EAC Cardio-Vascular CV System Flashcards
functions of the CV system
To transport essential foodstuffs, oxygen, water, enzymes and hormones to the cells of the body
To remove waste products that are produced by cell metabolism to the excretory organs
components of the CV system
Heart
Blood vessels
Blood
CV circulation divisions
Systemic: passage of blood around the body
Pulmonary: passage of blood through the lungs
Coronary: supply of blood to/from the heart muscle
Hepatic Portal: supply of blood to/from the liver (is a branch of systemic)
describe:
structure of the heart
The heart is a hollow cone shaped muscular organ
In an average adult it is the size of the owners clenched fist
state the location of the heart
The heart is situated within the thoracic cavity.
It lies in the mediastinum behind the sternum, in front of the spine, between the lungs and above the diaphragm.
The base lies behind the sternum and extends to the 2nd rib
The apex is approx. 9cm to the left of the midline, in the mid-clavicular line at the 5th intercostal space
describe the structure of the heart
The walls of the heart are composed of three main layers:
Pericardium (outer)
Myocardium (mid)
Endocardium (inner)
Pericardium consists of
Fibrous pericardium
Parietal pericardium
Pericardial space fill with Pericardial fluid
Visceral pericardium
function of: Pericardium
The pericardium prevents over distension of the heart and the pericardial serous fluid allows for smooth frictionless movement when the heart beats.
function of: Myocardium
Muscle of the heart, thickest around the left ventricle. has automaticity which means it doesn’t require outside stimulus to produce muscle contraction.
function of: Endocardium
A thin smooth squamous epithelial membrane to ensure smooth flow of blood through the heart.
It lines the chambers of the heart and the valves.
Its continuous with the lining of blood vessels.
Helps to prevent local blood clotting.
flow of blood through the heart (right side)
Inferior and superior vena cava
Right atrium
Tricuspid valve
Chordae tendineae
Papillary muscle
Right ventricle
Pulmonary valve
Pulmonary trunk
Left and right pulmonary artery
Lungs
flow of blood through the heart (left side)
Lungs
left and right pulmonary vein
Left atrium
Bicuspid valve
Chordae tendineae
Papillary muscle
Left ventricle
Aortic valve
Arch of aorta
Aorta
Rest of body
Describe:
Coronary circulation
Coronary circulation is the circulation of blood in the blood vessels of the heart muscle.
Right coronary artery
Left coronary artery
-which the Circumflex artery branches off
Describe:
Cardiac Cycle
Atrial systole - contraction of atria - 0.1 sec
Ventricular systole - contraction of ventricles - 0.3 sec
Cardiac diastole - relaxation phase - 0.4 sec
Describe:
Electrical Conduction System of the heart
specialised cardiac cells that produce electrical impulses to cause the heart to contract
Sino-Atrial node SA
Atrio-Ventricular node AV
Left and Right bundle branches
Purkinje Fibres
Explain:
Nervous Control of the heart
Cardiovascular centre located within the medulla oblongata
sympathetic/Parasympathetic nervous control regulates heart rate
Average heart rates
60-100 = adult
100-120 = 6-12yrs
120-140 = 1-5yrs
140-160 = 1mnth-1yr
factors that increase heart rate
position
age/sex
exercise
emotion
cardiac/medical conditions
shock and blood loss
drugs/chemicals
factors that decrease heart rate
age
general health
vagal stimulation
cardiac conditions
medical conditions
drugs
define:
Bradycardia
Slow heart rate of less then 60bpm
define:
Tachycardia
Rapid heart rate of more then 100bpm
name the 5 types of blood vessel
Arteries Arterioles Capillaries Venules Veins
describe:
structure of blood vessels
Three layers:
outer fibrous sheath = Tunica Adventitia
middle layer of muscle and elastic fibre = Tunica Media
smooth inner lining of endothelium = Tunica Intima
describe the structure and function of:
Arteries
carry blood away from the heart
they have a strong outer (tunica adventitia) coat and thick muscle layer (tunica media)
describe the structure and function of:
Arterioles
these are smaller arteries
dilate or contract to control the blood flow into the capillary bed
describe the structure and function of:
Capillaries
Have very thin walls. A single layer of cells.
they allow for the interchange of gases and transfer of nutrients and waste products
describe the structure and function of:
Venules
these are smaller veins
Venules dilate or contract to control the blood flow out of the capillary bed
describe the structure and function of:
Veins
Veins carry blood back to the heart
they have thinner walls then arteries
some veins have valves to prevent back-flow of blood
Define:
Venous Return
The amount of blood returning to the heart. The force of contraction of the left ventricle is not sufficient on its own to ensure effective return of the blood to the heart via the veins.
Four factors that assist in venous return
Position of the body
Muscular contraction
Respiratory movements
Suction of the heart
Define:
Pulse
a rhythmical pulsation of the arteries as blood is propelled through them, typically as felt in the wrists (radial) or neck (carotid)
what information can be obtained from a pulse
Pulse rate
A rough blood pressure
circulatory issues i.e. no pedal pulse in fractured leg/ankle/foot
Define:
Blood Pressure
The force or pressure exerted on the walls of the blood vessels by the blood.
This pressure is higher in the arteries than in the veins.
Define:
Pulse Pressure
the difference between systolic and diastolic pressures
the component parts of blood
Liquid part:
Plasma 55%
Solid part:
Erythrocytes
Leucocytes
Thrombocytes
the 7 main functions of blood
carry o2 and co2
carry nutrients and water
carry waste products
protect body from infection
sealing of wounds
distribute the secretions of glands
distributes heat
State the normal range of blood volumes
70ml per kg of body weight
describe the blood clotting process
Damage platelets release the enzyme Thrombokinase around site of injury
Thrombokinase, calcium salts and prothrombokinase (plasma protein) all combine to form an activating enzyme called thrombin
Thrombin converts fibrinogen (plasma protein) into fibrin threads
Fibrin threads entrap blood cells and bind them to the tissues to form a clot
position and function of the spleen
The spleen is an organ in the upper far left part of the abdomen, to the left of the stomach.
It acts as a filter for blood as part of the immune system. Old red blood cells are recycled in the spleen, and platelets and white blood cells are stored there.
