Cardiovascular System Flashcards
name the components of the heart
-vena cava
-tricuspid valve
-pulmonary valve
-right atrium
-aorta
-pulmonary artery
-left atrium
-mitral valve
-aortic valve
-left ventricle
discuss the initiation at the (SA) node
-located in right atria, medial to opening of superior vena cava.
-generates cardiac action potentials spontaniousley which allows heart to beat spontaneousley and independant of nerves.
-generates cardiac action potentials at a greater frequency than other cardiac muscle cells.
-activation leads to excitation along internodal tracts towards left atrium and AV node, resulting in atrial contraction
Discuss the depolarisation delay at the AV node
-av node is located medial to the right atrioventricular valve
-action potentials are propagated slowly through these areas compared to the rest of the hearts conducting system
-ventricular depolarization predcedes ventricular contraction
-the propagation delay allows atrial contraction to be completed, and the ventricles to fill with blood before contraction begins
Discuss bundles of HIS
-the electrical conduction pathway that divides at the inter ventricular septum to from left and right bundle branches
-the branches descend to to the apex of each ventricle
-at the ventricle apex, the bundle branches divide repeatedly for distribution throughout the ventricular walls.
-ventricular depolarization precedes ventricular contraction
discuss purkinje fibres
-the terminal branches of the bundle branches become purkinje fibres, cardiac muscle fibres that have special structural modifications
-these modifications allow action potentials to travel more rapidly than they would in cardiac muscle tissue
-the purkinje fibres are also found towards the endocardial surface. Thus, electrical activity at any level travels outwards towards the epicardial surface
What is an (ECG)
Electrocardiogram
Describe the Pwave, QRS complex and Twave in ECGs
P wave-activation of the atria (atria depolarization)
QRS complex-activation of ventricles (atrial repolarization and ventricular depolarization)
T wave-recovery wave (ventricular repolarization)
Describe systolic pressure
(SP) is the maximum arterial pressure reached during peak ventricular ejection
Discuss diastolic pressure
(DP) is the minimum arterial pressure just before ventricular ejection begins
What is pulse pressure
(PP) the difference between SP and DP
What is mean arterial pressure
(MAP) the average pressure in the cardiac cycle
Describe capillaries
-site of exchange
-provide nutrients to tissue
-remove waste from, tissue
Discuss capillaries in micro circulation
-metarteriole
-capillaries
-postcapillary venule
-5/10 micrometers
-function as part of capillary bed
-pre capillary sphincters control blood flow through capillary bed
name the types of capillaries and describe them
Continuous
-plasma membranes form continuous tube
-intercellular clefts
-most capillaries are this type of
Fenestrated
-plasma membranes have fenestration
-found in regions where high levels of filtration/absorption needed
Sinusoid
-wider and more winding
-large fenestration
-incomplete/absent basement membrane
-large intercellular clefs
Discuss diffusion in capillaries
-lipid soluble molecules diffuse through plasma membranes
-water soluble substances diffuse through intercellular spaces or fenestration
Discuss lymphatic capillaries
-closed end network
-close to blood capillaries
-no basement membrane
-anchored to CT via fine filaments
-ONE WAY FLOW in lymphatic capillaries
-merge into larger vessels
describe the ways in which lymph can move
-contraction of lymphatic vessels
-contraction of skeletal muscle
-thoracic pressure changes
Describe lymph nodes
-distributed along lymphatic vessels (in series)
-filters lymph
-congregation and proliferation of lymphocytes
How does lymph return to the blood
Lymph nodes-lymph vessels-lymph trunks
RIGHT LYMPHATIC DUCT
lymph from upper right body drains into venous blood at junction of right internal jugular and subclavian veins
OR
THORACIC DUCT
lymph from everywhere else drains into venous blood at junctions of left internal jugular subclavian veins
Describe oedema
-loose tissue (subcutaneous tissue from around eyes or in scrotum) more prone than firm tissue (muscle) or enscapulated structures (kidney)
-can be organ specific
-increase diffusion distance from oxygen and nutrients
-limits diffusional removal of waste
Discuss inflammation in oedema
-capillary permeability increased
- increased fluid loss from capillaries
- movement of plasma proteins
Describe lymph oedema
-oedema due to impaired lymphatic drainage
-often due to surgical removal or irritation of lymph nodes
