The Circulatory System.

The Circulatory System The circulatory system is made of: The circulatory system is made of: The Heart The Heart Arteries and Arterioles Arteries and Arterioles Veins and Venules Veins and Venules Capillaries Capillaries Blood Blood

Functions Circulate blood to all parts of the body Circulate blood to all parts of the body Transport water, oxygen and nutrients to cells Transport water, oxygen and nutrients to cells Remove wastes, including carbon dioxide, from cells Remove wastes, including carbon dioxide, from cells Maintain body temperature Maintain body temperature

The Heart Composed of four chambers Composed of four chambers Two Atria (upper chambers) & two Ventricles (lower chambers). Two Atria (upper chambers) & two Ventricles (lower chambers). The Atria receive blood from the body, the ventricles pump blood back out into the body. The Atria receive blood from the body, the ventricles pump blood back out into the body.

The Heart The Septum divides the heart into two pumps. The Septum divides the heart into two pumps. The left pump is the left atrium and left ventricle – full of oxygen rich blood from the lungs which gets pumped around the body. The left pump is the left atrium and left ventricle – full of oxygen rich blood from the lungs which gets pumped around the body.

The Heart The right pump is the right atrium and right ventricle – full of de- oxygenated blood from the body, gets sent to lungs to get rid of carbon dioxide and pick up oxygen. The right pump is the right atrium and right ventricle – full of de- oxygenated blood from the body, gets sent to lungs to get rid of carbon dioxide and pick up oxygen.

Anatomy of the Heart

Heart Function The blood from the left pump (oxygen rich) does not mix with that of the right pump (oxygen poor), the septum of the heart keeps them separate. The blood from the left pump (oxygen rich) does not mix with that of the right pump (oxygen poor), the septum of the heart keeps them separate. For blood to make a complete circuit around the body it passes through the heart two times. For blood to make a complete circuit around the body it passes through the heart two times.

Features of the heart Located slightly left of the sternum Located slightly left of the sternum The adult heart is about the size of a large fist The adult heart is about the size of a large fist At rest, the average heart-rate is 72 beats per minute At rest, the average heart-rate is 72 beats per minute Maximum Heart-rate = 220 – age Maximum Heart-rate = 220 – age At rest the heart pumps 5 litres of blood per minute At rest the heart pumps 5 litres of blood per minute During maximum work it can pump over 30 litres per minute. During maximum work it can pump over 30 litres per minute.

The Circulatory System PART B

Blood Vessels Arteries – Arterioles – Capillaries – Venules – Veins. Arteries – Arterioles – Capillaries – Venules – Veins.Arteries The aorta is the largest artery in the body. The left ventricle pushes the blood into the aorta and onto the rest of the body. The aorta is the largest artery in the body. The left ventricle pushes the blood into the aorta and onto the rest of the body.

Arteries The artery walls are elastic so they are able to expand with each heartbeat to accommodate blood. The artery walls are elastic so they are able to expand with each heartbeat to accommodate blood. When you take your heart rate, you are feeling the pressure of the blood being pushed into the arterial system. When you take your heart rate, you are feeling the pressure of the blood being pushed into the arterial system.

Arteries Arteries further reduce in size to become arterioles as the network of blood vessels work their way into the depths of the body. Arteries further reduce in size to become arterioles as the network of blood vessels work their way into the depths of the body. Bleeding from an artery can be recognised by the blood spurting out with each heart beat and by its bright red (oxygen rich) colour. Bleeding from an artery can be recognised by the blood spurting out with each heart beat and by its bright red (oxygen rich) colour.

Arteries Coronary Artery – supplies the hearts chambers with oxygen and nutrients. Coronary Artery – supplies the hearts chambers with oxygen and nutrients. Heart attacks are often caused by a blockage of the coronary artery. Heart attacks are often caused by a blockage of the coronary artery. Smoking, drinking, eating fatty foods and lack of exercise contribute to coronary artery blockages. Smoking, drinking, eating fatty foods and lack of exercise contribute to coronary artery blockages.

Capillaries The exchange of nutrients and waste between the body and blood cells occurs in the capillaries. The exchange of nutrients and waste between the body and blood cells occurs in the capillaries. Heat from cells is also absorbed into blood through the capillaries Heat from cells is also absorbed into blood through the capillaries

Exchange of materials is easy as capillaries are only one cell thick. Exchange of materials is easy as capillaries are only one cell thick. When you begin to exercise capillaries dilate to allow increased blood flow. When you begin to exercise capillaries dilate to allow increased blood flow. Other capillaries come into use through the opening of pre-capillary sphincters. Other capillaries come into use through the opening of pre-capillary sphincters.

Capillaries A long term exercise program may increase the number of capillaries supplying blood to muscles, allowing an increased oxygen supply to muscle and removal of wastes. A long term exercise program may increase the number of capillaries supplying blood to muscles, allowing an increased oxygen supply to muscle and removal of wastes.

Veins Veins carry blood back to the heart. Veins carry blood back to the heart. Veins have no pulse, blood flow is steady and constant. Veins have no pulse, blood flow is steady and constant. The walls of veins are thin and not as elastic as artery walls. The walls of veins are thin and not as elastic as artery walls.

