The circulatory system Flashcards
What is the circulatory system?
A transportation system for oxygen, nutrients, and cell waste, to move throughout body
What are the main functions of the circulatory system?
- Transports gases, nutrient molecules, and waste
- regulates internal temperature, transports hormones
- protects against blood loss, against diseases
What are the 3 main components of the circulatory system?
- the heart-pushes blood throughout body
- blood vessels-pathway for blood|
- blood-carries nutrients, hormones, gases and waste. O2+CO2 exchange
What are the pathways of the circulatory system and what do they dp?
- pulmenary circuit- transports blood to lungs to get O2
- systemic circuit: transports O2 rich blood to body
- coronary circuit: brings O2 rich blood to the heart
What are arteries?
-takes O2 rich blood away from heart, elastic walls, strong/thick,high pressure
What are veins?
-takes O2 poor blood back to heart, thin walls, not elastic, low pressure, have valves to prevent backflow
What are capillaries?
-where gases and nutrients are exchanged, smallest blood vessel. very think walls, single blood line
What is vasodilation?
the expansion of blood vessels, more blood cells
What is vasoconstriction?
constricting of blood vessels, less blood flow
How do veins prevent backflow?
- valves
- skeletal muscle contractions
What is atherosclerosis?
build up of plaque+ fat inside artery
causes higher blood pressure+ higher chance of artery rupture
What is the order of events of blood in the heart?
- vena cavae (No O2)
- right atrium
- tricuspid (AV) valve
- right ventricle
- semilunar valve
- pulmonary artery
- lungs (to get O2)
- pulmonary vein (now oxygenated)
- left atrium
- Bicuspid (AV) valve
- left ventricle
- semilunar valve
- Aorta—to rest of body
What is a heartbeat?
An electrical signal coming from the heart
How does a heart beat?
- sinoatrial node (SA)- at top of right atrium, pace maker, creates an electrical impulse,
- atrioventricular (AV) node—- bottom of right atrium, magnifies impulse, sends message to ventricles to contract
What are the order of events of a heart beat?
- SA node creates an impulse
- atria contract and pushes blood to ventricles
- AV node magnifies impulse
- ventricles contract
- semilunar valves open, blood leaves heart
What sounds do a heart make and why?
lub- atrium contracts, av valve slams shut, sound comes from blood colliding with closed valve
dub- ventricles contract, semi lunar valves slam shut, sound come from blood colliding with valves
What is blood pressure?
Normal bp: 120/80 mm/hg
120= systolic pressure, ventricles contract 80= diastolic pressure, ventricles relax
What would raise/lower BP?
raise: Stress, increased blood cells, increased heart rate, clogged arteries, vasoconstriction
lower: exercise, healthy diet, vasodilation
What us hypertension?
increased resistance to blood flow, vessels may rupture