3. •
a single-celled protist living in water has a sufficient
surface area of plasma membrane to service its entire
volume
•
the gastrovascular cavity of hydra opens to the
exterior, both outer and inner layers of cells are
bathed in water
4. •
in cnidarians like Aurelia, the products of digestion in
the gastrovascular cavity are directly available to the
cells of the inner layer
•
only a short distance to diffuse to the cells of the
outer layer
5. •
flat body = way to maximize exposure to the
surrounding medium
6. – most organisms
have extensively
folded or
branched internal
surfaces specialized
for exchange with
the environment
– the circulatory
system shuttles
material among
all the exchange
surfaces within the
animal
9. Two Types of Circulatory System
•
Two types of circulatory systems
•
Closed – heart pumps blood in a network of
blood vessels and capillaries
•
Open – heart pumps haemolymph into
tissue spaces
10. Two Types of Circulatory System
insects, other arthropods, earthworms, squids,
most mollusks octopuses, vertebrates
11. Plan and Parts of Vertebrate Circulatory System
• often called the cardiovascular system
• the heart consists of one atrium or two atria, and
one or two ventricles
• arteries, arterioles, veins, venules, and capillaries
• blood
12. Plan and Parts of Vertebrate Circulatory System
•
The Vertebrate Circulatory System
•
Closed type
•
Heart :
•
Atrium – receive blood from circulation
•
Ventricle – pumps blood to blood vessels
13. Plan and Parts of Vertebrate Circulatory System
•
The Vertebrate Circulatory System
•
Blood vessels :
•
Artery – brings blood AWAY from the heart
•
Arteriole – leads to capillaries
•
Capillary – where gas exchange takes place
•
Venule – leads to vein
•
Vein – brings blood TO the heart
18. •
Reptiles also have double
circulation with
pulmonary (lung) and
systemic circuits
•
reptilian heart is three-
chambered (except for
crocodiles)
•
ventricle is partially
divided
25. •
cardiac output (5.25 L/min) depends on two
factors:
–
the rate of contraction or heart rate (number
of beats per second)
–
stroke volume (75 mL), the amount of blood
pumped by the left ventricle in each
contraction
26. •
the heart sounds we can hear with a stethoscope
are caused by the closing of the valves
–
sound pattern is “lub-dup, lub-dup, lub-dup”
–
“lub” is created by the recoil of blood against
the closed AV valves
–
“dup” is the recoil of blood against the
semilunar valves
27. •
the impulses generated during the heart cycle
produce electrical currents that are conducted
through body fluids to the skin
•
the currents can be detected by electrodes and
recorded as an electrocardiogram (ECG or
EKG).
30. –
two sets of nerves (sympathetic and
parasympathetic) affect heart rate with one
set speeding up the pacemaker and the other
set slowing it down
–
the pacemaker is also influenced by
hormones
–
rate of impulse generation by the pacemaker
increases in response to increases in body
temperature and with exercise
34. Measurement of blood pressure
Makes use of a sphygmomanometer and the brachial artery
•
Systolic pressure - peak pressure in the arteries, which occurs near the end
•
of the cardiac cycle when the ventricles are contracting
Dyastolic pressure - minimum pressure in the arteries, which occurs near the
•
beginning of the cardiac cycle when the ventricles are filled with blood
35. Changes in blood pressure
Varies within the day due to circadian rhythm
•
Also change due to stress, nutrition, exercise,
•
drugs, disease, and simply standing up
Hypertension – when arterial pressure is abnormally
•
high
Hypotension – when arterial pressure is abnormally low
•
40. •
Hemophilia – inability to clot blood
– a sex-linked trait
•
Hemophilia A – clotting factor VIII deficiency
•
Hemophilia B – clotting factor IX deficiency
