Blood Circulation System (page 148-155, 158-160) Flashcards
circulatory system
system that circulates fluids through the body
closed circulatory system
circulatory system in which blood is confined to vessels
pulmonary circulatory system
system that carries blood from the heart to the lungs and back
systemic circulatory system
system carries blood from the heart to the body and back
apex
bottom section of the heart, slightly pointy
pericardium
double membrane that surrounds the heart
cardiac
relating to the heart
coronary blood vessel
blood vessel that supplies the heart muscle with blood
open circulatory system
blood pumped by the heart travels through blood vessels. blood goes directly to the cells and is returned by different mechanisms
what animals have closed circulatory system
mammals (majority animals)
how does blood flow through tissues
tissues well supplied with blood vessels. substances diffuse from blood into body cells that make up tissues. move across walls of capillaries (smallest blood vessels). oxygen and food travel to and diffuse into the body cells, carbon dioxide and waste products leave tissues and diffuse back into blood
why is a close circulatory system efficient
movement of blood to the different tissues can be easily controlled
what are humans two circulatory systems
pulmonary and systemic, means blood passes through our body twice in one circuit
heart
muscular organ that pumps blood through blood vessels to al parts of the body, size of clenched fist, first organ to develop/work while embryo
where is the heart found
middle of the thorax, between lungs and underneath the breastbone, slightly towards left
what surrounds the heart
double membrane known as pericardium, fluid between two membranes which reduces friction as hearth contracts and relaxes
what is the hearth made of
cardiac muscle
what is on the surface of the heart
blood vessels that supply the heart muscle with blood called coronary blood vessels
what happens if blockages occur in coronary blood vessels
heart starved of oxygen and nutrients and can result heart attack
atria
upper chambers of heart
ventricles
lower chambers of heart
septum
muscular wall that separates the left and right side of heart
atrioventricular valves
heart valves found between atria and the ventricles, cuspid valves
tricuspid valves
valve found between the right atrium and ventricle
bicuspid valves
valve found between left atrium and ventricle
why is the heart a double pump
left and right sides are separated from each other by a muscular wall called the septum
is there mixing of oxygenated and deoxygenated blood
no, right side low oxygen content (deoxygenated) and left side oxygen-rich blood (oxygenated)
where are semi-lunar valves found
base of two major arteries that carry blood away from heart
what are the major blood vessels associated with the heart
venae cavae (superior vena cava and inferior vena cava), pulmonary veins, aorta, pulmonary artery
explain how blood flows through the heart
1.deoxygenated blood from the body enter right atrium via inferior vena cava and superior vena cava.
2.blood flows via tricuspid valve into the right ventricle.
3.blood leaves heart via pulmonary artery and travels to lungs.
4. blood oxygenated in the lungs.
5.oxygenated blood returns left atrium of the heart via pulmonary veins.
6.blood flows via bicuspid valve into left ventricle.
7.aorta carries oxygenated blood to the body.
inferior vena cava
vein carries lower from lower parts of body to the heart
superior vena cava
vein carries blood from upper parts of body to the heart
pulmonary artery
artery carries deoxygenated blood from the heart to the lungs
pulmonary vein
vein carries oxygenated blood from lungs to the heart
aorta
main artery that carries blood away from heart
cuspid valve
valve lies between atrium and ventricle in the heart
semi-lunar valves (pocket valves)
valves found inside the aorta and pulmonary artery
how do the cuspid valves function
- when blood flows from atrium into ventricle, valve pushed open and flattened against inside of the heart wall
-as ventricle contracts, blood forced into cusps which are small, membrane-like flaps of the valve
-cusps trap the blood and valve closes
-valve tendons keep cusp firmly in position, preventing blood from entering atrium
what are papillae
points where valve tendons are attached to heart wall
how do semi-lunar valves function
-as ventricles contract, blood leaves heart, forcing valves open
-valve open, lies flat against inside of artery wall
-heart relaxes, blood does not flow back into heart because valve closes as valve pockets filled with blood
cardiac cycle
contraction and relaxation of the cardiac muscle during one heart beat
atrial systole
contraction of atria during cardiac cycle
ventricular systole
contraction of ventricles during cardiac cycle
diastole
phase of the heart beat when the heart muscle is relaxed
what is the average heartbeat
70 beats per minute
how long does a cardiac cycle last
0.8 seconds
what is the order of the cardiac cycle
- atrial systole
- ventricular systole
- diastole
what occurs during the atrial systole
-lasts 0.1 seconds
-atria contract
-blood vessels carry blood into atria constrict
-blood pushed from atria into ventricles via bicuspid and tricuspid valves
what occurs during the ventricular systole
-last 0.3 seconds
-ventricles contract
-increased pressure inside ventricles causes the cuspid valves to close
-blood leaves heart via aorta and pulmonary arteries
what occurs during the general diastole
-lasts 0.4 seconds
-heart relaxes
-pulmonary and aortic valves close which prevents blood flowing back into the heart
-blood enter atria via venae cavae and pulmonary veins
-cuspid valves open so blood trickles into ventricles
what does the cardiac cycle ensure
blood flows in one direction through the heart making it pump blood efficiently through the body
oxygenated blood
blood that is rich in oxygen
deoxygenated blood
blood with low oxygen content and high levels of carbon dioxide
what does the pulmonary circulatory system do
carries blood between the heart and lungs.
