Cardiovascular system Flashcards
3 components
- Four-chambered heart
- Blood vessels: veins and arteries.
- Blood
Pathway of blood through heart
left atrium–>left ventricle–>aorta–>arteries–>arterioles–>capillaries–>venules–>veins–>inferior/superior vena cava–>right atrium–>right ventricle–>pulmonary arteries–>lungs–>pulmonary vein–>left atrium.
Veins
carry deoxygenated blood (except for pulmonary vein)
inferior/superior vena cava
largest vein in body.
arteries
carry oxygenated blood (except for pulmonary artery).
Aorta
largest artery in body
atrium
thin walled, blood is received here (waiting room)
ventricles
thick, and do the actual work of pumping blood.
capillaries
arterioles that perfuse tissues.
portal system
when blood passes thru 2 capillary beds.
Heart
muscular organ made of cardiac muscle of varying thickness.
coronary arteries
provide oxygen and nutrients to the heart muscle.
4 valves
tricuspid valve
bicuspid valve
pulmonary valve
aortic valve
antrioventricular valves:
valves between atrium and ventricles. tricuspid- right AV valve bicuspid- left AV valve (LAB RAT) close DURING CONTRACTION-SYSTOLE.
Semilunar valves
valves protect the ventricles
pulmonary valve-right semilunar valve
aortic valve-left semilunar valve.
USED DURING RELAXATION-DIASTOLE)
Contraction phases
- Systole
2. diastole
Systole
ventricular contraction, closure of the AV valves.
blood is pumped out of the ventricles
higher pressure.
diastole
heart is relaxed and semilunar valves are closed. so blood is filling the ventricles from the atria.
decreased blood pressure.
cardiac output
total blood volume that’s pumped by ventriole in a minute. (5 L/min in humans)
Heart rate x stroke volume.
Control of cardiac output
ANS increases/decreasing heart rate to regulate cardiac output.
parasympathetic-slows heart rate by vagus nerve
sympathetic increases heart rate.
Rhythmic contraction of cardiac muscle
originates in electric impules travelling thru pathway formed by 4 electrically excitable structures:
- sinoartrial (SA) node.
- atrioventricular (AV) node
- Bundle of His
- Purkinje fibers.
Arteries
Stong, thick-walled structures.
Blood is carried away from the heart.
offer high resistant to flow of blood, so ventricles must generate high pressure.
Veins
thin-walled inelastic vessels.
blood is carried to the heart.
total blood volume is mainly here.
one-way valves
prevent back flow of blood in veins.
skeletal muscle and veins
keep the blood moving forward, veins are squeezed as muscles contract.
capillary
vessels with a single endothelial cell layer. allows for exchange of nutrients and gases
very delicate.
Blood pressure
potential difference between 2 points.
- measured force/area exerted on wall of blood vessels
- ratio of systolic/diastolic pressure.
largest pressure drop
-across aterioles b/c capillaries and viens are thin walled and would not be able to handle pressure levels of arteriols.
Blood composition
55% liquid
45% cells
Cells of blood
Erythrocytes
Leukocytes
Platelets
hematoporetic stem cells
cells from bone marrow, where erythrocytes, leukocytes, and platelets are composed from.
Erythrocytes
- Red blood cells.
- transport oxygen
- each cell has about 250 million hemoglobin proteins.
- biconcave disk shape, allow for traveling thru capillaries.
- mature RBC lose their nuclei and mitochondria.
leukocytes
white blood cells.
increase during infection
important part of immune system
2 classes and 5 types exist.
2 classes of leukocytes
- Granulocytes
2. Agranulocytes.
Granulocytes types (3)
- Neutrophils
- eosinophils
- Basophils
these have cytoplasmic granules that are toxic and invade microbes. involved in inflammatory reactions.
Agranulocytes types (2)
- lympocytes: B and T cells. Specific immune response.
- monocytes- macrophages
platelets
cell fragments from breakup of cells known as megakaryocytes in the marrow. function is to clot blood.
Blood antigens
surface proteins on cells.
