Bellwork: What happens when you have a heart attack? Why do 1.2 million American's a year experience them?

Circulatory and Respiratory System

Section 33.1 – The Circulatory system

What does the circulatory system do?

• It transports oxygen, nutrients and other substances throughout the body, and removes wastes from tissues

•The heart acts as the pump, or driving source for the circulatory system

What does your heart look like? • Your heart is a muscle• It begins contracting before you were born, and only stops

when you die• In the walls of a heart, two thin layers of epithelial and

connective tissue form a sandwich around the myocardium• The myocardium has a series of powerful contractions

which pump blood through the circulatory system• The average heart beats 72 times a minute, pumping 70ml

of blood with each contraction• The heart is divided into 4 chambers, • The left and right side are separated by the septum

• Prevents oxygen poor and oxygen rich blood mixing

• Atria receive blood, ventricles pump out blood

What is a valve, why are they important to the heart?

• Valves prevent the back flow of blood in the heart• They are essentially just flaps of tissue• They separate the atria and ventricles•When blood moves from atria into

ventricles, valves open•When ventricles contract to send blood

out of the heart, the valves close• Valves are also located at the exit of

each ventricle

Does the heart need it’s own separate blood supply?

• Yes!• The heart is a muscle, so needs a constant

supply of oxygen and nutrients • It does not get this from blood going

through it’s chambers, it instead relies on the coronary arteries• They branch from the aorta, and provide a

blood supply to the heart muscle • They are narrow, so if the become blocked,

that can lead to a heart attack

Is the heart one pump or two? • Although it is one organ, it

functions as two pumps

•One pump (side) sends blood to the lungs

• The other pump (side) sends blood around the body

• The Right Side : Pulmonary circulation – blood to the lungs

• The Left Side: Systemic circulation blood around the body

What happens during a heartbeat? • When the heart beats, it starts a well organized process that sends the blood where it needs to

go• Step 1: The SA node in Right atrium (pacemaker), fires an impulse causing the atria to contract

• Step 2: The impulse from SA node is picked up by the AV node (another group of muscle fibers)

• After a very slight delay (a fraction of a second), the AV node produces impulses that cause the ventricles to contract

• It is a two step pattern – bu-boom! Bu-boom!

What is your current heart rate? How can you change it? • Your heart rate varies depending on the

body’s needs

• Can get as fast as 200 beats per minute

• Hear-rate is not directly controlled by the nervous system, but the autonomic nervous system does influence SA node activity

• Neurotransmitters released by the sympathetic nervous system can increase the heart rate

• Parasympathetic nervous system can decrease heart rate

What are the three different types of blood vessels?

• Arteries – large vessels that carry blood from heart to tissues• The bodies Freeways network• Do they all carry oxygenated blood? • Thick elastic walls allow them to withstand pressure from the

heart’s contractions• Made of connective tissue, smooth muscle and endothelium

• Capillaries – smallest blood vessels – side streets and alleys• Blood cells move in single file• Thin walls allow oxygen and nutrients to move across, and

waste products to enter the blood

• Veins – Blood returns to the heart in veins• Often act against the flow of gravity, as such major veins are

often found near skeletal muscles. • Muscle contractions assist, by squeezing blood towards heart• Many also contain valves – ensuring one way flow!

Why is blood pressure important? • Like any pump, the heart produces pressure

• Pumping causes pressure to rise, relaxing causes pressure to fall

• Elasticity in artery walls maintains pressure

• Without blood pressure, the blood would not flow around the body

• Can be measure with a sphygmomanometer

• Produces two values – systolic pressure and diastolic pressure• Systolic: The force in the arteries when ventricles contract• Diastolic: The force in the arteries when the ventricles relax• Typical healthy reading - 120/20

• Can be controlled by brain – neurotransmitters can be released to relax/or contract smooth muscles in vessel walls

• Kidneys can affect volume of blood, by removing more/less water

Key points

•Why do humans need a circulatory system?

•What are the two paths of blood circulation in the body?

•How would damage to the sinoatrial node (SA node) affect how the heart functions? How could it be fixed?

•What are the three types of blood vessels? What are some of their key features

• If you are standing is blood pressure higher in your arm or leg? Why

Bellwork: How can you limit the possibility of developing circulatory diseases in old age?

