Lecture 7-Hemodynamic Disorders Congestion, Edema, Hyperemia

What are the three main hemodynamic disorders?

Congestion, Edema, Hyperemia.

What is hyperemia?

An increase in blood flow and active engorgement of vascular beds.

What components make up the circulatory system?

Blood (RBCs, WBCs, Platelets, Plasma), Heart, arterial vessels, venous vessels, lymphatic vessels.

What is the central pump of the circulatory system?

The Heart.

How is cardiac output (CO) determined?

By heart rate (HR) and stroke volume (SV); CO = HR x SV.

What is the role of arteries in the circulatory system?

To facilitate rapid blood flow with minimal resistance and provide tensile strength and elasticity.

What is the diameter of arterioles and their function?

Narrow lumens that are major resistance vessels; their diameter is controlled by smooth muscle cells.

What is the primary site for nutrient and waste product exchange?

Capillaries.

What types of capillaries exist and where are they found?

Continuous (found in the brain, muscle, lung, bone), Fenestrated (found in renal glomeruli, intestinal villi, endocrine glands), Discontinuous (found in liver, spleen, bone marrow).

What are venules and veins primarily made of?

Venules consist of similar tissues as capillaries with thin muscle layers; veins are mainly collagen with some elastin and smooth muscle.

What allows veins to hold/store a large volume of blood?

Their distensibility allows them to hold about 65% of total blood volume.

Define lymphatic circulation.

Originates from blind-ended lymphatic capillaries that drain fluid back to the venous system.

What is the function of endothelium in the circulatory system?

It lines all components of the system and is critical for fluid distribution, inflammation, immunity, and homeostasis.

What defines microcirculation?

The system of arterioles, metarterioles, capillaries, and postcapillary venules.

What is Starling’s Forces?

Forces governing the exchange of water between capillary microcirculation and interstitial fluid.

What is edema?

Swelling due to fluid accumulation in the interstitial space.

List the four major mechanisms causing edema.

Increased microvascular permeability, increased intravascular hydrostatic pressure, decreased intravascular osmotic pressure, decreased lymphatic drainage.

What is a physiological consequence of increased microvascular permeability?

Localized edema due to inflammation.

What condition can result from decreased concentrations of plasma proteins?

Hypoalbuminemia, leading to generalized edema.

Name a factor that helps move venous blood back to the heart.

Venous valves, skeletal muscle contraction, or negative thoracic pressure.

What happens with decreased lymphatic drainage?

Localized edema occurs due to the inability of lymph vessels to remove excess fluid.

What should you expect from gross characteristics of edema?

Swelling and altered coloration of tissues.

What is the clinical significance of edema?

It depends on the location and extent of the edema.

What results from increased blood volume due to hyperemia?

Bright red and warm tissues with observed engorgement of vessels.

What are the factors controlling fluid distribution?

Physical barriers, concentration gradients, and Starling’s forces.

What role does hydrostatic pressure play in fluid distribution?

It is the physical force exerted by fluids against enclosing barriers.

What happens in the circulatory system during inflammation?

Vascular changes allow increased permeability and recruitment of immune cells.

What does the term 'active hyperemia' mean?

Increased blood flow due to increased metabolic activity of tissues.

What can cause a passive accumulation of blood known as congestion?

A decrease in venous outflow with normal or increased blood inflow.

How does the venous system differ from the arterial system?

Veins have thinner walls, less muscular and elastic tissue, and they collect blood back to the heart.

What is a common outcome of right-sided heart failure?

Congestion in the systemic circulation, particularly in the abdominal organs.

Why do capillaries have slow blood flow?

To allow for adequate diffusion of nutrients and waste exchange.

What is the involvement of the renin-angiotensin-aldosterone system related to edema?

It can lead to sodium retention and generalized edema due to reduced plasma volume.

What is the impact of long-term inflammation on blood vessel function?

May lead to chronic changes in permeability and increased risk for edema.

Describe the composition of plasma in the circulatory system.

Plasma consists of water, proteins (albumin, globulin, fibrinogen), glucose, electrolytes, and clotting factors.

What are the two main types of vasodilation stimuli in tissues?

Metabolic activity increases and release of vasoactive substances during inflammation.

What happens to tissues during hypovolemia?

There is a flow of water out of cells, leading to cell shrinkage.

What is the result of capillary wall permeability changes in pathology?

Larger molecules can pass through, contributing to extravasated fluid.

How does the body adjust blood flow based on metabolic needs?

Via local intrinsic controls altering arteriolar diameter.

How do negative pressures in the thoracic cavity affect venous return?

They create a pressure gradient that aids in returning blood to the heart.

What can lead to systemic venous congestion?

Generalized heart failure or obstruction of blood flow through veins.

What nutritional deficiencies might contribute to edema?

Liver failure or malnutrition impacting protein synthesis.

What type of endothelium is found in renal glomeruli?

Fenestrated endothelium.

List the ion electrolytes commonly present in plasma.

Na+, Ca2+, Mg2+, HCO3-, Cl-.

What is the role of smooth muscle in arterioles?

To regulate the diameter and resistance of blood flow through intrinsic and extrinsic mechanisms.

What is the difference between hyperemia and congestion?

Hyperemia is an active process of increased blood flow, while congestion is a passive accumulation of blood.

What occurs with decreased osmotic pressure in the blood?

It leads to an increased fluid filtration out of the blood vessel into surrounding tissues.

How do capillaries differ structurally from arteries?

Capillaries have thin walls (single epithelial layer) and narrow lumens compared to the thicker muscular arteries.

What does the pressure gradient within the circulatory system refer to?

