Circulatory System Flashcards
Open circulatory system
Heart pumps blood into vessels that are open ended eg insects
Closed circulatory system
Blood remains in a continuous system of blood vessels eg humans
Adv of closed circulatory system
Blood can be pumped faster = more nutrients to be delivered faster to cells
Blood vessels
Arteries
Narrow lumen
Thick walls
No valves
Carry blood away from heart
Blood high in o2
Low in co2
Blood vessels
Veins
Wide lumen
Thin walls
Valves present
Carry blood to heart
Blood low in o2
High in co2
Small blood vessels
Arterioles - connects arteries and capillaries
Venules- connect veins and capillaries
Capillaries - connects arteries and veins
Adaptations of capillaries for their function
Thin walls allowed for easy exchange of materials with cells
The heart
-between the lungs
-pump blood around the body
- made of cardiac muscle - involuntary muscle does not tire
Role of the valves
Prevents black flow of blood
Tricuspid valve
Prevents back flow into right atrium
Semi lunar valve location
At the base of the pulmonary artery and base of aorta
Deoxygenated blood
-blood low in oxygen enters heart thru vena cava
-blood enters right atrium and blood is forced down thru tricuspid valve
-vena cava closes to prevent back flow - blood enters right ventricle
-blood is forced thru semi lunar valves in the pulmonary artery to the lungs
Oxygenated blood
-oxygen rich blood returns from the lungs to the heart thru the pulmonary veins into left atrium
-blood is pumped thru bicuspid valve into the left ventricle
-bicupsid valve closes and blood is pumped out thru semi lunar valves in the aorta
Systematic circuit
Pumps to head arms body legs and back to heart
Pulmonary circuit
Pumps to the lungs and back to the heart thru
Adv of double circulation system
Prevents oxygenated blood and de oxygenated blood from mixing
Portal system
A blood pathway that begins and ends in capillaries
Hepatic portal system
Connects the stomach and intestines with the liver
Heartbeat
Consists of alternate contraction and relaxation of the cardiac muscle does
Heartbeat controlled by
Pacemaker
Lub dub sound
Pacemaker /sa node
F - generates an impulse and causes atria to contract
Locatuon - wall of right atrium
Diastole
When heart chambers relax
Systole
When heart chambers contract
Pulse
The alternate expansion and contraction of arteries
- arteries are near to the skin
Blood pressure
Is the force the blood exerts against the wall of a blood vessel
Smoking
Increases heart rate and blood pressure
Diet
High intake of fat causes build up of cholesterol- may block vessels - strokes
Exercise
Strengthens the heart muscle
Increases heart rate
