3 Major Parts of the Circulatory system Medium

3 Major Parts of the Circulatory system • Medium – blood or haemolymph - carries important “ *stuff ” through body • Heart – pumps or pushes blood through body • Blood Vessels – arteries, veins and capillaries. - routes blood travels * Stuff – includes oxygen, food, & waste

what’s in Erythrocytes Leucocytes (red blood cells) (white blood cells) plasma platelets

The Blood red blood cell platelets white blood cell plasma

Plasma It also contains useful things like; • carbon dioxide A strawcoloured liquid that carries the cells and the platelets which help blood clot. • glucose • amino acids • proteins • minerals • vitamins • hormones • waste materials like urea.

Erythrocytes

Erythrocytes a biconcave disc that is round and flat without a nucleus contain haemoglobin, a molecule specially designed to hold oxygen and carry it to cells that need it. can change shape to an amazing extent, without breaking, as it squeezes single file through the capillaries.

Platelets are bits of cell broken off larger cells. Platelets produce tiny fibrinogen fibres to form a net. This net traps other blood cells to form a blood clot.

• Leucocytes – Fight and kill germs that may enter your bloodstream

Leucocytes Granulocytes Neutrophils Eosinophils Agranulocytes Basophils Lymphocytes Monocytes

Erythrocytes Leucocytes Has biconcave disc shape No fixed shape No nucleus Has a big nucleus Transporting Oxygen gases Fight infection in various way

blood from the heart gets around the body through blood vessels There are 3 types of blood vessels a. ARTERY b. VEIN c. CAPILLARY

Arteries Wall (thick, muscular and elastic) lumen Veins Elastic fibre Capillaries Wall (thin, less muscular and less elastic) Wall (one cell thick)

The ARTERY Arteries carry blood away from the heart. Arteri membawa darah dari jantung the elastic fibres allow the artery to stretch under pressure Elastic fibre Blood pressure is high Carries blood from heart to tissues (organ) Bring oxygenated blood except pulmonary artery

The VEIN Veins carry blood towards the heart. Membawa darah kepada jantung veins have valves which act to stop the blood from going in the wrong direction. Blood pressure is very low Carries blood from tissues (organ) to the heart Bring deoxygenated blood except pulmonary vein

The CAPILLARY Capillaries link Arteries with Veins Menghubungkan arteri dan vena Enable the diffusion of gases, nutrients, hormones, waste product between blood and tissue the wall of a capillary is only one cell thick Blood content is mixed The exchange of materials between the blood and the body can only occur through capillaries.

The CAPILLARY A collection of capillaries is known as a capillary bed artery body cell vein capillaries

How does this system work? pulmonary vein pulmonary artery lungs head & arms aorta main vein Right Left liver digestive system kidneys legs Circulatory System

Our circulatory system is a double circulatory system. This means it has two parts Lungs the right side of the left side of the system deals with oxygenated blood. deoxygenated blood. Body cells Circulatory System

The Heart This is a vein. It brings blood from the body, except the lungs. These arteries. They carry blood away from the heart. 2 atria 2 ventricles Coronary arteries, the hearts own blood supply The heart has four chambers now lets look inside the heart

The Heart Pulmonary artery Vena cava Right Atrium Aorta Pulmonary vein Left Atrium Tricuspid valve Bicuspid valve Right Ventricle Left Ventricle

How does the Heart work? STEP ONE blood from the body blood from the lungs - The heart beat begins when the atria muscles relax and blood flows into the atria. -Deoxygenated blood (from whole body) enter the right atrium via vena cava - oxygenated blood (from the lung) enter the left atria via pulmonary vein.

How does the Heart work? STEP TWO - The atria then contract and the valves open to allow blood into the ventricles. - Blood in RA go through tricuspid valve to enter RV - Blood in LA go through bicuspid valve to enter LV.

How does the Heart work? STEP THREE - When the ventricles contract, the tricuspid and bicuspid valve will close and semilunar valves is forced to open. - At the same time, blood is pushed into pulmonary artery and aorta. - At the same time, the atria are relaxing and once again filling with blood. - What happen when the ventricles relax? The cycle then repeats itself.

Lub If you listen to your heartbeat, it makes a lub dub sound. The lub is when blood is pushed out of the heart into the body and the dub is the reloading of the heart with more blood ready to push it out to the body Dub

The pumping of heart • Cardiac muscle is myogenic, which means can contract and relax without the impulse from nervous system. • The pumping of heart coordinated by a pacemaker • The primary pacemaker is known as SA node which located at upper wall of right atrium • The impulse from SA node will cause the atria to contract before the impulse reach the AV nodes which located at the bottom wall of right atrium.

• From AV node, the impulses spread to bunle of His, bundle branches and Purkinje fibres which cause the ventricles to contract. • The pacemaker is regulated by: – Parasimpathetic nerve: slow down the heart beat – Sympathetic nerve: speed up the heart beat. – Adrenaline hormone: speed up the heart beat during fear/excitement

1. 7 contraction of skeletal muscle around the veins • Blood pressure in veins is lower compared to artery. • Therefore, the flows of blood back to heart are helped by… • When the skeletal muscles contract, the veins will constrict and the blood push along the veins in one direction due to the presence of valve in vein.

SUMMARY copy and complete the following; away from the heart. The walls of an artery Arteries take blood ______ muscular walls and elastic fibres. Veins carry are made up of thick _____ towards blood ____ the heart and also have valves. The _____ link capillaries arteries and veins, and have a one cell thick wall. Blood is made up of plasma four main things ______, the liquid part of the blood; Red Blood oxygen Cells to carry ______; White Blood cells to protect the body from platelets disease and _____ to help blood clot.