1 / 25

Cardiovascular System

Cardiovascular System. Week 11 Dr. Walid Daoud A. Professor. Arterial Blood Pressure ____________________________________________________________________________________________________________________________________________. Factors which determine ABP & Pulse P.: F = ∆ P

havard
Download Presentation

Cardiovascular System

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Cardiovascular System Week 11 Dr. Walid Daoud A. Professor

  2. Arterial Blood Pressure____________________________________________________________________________________________________________________________________________ Factors which determine ABP & Pulse P.: F = ∆ P R CO = ABP – Rt. Atrial P (zero) TPR CO = ABP TPR ABP = CO x TPR = SV x HR x TPR

  3. Arterial Blood Pressure____________________________________________________________________________________________________________________________________________ Factors which determine ABP & Pulse P.: 1-Stroke volume: SV ↑ SP more than DP → ↑ pulse P. 2-Heart rate: ↑ HR ↑ DP due to shortening of diastole. 3-Total peripheral resistance: ↑ TPR ↑ DP. 4-Elasticity of aorta and arteries: Atheroscerosis: ↑ SP and ↓ DP → ↑ Pulse pressure. SP is determined by SV mainly. DP is determined by TPR mainly.

  4. Regulation of ABP____________________________________________________________________________________________________________________________________________ ABP is regulated by 3 mechanisms: 1-Nervous mechanisms (Rapid). 2-Capillary fluid shift mechanism (Intermediate) 3-Hormonal and renal mechanisms (Slow).

  5. Nervous Mechanism______________________________________________________________________________________________________________________________ Cardiovascular centers in medulla: 1-Pressor area: CAC and VCC. 2-Depressor area: CIC and VDC. Activity of centers is modified by afferents from: 1-Receptors inside cardiovascular system. 2-Receptors outside cardiovascular system. 3-High centers and blood gases changes: .Mild ↓ O2, ↑ CO2 → ↑ ABP. .Severe ↓ O2, ↑ CO2 → ↓ ABP and death.

  6. Cardiovascular centers______________________________________________________________________________________________________________________________

  7. Cardiovascular centers______________________________________________________________________________________________________________________________

  8. Capillary fluid shift mechanism____________________________________________________________________________________________________________________________________________ ↑ blood volume ↑ ABP ↑ capillary hydrostatic pressure ↑ filtration from plasma to tissue fluid ↓ plasma volume ↓ VR ↓ ABP. ↓ ABP ↓ capillary hydrostatic pressure ↓ filtration at arteriolar end of capillaries ↑ reabsorption at venular end ↓ plasma volume ↑ VR ↑ ABP. i.e, tissue fluid acts as a reservoir of plasma.

  9. Hormonal Regulation of ABP____________________________________________________________________________________________________________________________________________ Kidney regulates ABP by regulating plasma volume and extracellular fluid volume. When ABP drops: 1-Renin-angiotensin system. 2-Atrial mechanoreceptors.

  10. Arterial Pulse___________________________________________________________________________________________________________________________________________ It is a propagated wave that travels along the wall of arteries as blood is forced into aotra. Clinical significance of palpation of radial pulse: 1-Rate. 2-Rhythm. 3-Pulse deficit. 4-Force of ventricular contraction. 5-Force equality on both sides. 6-State of arterial wall.

  11. Capillary Circulation____________________________________________________________________________________________________________________________________________ Equilibrium with interstitial fluid and exchange of materials across capillary wall occur by 2 mechanisms: 1- Diffusion. 2- Filtration.

  12. Diffusion____________________________________________________________________________________________________________________________________________Diffusion____________________________________________________________________________________________________________________________________________ It is passive occurs on both directions and concerned with H2O & dissolved substance. Factors affecting diffusion rate: .Factors in substance: 1-Concentration gradient. 2-Solubility. 3-Molecular weight. Factors in capillary permeability: 1-Liver capillaries. 2-Muscle, skin, heart and lung capillaies. 3-Kidney and intestine capillaries.

  13. Filtration____________________________________________________________________________________________________________________________________________Filtration____________________________________________________________________________________________________________________________________________ It is a passive flow across capillaries in one direction. It is the bulk transport of H2O, electrolytes and crystalloids. Factors affecting filtration: 1-Forces tending to move fluid outwards: . Hydrostatic capillary pressure. . Interstitial fluid colloidal OP 2-Forces tending to move fluid inwards: . Colloidal OP of plasma proteins. . Hydrostatic pressure of interstitial fluid.

