Cardiovascular System: Blood Composition

• Lab is on the cardiovascular system

Blood Composition

• Blood is a connective tissue with cells within a matrix.
• Blood's components are plasma and formed elements
• Plasma is an nonliving fluid matrix.
• Formed elements are cells and cell fragments.
• Plasma contains over 100 dissolved or suspended substances.
• Water is a major component of plasma and a solvent that absorbs heat
• Electrolytes such as sodium, potassium, calcium, magnesium, chloride and bicarbonate contribute to osmotic and pH balance in the plasma
• Plasma proteins such as albumin, fibrinogen, and globulins contribute to osmotic balance, blood clotting and defense functions
• Nutrients, waste, respiratory gases (O2 and CO2), and/oromones are substances transported by the blood
• Erythrocytes (red blood cells) number 4-6 million per mm3 of blood and function to transport oxygen and carbon dioxide
• Leukocytes (white blood cells) number 4,800-10,800 per mm3 of blood and function in defense and immunity
• Platelets number 150,000 - 400,000 and function to assist in blood clotting.
• Neutrophils, eosinophils, and basophils are granulocytes
  • Neutrophils: have a multilobed nucleus and pale red and blue cytoplasmic granules
  • Eosinophils: have a bilobed nucleus and red cytoplasmic granules
  • Basophils: have a bilobed nucleus and purplish black cytoplasmic granules
• Lymphocytes and monocytes are agranulocytes
  • Lymphocytes: have a large spherical nucleus and a thin rim of pale blue cytoplasm
  • Monocytes: have a kidney-shaped nucleus and abundant pale blue cytoplasm

Anatomy of the Heart

• The heart resides in the mediastinum, a space in the chest between the lungs.
• The mediastinum contains the heart, part of the trachea, the esophagus, and major blood vessels.
• Essentially, all organs in the chest reside in the mediastinum except the lungs.
• The heart is enclosed in a double-walled serous membrane called the pericardium, separated by the pericardial cavity
• The heart wall is composed of 3 layers:
  • Epicardium (outer layer)
  • Myocardium (middle layer)
  • Endocardium (inner layer)
• The heart has 4 chambers: two superior atria and two inferior ventricles.
• The interatrial septum separates the atria and the interventricular septum separates the ventricles
• The heart contains 4 valves to ensure one-way blood flow:
  • Tricuspid valve (right atrioventricular valve)
  • Mitral valve (left atrioventricular valve)
  • Pulmonary valve (semilunar valve located between the right ventricle and pulmonary truck)
  • Aortic valve (semilunar valve located between the left ventricle and aorta)
• The circulatory system consists of includes the heart, blood vessels, and blood.

Pulmonary circulation

• Includes blood vessels that carry blood to and from the lungs
• The right side of the heart pumps deoxygenated blood to the lungs
• Blood is oxygenated in the lungs and returned to the left side of the heart

Systemic circulation

• Delivers oxygenated blood from the left side of the heart coming from the lungs to the tissues of the body.
• Returns deoxygenated blood back to the right side of the heart via venae cavae.
• Blood vessels carry blood to and from all body tissues.

Coronary circulation

• The circulation of blood in the blood vessels that supply the heart muscle (myocardium)
• The myocardium is not nourished by blood in the heart chambers
• Delivers oxygen-rich blood to the heart muscle and removing waste
• Components include:
  • Coronary arteries: branch off from the aorta supplying oxygenated blood
  • Cardiac veins: collect deoxygenated blood returning it to the right atrium through the coronary sinus.
• Coronary circulation ensures the heart receives the necessary oxygen and nutrients.

Anatomy of Blood Vessels

• Arteries move blood away from the heart and have thick walls and small lumens.
• Veins move blood toward the heart and have thin walls, large lumens, and valves.
• Capillaries facilitate the exchange of nutrients and waste and have 1 cell thick
• Walls of blood vessels contain three layers or tunics (except capillaries)
  • Tunica intima: lines lumen of vessels
  • Tunica media: composed of smooth muscle and elastin
  • Tunica externa: composed of areolar or fibrous CT.
• Veins have a tendency to collapse on a slide, while arteries maintain their shape

Systemic Circulation

• The Circle of Willis is a ring-like structure of interconnected arteries located at the base of the brain
• Provides a backup route for blood flow to the brain
• The Circle of Willis is formed by: - Internal carotid arteries - Vertebral arteries (join to form the basilar artery) - Anterior cerebral arteries (connected by the anterior communicating artery) - Posterior cerebral arteries (connected by the posterior communicating arteries to the internal carotid arteries)

Fetal Circulation

• In a developing fetus, the lungs and digestive system are nonfunctional
• All nutrient, excretory and gaseous exchanges occur via the placenta

Cardiovascular system models:

• Vein and artery
• Plaque of the heart and typical blood vessels
• Heart model (3D) - parts and vessels associated ■ Model of circle of Willis (3D)
• Fetal circulation ■ Blood vessel model (thorax) ■ Blood vessel model (plaque)

Cardiovascular system histological slides

• Blood, smear, 400X
• Labels: - 7 formed elements (RBC, basophil, platelet, monocyte, neutrophil, lymphocyte, eosinophil)
• Vein and artery, c.s
  • Labels: Tunica intima, tunica media, tunica externa, Valve (vein)