explain how pulmonary circulatory system works
deoxygenated blood carried from right side of heart to lungs via pulmonary artery. at lungs carbon dioxide leaves blood and we breathe it out. oxygen we breathe in, enters blood. oxygenated blood travels back to left side of the heart in pulmonary veins
what does the systemic circulatory system do
carries blood between heart and the body
explain how systemic circulatory system works
-oxygenated blood carried from left side of the heart in aorta.
-blood supplies oxygen and nutrients to body cells
-different organs of the body are supplied with blood via specific blood vessels (named according to organ enter/leave)
-carbon dioxide and waste products move from cells of the body into the blood
-deoxygenated blood then travels back to right side heart via superior vena cava and inferior vena cava
artery
blood vessel carries blood away from heart
endothelium
layer of endothelium lining blood vessels
pulse
contraction and relaxation of arteries each time heart beats
capillary
tiny blood vessels that links arterioles to venules
vein
blood vessels carrying blood towards heart
arteriole
branch of an artery
venule
branch of a vein
what are the 3 layers of arteries
- outer fibrous layer
- middle layer made of elastics and muscular tissue
- inner layer (endothelium)
explain how blood travels through arteries
-under high pressure
-heart beats, blood forced into artery, causing elastic, muscular wall to stretch and bulge
-bulging is the pulse
what is the only artery carries deoxygenated blood
pulmonary artery
what does a capillary consist of
small layer endothelium
how do capillaries function
-form network that branches between cells
-blood cells squeeze along them single file
-slows down blood flow rate allowing exchange of substances between blood and surrounding tissue cells
-substances move across walls of capillaries
-oxygen and nutrients move from blood to cells
-carbon dioxide and waste products move from body cells into blood
-white blood cells squeeze out capillaries to destroy germs
3 layers of a vein
- outer fibrous layer
- elastics, muscular middle layer
- inner endothelium
how does a vein function
-blood flows through veins low pressure
-valves found inside veins prevent backflow of blood
which vein carries oxygenated blood
pulmonary vein
how do the blood vessels link
-blood leaves heart in arteries
-arteries divide arterioles then into capillaries
-capillaries rejoin and form venules
-venules combine and form veins return blood to the heart
plasma
liquid part of blood
red blood cells (erthrocytes)
disc-shaped, biconcave cells found in the blood which carry respiratory gases
white blood cells (leucocytes)
cells that travel in the blood and fight infections
platelets
blood proteins that help ith blood clotting
percentage of liquid plasma
55%
description of liquid plasma
clear, yellowish liquid, 95% water
functions of liquid plasma
-carries blood cells and other substances around body
-eg. sugars, fats, proteins, blood-clotting factors, vitamins, minerals, hormones, enzymes antibodies
percentage of red blood cells
40-50%
description of red blood cells
disc-shaped biconcave cells no nucleus
function of red blood cells
-contains pigment called haemoglobin which carries oxygen and carbon dioxide around bodies
-biconcave shape creates large surface area for gaseous exchange
percentage of white blood cells
1%
description of white blood cells
large cells with nuclei and have unusual shapes
functions of white blood cells
-various roles immune response
-protect bodies by destroying foreign cells (bacteria and viruses)
-gets rid of dead or dying blood cells and foreign matter (dirt - couldve entered blood through open wounds)
percentage of platelets
<1%
description of platelets
cell fragments that lack nucleus
functions of platelets
-clot blood form scabs (along blood clotting factors)
-fight infection by releasing chemicals destroy bacteria
3 functions of blood
- carry substance from one part of the body to another
- plays important role in fighting disease and infection
- blood helps control and regulate body tempreture
