal environment.

• What needs to be kept the same in our bodies?

• Two of the most important are body temperature and glucose levels.

• If we get too hot or too cold, we can die. Not enough glucose and we don’t have any energy.

Homeostasis- Temperature

• A change in our external temperature starts to change our internal temperature.

• How does our body respond if we are too hot?

Sweat more Thirsty

Hairs lie flat Blood capillaries on arms open up more - face goes red• These responses allow heat to escape from our bodies,

cooling us down and keeping our temperature at about 37oC.

Homeostasis- Temperature• What happens if we are too cold?

Shivering Blood capillaries narrow – look

pale

Hairs on arms Decrease in stand on end sweating (goosebumps)• The brain detects changes in temperature and sends

information to skin or muscles to produce the necessary response.

Normal body

temperature (37oC)

Normal body

temperature (37oC)

Increase in body temp

Decrease in body temp

Nervous impulses to skin

Detected by the brain

Decrease in body temp

Increase in body temp

Responses:1.Shiver2.Goose bumps to trap air

Detected by brain Nervous impulses to skin/muscles

BASIC CONTROL OF BODY TEMPERATURE

Responses:1. Sweat2. Extra blood flow to skin

Activity 3: Video

• Richard Hammonds Miracles of Nature Ep 3/3 – YouTube

• (1min 50s- 14min 08s affect of changing temperature)

Write down any facts you can about the effect of temperature on our bodies.

Starter activity

• What do we need energy for?

• Movement, chemical processes, growth, reproduction, organs function properly, maintain body temperature

• Where does this energy come from?

• Food- Carbohydrates (sugar) such as Glucose.

Homeostasis- Blood Glucose• Our bodies need a regular supply of energy for it to

function properly.

• Some organs such as our brain need a constant supply, as they can’t store energy (glucose).

• The level of glucose available in our blood depends on what we have eaten and what activities we are doing.

Homeostasis- Blood Glucose• Our blood sugar level is controlled by hormones.

• Insulin (a hormone) helps covert glucose into a storage carbohydrate called glycogen.

• Glycogen can then be stored in the muscles or the liver to be used when needed. e.g. playing sport.

• Insulin is produced in the pancreas.• When we eat our blood sugar level goes up, this

increases the level of insulin produced.

Glucose Storage

Glucagon

Glucose Glycogen (Stored in liver or muscles)

Insulin

Normal blood

glucose level

Normal blood

glucose level

Increase blood glucose level e.g. eating

Decrease in blood glucose levele.g. exercising

Pancreas produces more insulin

Detected by the brain

Decrease blood glucose level

Increase in blood glucose level

Response:Less Glycogen producedDetected by brain Pancreas

produces less insulin

BASIC CONTROL OF BLOOD GLUCOSE LEVEL

Response:Glucose converted to Glycogen for storage

Diabetes

Learning Intention: To understand how diabetes is caused.

Success Criteria: To research what causes diabetes and how it can be controlled.

Starter - Discussion• With your partner - Spend 2 minutes

• Why is it important that we maintain a fairly constant blood glucose level?

• What happens if we don’t?

Research topic- Diabetes• If we cant control our blood sugar levels then we can

develop a condition called Diabetes.

• Your task is to research information about diabetes. • You should include-

what is it?types- number of suffererseffects on the bodycausestreatments- types, costs to NHSaffect of lifestyle

And any other significant/interesting information.

Research topic- Diabetes

• Your research project can be a poster presentation,

power point, leaflet, movie presentation, the choice is yours!!

• You should be ready to present your findings and information to class on the date given by your teacher.