Cardiovascular System Flashcards
(23 cards)
What is the purpose of the cardiovascular system?
Supply oxygen and nutrients to the tissues and organs and to remove waste products
To defend the supply of nutrients to organs by;
Maintaining cardiac output
Maintaining organ perfusion pressure
How does the CV system supply oxygen and nutrients and remove waste products?
Is a closed circuit system
Heart muscle is central dual chamber pump
Perfusion is maintained through adequate pressure in the system. Mean arterial pressure (MAP)
What is the pressure in the four chambers?
Right Heart (low pressure) Right atrium, right ventricle
Left heart (high pressure) Left atrium, left ventricle
Name the four valves?
Tricuspid, pulmonary
Mitral, aortic
What are coronary arteries?
Heart muscle is supplied with oxygen and nutrients by
- left coronary artery
- right coronary artery
Left coronary artery supplies left ventricle
These arteries are narrow and highly susceptible to obstruction
What is cardiac output?
Volume of blood pumped per ventricle per unit of time
CO = heart rate x stroke volume
CO= 72 bpm x 70ml = 5040ml
Approx 5 litres
Describe control of stroke volume?
Sympathetic neurones release norepinephrine and circulating epinephrine
Increases contractility
Stronger and shorter systole
Describe control of heart rate?
Sympathetic neurones release norepinephrine and circulating epinephrine increases heart rate
Parasympathetic neurones (vagus) releases ACh, slows heart rate
What is total peripheral resistance (TPR) ?
Functions of vessels
Local control of resistance (vessel tension)
Central control of resistance (vessel tension)
How to calculate MAP?
MAP = CO x TPR
Local control of blood flow?
Metabolic autoregulation and tissue hypoxia
Central control of blood flow (maintains MAP)?
Sympathetic nervous system releases noradrenaline
Adrenal gland releases adrenaline
Picked up by alpha receptors (cause vasoconstriction) and B2 receptors (vasodilation)
State the electrical conducting pathways?
Sinoatrial node Atrioventricular node Bundle of HIS Bundle branches Purkinje fibres
To work the heart needs?
Electrical normality- nodes and pathways able to initial electrical activity and pass on effectively
Structural/ mechanical normality- valves, vessels and myocardium
Sufficient oxygen supply- lack of oxygen can damage both electrical pathway and myocardium itself and ability to respond / pass on electrical activity
What is an ECG?
Records and analyses electrical activity throughout cardiac cycle
Electrical activity radiates through surrounding tissue and is picked up by electrodes on skin
Converts currents into waveforms that represent depolarisation/ repolarisation to identify rhythm and conduction disturbances
What are the functions of blood?
- Transportation
Dissolved gases, nutrients, hormones and metabolic wastes, excess body water for excretion - Buffer
regulation of pH and ions in interstitial fluid - Protection
Restriction of fluid loss at injury sites
Defence against toxins and pathogens
Stabilising body temperature
What is the composition of blood?
Plasma:
Water
Substances- nutrients + O2/CO2
Proteins- buffer , clotting, antibodies
Formed elements:
Erythrocytes
Leukocytes
Thrombocytes
What are the types of plasma proteins?
Albumins
Globulins
Fibrinogen
Active and inactive enzymes and hormones
What are erythrocytes?
Red blood cells
Oxygen transport in blood
What are leukocytes?
White blood cells
Body’s defence mechanisms
What are thrombocytes?
Platelets
Membrane bound cell fragments involved in clotting
What is haemoglobin?
Globin- 4 polypeptide chains
Binds to oxygen to form oxyhaemoglobin
Each heme is associated with one polypeptide chain and contains an Fe 2+ ion that combines reversible with oxygen molecule
What is heamostasis?
Response sequence stopping bleeding
- Vascular spasm- artery/arteriolar smooth muscle contraction
- Platelet plug formation
Platelet adhesion
Platelet release reaction - Blood clotting (coagulation)