  14. Variation in the bulk flow____________________________________________________________________________________________________________________________________________ 1- Decrease colloidal OP of plasma proteins: Liver and kidney diseases ↑ filtration. 2-Increase capillary blood pressure as in venous obstruction ↑ filtration. 3-Increase capillary permeability as in activity, inflammation, albumin goes out ↑ filtration. 4-Decrease hydrostatic pressure of tissue fluid ↓ filtration.

  15. Edema____________________________________________________________________________________________________________________________________________Edema____________________________________________________________________________________________________________________________________________ Excessive infiltration of plasma fluid into tissue fluid leading to accumulation of tissue fluid. Edema may be generalized or localized. Causes: 1-↑ capillary blood pressure: cardiac edema, pregnancy edema and localized edema. 2-↓ colloidal OP of plasma proteins: nutritional, hepatic and renal edema. 3-↑ capillary permeability: allergy, inflam. 4-Lymphatic obstruction: Filaria, cancer.

  16. Venous Circulation____________________________________________________________________________________________________________________________________________ Central venous pressure (CVP): Pressure in right atrium & veins opening into it. Normal value: 0-2 mmHg. CVP fluctuates with respiration & cardiac cycle. Importance: - CVP ↓ in hemorrhage. - CVP ↑ in heart failure.

  17. Functions of Veins___________________________________________________________________________________________________________________________________________ 1-Transport vessels. 2-Capacitance vessels or blood reservoir: Capacity is a ratio= Change in volume Change in pressure

  18. Effects of gravity on venous return________________________________________________________________________________________________________________________________________________ 1-Orthostatic hypotension. 2-Pressure in different veins during orthostasis. . Pressure in leg veins. . Pressure in superior sagital sinus

  19. Mechanisms helping venous return against gravity in standing position____________________________________________________________________________________________________________________________________________ 1-Sympathetic vasoconstrictor tone. 2-Muscular pump. 3-Thoracic pump. 4-Cardiac suction: . Atrial suction. . Ventricular suction.

  20. Comparison of Pulmonary & Systemic Circulation

  21. Coronary Circulation____________________________________________________________________________________________________________________________________________ Anatomical considerations: Right & left coronary arteries arise from coronary sinuses behind aortic valve. Left coronary artery supplies anterior & lateral parts of left ventricle. Right coronary artery supplies right ventricle and posterior part of left ventricle. Venous blood of left ventricle drains into coronary sinus (75% of coronary blood). That of right ventricle goes through small anterior cardiac veins directly to right atrium.

  22. Regulation of coronary blood flow______________________________________________________________________________________________________________________________________________ 1-Autoregulation (intrinsic mechanism): ↑ cardiac work → hypoxia, ↑ CO2, ↑ H+ ,↑ K+, Lactate, prostaglandins & adenosine ------→ Coronary VD. 2-Mechanical regulation: .During systole → ↓ coronary blood flow. .During diastole → ↑ coronary blood flow. 3-Neural factors: .Sympathetic: α-adrenergic (VC),β-adren (VD) .Parasympathetic (vagus): VD.

  23. Cardiovascular homeostasis in health & disease____________________________________________________________________________________________________________________________________________ Circulatory shock: It is inadequate tissue perfusion due to ↓ CO Types & causes: 1-Hypovolemic: Hge, burn, trauma, surgery. 2-Disributive: fainting, anaphylaxis. 3-Cardiogenic: MI, CHF, arrhythmias. 4-Obsructive: obstruction of blood flow.

  24. Hemorrhagic Shock__________________________________________________________________________________________________________________________________________ Manifestations: ↓ ABP ↑ Heart rate ↑ Respiratory rate ↓ skin temperature Pallor Thirst Oliguria Acidosis.

  25. Compensatory reactions to hemorrhagic shock____________________________________________________________________________________________________________________________________________ Rapid compensatory reactions: 1-Nervous factors. 2-Humoral factors. Long-term compensatory reactions: 1-Correction of plasma volume. 2-Correction of plasma proteins. 3-Correction of red cell mass.

More Related