The difference in blood pressure throughout the circulatory pathways.

What physiological process occurs during acute inflammation?

Release of vasoactive substances leading to vasodilation and increased blood flow.

What factors influence the movement of molecules across capillaries?

Size of molecules, solubility, and the pressure gradients present.

How does the body respond to increased metabolic activity in tissues?

By increasing blood flow through vasodilation and recruiting more blood vessels.

What commonly leads to decreased lymphatic drainage?

Compression or obstruction of lymph vessels.

What characteristics define chronic passive congestion?

Swollen tissues that are dark red due to persistent blood accumulation in venous circulation.

What can the presence of ascites indicate regarding fluid balance?

Disturbance in normal fluid distribution and retention within the abdominal cavity.

How do arterioles play a role in regulating blood pressure?

By adjusting their diameter, they can alter resistance and thereby influence blood pressure.

What is a key characteristic of the extracellular matrix (ECM)?

Provides structural support and regulates cell functions in the interstitial space.

What is the consequence of increased blood volume within the microvasculature?

It can lead to edema due to increased hydrostatic pressure.

What does the term 'decreased intravascular osmotic pressure' indicate?

It indicates a lower concentration of plasma proteins, leading to fluid leakage into interstitial tissues.

What physiological change occurs as a result of activation of tissue receptors in pathological states?

Increased vascular permeability and inflammation.

What causes localized edema during inflammation?

Endothelial contraction and changes in vascular permeability from local stimuli.

What role do blood vessel beta receptors play during stress?

They stimulate vasodilation, leading to increased blood flow to muscles and organs.

How might the venous system adapt to retain blood during hemorrhagic events?

By vasodilating and allowing more blood to remain within venous reservoirs.

What can be inferred from observing dark red, swollen tissues post-venous obstruction?

Indicates congestion and impaired venous return.

What role does fibrinogen play in the blood?

It is a protein important for blood coagulation and wound healing.

What can chronic pulmonary hypertension lead to in the circulatory system?

Right-sided heart failure and systemic congestion.

What kind of injury can exacerbate the effects of congestion?

Inflammatory injuries that increase vascular permeability.

What is a common presentation of chronic heart failure in clinical settings?

Edema in surrounding tissues and organs.

How do arterioles regulate the flow of blood into capillary beds?

By adjusting their diameter based on metabolic needs and systemic signals.

What is a major consequence of decreased production of albumin?

Increased interstitial fluid accumulation and generalized edema.

What condition is indicated by an increase in hydrostatic pressure in blood vessels?

It can lead to edema and swelling of surrounding tissues.

What occurs when the balance between osmotic and hydrostatic pressures is disrupted?

Fluid accumulation in interstitial spaces, leading to edema.

How does the body's response to healing differ between normal and injured endothelium?

Normal endothelium prevents clotting, while injured endothelium promotes clot formation.

What underlying conditions can lead to generalized edema?

Heart failure, liver disease, or renal impairments.

What types of substances can pass through continuous capillary endothelium?

O2, CO2, H2O, and ions.

What does the term 'hypervolemia' mean?

An excess of plasma volume in the blood.

How do venous valves contribute to venous return?

They prevent backflow of blood, ensuring it moves toward the heart.

What importance does smooth muscle have in arterial walls?

It helps maintain blood pressure and regulate blood flow.

What happens to the velocity of blood flow as it moves through the capillary network?

The flow velocity decreases to facilitate exchange.

What changes to capillaries occur during inflammation?

Increased permeability to allow immune cell and fluid movement.

What conditions might lead to parasitic emboli resulting in intestinal congestion?

Infections or weakened immune responses.

How does systemic arterial pressure affect venous return and circulation?

High pressure promotes better flow, while low pressure hinders return.

What could chronic inflammation cause in the blood vessels?

Changes that perpetuate increased permeability and leakage.

What effect does increased lymphatic capillary pressure have on edema?

It can promote fluid reabsorption back into the vascular system.

How does the structure of capillaries assist in their function?

Their thin walls facilitate quick exchange of nutrients and wastes.

What is the significance of balancing hydrostatic and osmotic pressures?

Essential for maintaining fluid homeostasis in the body.

What is an example of an organ that typically experiences a higher blood volume than needed?

Liver during digestion.

How do local receptors affect blood vessel function during stress responses?

They can cause vasodilation or vasoconstriction based on metabolic needs.

What are the implications of having more blood in the venous system at rest?

75% of circulating blood volume is in veins, making them key in long-term regulation.

What systemic responses could exacerbate edema conditions?

Hormonal changes or infections that increase vascular permeability.

What do swollen tissues during acute heart failure indicate?

Congestive changes due to impaired venous return.

How does body temperature regulation connect to hyperemia?

Vasodilation helps dissipate heat through increased blood flow to the skin.

What are vasoactive substances that contribute to hyperemia during inflammation?

Histamine and prostaglandins.

What process is used to restore normal fluid levels after edema formation?

Lymphatic drainage assists in removing excess fluid.

What structural change occurs in capillary endothelium during an allergic reaction?

Increased permeability allows fluids and immune cells to exit the vessel.

What function does the spleen serve in relation to blood volume?

It can store a reserve of blood and contribute to greater systemic volume control.

Describe a physiological mechanism that reduces venous pressure.

The thoracic pump effect enhances blood return during inhalation.

What can be inferred when more than 60% of blood is observed in the veins?

Veins serve as major storage and regulatory sites for blood volume.

How does shear stress affect endothelial function?

It regulates the release of nitric oxide which can modulate blood flow and pressure.

What role do immune complexes play in vascular permeability during infection?

They can trigger increased permeability and inflammation.