Transcript Blood Vessels

Chapter 15:
Circulation
The Cardiovascular System
• Consists of the heart, blood, and
blood vessels.
• Carries needed substances to cells
and carries waste products from
cells.
• Contains cells that fight disease
(white blood cells or WBCs).
Delivering Needed Materials
• Blood carries oxygen from your lungs to
your body cells.
• Blood transports glucose to your cells so
they can make energy.
Removing Waste Products
• Blood takes carbon dioxide wastes
from cells to lungs.
The Heart
• The heart is a hollow muscular organ
that pumps blood throughout the
body.
• Each time the heart beats it pumps
blood through your cardiovascular
system.
Heart Structure
• The right side of the heart is completely
separated from the left side by the
septum.
• Atria- upper chambers of the heart
• Ventricles- lower chambers of the heart
• Pacemaker- group of heart cells that send
out signals to make the heart beat.
• Valve- flap of tissue that prevents blood
from flowing backward.
Blood Vessels
• Your body has 3 types of blood
vessels: arteries, veins, and
capillaries.
• Arteries- carry blood away from
heart.
• Veins- carry blood towards heart.
• Capillaries- tiny vessels where
substances are exchanged.
Two Loops
• 1st loop- Blood travels from heart to
lungs then back to heart (pulmonary
circulation).
• 2nd loop- Blood travels from heart to
body and back to heart (systemic
circulation).
• Right side of heart pumps to lungs.
• Left side of heart pumps to body.
- Food and Energy
Loop One- Pulmonary
• One drop
of blood
takes only
one minute
to make the
entire trip
around the
body!
Loop Two- Systemic
Arteries
• When blood leaves the heart it travels
through arteries.
• Coronary arteries- branch off aorta
and carry blood to heart.
• Artery walls are very thick! They have
to withstand high pressure from the
heart’s pumping.
Pulse
• Caused by alternating expansion and
relaxation of artery walls.
• Artery pulses = heartbeats
• Layer of muscle in arteries acts as a
gate. They can get wider or more
narrow depending on body’s blood
supply needs.
Capillaries
• Where materials are exchanged
between blood and body’s cells.
• Diffusion- when particles move from
high to low concentration.
Veins
• Carry oxygen-poor blood back to
heart.
• Have thick walls, but not as thick as
arteries. Have less pressure from
heart’s pumping.
• Veins need help!
- Skeletal muscles help move blood
- Valves- prevent backflow of blood
- A Closer Look at Blood Vessels
Blood Vessels
• The walls of arteries and veins have three
layers. The walls of capillaries are only one cell
thick.
- A Closer Look at Blood Vessels
Artery and Vein
• In this photo, you can
compare the wall of an
artery with the wall of a
vein.
Blood Pressure
• Blood exerts a force called blood
pressure (BP) against the walls of
blood vessels.
• Caused by the force of the ventricles
contracting.
• As blood moves away from heart,
blood pressure decreases.
• Arteries have higher BP than veins.
Measuring Blood Pressure
• Sphygmomanometer- measures BP,
expressed in millimeters of Mercury
• Cuff is wrapped around upper arm until
blood flow stops.
• Pressure is released and 2 numbers
are recorded:
120
80
Systolic (when ventricles contract)
Diastolic (when ventricles relax)
Blood and Lymph
• Blood- has 4 parts: plasma, red blood cells
(RBCs), white blood cells (WBCs), and
platelets.
• Plasma- liquid part of blood.
- Water makes up 90% of plasma.
- Carries nutrients
- Carries chemical messages
- Removes wastes
- Looks yellow because of proteins
Red Blood Cells (RBCs)
• RBCs take oxygen in lungs to body.
• Thin in center so they can bend easily.
• Made mostly of Hemoglobin, which contains
iron.
• Hemoglobin + oxygen makes cells bright red.
• No nuclei = cannot reproduce or repair
themselves.
• Life span = 120 days. Made in bone marrow.
White Blood Cells (WBCs)
• Body’s disease fighters.
• Fewer WBCs in blood than RBCs.
• 1 WBC for every 500 to 1,000 RBCs.
• Larger than RBCs.
• Have nuclei, Life span = months to years
Platelets
• Help blood clot.
• Fragments of blood cells.
• Platelets rush to wound and release
chemicals that cause chain reaction.
• Fibrin- a protein that forms a net across
wound; gives platelets a place to stick.
• Scab- dried blood clot on the skin’s surface.
- Blood and Lymph
Blood
• Blood consists of liquid plasma and three kinds of
cells—red blood cells, white blood cells, and
platelets.
Blood Types
• First blood transfusion- performed by
Karl Landsteiner in early 1900s.
• Four types of blood:
- A, B, AB, O
• Blood types are determined by marker
proteins on red blood cells.
• Plasma has clumping proteins
(antibodies) that cause foreign markers
to clump together.
- Blood and Lymph
Blood Types
• The marker molecules on your red blood cells determine
your blood type and the type of blood that you can
safely receive in transfusions.
• Type 0- Universal Donor; Type AB- Universal Recipient
Rh Factor
• A marker on RBCs.
• 85 % of people have Rh marker (Rh +)
• 15 % of people lack Rh marker (Rh -)
• If you are Rh - and receive Rh + blood, it
will clump and could kill you.
Cardiovascular Health
• Atherosclerosis- condition in which artery
walls thicken as a result of fatty material
build-up.
• Heart attack- occurs when blood flow to one
part of the heart is blocked.
• Hypertension- high blood pressure (140/90
mmHg or higher).
- Makes the heart work harder.
- Limit salt intake
Cardiovascular Health
• Exercise!
• Avoid fatty
foods!
• Don’t smoke!
• Limit salt
intake!
- Blood and Lymph
The Lymphatic System
• The lymphatic system is a
network of veinlike vessels
that returns the fluid to the
bloodstream.
Lymphatic System
• A network of vein-like vessels that return
fluid that leaks out of blood vessels back
to the bloodstream.
• Lymph- fluid in the lymphatic system
• Has no pump- lymph moves slowly
• Nodes- small knobs of tissue that filter
lymph and trap bacteria. Enlarge when
you are sick.