Blood and the Lymphatic System

Section 33.2

Whys is Plasma so important? • The human body contains 4 – 6 liters of blood• 55% of this is plasma• This is 90% water, and 10% dissolved gasses, salts,

nutrients, enzyme, hormones, waste products, cholesterol etc…

• Water helps control body temperature• There are 3 types of protein: albumin, globulin and

fibrinogen • Albumin and globulin aid in transport of fatty acid,

hormones and vitamin• Albumin regulates osmotic pressure and blood volume• Some globulins help fight viral and bacterial infections • Fibrinogen allows blood to clot

What do red blood cells do? • Red blood cells play a key role in transporting

gases around the body• They are the most numerous cells in the

blood• Crimson color comes from Hemoglobin – a

protein that binds oxygen• Flying doughnut shape• Full of hemoglobin – nucleus and other

organelles pushed out s cell matures• Produced by red bone marrow• Last in body for about 120 days before being

destroyed in liver and spleen

What do white blood cells do? • They protect the body from invaders

• They guard against infection, fight parasites and attack bacteria

• During a “battle” white blood cell numbers can increase dramatically

• White blood cells also work outside of the blood• There are a number of different types

• Macrophages – engulf pathogens• Lymphocytes – involved in immune response• B lymphocytes – produce antibodies that fight

infection and provide immunity• T lymphocytes help fight tumors and viruses

• Keep their nuclei and live for years. Also produced in the bone marrow

How does your body stop a cut from bleeding? • Platelets! • Platelets allow blood to clot (with the

help of plasma proteins)• Platelets are produced from the

cytoplasm of certain bone marrow cells – each fragment is enclosed in a cell membrane

• When they come into contact with a broken blood vessel, they become sticky

• They cluster around the wound, and release proteins called clotting factors that start a series of reactions

What does your lymphatic system do?

• A network of vessels, nodes and organs that collects the lymph that leaves capillaries, screens it for microorganisms, and returns it to the circulatory system

• Lymph is fluid found between cells that contains salts , nutrients and dissolved oxygen

• Lymph collects into a series of lymph vessels that get progressively larger

• Moves around the body, but with no pump. Relies on valves and skeletal muscle movements

• Lymph returned to blood through openings in the subclavian brains just below the shoulder

• Swelling due to excess lymph in tissue – edema

Why is Lymph important? • Lymph vessels inside intestine aid in absorption of

fats and fat soluble vitamins • The body contains numerous lymph nodes, which

act as filters, trapping microorganisms, cancer cells, and debris from lymph

• White blood cells inside lymph nodes then destroy what has been caught

• When large numbers of microorganisms are trapped, lymph nodes swell. Commonly referred to as glands. Example – tonsillitis

• Thymus – located beneath sternum, where t lymphocytes mature

• Spleen – operates like lymph nodes, but filters blood of micro-organisms and old damaged platelets.

What are the most common circulatory diseases? • Heart disease

• Most common when coronary arteries get blocked (atherosclosis - fatty deposits of plaque build up on artery)

• Angina (chest pain) an example of restricted blood flow• Can lead to oxygen deprivation and heart failure • If the cap on the plaque ruptures, a clot can form, blocking the artery – and causing a heart attack• SA and AV nodes can be damaged, cocaine usage and smoking can all result in increased chance of

heart attack• Symptoms are nausea, shortness of breath, chest pain, neck pain, jaw pain, left arm pain• Immediate medical treatment required

Circulatory disease continued• Stroke• A stroke is sudden death of brain cells when blood supply is interrupted • Can be caused by a blood clot blocking blood vessels in the brain• Can be caused by weak blood vessel rupturing in the brain• Symptoms – dizzyness, severe headache, numbness, confusion, trouble

speaking• The results of a stroke are highly variable • High Blood pressure (Hypertension). Reading of 140/90 or higher•Often no symptoms – people can have it for years• Places strain on heart, and cause small tears in blood vessels – can result in

heart attack, stroke or kidney damage

What is cholesterol? • Cholesterol is a lipid found in animal cell membranes• It is also used in the synthesis of some hormones, bile and

vitamin D• It is transported in the blood by two types of lipoproteins

(low and high density)• LDL becomes plaque• HDL is often referred to as good cholesterol, because it

transports cholesterol away from tissues and arteries to the liver

• Cholesterol is measured by amount of lipoproteins. Normal values = 100 – 200 mg/dl

• LDL should be less than 100 mg/dL • HDL should be greater than 40 mg/dL for a man, 50 mg/dL

for a woman

The link between Cholesterol and Atherosclerosis • Research has shown that high cholesterol in conjunction with other risk factors can

lead to increased atherosclerosis and a higher risk of heart attack• Trans fats and fried food contain large amounts of LDL•Michael Brown and Joseph Goldstein received the noble prize for their work on

cholesterol and heart attacks• They discovered LDL receptors on the cell membrane of the liver, which LDL binds to

when cholesterol levels are high, and the liver then breaks down the cholesterol• Some people however have defective LDL receptors

• This means LDL can’t be removed, and the liver doesn’t realise that it should stop making cholesterol

• It also means that some people can eat healthily but have high LDL levels

What is a statin?

• Statin drugs block the synthesis of cholesterol in liver cells, stimulating the liver to produce LDL receptors and remove excess cholesterol from the blood

•They are necessary, as the effects of eating high cholesterol diets can be the same as people with the genetic problem

How to prevent heart disease

•Prevention is really key

•Not smoking, a healthy balanced diet and regular exercise from a young age all help to prevent atherosclerosis!

