Unit 9 Human Transport

Why is the circulatory system needed?

transports useful substances like oxygen absorbed from gas exchange surfaces, nutrients from the gut adapted for absorption, transporting waste from all over the body to the gas exchange surface.

What is the heart

A pump that circulates blood through the blood vessels

What is the function of the artery

transporting blood away from the heart to different organs of the body

What is the function of the vein

transporting blood from the organs back to the heart

How are arteries connected to the veins?

By small blood vessels called capillaries⇒ cells are close to the capillaries so they can receive a good oxygen supply and get rid of co2 easily

Does the high pressure of blood damage the delicate capillaries

No, because of the smaller arterioles that reduce the pressure before the blood enters the capillaries

How does the blood not flow backwards away from the heart?

Through semi lunar valves in which they open when the pressure of the blood pushes against them and close when the blood flows back to fill the pockets.

What would happen to the veins without the semi lunar valves?

The veins would swell up and the blood would not be circulated properly.

Where are the semi lunar valves placed?

At the places where the blood leaves the heart chambers to enter arteries, there are valves between the chambers of the heart.

What is single circulation?

Single circulation is where the blood flows through the heart once during to complete a full circuit of the body.

How does the blood flow in single circulation?

In a fish, Deoxygenated Blood flows from the organs to the heart (in veins)⇒ The heart pumps blood into an artery and takes it to the gills to be oxygenated⇒ blood flows from gills in arteries to the organs

What is double circulation?

Blood flows through the heart twice to complete a single circuit around the body

What is a septum?

Septum is a thick wall of muscle that separates the two halves of the heart that stops the blood from mixing with either side.

How does the blood flow in double circulation?

Right side of the heart pumps deoxygenated blood to the lungs and back to the heart, the left side pumps oxygenated blood from the lungs to the rest of the body.

Why are the valves important?

They prevent the backflow of blood

Why do the ventricles have more muscle wall than the atria?

they have to pump the blood much further than the atria to the lungs or the body

Why is the left ventricle more muscular and have more pressure than the right ventricle?

because it has to pump blood around the body and has to overcome more resistance to flow.

Do the two sides of the heart work together?

Yes, the atria contracts and relaxes at the same time, the ventricles contract and relax at the same time.

What happens during the relaxation phase?

The blood flows into the atria from the veins

What happens during the contraction phase?

atria contracts and blood goes into the ventricles through the valves that open because of the pressure of the blood (lub). The ventricles contract to force the blood out of the arteries and the artrioventricular valves close to prevent backflow. (dub)

What is an ECG?

Electrocardiogram, detects defects in irregularities of the heartbeat which is a sign of various heart disorders

How does an ECG work?

electrodes are placed around the body, the electrical activity of the heart is displayed on a monitor.

What does the PQRS and T waves show?

The P curve shows the contracting of the atria, the QRS spike shows the contracting of the ventricles and the T wave represents the ventricles relaxing.

What does a low resting pulse rate mean about the person?

That they are fit.

How are the structure of the arteries adapted to withstand the high pressure of blood?

Thick walls made of muscle and elastic fibres that withstand pressure, it stretches and recoils, the recoil helps push the blood along maintaining its pressure. This is how the pressure remains similar to how it was when it left the heart.

How is the structure of the vein adapted for low pressure of blood?

have wider space for blood to flow, less muscular, less elastic walls

How are the structure of the capillaries adapted for easy flow of blood?

very narrow so substances can pass to and from the blood easily, this makes it easy to supply oxygen and nutrients, and remove waste products such as co2.

What are arterioles and their function?

small subdivisions of artieries that carry blood to capillary networks, blood transport and regulation of blood pressure, they have muscle in their walls.

What are venules and their function?

small blood vessels that collect blood from the capillary beds, they unite to form veins.

What are shunt vessels and their function?

blood vessels that links arteries directly to the vein, allowing the blood to bypass the capillaries in certain areas, controls blood flow by constriction and dilation.

How do shunt vessels respond to the cold in warm blooded animals?

constrict which cuts off blood flows to the extremities and reduces waste energy from the body⇒heats environment.

What nutrients does the heart need to keep it contracting?

glucose and oxygen

In what are the glucose and oxygen transported to the heart?

coronary arteries

How is coronary heart disease caused?

when the coronary arteries get blocked so the heart no longer has glucose and oxygen supply, the heart could become starved of oxygen and die

What happens to the arteries in atherosclerosis?

when the cholesterol (made in liver) sticks to the walls narrowing the artery and slowing down the blood flow.

