This is about human heart and its function suitable to teach school biology

1. HUMA N
CI RCULA T O RY

2. •Is a muscle about the size of your
fist
•Weighs approximately one pound
•Is located behind and slightly to the
left of the breastbone
•Pumps about 4.7 liters of blood
every minute

3. Heart
size - about 14 cm
long by 9 cm wide
Cardiovascular system

4. 1)
pericardium = double-
layer serous membrane
2) endocardium
- squamous
epithelial inner
lining of the heart
coverings

5. c. chambers
1) atria - receive blood
from the vessels
a) pectinate muscles
- ridges of muscle in anterior
wall

6. 2) auricles - small
expandable attachments to
the atria
a) pectinate
muscles (Latin pecten =
comb)

7. 4) ventricles - pump blood to body by contraction of
myocardium.
a) walls are thicker than
atria, left side thickest
ventricles - pump blood
to body by contraction of
myocardium.
a) walls are
thicker than atria, left
side thickest

8. interventricular septum - parallels a
groove in the outer surface of the
heart (the interventricular sulcus).
valves - allow only one direction of flow
1) atrioventricular (AV)
valves
a) tricuspid - 3 folded
valve between right A and V
b) biscuspid - mitral
valve - 2 folded on left side
c) made of dense
connective tissue

9. Semilunar valves -
between ventricle and the first major artery.
a) Right ventricle and
pulmonary trunk - pulmonary
b) Left ventricle and aorta -
aortic valve
chordae tendineae = attach
cusps to papillary muscles.
c) 3 half-moon shaped
cusps

10. a) Thinner walls and smaller
lumen.
3) Capillaries
a) Single layer of epithelium
only
b) lumen diameter .01 mm
2. Blood Vessels
a. Structure
1) Arteries and
veins
2 1) s
. Blood Vessels
a. Structure
2. Blood Vessels
1) Arteries and veins
c) form vast branching
networks
a) Arteries have thicker
smooth muscle layer while veins have larger
lumen and also have valves.
2) Arteriloe and
venules

13. a. Cardiac cycle - the
contraction of both atria and then both
ventricles.
Cardiac cycle - the
contraction of both atria and then both
ventricles. 1) systole = state of
contraction (blood forced out)
2) diastole = state of
relaxation (blood drawn in)
3) both ventricles at the relax
or contract at the same time
4) likewise atria are
simultaneous

14. Heart
sounds - results from valves
shutting
lub = AV valves
dup = Semilunar valves