Circulatory System Power Point
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Transcript Circulatory System Power Point
Human Circulation
The Need for Circulation
All living things must
be able to supply
their cells with
materials from the
surrounding
environment (Ex.
Oxygen, nutrients,
enzymes ,etc.)
Special Circulatory
Systems
In this case materials are
absorbed across the cell
membrane by diffusion.
For larger organisms,where
some cells may be located
far away from the outside,
a special circulatory system
is required.
These systems may be
open or closed.
Closed and Open Systems
A closed system, is one in which the blood is
always confined in vessels (Ex. Earthworm).
An open system, is one in which the blood is not
always enclosed in vessels, but flows into open
spaces where it bathes the tissues of the body
directly(Ex. Grasshopper).
Assignment: Write a detailed summary of open
and closed circulation in the earthworm and
grasshopper (pages 146-147). Also complete the
coloring sheet-Correlative Circulatory Patterns.
Components Involved
Three components:
1. A fluid to transport
dissolved materials (Blood)
See handout-Components
and Function.
2. A network of tubes (or
body spaces) to carry fluid
(Blood vessels).
A means of pumping the fluid
(Heart).
Blood
Blood is a special type
of connective tissue.
Two components;
Formed Elements
(the blood cells) and
Plasma (fluid).
Blood-Erythrocytes-Red
Blood Cells
Make up 44% of
blood.
Biconcave
no nucleus
contain the respiratory
pigment hemoglobin
(carries oxygen)
life span of 100-120
days
Blood-Erythrocytes-Red
Blood Cells continued
Lost cells are replaced by new
cells produced in the red bone
marrow.
The rate of RBC production is
called hemopoiesis, and is
controlled by the hormone
erythropoietin (released by
the kidneys in response to
decreasing oxygen levels in
the blood).
Blood- White Blood Cells
More like body cells.
Make up 1% of blood.
Have nuclei.
Produced by lymphatic
tissue.
Serve as a “movable
army”-protect the body
from bacteria, viruses
and tumor cells.
Blood - Platelets
Believed to be
fragments of other
blood cells formed in
red bone marrow.
Small, irregular
shapes.
Needed for clotting.
Blood Clots
A whole series of
reactions called the
blood clotting
cascade creates the
clot.
Reduces blood loss.
Clotting process
involves a number of
substances.called the
clotting factors.
Plasma
Liquid portion
Make up 55% of
blood.
Contains water, salts,
proteins, nutrients,
waste products and
hormones.
The Blood Vessels
There are three main types of blood
vessels:
1. Arteries
2. Veins
3. Capillaries
Arteries
Carry blood away
from the heart.
Thick muscular walls.
No valves.
Form arterioles that
join with capillaries in
the capillary network.
Blood pressure higher
than in veins.
Artery Structure
Connective tissue
Smooth muscle
Elastic fibers
Endothelium
Veins
Veins are the vessels that
carry the blood to the heart.
Thin muscular walls.
Valves to prevent back flow.
Venules that join capillaries
in the capillary network.
Blood pressure tends to be
lower than in arteries.
Veins Structure
Connective Tissue
Smooth muscle
Elastic Fibers
Valve
Endothelium
Capillaries
Capillaries connect
arterioles and venules.
The wall of a capillary is
made up of a single layer
of endothelial cells.
Thin walls allow for
nutrients and gases to
diffuse quickly between
the blood and body cells.
Single layer
of endothelium.
Blood Flow in the Heart
Deoxygenated blood from the
body enters the right atrium
and is pumped to the lungs by
the right ventricle.
Oxygenated blood returns to
the left ventricle under high
pressure and is pumped to the
body tissues.
Note the thicker walls in the left
ventricle that serve to handle
the higher pressure.
Blood Flow in the Heart
This animation shows
the flow of blood in
the heart.
The Heart Beat Cycle
(HBC)
The HBC refers to the periods of
contraction and relaxation of the
atria and ventricles in the heart.
Relaxation is known as diastole
and contraction is called systole.
The accompanying blood pressure
changes are called diastolic and
systolic.
See the handout called The
Heart Beat Cycle.
Pulmonary Circulation
Alveoli
Capillary
Network
Gas Exchange
Blood travels through
pulmonary arteries to the
lungs.
Gas exchange occurs at
the capillary level in the
alveoli.
Veins pick up the
oxygenated blood and
bring it back to the left
atrium via the pulmonary
vein.