Blood Cells, Hemostasis, and the Cardiac Cycle: A Comprehensive Guide

Posted on May 16, 2024 in Biology

Blood Cells

Functions

  • Transport of gases, primarily oxygen
  • Obtain energy by glycolysis, since they have virtually no organelles inside
  • The basic protein is hemoglobin, whose prime role is oxygen transport between lungs and cells
  • In humans, the hemoglobin should be within the erythrocyte to maintain (only a small part is outside and does not last long)
  • Carbonic anhydrase has a key role in transport of CO2
  • Hemoglobin is the main blood buffer. Most of this function is due to hemoglobin

Iron Metabolism

Most anemias are caused by iron deficiency. It is very characteristic in athletes. We usually have between 3 and 5 g of iron in the body. The 65% is in the form of hemoglobin. Between 15 and 30% in ferritin, 4% myoglobin, 1% other components HEM 0.1% iron circulating in the form of transferrina.Se absorbed by the small intestine in the diet. There are two forms of contribution:

  • Iron in the form HEM (animal) or
  • as non-heme iron (plant):

Once absorbed, binds to an enzyme (apotransferrin) constituting the transferred (the main form of transport in the blood). Through the movement, the iron reaches the bone marrow. The cell membrane of erythroblasts have receptors specific for iron, as they shot and introduced inside the cell, where will the mitochondria. When iron deficiency, iron as ferritin transferrin passes, ensuring stable iron levels in blood. When iron stores as ferritin are saturated, is deposited as hemosiderin. Since erythrocytes live shortly (4 months) during the movement will break a few markers, becoming shorter, which activates cells that destroy them. This, coupled with the membrane becomes less flexible, causing lysis thereof. Hemoglobin and globin fragments into HEM. The globin is broken and amino acids circulating in blood. HEM also breaks down and is captured by the protoferritina transferrin, which undergoes transformation to become bilirubin. Derivatives of this follow two courses:

  • Eliminated in the feces
  • excreted in the urine

On average, a man loses 1 mg of iron per month, while women lose 2 mg.

Hemostasis

Swelling reaction of the organism to any aggressive reaction.

Features

  • local vasodilation
  • Increased capillary permeability
  • Clogging of the interstitial fluid
  • Migration of granulocytes and monocytes
  • Swelling (swelling) of tissue cells

oRespuesta macrophage and neutrophil in inflammation:

  1. The mature tissue macrophage specific acts in the opening minutes of aggression.
  2. Neutrophilic blood (1st time): exit the capillary into the source of infection. Hours after infection are already acting.
  3. Monocytes: leave the capillary and mature (8 hours). From 9 am are the main defensive elements in the source of infection, initiating the creation of antibodies.
  4. Increased production of granulocytes and monocytes in bone marrow (3-4 days). You can increase production by 20-50.

Concepts of the Cardiac Cycle

  • End-diastolic volume (EDV) blood volume in each ventricle at end diastole (resting 120-130 ml)
  • Systolic volume (ESV) volume of blood in each ventricle at end systole (50 ml)
  • Beat or stroke volume (SV): difference between diastolic and systolic volume
  • Approximately ejection fraction 60%. It is the blood Candita ventricle ejects about which is filled (efficiency of the heart muscle)
  • Cardiac output or stroke volume: amount of blood from both ventricles in one minute. Approximately 80 ml x kg x min
  • Cardiac index: amount of blood leaving the ventricle, but expressed in L x min xm2 body surface area (produces echocardiographic studies)

Primary Hemostasis

  • Vasoconstriction of the vascular wall (the more traumatic the injury, the greater contraction, vascular spasm). It reduces the blood flow. For example, if we had a small cut in the skin bleeding will be greater than if it is deep. The heat prevents vessel contraction
  • platelet plug: The damaged vessel wall and other extravascular tissue cells produce a platelet activation (glycoprotein I activate the platelet, transforming it into star-shaped (of Von Willebrand factor). This allows membership of a platelet with others, forming a platelet plug.)

Coagulation

A series of events which have resulted in fibrinogen becomes fibrin fibers, which is the framework that turn what was liquid gel.

  • Extrinsic mechanisms: extrinsic to the vessel that is broken. Occurs when blood comes into contact with tissue factor (TF) of extravascular cell membrane exposed after vascular rupture
  • Mechanism intrinsic to the injured vessel, the blood comes into contact with the collagen in the damaged vessel wall (adventitia)

Fibrinolysis

Prevents clots where there is endothelial damage and after repair. The culprit is plasmin.

The Cardiac Cycle

The blood reaches the heart through the superior vena cava (the heart) and inferior vena cava (below the heart). These cava flow into right atrium (without valve).”The blood enters the right ventricle through the tricuspid valve (which prevents venous return (three-valved)” The balance of the heart blood through the pulmonary artery (O-poor blood2). The pulmonary valve prevents blood reflux and branching blood oxygenated by the lungs. -Return of blood through the pulmonary veins (two right pulmonary veins and two left to reach the left atrium) without valves.”From the left atrium, passes into the left ventricle through the mitral valve or bicuspid (two cusps).”The blood from the left ventricle through the aorta (aortic valve: similar to the lung, but with two holes in its shell, which allows coronary flow. These two holes in ventricular filling phase, collect blood for circulation coronary). When the coronary arteries become clogged coronary failure occurs

PHASE 1 – or diastolic ventricular filling

Ventricular Blood enters the atria to the ventricles. The atria contract and just fill the ventricles. 2 – Isovolumic Contraction:

The ventricle is contracting, but still not out blood, so the pressure increases. The fibers are gradually shrinking to prepare for the expulsion of blood. 3 – ventricular systole: Leaving blood through the arteries (and valves). The typical heart-shaped cone, as it does have efficiency: to enter the blood hits the wall of the ventricle and goes in the opposite direction (this is due to the fold of the glasses when the body is in training).
4 – isovolumic relaxation:

Same phenomenon isovolumic contraction. Because calcium pumps are closed, relaxation occurs. Calcium exits the cell and myofibrils begin to relax, but is not yet blood into the ventricles (valves closed).