Blood Composition and Functions

Blood Functions

• Transports oxygen, carbon dioxide, nutrients, hormones, and waste products.
• Regulates body temperature, pH, and fluid volume.
• Protects against infection and blood loss.

Plasma Components

• Plasma is composed of water, proteins (e.g., albumin), electrolytes, nutrients, gases, and waste products.
• Albumin maintains osmotic pressure and transports lipids, hormones, and drugs.

Hematocrit

• Hematocrit is the percentage of blood volume occupied by red blood cells (RBCs).
• Clinical hematocrit: percentage of RBC's in blood sample
• Real hematocrit: accounts for plasma trapped between RBC's

Red Blood Cells (RBC)

• RBCs transport oxygen from the lungs to the tissues and carbon dioxide from the tissues to the lungs.
• Biconcave shape increases surface area for gas exchange.
• RBCs lack a nucleus to maximize space for hemoglobin.

Hemoglobin

• Hemoglobin is the protein in RBCs that binds to oxygen and carbon dioxide.
• Its structure includes four polypeptide chains (globins) and four heme groups, each containing an iron atom that binds to oxygen.

Leukocytes

• Leukocytes (white blood cells) are involved in immune responses.
  • Granular leukocytes: neutrophils, eosinophils, and basophils
  • Agranular leukocytes: lymphocytes and monocytes

Erythropoietin

• Erythropoietin is a hormone produced by the kidneys that stimulates red blood cell production in the bone marrow.

Megakaryocytes

• Megakaryocytes are large bone marrow cells that produce platelets.

Blood Types

• Blood types (A, B, AB, O) are determined by the presence or absence of certain antigens on the surface of RBCs.
• Blood type O is the universal donor; AB is the universal recipient.

Incompatible Blood Transfusion

• Results in agglutination (clumping) and hemolysis (rupture) of red blood cells

Hemolytic Disease

• Hemolytic disease of the newborn (HDN) can occur when an Rh-negative mother carries an Rh-positive fetus and mother produces antibodies against the Rh factor, potentially harming subsequent Rh-positive fetuses.

Platelets

• Platelets (thrombocytes) are cell fragments that play a role in blood clotting.

Vitamin K

• Vitamin K is essential for the synthesis of several clotting factors.

Fibrinolysis

• Fibrinolysis is the breakdown of blood clots.

Last Stage of Blood Clotting

• Clot retraction, where the clot condenses.
• Vessel repair

Prostoglandin

• Prostoglandin is a lipid compound with hormone-like effects, including vasodilation and inhibition of platelet aggregation.
• The smooth lining of epithelium helps prevent blood clotting and reduces friction in blood vessels.

Digestion

• Includes: ingestion, propulsion, mechanical breakdown, chemical digestion, absorption and defecation

Mechanical and Chemical Digestion

• Mechanical digestion: Physical breakdown of food into smaller pieces (e.g., chewing, churning).
• Chemical digestion: Enzymatic breakdown of food into smaller molecules (e.g., saliva in the mouth breaking down carbohydrates).
• Examples occur in the mouth, stomach, and small intestine.

Organ Functions in Digestion

• Examples of organ functions in digestion include the stomach, small intestine, and large intestine.
• Small intestine is involved in absorption of most nutrients

Digestion Organs

• Gallbladder: Stores and concentrates bile.
• Liver: Produces bile, metabolizes nutrients, and detoxifies substances.
• Pancreas: Secretes digestive enzymes and hormones (insulin and glucagon).

Bile and Epiglottis

• Bile emulsifies fats to aid in their digestion and absorption.
• Epiglottis prevents food from entering the trachea during swallowing.

Peristalsis

• Peristalsis is the rhythmic contraction of smooth muscles in the digestive tract that propels food forward.

Digestive Hormones

• Gastrin stimulates the release of gastric acid in the stomach.
• Secretin stimulates the release of bicarbonate from the pancreas.
• Cholecystokinin (CCK) stimulates the release of digestive enzymes from the pancreas and bile from the gallbladder.

Fat & Carbohydrate Digestion

• Lipase digests fats.
• Amylase digests carbohydrates.

Absorption

• Fat-soluble vitamins (A, D, E, K) are absorbed with fats.
• Intrinsic factor (produced in the stomach) is essential for the absorption of vitamin B12.

Hepatic Artery

• The hepatic artery supplies oxygenated blood to the liver.

Overview of blood functions including transportation, regulation, and protection. Details on plasma components such as water, proteins, and electrolytes. Focus on hematocrit and red blood cells (RBCs), their role in gas exchange, and hemoglobin.