Chapter 13 – BloodChapter 22 – Fetal Circulation

Chapter 22 pages 458 - 459

Blood

• Blood is made up of two parts1. Formed Elements• Red blood cells• White blood cells• Platelets

2. Plasma

Formed Elements• Red Blood Cells– Also called erythrocytes– No nucleus– Made in the Marrow of Bones (the middle of

bones)– Contains the protein Hemoglobin. This allows the

cell to carry oxygen.– If arterial blood is carrying low amounts of oxygen

then the kidney produces a hormone called erythropoietin. This tells the body to produce more red blood cells

Red Blood Cells•Double Concave•No nucleus•Protein Hemoglobin•Made in Bone Marrow

White Blood Cells

• Called Leukocytes• Many different types of white blood cells• Made in the marrow of bones• Use a combination of special proteins,

enzymes, and phagocytosis to kill infections

Platelets

• Also called Thrombocytes• Made in the Marrow of bones• Involved with blood clotting• No Nucleus

PlateletNo NucleusSmaller than RBCForms Blood Clots

Where do blood cells come from

• There are a type of stem cell found in the marrow of bones

• These stem cells can create any type of blood cell including– Platelets– Red Blood cells– All types of White blood cells

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Plasma• Mostly made up of water• Transports dissolved gases CO2, O2

• Transports nutrients Amino acids, glucose• Transports wastes Urea, Uric Acid• Transports hormones Insulin, epinephrine• Has Plasma Proteins– Fibrinogen, prothrombin These proteins help

create blood clots

Capillary Exchange

• On the arterial end of capillaries the blood pressure pushing into cells is greater than the osmotic pressure pushing out of cells.– The result is that materials move into cells

• On the Venous end of capillaries the blood pressure pushing into cells is lesser than the osmotic pressure pushing out of cells.– The result is that materials move out of cells

Review

• Page 260 -261• Testing yourself– Questions 1- 12

Blood Circulation in a Fetus• A fetus does not use its lungs for gas exchange– Instead it relies on the mother for gas exchange

• The fetus has a whole in the heart that connects the right atrium to the left atrium called the oval opening– Most of the blood coming into the right atrium goes

to the left atrium• Any blood that goes into the Right Ventricle

goes up through the pulmonary trunk and is diverted and enters the aorta via the arterial duct

• The Fetus does its gas and nutrient exchange through the placenta.

• Oxygenated blood going to the fetus heart goes through the umbilical vein

• The umbilical vein enters the liver and then joins with the venous duct, which then enters the heart via the inferior vena cava

• When blood leaves the heart it goes to the body and deoxygenated blood goes back to the placenta through the umbilical artery