Topic 6.2: The Blood System Flashcards
The Blood System and William Harvey (3)
a) Blood vessels connected by a single network
b) Unidirectional bloodflow
c) The heart is a central pump (arteries = from heart; veins = to heart)
Further Discoveries of the Blood System
a) Arteries and veins are connected by capillaries
b) There is a separate circulation for the lungs
Blood components
a) Red blood cells
b) White blood cells
c) Platelets
d) Plasma
Material transported by the blood
a) Nutrients
b) Antibodies
c) CO2
d) Hormones
e) O2
f) Urea
g) Heat
Blood vessels
a) Arteries
b) Veins
c) Capillaries
Arteries
a) Function
b) Pressure
c) Lumen diameter
d) Wall thickness
e) Wall layers
f) Muscle & elastic fibers
g) Valves
a) Send blood away from heart
b) High
c) Narrow
d) Thick
e) 3x Tunica
f) Large amounts
g) No
Veins
a) Function
b) Pressure
c) Lumen diameter
d) Wall thickness
e) Wall layers
f) Muscle & elastic fibers
g) Valves
a) Send blood to heart
b) Low
c) Wide
d) Thin
e) 3x Tunica
f) Small amounts
g) Yes
Capillaries
a) Function
b) Pressure
c) Lumen diameter
d) Wall thickness
e) Wall layers
f) Muscle & elastic fibers
g) Valves
a) For material exchange with tissues
b) Low
c) Extremely narrow (one cell wide)
d) Extremely thin (single thick)
e) Tunica intima
f) None
g) No
Heart structure
a) Right / Left atrium
b) Right / Left ventricle
c) Tricuspid valve
d) Bicuspid valve
e) Pulmonary valve
f) Aortic valve
g) Vena cava
h) Pulmonary artery
i) Pulmonary vein
j) Aorta
Blood flow from the right side of the heart (3)
a) Deoxygenated blood (from tissues) enters right atrium via the vena cava
b) Blood in the right ventricle is pumped to lungs via the pulmonary artery
c) Gas exchange at the lungs (capillaries ↔ alveoli) oxygenates the blood
Blood flow from the left side of the heart (3)
a) Oxygenated blood (from lungs) enters the atrium via the pulmonary vein
b) Blood in the left ventricle is pumped to the body tissues via the aorta.
c) Material exchange occurs at the respiring tissue (deoxygenates the blood)
How is the contraction in the heart created?
Myogenic, initiated by the heart
Mechanism of Heartbeat by SA node (4)
a) Electrical signals are initiated by SA node in the right atrium
b) This pacemaker stimulates the atria to contract and also relay signals to AV node
c) The AV node sends signals to ventricular Purkinje fibers (via a Bundle of His within the wall of the septum)
d) The Purkinje fibers cause the ventricular walls to contract
Rhythm of the SA node
60 - 100 bpm
Methods used to regulate the heart rate (2)
a) Medulla due to changes in CO2 and O2 levels (pH / Pressure)
b) Epinephrine increases heart rate to prepare for vigorous physical activity
How does the medulla regulate the heartbeat?
a) Sympathetic nerves release noradrenaline (⇑ heart rate)
b) Parasympathetic nerves release acetylcholine (⇓ heart rate)
Systole phase of the cardiac cycle
a) As atria contract, atrial pressure exceeds ventricular pressure
b) As ventricles contract, ventricular pressure exceeds atrial pressure
c) Pressure builds until the ventricular pressure exceeds the arterial pressure
d) Semilunar valves open and blood flows into arteries
Diastole phase of the cardiac cycle
a) As blood flows into arteries, ventricular pressure drops.
b) Backflow closes semilunar valves
c) When ventricular pressure drops below atrial pressure, the AV valves open and cardiac cycle is repeated.
Coronary arteries definition
Blood vessels that surround the heart and nourish the cardiac tissue to keep the heart working.
Process of coronary occlusion
a) Vessels are damaged by cholesterol deposition (atherosclerosis)
b) The deposits reduce vessel diameter and increase blood pressure
c) The stress damages arterial walls (and is repaired with fibrous tissue)
d) The vessel wall loses elasticity and forms atherosclerotic plaques
e) If a plaque ruptures, blood clotting is triggered, forming a thrombus
f) If the thrombus blocks blood flow, a myocardial infarction results
Consequences of coronary occlusion
a) If coronary arteries become occluded, the region of heart tissue nourished by the blocked artery die.
b) Blood pumped through the heart is at high pressure and cannot supply O2 and nutrients to the heart
Risk factor for coronary occlusion
a) Age
b) Genetics
c) Obesity
d) Diet
e) Exercise
f) Sex
g) Smoking