What happens to the arteries in thrombosis?

artery walls become rough causing the blood to clot and block the vessel

What can happen to the a patient with a narrowing of coronary artery?

1. Angina⇒chest pain caused by not enough oxygen reaching the heart muscle especially caused if activity or emotion makes the heart work harder. Angina is a warning sign of heart attack
2. Heart attack⇒ total blockage or thrombosis where the oxygen supply is cut off
3. Cardiac arrest⇒ heart stops beating

- How many people die from chd every year?

7 2 million people

- Which country has the highest death rate from CHD

Ukraine

- Which country has the lowest death rate from CHD

Japan

- What are the risk factors for CHD

1. Genes⇒ inherited from families
2. Age⇒ Chances of CHD increase with age
3. Sex⇒ higher chance of men getting it
4. Smoking⇒increases chances of CHD

- What are two ways to reduce the risk of CHD

1. Diet
2. exersize

- What can you change in diet to reduce the risk of CHD?

1. balanced diet
2. low fat high fibre diet with fresh fruit and vegetables with whole grains
3. avoid foods with saturated fats (meats, butter, cream)
4. have foods with unsaturated fats which increases good cholesterol in the body and reduces blockages in arteries (oily fish, avocados, vegetable oils, nuts, seeds)
5. not more than a teaspoon of salt every day as it increases blood pressure
6. avoid sugar which increases risk of diabetes linked to increased chances of CHD

What can you do in exersize to reduce the risk of CHD

regular exercise as it raises the heart rate and makes the heart and blood circulatory system more efficient, lowers cholesterol level and keeps blood pressure at a healthy level

How much blood does one have in their body?

about 5 litres

What is blood made of?

cell and cell fragments suspended in yellow liquid called plasma, the colour red is due to the pigment haemoglobin in RBC

What does plasma contain?

1. water with chemicals dissolved in it
2. nutrients (glucose, amino acids, lipase, vitamins, mineral ions)
3. waste products (urea, co2)
4. blood proteins (albumen, antibodies)
5. hormones (insulin, glucagon, adrenaline)

What are the three main types of cells in the blood?

1. Red blood cells
2. White blood cells
3. Platelets

What are red blood cells and their function

have cytoplasm full of thousands of molecules of haemoglobin for transporting oxygen

What are white blood cells and their function?

have nuclei, one group of WBC (phagocytes) search out bacteria and takes them into vacuoles where they are digested⇒ process called phagocytosis, lymphocytes make protein molecules called antibodies that protect the body from different types of diseases.

What are platelets and their function?

tiny fragments of cells that cause the blood to clot, clotting stops blood loss and prevents entry of pathogens

What is the function of plasma?

transporting ions, nutrients such as glucose and amino acids, co2 and hormones

What is the structure of RBC and how does it help with its function?

disc shaped with a large surface area volume ratio which helps them absorb oxygen, as there is no nuclei there is space for haemoglobin

What does the haemoglobin combine with oxygen to form?

oxyhaemoglobin

Describe how oxygen transports from the lungs to body tissues in the RBC?

1. Oxygen diffuses from the alveoli into the blood
2. oxygen attaches temporarily to the haemoglobin in the RBC making oxyhaemoglobin
3. RBC carries oxygen to the cells that need it
4. oxygen leaves the oxyhaemoglobin and diffuses out of the blood to the cells making it haemoglobin again
5. RBC returns to the lungs for more oxygen

What are phagocytes?

white blood cells that ingest pathogens by surrounding them, ingesting them and taking them into vacuoles where they get digested using enzymes that kill them, can squeeze through capillary walls

What are lymphocytes?

Lymphocytes recognise foreign and dangerous substances and make proteins called antibodies that attack the pathogens

* What are the 3 ways antibodies attack pathogens?

1. agglutinate⇒ make them stick together
2. dissolving their cell membranes
3. neutralisation of toxins that some pathogens produce

How do you know that you have immunity to a particular disease?

lymphocytes are ready to produce more antibodies to fight the particular pathogen giving the body immunity to the disease.

How does blood clotting work?

When a blood vessel is damaged, platelets helps the blood thicken by converting the soluble protein fibrinogen to an insoluble protein fibrin, it forms a meshwork of fibres that trap the red blood cells so it clots, the clot hardens to make a scab, which falls off when the skin heals.

Why is blood clotting important?

helps the blood stay inside the body and protects from outside pathogens to enter.