The document provides information on the circulatory systems of animals. It discusses open and closed circulatory systems, as well as double circulation. The human circulatory system is described in detail, including the structure and function of the heart, blood vessels, and lymphatic system. Factors that influence heart rate and common diseases of the cardiovascular system are also summarized.

1. WELCOME BACK!!
• CONGRATULATIONS ON PASSING THE EXAM!
• BUT NOW KEEP UP THE GOOD WORK…IT’S
GOING TO BE A BUSY TERM!
• NEW LEARNER GUIDE – READ AND MAKE USE
OF IT!
• MAKE NOTE OF IMPORTANT DATES!
– PRAC 1 – NEXT TUESDAY, 24TH!
– CLASS TEST 1 – NEXT WEDNESDAY, 25TH!

2. NATIONAL SCIENCE WEEK
• Organised by the Department of Science &
Technology
• Launch hosted by UJ, Soweto Campus, 28th July
• Aims to excite youth with science at a young age!
• You are invited free of charge!
• Launch day: 07:00 – 15:00
• Register after class with ID number
• The rest of the week 14:30 – 15:30

3. POSTER PROJECT
•
•
•
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GROUPS OF 5 – names on back of poster
A3 POSTER
ANY BIOLOGICAL TOPIC
INTERESTING, INFORMATIVE, PICTURES,
DIAGRAMS, COLOURFUL, FUN
• TARGET: High School Students
• DUE DATE: Next Tuesday, 24th July in class!!

4. TRANSPORT
SYSTEMS IN
ANIMALS
(Campbell and Reece (2010), Chapter
42: P.898-915)

5. CIRCULATORY SYSTEMS IN ANIMALS
 Many invertebrates do not have
a circulatory system at all.
 Their cells are close enough to
their environment for oxygen,
other gases, nutrients, and
waste products to simply diffuse
out of and into their cells.
 E.g. Hydra

6. CIRCULATORY SYSTEMS IN ANIMALS
• In animals with multiple layers of cells,
their cells are too far from the external
environment for simple osmosis and
diffusion.
• In higher animals, there are two
primary types of circulatory systems -open and closed.

7. CIRCULATORY SYSTEMS IN ANIMALS
OPEN-
CLOSED-

8. CIRCULATORY SYSTEMS IN ANIMALS
OPEN• The circulatory fluid – Hemolymph (is the
same as interstitial tissue fluid)
• The heart pumps hemolymph through
vessels into sinuses (open fluid-filled
spaces)
• Certain substances are exchanged
between the hemolymph and the cells.
• Hemolymph returns to the heart through
pores.
• The heart is a tubular structure.

9. CIRCULATORY SYSTEMS IN ANIMALS
CLOSED• Circulate blood entirely within
vessels.
• So the blood is distinct from the
interstitial fluid.
• Chemical exchange occurs between
the blood and interstitial fluid as
well as between interstitial fluid and
body cells.

10. DOUBLE CIRCULATION
• The circulatory systems with two
distinct circuits.
• The pumps of the two circuits serve
different tissues but are combined
into a single organ, the heart.
• The two circuits are called:
1. Pulmonary circuit
2. Systemic circuit

11. DOUBLE CIRCULATION
1. Pulmonary circuit
The heart pumps deoxygenated blood
to the lungs and oxygenated blood
back to the heart.
2. Systemic circuit
The heart pumps oxygenated blood to
the body cells and the deoxygenated
blood back to the heart.

12. DOUBLE CIRCULATION

13. DIFFERENT BLOOD VESSELS:
ARTERIES, VEINS AND CAPILLARIES

14. FUNCTIONS OF CAPILLARIES
Capillaries: Connect arteries and
veins – are structurally suited to
facilitate the exchange of
substances between the blood in the
capillaries and the interstitial tissue
fluid

15. FUNCTIONS OF ARTERIES
Arteries: transport oxygenated blood except
for the pulmonary artery. Main artery is called
the Aorta – pumping oxygenated blood from
heart to rest of body.
Other arteries:
Renal artery (kidney)
Hepatic artery (liver)

16. FUNCTIONS OF VEINS
Veins : transports deoxygenated blood except
for the pulmonary vein. Main vein is called the
vena cava – pumping deoxygenated blood
towards the heart from the rest of the body.
Other veins:
Renal vein (kidney)
Hepatic vein (liver)

17. THE HUMAN CIRCULATORY SYSTEM:
HEART AND ASSOCIATED VESSELS

18. THE HUMAN CIRCULATORY SYSTEM:
HEART AND ASSOCIATED VESSELS
 Mammals have a four-chambered heart with two
atria and two ventricles
 The left side of the heart pumps and receives only
oxygen-rich blood, while the right side receives
and pumps only oxygen-poor blood
 The mammalian cardiovascular system meets the
body’s continuous demand for O2.
 Blood begins its flow when deoxygenated blood
flow from the body into the right atrium.

