Blood Pressure Regulation and Control Mechanisms

• These flashcards cover key terms and definitions related to blood pressure regulation and control mechanisms within the circulatory system.

Blood Pressure Basics

• Blood Pressure Measurement: Assessment of arterial pressure using a sphygmomanometer.
• Korotkoff Sounds: The noises heard while measuring blood pressure.
• Mean Arterial Pressure (MAP): The average blood pressure in a person's arteries, which is critical for organ perfusion and its dysregulation can lead to syncope or cerebral edema.
• Arterial Pressure: Increased pressure stretches vessel walls, causing constriction.

Venous Blood Return

• Venous Blood Return: Factors such as the skeletal muscle pump, respiratory pump, and venoconstriction aid blood flow back to the heart.
• Skeletal Muscle Pump: Muscle contractions aid venous blood return.
• Respiratory Pump: Pressure changes during breathing facilitate venous return.
• Venoconstriction: Narrowing of veins to increase blood return.
• Varicose Veins: Swollen veins resulting from poor blood return.

Factors Influencing Blood Pressure

• Blood Pressure Influencing Factors: Variables affecting arterial pressure levels.
• Cardiac Output (CO): Volume of blood pumped by the heart per minute.
• Vascular Resistance: Opposition to blood flow in blood vessels.
• Stroke Volume (SV): Amount of blood ejected by the heart per beat.
• Total Blood Volume: is the total amount of blood circulating in the body.
• Vessel Radius: Diameter of blood vessels affecting blood flow.
• Blood Viscosity: Thickness of blood influencing flow resistance and affecting arterial pressure.
• Heart rate: Speed of heartbeats influencing blood pressure
• Baroreceptors: Sensors detecting blood pressure changes in arteries.
• Chemoreceptors: Sensors monitoring blood chemical composition

Hormonal & Nervous System Control

• Hormonal Control of Blood Pressure: Regulation via hormones affecting vascular resistance.
• Sympathetic Nervous System: Part of the autonomic nervous system regulating blood flow, leads to sympathetic vasoconstriction.

Autoregulation & Blood Flow

• Autoregulation: Tissue's ability to regulate its own blood flow.
• Passive Stretch Response: Vascular smooth muscle reacts to vessel expansion.
• Long-term Autoregulation: Vessel diameter and number increase over weeks or months.
• Muscular Autoregulation: Blood flow adjusts to decreased oxygen concentrations.
• Exercise Hyperemia: Increased blood flow proportional to muscle activity.
• Ischemia : Inadequate blood supply leading to neuronal damage.
• Local Vasoconstriction: Constriction affecting specific arteries without systemic impact versus Systemic Vasoconstriction which affects overall blood pressure in the body.
• Vasodilation: Widening of blood vessels to increase blood flow.
• Nitric Oxide: Vasodilator released during low oxygen conditions.
• Endothelins: Vasoconstrictors released by blood vessel endothelium.
• Smooth Muscle Response: Muscle constricts to reduce blood flow during pressure increase.

Tissue Perfusion and Circulation

• Tissue Perfusion: Delivery of blood to tissues for oxygen and nutrients.
• Cerebral Blood Flow: Tightly regulated to meet neuronal metabolic needs, with cerebral edema being swelling from high mean arterial pressure.
• Coronary Blood Flow: Blood movement through heart's vessels during diastole.
• Systemic Circulation Speed: Fastest in aorta, slows in smaller vessels.
• Capillary Blood Flow: Slow flow promotes nutrient and gas diffusion.

Capillary Exchange

• Capillary Exchange: Process of nutrient and fluid transfer in capillaries, also refers to when nutrients and wastes are exchanged via diffusion.
• Bulk Flow: Fluid movement across capillary walls for mixing and maintains interstitial environment and tissue health.
• Intercellular Clefts: Spaces in capillary walls allowing fluid exchange.
• Arterial End: Location where fluid is forced out in capillaries.
• Venous End: Location where most fluid returns to blood in capillaries.
• Diffusion: Movement of substances from high to low concentration.
• Interstitial Space: Fluid-filled area surrounding cells for nutrient exchange, contains Interstitial fluid.
• Metabolic Activity: Energy expenditure influencing blood flow needs

Heart Phases

• Ventricular Systole: Heart phase when blood is pumped out.
• Ventricular Diastole: Heart phase when blood fills the chambers.

Pressures

• Hydrostatic pressure: Force exerted by fluid against a membrane.
• Capillary hydrostatic pressure: Blood pressure in capillaries pushing fluid out.
• Fluid hydrostatic pressure: Pressure pushing fluid back into blood vessels.
• Colloid osmotic pressure: Pressure opposing hydrostatic pressure due to proteins.
• Plasma colloid osmotic pressure: Pressure from plasma proteins pulling water into capillaries.
• Interstitial fluid colloid osmotic pressure: Minimal pressure due to low protein content in interstitial fluid.
• Net hydrostatic pressure: Difference between hydrostatic pressures promoting filtration.
• Net colloid osmotic pressure: Difference between osmotic pressures promoting reabsorption.

Fluid movement

• Filtration: Process of fluids leaving capillaries
• Reabsorption: Process of fluids entering capillaries.

Edema

• Edema: Abnormal increase in interstitial fluid volume.
• Increased capillary hydrostatic pressure causes fluid loss from blood, leading to edema.
• Incompetent venous valves: Faulty valves causing increased capillary pressure.
• Congestive heart failure: Heart condition leading to increased blood volume.
• Inflammatory response: Body's reaction causing increased capillary permeability.
• Increased colloid osmotic pressure: Caused by proteins leaking into interstitial fluid.
• Hypoproteinemia: Low plasma protein levels affecting fluid return.
• Malnutrition is the lack of nutrients leading to low protein levels
• Liver disease affects protein synthesis in blood.
• Glomerulonephritis is kidney disease causing protein loss in urine.
• Local vasodilation: Widening of blood vessels in a specific area.
• Systemic vasodilation: Widening of blood vessels throughout the body.