anatomy of cvs Flashcards
whats the function of the heart?
to pump blood
whats the function of the arteries?
distribute blood from the heart
whats the function of the capillaries?
exchange nutrients
whats the function of the veins
collect and return blood to the heart
whats the function of the lymphatics
drain excess extracellular fluid from tissues
where is heart located?
middle mediastinum
what are the two main circulations?
pulmonary
systemic
what is the pulmonary circulation?
heart-lungs- heart
what is the systemic circulation?
Heart-body-heart
whats the mediastinum?
area of the thoracic cavity between pleual sacs
what ribs does the heart lie in?
T5-T8
where is the apex of the heart
bottom of the heart, lies in the 5th intercostal space
what are the layers of the heart?
endocardium
myocardium
epicardium
what is the endocardium made of?
Epithelium + *BM + Connective tissue
what muscle is myocardium made out of?
cardiac muscle
what is epicardium made of?
Connective tissue + *BM + Epithelium
does endocardium form valves?
yes
is myocardium striated or non?
striated
what are myocytes connected by?
intercalated discs
what are cusps?
thin structures derived from endocardium
what prevents valve failure?
chordae tendineae
what are the two valves called
mirtal and tricuspid
which side of the heart is mitral valve?
left
which side of the heart lies the tricuspid
right
what does stenosis of a valve mean?
narrowing
what is incompetence of a valve?
abnormal cusp and blood flows back through it
where are coronary arteries located?
epicardium
what happens in systole openings?
aortic sinuses shielded by aortic valve cusps
what happens in diastole?
elastic recoil of aorta closes aortic valve and blood enters arteries
what holds the heart in place?
Hangs” by great vessels within fibrous pericardium
Dense connective tissue bag
Attachments
Central tendon of diaphragm
Sternum
Roots of great vessels
what does the serous pericardium produce
Secretes pericardial fluid – lubricant
whats the visceral layer of the serous pericardium?
bound to heart
whats the parietal layer of the serous pericardium?
bound to fibrous pericardium
what are the three tunics of blood vessels?
tunica intima, media, externa/adventitia
what is the tunica intima made of?
Epithelium + BM + Connective tissue
what is tunica media made of?
Muscle + Elastic tissue
what is tunica externa made of?
fibrous connective tissue
which has the smaller diameter between arteries and veins?
arteries
do arteries or veins have a thicker wall?
arteries
do arteries have a thick media and thick adventitia (externa)
thick media
thin adventitia
do veins have a thick media and thick adventitia (externa)
thin media
thick adventitia
what are the three type of arteries?
elastic
muscular
arterioles
what are the elastic arteries?
large conducting
eg aorta, common carotid, pulmonary
what are the muscular arteries?
distrubuting arteries
eg coronary arteries, radial, femoral
what are the arterioles arteries?
terminal branches which supply blood to capillary bed
what is the function of elastic arteries
Pressure reservoir
Stretched during systole
During diastole heart relaxes pressure falls, the artery recoils thereby maintaining pressure on the blood
This recoil and stretchability is due to presence of extensive amounts of elastic fibres in T. Media in the form of layers = laminae
what are elastic fibres secreted by?
smooth muscle cells
what is the function of muscular arteries?
Controls distribution of blood to regions
what type of muscle is T.media?
smooth muscle
what are the two defined sheets in which elastic fibres are concentrated in?
internal elastic lamina
where is the thin external?outer elastic lamina?
between T.media and T. adventitia
do arterioles have a T. adventitia?
no
what gradually changes histologically to become arterioles?
smaller muscular arteries
what are the function of arterioles?
Rich sympathetic nerve innervation
Control blood flow to capillary beds (local)
Control blood pressure (systemic)
whats the main site for nutrients, gases?
capillaries
are capillaries thick or thin
thin
do capillaries have all three tunicas?
no they only have T.intima
what are the three types of capillary?
continuous
fenestrated
discontinuous
what are the characteristics of a continuous capillary?
Can control what is exchanged
Selective transport mechanisms
where might there be fenestrated capillaries?
. endocrine glands, kidney renal corpuscle
what are characteristics of discontinuous capillaries?
Gaps between endothelial cells (and basement membrane)
Allow free passage of fluid and cells
Eg. liver, spleen, bone marrow
true or false: T.intima contains phagocytic cells
true
where do you find sinusoids?
liver and some endocrine glands
why do veins need a thicker adventitia?
they are floppy and need some support
what are the main difference between arterie and vein
diametre
thickness of wall
adventitia
true or false: capillaries are a single cell folded on itself
true
what are pericytes?
incomplete layer of cells surrounding basement membrane – have contractile properties which help control flow of blood in the capillaries.
what are sinusoids?
variation of a discontinuous capillary
has a large diametre and wider than you would expect
what are precapillary sphincters?
close the capillary to allow a AV shunt
are the internal and external lamina thick in veins?
no - thin or absent
do veins have T. meda?
thin or absent
what is the T. adventitia made out of in veins?
collagenous tissue
where are the difference in superficial and deep veins most obvious?
lower limb
whats the differene in superficial and deep veins?
superficial- thick walled
no surrounding support
deep- thin walled
surrounding support from deep fascia and muscles
what is the diagnostic difference between a vein and lymphatic channel?
there should be no red blood cells in lymphatic channels
