Module 8: Circulatory System: Cardiac Cycle pt.1 Flashcards
what are the main functions of the heart
Transport o2 and nutrients
Takes out wate and co2
Regulates body temp & pH
Transports+distributes hormones
Superior vena cava
Deliver blood to heart from head and upper limbs
Pulmonary artery
Passage where blood leaves right ventricle travel to lungs
aorta
Blood leaving left ventricle travels through aorta and is distributed to entire body
Right atrium
Recieves blood from body
Blood – high CO2, low O2
Right atrium pumps blood into right ventricle through right AV
Recieves blood from body
Blood – high CO2, low O2
Right atrium pumps blood into right ventricle through right AV
Receive blood from lungs
Rich in O2 AND low in CO2
Left atrium pumps blood to left AV
Right ventricle
Pumps blood into pulmonary artery
Left ventricle
Pumps blood into the aorta
Right AV (tricuspid) Valve
Makes sure blood will flow one way (right atrium to right ventricle)
Left AV (bicuspid) Valve
Makes sure blood will flow one way (left atrium to left ventricle)
Pulmonary Semilunar Valve
Makes sure blood will flow one way (right ventricle to pulmonary artery)
Aortic Semilunar Valve
Makes sure blood will flow one way (left ventricle to aorta)
Chordae Tendineae
Collagen cords attach valves to papillary muscles and valves
Prevent av valves from being pushed into the atria when the pressue in the ventricles is high
Papillary Muscles
Extensions of ventricular muscles
Attached to chordae tendineae
When ventricles contract so do papillary muscles
AV valves held in place
circulation through the heart
Blood enters at right atrium
From the right atrium, it passes through the right atrioventricular valve and into the right ventricle
When the right ventricle contracts, it ejects the blood out of the heart through the pulmonary valve and into the pulmonary artery to the lungs
After passing through the lungs, removing CO2, and picking up O2, the blood returns through the pulmonary vein to the left atrium
Blood enters the left ventricle through the left atrioventricular valve
When the left ventricle contracts, blood is ejected through the aortic valve into the aorta and out to the body
2 types Myocardial cells
Contractile cells – similar to skeletal muscle
Nodal/conducting cells – similar to nerve
contractile cells
Form most walls of atria and ventricles
Similar features to skeletal muscle
- Same skeletal proteins (Actin + Myosin
- Myofibrils surrounded in sarcoplasmic reticulum
- BUT Only one nucleus, lots more mitochondria
Extract lots of O2
Contractile cells are connected with intercalated discs
- Tight junction – bind cells together
- Gap junctions – allow movement of ions between myocardial cells (AP conduction)
myocardial cells – nodal/conducting cells
Weak – not many contractile proteins
Used for AP
Self-excitatory and transmission system
Located: ?
Sinoatrial node (SA node)
first area to depolarize (AP)
= PACE MAKER because it has the fastest spontaneous depolarization rate compared to other areas of the heart
Self excitability AP pathway through heart
Sinoatrial node SA Node
Atrial-ventricular node AV node
Bundle of His
Bundle of Branches
Purkinje fibers
movement of ions heart cells and APs
Self excitable
Na+ comes in (depolarize)
Ca++ also try to move in (depolarize)
K+ leaving (makes it hyperpolarize)
- K+ permeability decreases over time (makes it possible to make AP)
Na+/K+ pump pumps K+ into cell
Depolarize from –60 mV to –40mV
No neurons
Pace maker potential – sets heartbeat
speed of ap through myocardial cells
Sa node - slowest
Atrial muscle – quickens
Av node – slows to ensure atria have finished contracting
Bundle of his – very fast
- Want AP to reach apex of the heart to contract first
Purkinje fibers
Ventricular muscle
electrocardiogram
AP recorded – body fluid conducts electricity electrodes on skin detect ap
P-wave – depolarization atrial node
QRS complex – depolarization of ventricular muscle
T wave – repolarization of ventricular muscle
