Blood Components and Functions

Module 1: Blood

• Cardiovascular system components: heart, blood vessels (arteries, veins, capillaries) and blood

• Cardiovascular system functions: transports oxygen/nutrients, removes wastes, transports hormones, maintains body temperature, provides immune response, regulates fluid balance, and facilitates clotting

• Blood plasma composition: albumin (maintains osmotic pressure, produced in the liver), globulins (transport and immunity, produced in the liver and plasma cells) and fibrinogen (blood clotting, produced in the liver)

• Formed elements functions: gas exchange, oxygen transport, immune defense, and blood clotting

• Hematopoiesis: the production of blood cells to replace old cells and maintain a healthy blood cell supply

• Hemostasis steps:

  • Injury to a blood vessel
  • Vascular spasm (smooth muscle contraction)
  • Platelet plug formation (chemicals activate platelets)
  • Coagulation (seals the blood leak)

• Blood group classifications and compatibility:

  • Type A: A antigens; can receive A, O; can donate to A, AB
  • Type B: B antigens; can receive B, O; can donate to B, AB
  • Type AB: A and B antigens; can receive A, B, AB, O; can donate to AB
  • Type O: Neither A nor B antigens; can receive O; can donate to A, B, AB, O

Module 2: Heart

• Heart location: thoracic cavity between the lungs

• Heart structure: four chambers (right/left atria, right/left ventricles); layers include endocardium, pericardium, and myocardium

• Blood flow through the heart: Blood passes through vessels, chambers, and valves, and can be either oxygenated or deoxygenated.

• Cardiac muscle action potential phases:

  • Depolarization = Contraction
  • Plateau = continuous blood flow from chamber
  • Repolarization = Relaxation
  • Slow Na+ influx (prepotential more positive)
  • Rapid Ca2+ influx (depolarization)
  • K+ outflux (repolarization)
  • Threshold (special pacemaker cells)

• Cardiomyocyte action potential: opening of voltage-gated sodium channels, outward flow of potassium, opening of voltage-gated calcium channels (plateau tetany (refractory period) no stimulation), calcium channels inactivate, and potassium continues to flow out through voltage-gated ion channels

• ECG waveforms:

  • P wave: atrial depolarization
  • QRS complex: ventricular depolarization (ventricles contract)
  • T wave: ventricular repolarization

• Phases of the cardiac cycle: one complete contraction (systole) and relaxation (diastole) of the heart

  • Isovolumic/isovolumetric relaxation (diastole early closed)
  • Ventricular filling (diastole late open)
  • Atrial contraction (atrial systole begins open)
  • Isovolumic/isovolumetric contraction
  • Ventricular contraction (systole first phase closed)
  • Ventricular ejection (ventricular systole second phase open)

• Cardiac Output (CO) definition: the amount of blood the heart pumps per minute

• Cardiac output calculation: CO = HR x SV (heart rate x stroke volume)

• Cardiac output factors: stroke volume and heart rate

• Cardiac function regulation: autonomic nervous system (ANS), parasympathetic and sympathetic divisions, and hormones

Module 3: Blood Vessels

• Arteries: Thick walls, carry oxygen-rich blood away from the heart

• Veins: Thin walls, carry deoxygenated blood back to the heart

• Capillaries: Smallest vessels, connect arteries and veins for oxygen exchange

• Systemic Circuit: Oxygenated blood is pumped from the heart to the body, and deoxygenated blood is returned to the heart.

• Pulmonary Circuit: Deoxygenated blood is pumped from the heart to the lungs, and oxygenated blood is returned to the heart.

  • Arteries: Transports blood from the right ventricle through the pulmonary valve and into the lungs
  • Capillaries: Blood flows through beds in the lungs where gas exchange occurs (oxygen loading and carbon dioxide unloading)
  • Veins: Replenished oxygen is carried to the left atrium

• Clinical Measurements:

  • Pulse Pressure (PP): PP = Systolic Pressure - Diastolic Pressure
  • Mean Arterial Pressure (MAP): MAP= (2 x Diastolic Pressure) + Systolic Pressure, divided by 3
  • Stroke Volume (SV): SV= End-Diastolic Volume - End-Systolic Volume
  • Cardiac output (CO): Heart Rate x Stroke Volume

• Factors affecting blood flow and blood pressure: cardiac output, blood vessel resistance (diameter of blood vessels), pulse pressure, hormones, diet, lifestyle, and the nervous system

• Regulation of vascular homeostasis: neural, endocrine, and local mechanisms to ensure proper blood flow, pressure, and distribution

• Cardiovascular system location: medulla oblongata

Module 4: Lymphatic System & Immunity

• Lymphatic system components: lymph (white blood cells and fats), lymphatic vessels (transport lymph), and lymph nodes (filter lymph; defense against infection)

• Lymphatic system functions: fluid balance, fat absorption, and immune defense

• Lymph formation: fluid between cells absorbed from leaking blood vessels

• Lymph circulation: fluid merges to form larger lymphatic vessels, travels toward the heart

• Macroscopic features of the lymphatic system: tonsils, thymus gland, lymph nodes, thoracic duct, cisterna chyli

• Innate immune response: body's first line of defense

  • Physical/chemical barriers: eliminate threats, initiate adaptive immune response
  • Phagocytosis: engulfs and destroys
  • NK cells: kill infected/cancer cells
  • Basophils/eosinophils: inflammatory response against parasites
  • Mast cells: release histamine
  • Dendritic cells: messengers to present cells, initiate adaptive immune response

• Humoral immunity: B cells produce antibodies to target pathogens

• Cellular immunity: T cells directly attack infected cells and intracellular pathogens

• Active immunity: the body's system creates antibodies in response to an antigen

• Passive immunity: antibodies produced by another source provide temporary protection