cardiovascular system Flashcards
what are the organs of the cardiovascular system?
heart, blood vessels, blood
what are the layers of the heart?
pericardium, epicardium,myocardium,endocardium
what are the structures of the cardiovascular system?
valves, chambers,major vessels, major cell types of blood
what are the cell types the heart consists of?
-pericardium
-epicardium
-myocardium (cardiac myocytes)
-valves
-conducting nerve bundles
-pericardium
–blood vessels-endothelium
what are the different blood cells the blood consists of?
-leukocytes-white blood cells
-erythrocytes-red blood cells
what is the pericardium?
-dense,irregular connective tissue
what is the epicardium?
a visceral layer of the serous pericardium
what is the myocardium?
-a cardiac muscle layer
what does the endocardium consist of?
camber lining and valves and a smooth lubricating layer
how is the thickness of the cardiac walls?
-the myocardium of the left ventricle is thicker than the right ventricle
what is the histology of the cardiac muscle?
-there is branching,intercalated discs with gap junctions, involuntary striated, single central nucleus per cell
-there are desmosomes between myocytes which allow the depolarisation of adjacent fibres
how is the structure and function of the valves?
-they open and close in response to pressure changes as the heart contracts and relaxes
-dense connective tissue rings surround the valves of the heart and fuse with the inter ventricular system
what is the physiological function of the heart?
-it pumps over 1mill gallons per year
-it has over 60,000 miles of blood vessels
what is the physiological function of the vessels?
-they help to retain and circulate blood
-they help regulate pulse pressure
what is the physiological function of the blood?
-erthrocytes-distribute oxygen from & CO2 to lungs
-leukocytes-circulate immune cells to combat infection
what is the process of electrical conductance?
-SA node (right atrium)
-AV node
-AV bundle (bundle of His)
-right and left bundle branches
-purkinje fibres
what is systole and diastole?
-systole-contraction
-diastole-relaxation
what does an ECG represent?
the overall electrical activity of the heart
how is heart rate regulated by the nervous system?
by nervous control from the cardiovascular centre in the medulla which involves:
-sympathetic impulses
-parasympathetic impulses
-baroreceptors
what can heart rate be affected by?
-adrenaline
-noradrenaline
-thyroid hormones
-ions (Na,K,Ca2+)
-age,gender,physical fitness and temp
what do sympathetic impulses do?
increase heart rate and force of contraction
what do parasympathetic impulses do?
decrease heart rate
what do baroreceptors do?
they are pressure receptors that detect change in BP and send info to the cardiovascular centre
where are baroreceptors located?
in the arch of the aorta and carotid sinuses
what is the route of systemic circulation?
left side heart to body and back to the heart
what is the route of hepatic portal circulation?
capillaries of the GI tract to capillaries in the liver
what is the route of pulmonary circulation?
right side of the hear to the lungs and back to the heart
what is the route of foetal circulation?
from the metal heart through the umbilical cord to the placenta and back
what are the 4 major divisions of the aorta?
-ascending aorta
-arch of aorta
-thoracic aorta
-abdominal aorta
where are superficial veins found?
beneath the skin
where does venous blood drain to?
either superior or inferior vena cava or coronary sinus
what do veins of the systemic circulation do?
drain blood from the entire body and return it to the right side of the heart
where are deep veins found?
they parallel the arteries in the region
what are the three major layers in the arteries and veins?
-the tunica internal (ft the endothelium)
-tunica media (ft circular smooth muscle and elastic fibres)
-tunica externa (ft elastic and collagen fibers)
what are elastic arteries?
-large arteries with more elastic fibres and less smooth muscle and they are able to receive blood under pressure and propel it onward
why are elastic arteries also called conducting arteries?
they conduct blood from the heart to medium sized muscular arteries
what does the elasticity of large arteries mean?
-blood flow can proceed in a smooth and continuous manner, despite the start-stop pumping activity of the heart
what are muscular arteries?
-medium sized arteries with more muscle than elastic fibres in the tunica media
-they have relatively thick walls
what are muscular arteries capable of?
-greater vasoconstriction and vasodilation to adjust the rate of flow due to their smooth muscle content, which influences blood flow and the regional distribution of blood flow
why are muscular arteries called distributing arteries?
-because they direct blood flow
what are arterioles?
-small arteries that deliver blood to the capillaries
-they contain the tunica media containing few layers of muscle
what do metarterioles do?
-form branches in the capillary bed
-to bypass the capillary bed,precapillary splinters close and blood flows out of the bed in thoroughfare channel
what is vasomotion in relation to capillary beds?
-intermittent contraction and relaxation of sphincters that allow the filling of the capillary bed 5-10 times/minute
wat are capillaries?
-the site of gas exchange at the cellular level
-they are found near every cell but are more extensive in highly active tissue e.g muscles,liver,kidneys and the brain
when do capillary beds fill with blood?
-entire capillary beds fill with blood when tissue is active,;asking in epithelia of cornea and lens of eye and cartilage
what are the capillary walls composed of?
-a single layer of cells (endothelium) and a basement membrane
what are capillaries drained by?
-venules so they eventually feed into veins
what are venues?
-small veins that collect blood from the capillaries
-as venules develop they can develop tunica media with some smooth muscles and scattered fibroblasts
