The circulatory system delivers oxygen, nutrients, and energy to cells throughout the body and removes wastes. Blood is pumped from the heart through arteries, capillaries, and veins in two circuits - pulmonary circulation to the lungs and systemic circulation to the body. The heart has four chambers and valves that ensure blood flows in one direction. Blood vessels include arteries, veins, and capillaries. Blood pressure, heartbeat, and blood components like red blood cells, white blood cells, platelets, and plasma are also discussed.

1. Circulation
Unit 11 – Body Systems

2. Circulation
 Blood travels to
every cell in the
body
– Delivers O2,
nutrients, energy
– Removes wastes
j
Capillaries
of head and
arms
Pulmonary
arteryAorta
Superior
vena cava
Inferior
vena cava
Pulmonary
veinCapillaries
of right lung
Capillaries of
left lung
Capillaries of
lower body

3. Circulation in Humans
j
Capillaries
of head and
arms
Pulmonary
arteryAorta
Superior
vena cava
Inferior
vena cava
Pulmonary
veinCapillaries
of right lung
Capillaries of
left lung
Capillaries of
lower body
 4 chambered heart
 Double –loop
 Pulmonary
Circulation: blood is
pumped from the
right side of the
heart to the lungs
 Systemic
Circulation: blood is
pumped to the body

4. Human Heart
 Hollow muscular organ
 Surrounded by a protective sac called
pericardium
 Myocardium - muscle in the heart walls
 A septum divides the heart in half
 Each side has 2 chambers
– Atrium (upper) receives blood
– Ventricles (lower) pump blood OUT of the heart
 Valves keep blood flowing in the right
direction

5. Human Heart
Mitral (Bicuspid) Valve
• Prevents backflow from the
left ventricle into the atrium
Septum
Right Ventricle
Tricuspid Valve
• Prevents backflow between
the right atrium and ventricle
Right Atrium
Pulmonary Artery
• Carries deoxygenated blood
from heart to the lungs
Pulmonary Valve
• Prevents backflow between the
right ventricle and pulmonary
artery
Pulmonary Veins
• Carries oxygenated blood from
lungs BACK to the heart
Aortic Valve
• Prevents backflow into the
left ventricle from the aorta
Left Atrium
Left Ventricle
Superior Vena Cava
• Large vein which brings
O2 poor blood from upper
body to the right atrium
Inferior Vena Cava
• Large vein which brings
O2 poor blood from upper
body to the right atrium
Aorta
• Brings oxygenated blood from
the heart to the rest of the body

6. Blood Vessels

7. Blood Vessels -Veins
 Veins have valves
 Return blood to the heart

8. Blood Vessels - Arteries
 Carry blood Away from the heart
 Blood is under the highest pressure in
the arteries
– Thick muscular walls
– Elastic
 Artery disease may lead to heart
attack or stroke

9. Blood Vessels - Capillaries
 Smallest vessels, only one cell thick
 Diffusion occurs between capillaries and all
cells
 Gas exchange

10. What is Blood Pressure?
 Pressure exerted by
blood against artery
walls
 Systolic – force
when ventricles
contract
 Diastolic – force felt
when ventricles relax
 Normal 120/80

11. What is Heartbeat?
 Controlled by the SA Node or “Pacemaker”

12. How is Heartbeat Measured?

13. Lymphatic System
 Collects fluid that leaks from the blood, and
returns it to the circulatory system
 Lymph flows through vessels
 Lymph nodes trap bacteria

14. Lymphatic System
 Two Organs
– Spleen removes old
RBCs
– Thymus - site where
T-cells mature
Superior
vena cava
Lymph
nodes
Thymus
Heart
Thoracic
duct
Spleen
Lymph
vessels

15. Components of Blood
 55% Plasma
 45% cellular
components
– Red Blood Cells
(RBC)
– White Blood Cells
(WBC)
– Platelets

16. Components of Blood
 What does each component look like?
What is the structure?
 What is the function of each component?
(plasma, RBC, WBC, platelets)
 How does structure determine function?
 Which cells are the most numerous?
 What is the scientific name for each cell
type?

17. Components of Blood
 Red Blood Cells (Erythrocytes)
– Iron containing hemoglobin binds O2
– Disc shape increases surface area
– Most numerous cell type
 White Blood Cells (Leukocytes)
– Fight infection
– Largest blood cell, least numerous
 Platelets (Thrombocytes)
– Release chemicals to clot blood
– Small cellular fragments

18. Blood Cells
Red Blood Cells White Blood Cells Platelets

19. Blood Types
 Incompatible blood types will result in
agglutination (clumping)

20. Blood Types
A, B, AB,
and O
OAnti-A &
Anti-B
NoneO
ABA, B, AB
and O
NoneABAB
B and ABO and BAnti-ABB
A and ABO and AAnti-BAA
Can Donate
To…
Can Receive
Blood
From…
Antibodies
in Plasma
Antigens on
RBC’s
Blood Type