Cardiovacular System (week 7) Flashcards
what is the cardiovascular system?
a closed system of the heart and blood vessels
—> the heart pumps blood
—> blood vessels allow blood to circulate to all parts of the body
what are the functions of the cardiovascular system?
transport oxygen, nutrients, cell wastes, hormones to and form cells and regulation of body temperature
how big is the heart?
size of a human fist, weighing less than a pound
where is the heart located?
in the thoracic cavity (the medial section of the thoracic cavity- i between the lungs in the inferior mediastinum)
describe the orientation of the heart
Apex (pointed region) is directed toward left hip and rests on the diaphragm
base (area where great blood vessels emerge) points toward right shoulder
how is the heart covered?
with a double walled sac called pericardium
- fibrous pericardium is loose and superficial
- serious membrane is deep to the fibrous pericardium and composed of 2 layers
what is fibrous pericardium layers composed of?
- parietal pericardium: outside layer that lines the inner surface of the fibrous pericardium
- visceral pericardium: next to the heart; also known as epicardium
* serious fluid fills the space between the layers of pericardium called pericardial cavity
describe and name the 3 walls of the heart
- epicardium: outermost layer of the heart wall; also known as the visceral pericardium
- myocardium: middle layer composed mostly of cardiac muscle (this muscle contracts)
- endocardium: inner layer known as endothelium
what are the 4 chambers of the heart?
- Atria (right and left): superior receiving chambers
- Ventricles (right and left): inferior discharging chambers
what is the role of the left and right Atria
- Atria (right and left): superior receiving chambers
- assist with filling the ventricles
- blood enters under low pressure from veins of the body
what is the role of the left and right ventricles
- Ventricles (right and left): inferior discharging chambers
- thick- walled pumps of the heart
- during contraction, blood is propelled into circulation
what is interatrial septum?
this section separates the two atria longitudinally
what is interventricular septum
this section separates the two ventricles longitudinally
what are 3 processes in the heart?
Heart functions as a double pump, pulmonary circulation and systemic circulation
what does the double pump process achieve in the heart?
right side works as the pulmonary circuit pump while left side works as the systemic circuit pump
what do arteries do to blood?
they carry blood away from the heart
what do veins do to blood?
they carry blood towards the heart
what is pulmonary circulation?
blood flows from right side of the heart to the lungs and back to the left side of the heart
in pulmonary circulation, where is blood pumped out of?
right side through the pulmonary trunk, which splits into pulmonary arteries and takes oxygen- poor blood to lungs
*oxygen- rich blood returns to the heart from the lungs via pulmonary veins
what is systemic circulation?
where oxygen- rich blood returned to the left side of the heart is pumped out into the aorta
blood returned to the right atrium via systemic veins, which empty’s blood into the superior or inferior vena cava
where does blood circulate in systemic circulation?
blood circulates to systemic arteries and to all body tissue
(T/F) does the left ventricle have thicker walls because it pumps blood to the body through the systemic circuit
True
what is the role of heart valves?
allow blood to flow in only one direction to prevent back flow
what are the two types of heart valves?
atrioventricular (av) valves and semilunar valves
where is atrioventicular (av) valves located?
between atria and ventricles
where are semilunar valves located?
between ventricle and arteries
when do valves open and close?
in response to pressure changes to the heart
what is the left av and right av valves called?
left av valve: bicuspid (mitral) valve
right av valve: tricuspid valve
when do the atrioventricular (av) valves open and close?
open during heart relaxation, when blood passively fills the chambers
closed during ventricular concentration
where do chordae tendineae anchor?
on the cusps to the walls of the ventricles
(T/F) does blood in the heart chambers nourish the myocardium?
false, the heart has its own nourishing circulatory system
what does the hearts own nourishing circulatory system consist of?
coronary arteries, cardiac veins, and coronary sinus
what are coronary arteries?
arteries that branch form the aorta to supply the heart muscle with oxygenated blood
- on the left: anterior interventricle artery and circumflex artery
- on the right: posterior interventricle artery and marginal artery
what are cardiac veins?
veins that drain the myocardium of blood
what are coronary sinus?
a large vein on the posterior of the heart; receives blood from cardiac veins
*blood empties into the right atrium via the coronary sinus
what is intrinsic conduction of the heart?
cardiac muscle that contracts spontaneously and can occur independently of nerve impulses
(Intrinsic conduction of the heart) how do contractions occur?
in a regular and continuous way
- atrial cells beat 60 times per minute
- ventricular cells beat 20-40 times per minute
** need a unifying control system- the intrinsic conduction system (nodal system)
what are the 2 systems regulate heart activity
- autonomic nervous system
2. intrinsic conduction system (nodal system)
what does the intrinsic conduction system (nodal system) do?
- sets the heart rhythm
- composed of special nervous tissue
- ensures heart muscle depolarisation in on direction (atria to ventricle)
- enforces a heart rate of 75 beats per minute
what are the components of the intrinsic conduction of the heart?
- sinoatrial (sa) node
- atrioventicular (av) node
- atrioventicular (av) bundle
- purkinje fibers
what is the sinoatrial (sa) node
the sa node is located in the right atrium- serves as the hearts pace maker
what is an atrioventricular (av) node?
a node at junction of the atria and ventricles
what is a atrioventricular (av) bundle
bundle of branches that are in the interventricular septum
what are purkinje fibers?
fibers that are spread within the ventricle wall muscles
what is the process of intrinsic conduction system of the heart?
- the sinoatrial node (SA node) starts each heart beat
- impulse spreads through the atria to AV node
- Atria contracts
- At the AV node, the impulse is delayed briefly
- impulse travels through the AV bundle, bundle branches and purkinje fibers
- ventricle contracts; blood is ejected from the heart