Veins. The return of blood to the heart depends on contraction of skeletal muscle. The return of blood to the heart depends on contraction of skeletal muscle. Veins are squeezed by muscle as they contract. Veins are squeezed by muscle as they contract. One way valves working against gravity and prevent backflow of blood to organs and muscles. One way valves working against gravity and prevent backflow of blood to organs and muscles.

Veins. Blood Pooling after exercise is a problem if you don’t cool down. Blood Pooling after exercise is a problem if you don’t cool down. During a warm down, the muscle pump system continues to move the gradually diminishing excess blood flow around the body until it has reached a resting level. During a warm down, the muscle pump system continues to move the gradually diminishing excess blood flow around the body until it has reached a resting level.

Homework Complete “Circulatory System Homework Sheet 2” Complete “Circulatory System Homework Sheet 2”

The Circulatory System PART C

Blood Red Blood cells: Red Blood cells: Make up 99% of all blood cells Make up 99% of all blood cells Carry oxygen to, and carbon dioxide from, the cells and muscles. Carry oxygen to, and carbon dioxide from, the cells and muscles. Have a life span of four months Have a life span of four months

Blood White Blood Cells: White Blood Cells: Exist in the body in a ratio of 1:700 red blood cells. Exist in the body in a ratio of 1:700 red blood cells. Have a role in immune function Have a role in immune function Have a life span of a few days. Have a life span of a few days. Platelets: Platelets: Cause blood to clot when blood vessels are damaged. Cause blood to clot when blood vessels are damaged.

Path of Blood Around the Body Oxygenated blood travels from the lungs to the left atria.. Oxygenated blood travels from the lungs to the left atria.. It goes down into the left ventricle which then squeezes it out the Aorta into arteries and to the muscles, organs, brain etc.. It goes down into the left ventricle which then squeezes it out the Aorta into arteries and to the muscles, organs, brain etc.. Oxygen,water and nutrients are dropped off, Carbon dioxide and wastes are picked up at the capillaries…. Oxygen,water and nutrients are dropped off, Carbon dioxide and wastes are picked up at the capillaries….

Path of Blood Around the Body De – oxygenated blood travels back to the right atria via the veins.. De – oxygenated blood travels back to the right atria via the veins.. Deoxygenated blood moves from the atria into the right ventricle.. Deoxygenated blood moves from the atria into the right ventricle.. Deoxygenated blood is pumped from the right ventricle to the lungs, where it drops off carbon dioxide (plus water plus heat) and picks up oxygen.. Deoxygenated blood is pumped from the right ventricle to the lungs, where it drops off carbon dioxide (plus water plus heat) and picks up oxygen.. The cycle then continues.. The cycle then continues..

In short… Oxygenated blood  lungs  left atria  left ventricle  arteries  arterioles  capillaries (drop off O 2, pick up CO 2 )… Oxygenated blood  lungs  left atria  left ventricle  arteries  arterioles  capillaries (drop off O 2, pick up CO 2 )… Deoxygenated blood  capillaries  venules  veins  right atria  right ventricle  lungs(drop off CO 2, pick up O 2).. Deoxygenated blood  capillaries  venules  veins  right atria  right ventricle  lungs(drop off CO 2, pick up O 2)..

Blood pressure Blood pressure is caused by the ventricles contracting. Blood pressure is caused by the ventricles contracting. In arteries it fluctuates with each heart beat. In arteries it fluctuates with each heart beat. The higher pressure (systolic) occurs when the ventricles contract. The higher pressure (systolic) occurs when the ventricles contract. The lower pressure (diastolic) occurs when the ventricles relax. The lower pressure (diastolic) occurs when the ventricles relax. Blood pressure is usually described by these two limits Blood pressure is usually described by these two limits Average blood pressure is 120/80mmHg Average blood pressure is 120/80mmHg

Blood pressure In mammals, the chambers of the heart contract rhythmically and spontaneously under the control of certain group of heart muscle cells called nodes. In mammals, the chambers of the heart contract rhythmically and spontaneously under the control of certain group of heart muscle cells called nodes. Sinoatrial and Atrioventricular. Sinoatrial and Atrioventricular.

Exercise & the Circulatory System The benefits of a long term exercise program on the circulatory system are: The benefits of a long term exercise program on the circulatory system are: Greater efficiency of the heart Greater efficiency of the heart Lower resting heart rate Lower resting heart rate Increase in left ventricle size Increase in left ventricle size Lower blood pressure Lower blood pressure Greater blood volume Greater blood volume Increase in haemoglobin count. Increase in haemoglobin count.

Important Terms Stroke Volume – the amount of blood pumped into the systemic circuit with one heart beat. Avg. Adult female = 60ml Avg. Adult Male = 80ml Stroke Volume – the amount of blood pumped into the systemic circuit with one heart beat. Avg. Adult female = 60ml Avg. Adult Male = 80ml In an endurance trained male under maximal conditions it could reach 160ml! In an endurance trained male under maximal conditions it could reach 160ml!

Important Terms Cardiac Output – the amount of blood the body pumps in one minute. Around 5 litres at rest, up to 30 litres under maximum effort. Cardiac Output – the amount of blood the body pumps in one minute. Around 5 litres at rest, up to 30 litres under maximum effort. Cardiac output = Q Cardiac output = Q Stroke Volume = SV Stroke Volume = SV Heart Rate = HR Heart Rate = HR Q= SV x HR Q= SV x HR

Homework Complete Circulatory System Homework Sheet 3 Complete Circulatory System Homework Sheet 3