DAY 3 - Homeostasis

DAY 3 - Homeostasis

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Multiple Select

If homeostasis tries to keep a healthy internal balance, how will your body react to running a mile under 12 minutes?

(There are TWO right choices. Pick both!)

• Breathing hard to restore oxygen to cells.

• Breathing hard to keep moving and burning calories.

• Sweating to cool off your body through your skin.

• Sweating to warm up your body through your skin.

The (very involved) process of sweating:

+ Muscles work harder to help you move faster.

+ Muscle cells demand more energy to keep moving - ATP!

+ Using this energy creates heat inside body.

+ Hypothalamus (brain) tells skin to release the heat trapped within.

+ Salty chemicals move inside sweat glands in skin.

+ This "pulls in" water from skin cells.

+ Water pressure makes the sweat "leak" out of the gland.

+ Water carries heat from inside the body, then

+ Water evaporates and takes the heat into the atmosphere!

Multiple Choice

Which parts of the body work together to create sweat?

• Muscles, hypothalamus, skin.

• Liver, tongue, and femur bones.

• Muscles, femur bones, and heart.

In short, homeostasis is...

How human bodies keep a healthy internal balance.

How do they do this?

They react to changes inside and outside to bring

the body back into "balance" and good health.

Multiple Choice

What word below would you use to describe homeostasis?

• Strong

• Weak

• High

• Low

• Healthy

Let's see some examples!

You already learned how sweating works.

Shivering

+ Brain senses temperature drop

^{----> Normal temperature is around 98.6° F}

+ Muscles contract and relax

+ This uses up energy and...

+ This causes heat inside body

+ You feel it like a shiver

Thirst

+ Kidneys find blood low on water

^{---> Kidneys actually filter blood for urea}

+ They send a signal to the brain

+ Brain makes you feel thirsty until you drink enough water

+ When blood has enough water...

+ Kidneys send a "stop" signal

Hunger

+ Body cells use sugar for energy

+ Sugar levels in the blood drop low

+ Pancreas releases glucagon

+ Liver then breaks down sugars

+ You feel hungry at this point

+ You eat (hopefully healthy) foods

+ Digestive system breaks down more sugar from the foods you ate

+ Pancreas releases insulin

+ Liver stops breaking down sugars

+ You feel full and satisfied

Balance

+ You strike a pose (like picture)

+ Tiny bones in your ear sense it

+ They signal the brain about it

+ Brain signals the muscles to help

+ Muscles activate to help you

+ Ear bones keep sensing and the brain keeps updating movements

Multiple Choice

Because the brain is the organ that senses and controls almost everything in the human body, it is very involved in homeostasis.

• True

• False

Multiple Choice

What is the main purpose of homeostasis?

• To make sure you live 100 years.

• To make you the strongest person alive.

• To keep you alive and healthy.

• To make sure you get enough energy.

Many, many more examples!

• How much oxygen there is in your blood

• How much carbon dioxide there is in your blood

• How much acid there is in your blood

• Blood pressure in arteries (deeper) and veins

• How many nutrients there are in your blood

Everything that keeps you healthy is affected by homeostasis!

Because homeostasis is how the body keeps you healthy.

Every system is involved!