Circ System Histo Flashcards
components of CV system
heart, BVs, blood
fnctn of CV system
transport (nutrients and oxygen, waste products, hormones)
chambers of the heart
- 2 artia: receiving chambers (walls thinner than vents)
- 2 ventricles: discharging chambers (L wall much thicker then R)
L side
systemic circuit
LA receives oxygenated blood
R side
pulmonary circuit
RA receives deoxygenated blood
components of heart wall
- cardiac m
- fibrous skeleton of heart (4 fibrous rings surround valve orifices, 2 fibrous trigones connect fibrous rings, membraneous portion of IV and IA septa)
- conducting system
- coronary vasculature
- serous membrane
- endothelial cells with underlying CT
what are the 4 fibrous rings made of
dense irregular CT
layers of heart wall
- epicardium: outer layer (visceral layer/serous pericardium)
- myocardium: middle, mainly cardiac m and fibrous skeleton of heart
- endocardium: inner, 3 components
3 components of endocardium
- endothelial cells: against blood, inner
- subendothelial layer: CT and smooth m
- subendocardial layer: deep, CT and intrinsic conduction system
composition of valves
CT and overlying endocardium
semilunar valves
- prevent backflow into ventricles
- aortic and pulmonary valves
- both have three cusps
do vena cava, coronary sinus, and pulm veins have valves?
no
layers of valves
- spongiosa: LCT covered in endothelium, atrial or BV side, collagen and elastic fibers auricularis
- fibrosa: core of value, fibrous extensions fron DICT of skeletal rings arterialis
- ventricularis: DCT with layers of elastic convered in endothelium, ventricular side of valve
intrinsic conduction system
- cardiac m can depolarize and contract w/o impulses from NS
- 2 types of conducting cells
- organized into nodes, resp for initiation and distribution of impulse
2 types of conducting cells
- nodal cardiac cells: in SA and AV, modified, both cardiac m cells, no intercalated discs
- purkinje fibers: AV bundle, bundle brs and subendo brs, intercalated discs, myofibrils, positive for PAS staining
what influences rate of contraction
sympathetic: increase
parasympathetic: decrease
types of BVs
- arteries: blood away from heart, oxygenated to systemic, deoxy into pulm circ
- capillaries: smallest BV, role in exchange, endothelial cell and basal lamina
- veins: blood toward heart, deoxy blood insystemic, oxy blood in pulm
layers of walls of BVs
- tunica interna: endothelium->basal lamina->subendothelial layer *internal elastic membrane in aa and some arterioles
- tunica media: rings of smooth m cells, sheets of elastin *external elastic mem: aa
- tunica externa/adventitia: vasa vasorum in larger vessels
thickest layer in vv
tunica externa
thickest layer in aa
tunica media
4 types of aa
- elastic/conducting (large): >10 mm, large amts of elastic fiber, for expand and recoil
- muscular/distributing (med): 2-10mm, large amts of elastic fiber, SM, reg blood flow in body regions
- small aa: 1-2 mm, as many as 8 layers SM in tunica media
- arterioles: only 1-2 layers SM in tunica media
3 types of capillaries
- continuous: muscle, lunds, CNS, uninterrupted lining with tight jncnts, pinocytotic vesicles
- fenestrated: endocrine glands, oval pores, pino vesicles
- discontinuous (sinusoids): liver, spleen, bone marrow, large diameter, irregularly shaped
2 types of vessels in cap network
- true capillaries
- AV shunts (finger tips and erectile tissue)
* relaxed precap sphincter and contracted AV shunt=blood thru true caps
* contracted precap sphincter and relaxed AV shunt = blood thru shunt
4 types of vv
- venule: smallest diameter, receive blood from caps, 1. postcap, 2. muscular venules
- small vv: receive blood from musc venule
- med vv: all three layers present
- large vv: all three layers present
do vv in limbs have valves?
yes
