Download Figure 42.5 The mammalian heart: a closer look

Internal transport in the Cnidarian
Aurelia
Open and Closed Circulatory Systems
The Mammalian Heart: A Closer Look
The Heart
Cardiac muscle
Atria have thin walls
Ventricles have thick and
powerful walls
Systole = ventricular contraction
blood is pumped
Diastole = ventricular filling
•Lub dub = heart sounds opening and
closing of the valves
–Lub = contraction of ventricles (AV
closing)
–Dub = blood recoiling against SL
valves
•Heart murmur = valve defect
Generalized Circulatory Schemes
of Vertebrates
The Mammalian Cardiovascular System: An
Overview
The Cardiac Cycle
The Control of Heart Rhythm
The Structure of Blood Vessels
Blood Pressure
The force that blood exerts against
vessel walls
BP is greater in arteries than veins
Pulse is measure of BP
Exact BP is measured as
systolic/diastolic pressures
Constricted blood vessels have
higher BP than dilated vessels
In veins heart has little effect on BP
Measurement of Blood Pressure
The Interrelationship of Blood Flow Velocity,
Cross-Sectional Area of Blood Vessels, and
Blood Pressure
Blood Flow in Capillary Beds
The thoroughfare
channels remain
open whether or
not the sphincter
muscles are
contracted or
relaxed
The Movement of Fluid Between
Capillaries and the Interstitial Fluid
fluid moves out of capillary
fluid moves into capillary
Dissociation Curve – shows how much
oxygen is bound to hemoglobin when
it is exposed to solutions
varying in their partial pressure of
dissolved oxygen, pH, and other
substances; oxyhemoglobin
dissociates into oxygen and hemoglobin
(Oxyhemoglobin is formed from one
molecule of hemoglobin bound to four
molecules of oxygen)
pH decreases during activity
because the CO2 reacts with
water forming carbonic acid
Hemoglobin picks up oxygen
when the partial pressure is
high and releases oxygen
when the partial pressure is
low.
Hemoglobin can release its oxygen
to metabolically very active tissues,
such as muscle tissue during
exercise.
Partial Pressure – a measurement of the
concentration of one gas in a mixture of
gases; the pressure exerted by a
particular gas in a mixture of gases
(abbreviated Po.)
In the lungs, hemoglobin is about 98%
saturated with O2 (high Po) whereas in
the tissues it is only about 70%
saturated (low Po)
Lymphatic System
Lymphatic system returns
lost fluid to circulatory
system (about 4L per day)
Lymph nodes filter the lymph
Help fight infection
Differentiation of Blood Cells
Atherosclerosis: Normal Artery and
Artery With Plaque
Blood Clot