main function of circulatory system
transport of oxygen, nutrients, waste products and hormones among the tissues and organs of the body
circulatory system
heart, blood vessels, blood
heart
4 chambers:
- right atrium
- left atrium
- right ventricle
- left ventricle
atria
collect blood from the body and lungs and pass it to the ventricles
ventricles
eject blood throughout the body
myocardium
chamber walls consisting of cardiac muscle
- internal lining consists of a smooth membrane called endocardium
pericardium
double-layered membrane that encloses the heart
atrioventricular (AV) valves
permit one-way blood flow form the atria to the ventricles
tricuspid valve
three flaps (cusps) that meet when valve is closed between the right atrium and right ventricle
pumping cycle
chamber relax as they fill and the contract when the pump blood
- diastole: filling period
- systole: contracting period
- alternation contraction and filling called cardia cycle
sinoatrial node (SA node)
pacemaker of the heart
- initiates impulse for contraction thats spreads over atria and passes to the ventricles via conductive tissue called the atrioventricular node (AV node)
- impulse continues along and terminate in the Purkinje fibres
heart muscle contraction influenced by
autonomic nervous system and hormones such as epinephrine
sets of nerves
two sets work with one slowing the heart and the other accelerating it
- vagus nerve: slows heart rate during rest ad sleep by acetylcholine
aorta
branches carry blood to head, chest, abdomen, pelvis, and lower extremities
- arteries divide into smaller arteries and eventually into arterioles, which then lead into capillaries
- walls of arteries are muscular, thick, strong, elastic, and lined with endothelium
red blood cells (erythrocytes)
hemoglobin
plasma
white blood cells (leukocytes)
platelets
blood tests
diagnostic for systemic diseases and specific blood disorders
- measure total blood count (RBC + WBC + platelets) and other components within blood
- provides qualitative information including size, shape, and ratio
bone marrow smear
used to diagnose malignant blood disorders and increases or decreases in blood counts
- provide information on the function of the bone marrow an the qualitative characteristics of stem cells that create blood cells
electrocardiogram
electrical recording of heart action aiding in the diagnosis of coronary artery disease, myocardial infarction, valve disorders, and some congenital heart disease
echocardiography
high-frequency sound waves utilized to examine size, shape, and motion of hear structured
doppler echocardiography
explores blood flow patterns and changes in velocity of blood flow within the heart and great vessels