The Circulatory

System

1. Using your first two fingers (not your thumb), try to find your pulse. There are several places you can check.

 

2. Once you have found a good pulse point, have a partner time you for 15 seconds and count the number of times you feel your pulse. ___________

 

3. Multiply that number by 4 to get the resting beats per minute _____________

 

The Circulatory System• Made up of the cardiovascular system

and the lymphatic system

The Cardiovascular System

• Made up of (organs):– heart– blood vessels (veins

and arteries)– blood

The Cardiovascular System

• Functions– Carries nutrients, gases, hormones and

waste around the body.• carbon dioxide and waste away• oxygen, nutrients, and hormones to

– Helps your body maintain a balanced temperature.

• heart – hollow muscular organ that pumps blood around the body.

• Size of your fist• Located in the center of your

chest• right side pumps oxygen

poor blood to the lungs• left side pumps oxygen

rich blood to the body.

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Structure of the Heart• The heart has two sides• Each side has an upper chamber

– Atrium• Each side has a lower chamber

– Ventricle

How the Heart Works

• The heart’s action has two phases– The heart relaxes and the atria fill with

blood– The atria contract, blood is pumped into

the ventricles, then the ventricles contract and send blood out of the heart

• Blood only travels in one direction, it cannot flow backwards

Regulation of the Heartbeat

• The heart contains pacemaker cells that tell the heart when to beat– When you are exercising, excited, scared

etc…, your heart beats faster.– When you are relaxed, calm, asleep etc…,

your heart beats slower.

• blood – the tissue that carries gases, hormones, nutrients and wastes through the body.

• Helps the body maintain homeostasis (balance)

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Oxygen rich blood from an artery

Oxygen poor blood from a vein

FACT: blood is NEVER blue!!!!

Unless you’re a horseshoe crab.

• blood vessels – the tubes that your blood travels in.– arteries– capillaries– veins

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Arteries• arteries - carry oxygen rich blood away

from the heart.– Walls are thick, strong and flexible– Contain smooth muscle that can contract

and relax

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Arteries

Capillaries

• capillaries - tiny blood vessels where material is exchanged between the blood and the body’s cells.

• Oxygen and glucose rich blood from the arteries goes into the capillaries

• From the capillaries needed materials pass into the cells and waste material is removed from the cells

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Capillaries

Veins• veins - carry oxygen poor blood back to

the heart.– Veins have 3 layers to their walls too but

the wall is much thinner– Muscle contractions, breathing and valves

help move blood through veins

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Veins

Create this chart in your notes and complete.

artery capillary

Blood moves in circuits inside blood vessels.• Oxygen poor blood enters the right

atrium.• It is then pumped to the right ventricle,

then to the lungs.• It picks up oxygen and goes back to

the left atrium• It pumps from the left atrium into the

left ventricle.• The left ventricle pumps oxygen rich

blood to the rest of the body.

Blood moves in two circuits around the body:

Maintaining body temperature

• Blood circulating through the body helps maintain homeostasis.• When we are hot, blood vessels

enlarge to allow more blood close to the surface of our skin where it can be cooled.

• When we are cold, blood vessels constrict to keep as much blood close to the chest as possible to keep us warm.

The Lymphatic System

• Made up of (organs):– lymph nodes– lymph vessels– lymph– spleen– bone marrow– Tonsils– thymus

The Lymphatic System

• Functions– Carries white blood cells.– Helps remove waste from the blood.– Helps us heal and fight disease.

• lymph – clear to white fluid found in blood that contains white blood cells.

• Lymph can move in and out of blood vessels and body tissues.

• It helps prevent infection and heals injuries.

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• lymph nodes – small, bean shaped organs that remove dead cells and pathogens.

• Found mostly in the arm pits, neck and groin.

• Stores white blood cells that help fight infection.

• bone marrow – soft tissue inside of bones where red blood cells are produced.

• tonsils – small lymphatic organs at the back of the throat.

• Tonsils help defend the body against infection.

• spleen – largest lymphatic organ. It stores white blood cells.

Working together:• These two systems work together to

form the circulatory system.• Blood stays in the blood vessels

(closed loop).• Lymph can travel in and out of lymph

vessels and into and out of blood vessels (open loop).

Working together:

Working together: