Required materials and hormones enter .
Wastes and hormones targeted for other cells must leave the cell that made them.
Circulatory system moves the materials throughout animals.

Plasma membrane
• Made of phospholipids arranged in a bilayer
• The fatty acids tails are repelled by water and point inward. The “phospho” ends like water and point out.

Phospholipid Bilayer

What can cross the plasma membrane?

How do large, uncharged polar molecules or ions pass into or out of a cell?
• The plasma membrane contains many different kinds of molecules.
• Some of these are designed to move materials in or out of a cell with out contacting the phospholipid bilayer.

Plasma membrane details

Diffusion
• The movement of materials from an area of higher concentration toward areas of lower concentration. Movement continues until there is an equal concentration everywhere.

Diffusion

Diffusion video
• https://www.youtube.com/watch?v=VY0mZU
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Osmosis
• Osmosis is the movement of WATER from areas of higher concentration to areas less concentrated.

Water can enter or leave a cell. This depends upon where the water is purest.

Osmosis
• https://www.youtube.com/watch?v=w3_8FSr qc-I

Cystic Fibrosis

Facilitated Diffusion
•
• Many substances cannot pass through the phospholipid bilayer. Impermeable
• Proteins embedded in the membrane create pathways for specific things to pass. Selectively permeable.

Favilitated Diffusion

Facilitated diffusion video
• https://www.youtube.com/watch?v=OV4PgZ
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Active Transport
• Movement of materials from one area to another. The result is an imbalance of materials.
• The imbalance is a form of potential energy.

Active Transport
• https://www.youtube.com/watch?v=kfy92hda
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Stained Yeast Cells

Phagocytosis or Pinocytosis
• Moving large quantities of material [not single molecules] into or out of the cell.
• A pocket forms and material that moves into the pocket is taken in.
• Bubbles of material inside the cell moves to join with the plasma membrane which open up to let the material escape the cell.

Kidney
• The kidney controls the composition of blood.
• Removes wastes.
• Eliminates excess water.
• Balances pH and electrolytes.
• Controls blood pressure.

Location of Kidneys

Nephron , functional unit of the kidney

Kidney Functions
• Filtrationsize dependent, cells and large molecules remain in the blood.
• Reabsorptionrecapturing needed materials.
• Secretioneliminating excess materials still in the blood.

How molecular composition of the blood is controlled
• Osmosis
, 100 liters of water leave the blood every day, 1 liter of urine is produced daily, 99 liters reabsorbed.
• Diffusion
• Facilitated Diffusion
• Active transport, reabsorption and secretion.