Toxic Waste?!

So now we’ve eaten…we have to get rid of the waste!

Excretory/Urinary System Notes

Continuation of digestion – food is transferred into nutrients and passes through the body as waste7.7B transformation of energy within an organism, for example to transfer from chemical energy to heat and thermal energy in digestion

You may use this notes page:

Food! Nutrients in the Body• So we eat food to survive, right?

• What do we do with this food though?

Our food is chemical energy. As the body breaks it down, these molecules are sent to all parts of the body. The cells, depending on what type of cell it is, then use those molecules for different processes.

Law of Conservation of Energy

• Remember this one?

• Energy cannot be created nor destroyed!

• Therefore, energy just changes forms.

• The energy stored in food changes to chemicalenergy, which is then changed into either thermal energy or mechanical energy

• Why thermal?

Examples of energy transformations in the human body

Chemical Energy in the Body• Carbohydrates and fats are utilized for energy.

• This energy is not only used for movement and to keep us warm, it is also used for biological processes within cells.

How?

• All molecules are made up of atoms which are joined together by bonds.

Chemical Energy in the Body• The bonds which join atoms contain energy.

• Because different bonds have different atoms will vary in their strength and amount of energy.

• The cells in your body function by manipulating and rearranging molecules to form new bonds or break old ones, in a process called metabolism.

From absorption and energy, and then…to waste!

• So we know how nutrients go into the body, how do we get rid of the things we don’t want?

• Excretion is the process of removing wastes from the body

• Three systems in your body work to get rid of wastes

Body Systems that remove wastes:

1. The integumentary system releases waste products and water when you sweat

2. The respiratory system releases carbon dioxide and water when you exhale

3. The urinary or excretory system contains organs that remove liquid and solid waste products from your body

Label on your page:

Main structures:

• kidneys, ureters, bladder and urethra

Functions of the excretory system:

• Removes wastes produced by the activities of cells that have been filtered by the blood stream

• Removes toxic nitrogen waste

• Maintains water balance which is crucial to maintaining homeostasis.

• Homeostasis is maintained by getting rid of wastes such as salt and urea

More on Homeostasis:

• Your cells have to maintain a certain level of salt and water to function properly

• The excretory system works with the endocrine system to help maintain homeostasis

• Chemical messengers, called hormones, signal the kidneys to filter more or less water or salt, depending on the current levels in your body

How the kidneys work to clean our blood!:

1. The kidneys filter the blood of waste using tiny structures called nephrons

a. Nephron consists of two parts – glomerulus and renal tubule

b. Includes a network of arterioles and venules

c. Unfiltered blood from an artery enters kidney and passes through nephrons, removing waste

d. Nephrons collect waste and release to ureters

e. Filtered blood returns to bloodstream in veins

Label the one in your notes

2. Ureters: tubes that carry urine from each kidney to the urinary bladder

3. Bladder: stores urine until it is released from the body

4. Urethra: carries urine from the bladder to the outside of the body

a. Males have common exit for both urine and sperm

b. Females have a single exit for urine

3

4

Other Excretory Organs

• Skin = releases

perspiration (water

& salts) to cool off

body

Other Excretory Organs

• Lungs = release carbon dioxide from the body

Excretory System

• Crash Course:

• https://www.youtube.com/watch?v=WtrYotjYvtU