19.  Blood then flows from the right atrium into the
right ventricle through the tricuspid valve
 The blood is then pumped into lungs, through the
semilunar valve via the pulmonary artery.
 In the lungs, the blood loads O2 and unloads CO2.
 Oxygen-rich blood from the lungs enters the heart
via the pulmonary vein at the left atrium
 Blood then flows into the left ventricle through the
bicuspid valve.
 This blood is then pumped through semilunar
valve into the aorta with takes blood to the entire
body.

20.  Deoxygenated blood returns to the heart through
the superior vena cava (blood from head, neck, and
forelimbs) and inferior vena cava (blood from
trunk and hind limbs)
 The superior vena cava and inferior vena cava flow
into the right atrium.
 The atrioventricular (AV) valves (tricuspid and
bicuspid valves) separate each atrium and ventricle
 The semilunar valves control blood flow to the
aorta and the pulmonary artery.

21. THE EXTERNAL STRUCTURE:HUMAN
HEART

22. THE INTERNAL STRUCTURE:HUMAN HEART

23. BLOOD FLOW THROUGH THE HEART
RED: OXYGENATED BLOOD BLUE: DEOXYGENATED BLOOD

24. CARDIAC CYCLE
 The heart contracts and relaxes in a
rhythmic cycle called the cardiac cycle
 The contraction, or pumping, phase is
called systole
 The relaxation, or filling, phase is called
diastole
 The heart rate, also called the pulse, is
the number of beats per minute

25. CARDIAC CYCLE
ARTRIAL SYSTOLE
ARTRIAL DIASTOLE
VENTRICULAR
DIASTOLE
VENTRICULAR
SYSTOLE
RED: OXYGENATED BLOOD BLUE: DEOXYGENATED BLOOD

26. CARDIAC CYCLE: CARDIOGRAM
RED: OXYGENATED BLOOD BLUE: DEOXYGENATED BLOOD

27. MAINTAINING THE HEART’S RHYTHMIC
BEAT
 Some cardiac muscle cells are self-excitable,
meaning they contract without any signal from
the nervous system
 The sinoatrial (SA) node, or pacemaker, sets the
rate and timing at which cardiac muscle cells
contract
 Impulses from the SA node travel to the
atrioventricular (AV) node
 At the AV node, the impulses are delayed and
then travel to the Purkinje fibers that make the
ventricles contract

28. MAINTAINING THE HEART’S RHYTHMIC
BEAT
Fig. 42-9-5
1 Pacemaker
generates wave of
signals to contract.
SA node
(pacemaker)
ECG
2 Signals are
delayed at
AV node.
AV
node
3 Signals pass
to heart apex.
Bundle
branches
Heart
apex
4 Signals spread
throughout
ventricles.
Purkinje
fibers

29. WHAT WILL INFLUENCE THE HEART’S
RHYTHMIC BEAT?

30. LYMPHATIC SYSTEM
 The lymphatic system returns fluid that leaks
out in the capillary beds
 This system aids in body defence
 Fluid, called lymph, re-enters the circulation
directly at the venous end of the capillary bed
and indirectly through the lymphatic system
 The lymphatic system drains into veins in the
neck.
 Lymph nodes are organs that filter lymph and
play an important role in the body’s defence
 Edema is swelling caused by disruptions in the
flow of lymph.

31. LYMPHATIC SYSTEM

32. LYMPHATIC SYSTEM VS. CIRCULATORY -

33. DISEASES OF THE HEART AND
CIRCULATORY SYSTEM
 Cardiovascular diseases are disorders of the
heart and the blood vessels
 They account for more than half the deaths in
the South Africa
 One type of cardiovascular disease,
atherosclerosis, is caused by the build-up of
plaque (fat) deposits within arteries.

34.  A heart attack is the death of cardiac muscle
tissue resulting from blockage of one or more
coronary arteries
 A stroke is the death of nervous tissue in the
brain, usually resulting from rupture or blockage
of arteries in the head.
 Hypertension, or high blood pressure, promotes
atherosclerosis and increases the risk of heart
attack and stroke.
 Hypertension can be reduced by dietary
changes, exercise, and/or medication