MP222 Lecture 1: Introduction to Cardiovascular and Respiratory Systems PDF

Introduction to the cardiovascular and respiratory systems Dr Susan Currie HW424 [email protected] Learning outcomes To know the physiology of the heart and lungs and how these systems can be targeted therapeutically To understand basic vascular structure and how blood flow is...

Introduction to the cardiovascular and respiratory systems Dr Susan Currie HW424 [email protected] Learning outcomes To know the physiology of the heart and lungs and how these systems can be targeted therapeutically To understand basic vascular structure and how blood flow is modulated To understand airway geometry and know how this can be affected  Learning outcomes - section 1 To know the physiology of the heart and vasculature  Reading Vander’s Human Physiology (16th Ed) Chapter 12 – cardiovascular physiology Chapter 13 – respiratory Cardiovascular and Respiratory Systems Pharynx – branches to oesophagus and larynx (part of the airways and voice box). Nose, Mouth, Pharynx and Larynx – upper airways Larynx – connects to Trachea (long tube) which subsequently branches substantially to structures in the lungs called alveoli which enable gas exchange. lmonary and Systemic Circulation Systemic circulation In both systemic and pulmonary circuits, vessels carrying blood Away from the heart – Arteries From organs/tissues back to the heart – Veins Bronchial circulation – complementary to Blood flow to and from the heart Vena cava Right atrium Right AV valve (tricuspid) Right ventricle Pulmonary (semi-lunar) valve Pulmonary artery Lungs Left atrium Left AV valve (bicuspid) Left ventricle Aortic (semi-lunar) valve Vascular Structure  Learning outcomes - Section 2 To understand basic vascular structure and how blood flow is modulated To know how the heart can be targeted therapeutically Structure of the Blood Vessel artery tunica intima - tunica adventitia tunica media (endothelium) (smooth muscle) vein vein  Smooth muscle cells Present in tunica media - Contraction and relaxation modify vessel diameter and consequently flow through vessel - Activity controlled by: Nerve supply, endogenous substances released from endothelium - Abnormalities in smooth muscle regulation can restrict blood flow (and airways) Endothelial cells Release bioactive substances to: Prevent inadvertent thrombus formation – release mediators that inhibit platelet activation. Clotting is an essential part of healing BUT clots in the heart can prove fatal. Cause relaxation/contraction  Blood Pressure BP = CO x PVR CO – cardiac output (pumping function of heart) PVR – peripheral vascular resistance (resistance of vessels to blood flow)  Blood Pressure Internal homeostatic pressure receptors (Baroreceptors) (see chapter 12, Vander) Hypertension , Cardiac Hypertrophy Therapies target cardiac output and/or peripheral vascular resistance (reduce)  Therapeutic targeting - heart Drugs that reduce blood pressure, targeting mechanisms/receptors that modulate BP e.g. ACE inhibitors (captopril), beta-blockers (propranolol, bisoprolol) Drugs that target oedema/BP e.g. furosemide less efficient cardiac function leads to systemic problems such as fluid retention  Learning outcomes – section 3 To understand airway geometry and know how this can be affected To know how the lungs can be targeted therapeutically  Anatomy of the Lung Artery Vein Bronchial tree Blood vessels  Respiratory Zone Respiratory zone Conducting zone Trachea (pl. Alveoli) Region of gas exchange No gas exchange between air and blood  The Process of DividedRespiration into 4 stages: Air is alternately moved into (inspiration) and out of (expiration) the lungs.  Exchange of O2 and CO2 between air in lung and blood in capillaries  Transport of O2 and CO2 by blood through the pulmonary and systemic circulation  Exchange of O2 and CO2 between  Why is breathing easy? Properties of lung tissues – compliance and elasticity Surfactant Pleural membranes  Regulation of breathing Normal breathing is INVOLUNTARY and involves the lower levels of the brain. A number of SENSORY inputs (peripheral and central chemoreceptors) help to control breathing rhythm. They respond to changes in the internal environment. Sensory inputs come from higher areas of the brain and breathing can  Neuronal control of breathing Breathing depends upon respiratory muscle excitation of the diaphragm and intercostal muscles by their motor neurons. Control of this neural activity resides in neurons in the medulla of the brain (medullary respiratory centre). Restriction of breathing  Respiratory system – routes of administration al route – cough linctus alation – quick absorption act locally and systemically Aerosols – nebuliser, metered-dose inha dry powder inhaler sal route – nasal sprays Respiratory Disorders Asthma, Bronchitis, COPD  Therapeutic targeting - Lungs Drugs that target receptors leading to improved airway smooth muscle relaxation e.g. salbutamol (b2 agonist) Anti-inflammatory drugs e.g. prednisolone Drugs can be administered via Reinforcement of learning points To know the physiology of the heart and lungs and how these systems can be targeted therapeutically – BP and contractile function and modulation by drugs – Respiration and modulation by drugs To understand basic vascular structure and how blood flow is modulated – Arteries and veins – Factors affecting BP To understand airway geometry and know how this can be affected – Bronchioles and alveoli Notes