1. What is the Circulatory System?

2. Circulatory system describes both the cardiovascular system and the lymphatic system
Both systems work closely together to move fluids around your body and protect it from disease
The two systems help maintain homeostasis
Both systems are made up of vessels
Both systems are part of the body’s defense against bacteria, viruses and other pathogens

3. Your heart, blood and blood vessels make up your cardiovascular system
Blood is the fluid that carries gases, nutrients and wastes through the body
It is a closed circulatory system – the blood is carried in vessels that form a loop
The lymphatic system is a group of organs and tissues that collect the fluids that leak from blood and returns it to the blood
The leaked fluid is called lymph
It is an open circulatory system – lymph can move in and out of the vessels

4. How Do The Systems Work Together?

5. Every time your heart pumps, a little fluid is forced out of the thin walls of the tiniest blood vessels called capillaries
Most of the fluid is reabsorbed by the capillaries
The rest of the fluid is collected by lymph capillaries
Lymph capillaries absorb fluid, dead cells and pathogens from around body cells
The fluid, called lymph is returned to the cardiovascular system when it drains into blood vessels at the base of the neck
The lymphatic system is where white blood cells mature - where they attack invading pathogens

6. Parts of the Lymphatic System

7. Lymph nodes are small, bean – shaped organs that remove pathogens and dead cells from lymph
Lymph nodes are concentrated in the armpits, neck and groin
Infection – fighting cells, called white blood cells, are found in lymph nodes
When pathogens cause an infection, the number of white blood cells can increase greatly
the increased number causes the lymph nodes to become swollen and painful

8. Lymph vessels are the thin walled vessels of the lymphatic system
They carry lymph back to lymph nodes
From the lymph nodes, the fluid is returned to the cardiovascular system
Vessels have valves inside them to stop lymph from flowing backwards
Bone marrow is part of the lymphatic system – the soft tissue inside the bone produces blood cells
Tonsils – small lymphatic organs at the back of the throat and tongue
Help defend the body against infection

9. White blood cells in the tonsil tissue trap pathogens
An infection of the tonsils is called tonsillitis – they become swollen and are painful
Spleen – the largest lymphatic organ – it stores white blood cells and allows them to mature
As blood flows through the spleen, white blood cells attack pathogens in the blood

10. Disorders of the Lymphatic System

11. Lymphoma is a type of cancer that often begins in a lymph node
The swelling it can cause in the node is called a tumor
Lymphedema is a swelling of body tissues caused by a blockage or injury to lymph vessels
Lymph vessels are unable to drain lymph from a certain area and the area becomes swollen
Bubonic plague is a bacterial infection of the lymphatic system
The bacteria can enter the body through the bite of an infected flea

12. Parts of the Cardiovascular System

13. The cardiovascular system is the organ system that carries nutrients, gases and hormones to body cells and waste products from the body cells
Heart – the pump that sends blood around the body
when heart muscle contracts, it squeezes the blood inside the heart
The squeezing creates a pressure that pushes blood through the body
Your heart has a left side and a right side – the two sides are separated by a thick wall

14. Heart Anatomy

15. The right side of the heart pumps oxygen – poor blood to the lungs
The left side pumps oxygen – rich blood to the body
Each side has an upper chamber and a lower chamber
The upper chamber is called an atrium
The lower chamber is called a ventricle
Blood enters the atria and is pumped down to the ventricles
Flap – like structures called valves are located between the atria and the ventricles and where large vessels are attached to the heart – valves prevent blood from flowing backward

16. Blood

17. Blood is a type of connective tissue that is part of the cardiovascular system
It serves as a transport system, providing supplies for cells, carrying chemical messages and removing wastes so cells can maintain homeostasis
Blood contains cells, fluid and other substances
It travels through miles and miles of blood vessels

18. Blood Vessels

19. Blood travels throughout your body in tubes called blood vessels
The three types of blood vessels are arteries, capillaries and veins
Arteries – blood vessels that carry blood away from the heart
Each heartbeat pumps blood into your arteries at high pressure, which is your blood pressure
Capillary – a tiny blood vessel that allows the exchange of carbon dioxide and wastes between body cells and the blood – capillary walls are one cell thick
Vein – a blood vessel that carries blood back to the heart – not under as much pressure as arteries

20. What is Blood Made Of?

21. Plasma – the fluid part of the blood - a mixture of water, minerals, nutrients, sugars, proteins and other substances
Platelets – tiny pieces of larger cells found in bone marrow
When you cut yourself you bleed because blood vessels are cut open – as soon as bleeding starts, platelets begin to clump together to form a plug – reduces blood loss – release a chemical to form tiny fibers
White blood cells – fight pathogens such as bacteria and viruses – when they find one they destroy it

22. Other white blood cells form antibodies
Antibodies are chemicals that identify pathogens
White blood cells destroy dead or damaged body cells
Red blood cells – disk – shaped cells that do not have a nucleus
They bring oxygen to every cell in your body
Each red blood cell has hemoglobin – an oxygen – carrying protein
The disk shape of the red blood cell helps them squeeze into capillaries

23. How Does Blood Move Through the Body?

24. Blood is pumped from the right side of the heart to the lungs
From the lungs it moves into the left side of the heart
From the left side of the heart the blood is pumped to the body
Blood in the arteries that come out of the heart is under great pressure from the pumping action of the heart
Veins carry larger volumes of blood more slowly – less pressure
Blood moves in two loops or circuits –pulmonary circulation (blood flow between heart and lungs) and systemic circulation (blood flow between heart and the rest of the body)

25. How Does Circulation Help maintain Body Temperature?

26. When the brain senses that that body temperature is rising, it signals blood vessels in the skin to widen
As the blood vessels get wider, heat from the blood is transferred to the air around the skin
The transfer helps lower body temperature
When the brain senses the body temperature is getting too low, it signals the blood vessels near the skin to get narrower
This allows blood to stay close to internal organs to keep them warm

27. Problems that Affect the Cardiovascular System

28. Atherosclerosis – hardening of the artery walls caused by the build up of cholesterol and other lipids
Build up causes the blood vessels to become narrower and less elastic
Hypertension – abnormally high blood pressure – may be caused by atherosclerosis
Heart attack – happens when an artery that supplies blood to the heart becomes blocked and the heart muscle tissue does not get oxygen
Stroke – a blood vessel in the brain becomes blocked or bursts – as a result, that part of the brain receives no oxygen