Transcript Cardiovascular System - AP Biology

Cardiovascular
System
The Heart
The Heartbeat
Diastole
Systole
Componants
Chambers
Left and Right
Valves
Left and Right
Atria
Atrioventricular
Ventricles
Valves
Blood Vessels
Arteries
Veins
Aorta
Venules
Arterioles
Capillaries
The Blood
White
Red
Blood Cells
Blood Cells
Platelets
Plasma
Semilunar
Valves
The Heart
It’s a muscle.
The chambers of the heart are divided
by layers of tissue called the septum.
Arterial Septum: divides left and right
Atria
Ventricular Septum: divides left and
right ventricles
Fast Facts:
1. Heart is the size
of your fist.
2. Located just
about in the center
of your chest
3. Has four
chambers and four
valves
4. Men usually have
larger hearts than
women do
Four Chambers
The Atria- walls of the atria tend to be thinner than those of the
ventricles; they serve mainly as a holding area of blood
Right Atrium: receives deoxygenated blood from the body
Left Atrium: receives oxygenated blood from the lungs
The Ventricles- walls are thicker and more muscular; they pump
the blood to the lungs and different parts of the body
Right Ventricle: receives deoxygenated blood
from the right atrium and pumps it to the
lungs
Left Ventricle: the strongest chamber of the
heart; receives oxygenated blood from left
atrium and pumps blood to most of the body
Four Valves
Primary role of the valves is to prevent backflow of blood
The valves can be divided into two types:
1.Atrioventricular: Includes the Tricuspid Valve and Mitral Valve;
these valves allow blood to pass from the atria to the ventricles
2.Semilunar: located at the exits of the heart; blood pushed
through them from inside the heart out of the heart; includes;
Pulmonary Valve,
and the Aortic Valve
Did you know?
When you use a steth0scope to listen
for someone’s heart beat, the beating you
hear is actually the sound of the valves
opening and closing.
Blood Vessels
Artery
Arteriole
Capillaries Venule
Heart
Vein
Veins
Heart
Deoxygenated blood travels through a series
Vena Cava
of veins (that increase in diameter) toward the
heart
Veins
When the oxygen in the blood is exchanged in
the capillaries, the deoxygenated blood pours
Venules
into the smallest type of veins; venules.
The blood in the venules then moves into
veins.
Capillaries The veins that pour blood directly into the heart
are called the vena cava.
Superior Vena Cava: blood comes from the
head, neck and arms (i.e. the upper body)
Inferior Vena Cava: blood from the rest of the
body (i.e. the lower body)
Arteries
The arteries carry oxygenated blood away from the heart
The largest artery is the Aorta: all blood pumped to the body
passes first through the aorta.
After the aorta, the blood is sent
through smaller and smaller arteries,
then atrioles, until it reaches the
capillaries at the extremities of its
path.
Capillaries
Capillaries have very very thin walls- this allow the
exchange of materials through them (by exocytosis and
diffusion)
Diffusion down a gradient is responsible for the exchange of
oxygen and carbon dioxide.
Near the point where arterioles meet capillaries, fluid leaves
the vessels. It re-enters near where venules meet
capillaries.
Did you know?
At any given time, the body only uses about 5%-10% of the
capillaries it possesses. However, there are so many that this
is enough to supply all tissue with the necessary blood.
The Heartbeat
A basic explanation of the heartbeat breaks it up into two
phases:
Diastole: the “relaxation phase”; the longer phase. During this
phase, the atrioventricular valves are open allowing blood to
enter the atria and pour into the ventricles of the heart
Systole: the “contraction phase.” During this part of the
heartbeat, the semilunar valves are open as the ventricles
pump blood out of
the heart.
Cardiac Cycle: the completion
of a diastole and systole phase
Cardiac Output: the blood
volume/min. pumped
The Blood
Red Blood Cells (erythrocytes): carry oxygen, they’re the
most numerous type of blood cell; they contain hemoglobin
molecules, which contain iron
White Blood Cells (leukocytes): fight infections; digest
bacteria and take care of remnants of dead blood cells;
responsible for the build up of immunities; spend most of
their time outside of the circulatory system
Platelets: smallest type of blood cell- they’re actually just
fragments of cytoplasm from the bone marrow; they form
clots
Plasma: a liquid matrix that erythrocytes, leukocytes, and
platelets are suspended in
Blood Flow
The average person has between 4.5 and 5 Liters of blood.
This is around 10 pints.
The heart cycles through all of the blood in the average
person’s body every one minute or so.
Blood in the aorta travels 1000x as fast as blood in the
capillaries.
A review of the chambers, valves, and vessels.
(Wouldn’t this make a GREAT essay question?
http://www.nhlbi.nih.gov/health/dci/Diseases/hhw/hhw_pumping.htm
Blood Pressure
Hydrostatic force: the pressure that fluid in the blood
vessels exerts on the walls of the vessels
Blood Pressure is…
-stronger in arteries than in veins
-strongest during the systole part of a heartbeat (when blood
is pushed out of the heart)
Did you know?
When taking your pulse, you are actually feeling an
momentary increase in blood pressure causing the artery to
expand.
The Lymphatic System
As mentioned earlier, fluid escapes through the
capillaries as it travels through the vasculature of the
body.
The amount of fluid lost daily would total up to 4L were it
not for the Lymphatic system.
Lymph: name for the lost fluid
Lymphatic capillaries return the necessary fluid and
proteins to the blood stream.
White blood cells spend most of their time in the lymph
nodes. When infected, the cells multiply.