Key Concepts

•What are the main components of blood? What are their functions?

•Hemophilia is genetic disorder associated with defective proteins in the clotting pathway .What happens when somebody with hemophilia has a minor cut?

•What is the role of the lymphatic system?

•How are veins and lymphatic vessels similar? How are they different?

•What are the most common causes of circulatory diseases?

•Why might atherosclerosis lead to hypertension?

•What is the difference between good and bad cholesterol?

The Respiratory systemSection 33.3

What does the respiratory system do?

•The human respiratory system picks up oxygen from the air and releases carbon dioxide

• It consists of the nose, pharynx, larynx, trachea, bronchi and lungs

Why do people have nose hair?

•Air entering the respiratory system must be filtered, moistened and warmed to keep lung tissue healthy

•Hairs in the nose start this filtering process – large particles get trapped

• Incoming air is warmed in the inner nasal cavity and sinuses

•Mucus moistens air and catches more dust

What happens in the pharynx, larynx and trachea?

• Pharynx – cavity at the back of the mouth (throat)• Air moves from pharynx into trachea (windpipe)• Epiglottis is a flap of tissue that prevents food

entering the trachea• Larynx is between trachea and pharynx - contains

vocal cords• When muscles pull vocal cords together, air moving

between them causes cords to vibrate, causing sound• Mucus traps inhaled particles• Cilia sweep mucus and trapped particles out into the

mouth

What happens next? • Form the trachea, air moves into two large

tubes in the chest cavity called bronchi. Each bronchus leads to one lung•Within each lung, each bronchi divides into

bronchioles• Bronchi and bronchioles are surrounded my

smooth muscles controlled by autonomic nervous system – regulating size of air passageways• Bronchioles continue to divide until they reach

dead ends – alveoli• Alveoli are grouped like bunches of grapes, and

are surrounded by a network of capillaries

How does an alveolus facilitate gas exchange? • When air enters alveoli, oxygen dissolves in the moisture

on the inner surface and diffuses across thin capillary walls into the blood

• Due to diffusion. Carbon dioxide flows in the opposite direction, also due to diffusion• Inhaled air is 21% O2, 0.04 % CO2• Exhaled air is 15 % O2, and 4% CO2

• Dissolved oxygen in plasma binds to hemoglobin in red blood cells• This constant removal of oxygen from plasma allows diffusion to

continue

• Hemoglobin causes the bloods oxygen capacity to increase more than 60 times

• Carbon dioxide either forms carbonic acid in red blood cells, dissolves in plasma or binds to hemoglobin

How do we breathe in and out?

•Movements of the diaphragm and rib cage change air pressure in the chest cavity during inhalation and exhalation

•Air pressure changes are the driving force for breathing

How is your breathing controlled?

• Breathing is initiated in the breathing center in the medulla oblongata • Sensory neurons gather information

about CO2 levels in the blood•When stimulated, the breathing center

send impulses to the diaphragm and chest muscles to contract • Air is brought into the lungs• The higher the blood CO2 levels, the

stronger the impulse• If it reaches a certain level, the impulse is

so strong that it cannot be resisted

What effect does smoking have on the respiratory system? • Tobacco smoke contains nicotine, carbon monoxide and

tar• Nicotine is an addictive stimulant that increase heart

rate and blood pressure• Carbon monoxide is a poisonous gas that prevents

hemoglobin from binding with oxygen• Tar contains 60 compounds that can cause cancer• Tobacco smoke also paralyzes cilia in the trachea,

allowing inhaled particles to stick to the walls of respiratory tract or enter the lungs

• Irritation from accumulate particles and mucus causes a smoker’s cough

• Airflow to alveoli is also reduced

What diseases can smoking cause? •Only 30% of male smokers live to 80.

55% of non smoking males do• Smoking can cause Bronchitis, whereby

the bronchi become inflamed and clogged. • Emphysema is the loss of elasticity and

breakdown of lung tissue, making breathing difficult. Lungs do not function properly• Lung cancer – particularly deadly as

when it is spotted it has often spread. Few people diagnosed live more than 5 years. 87% of people diagnosed are smokers

What are the other effects of smoking?

• Smoking can raise blood pressure by constricting blood vessels, forcing heart to work harder

• Passive smoking (exposure to second hand smoke) are also at a greater risk of respiratory and circulatory disease• Particularly dangerous for young children with developing lungs

• Link with asthma (alongside other things)

• Smoking during pregnancy can also lead to serious issues

• No matter the age of the smoker, quitting can significantly improve health

• Nicotine can make quitting hard – it is very addictive. Best advice is never to start!

Key Concepts

•What are the functions of the respiratory system

•What is the process of gas exchange in the lungs

•Why should you have carbon monoxide alarms in your homes?

•What is the process of breathing?

•What is the effect of smoking on the respiratory system?