Biology Chapter 6

Waste products can be rapidly removed from the cell by simple diffusion.(T/F)

True

What is the purpose of a transport system?

To carry substances from one part fo the body to another

What are the parts of the circulatory system?

Blood vessels

Heart

Blood

What is the purpose of blood?

Blood transports substances around the human body and defends it against diseases

What are the main components of blood?

Plasma

Red blood cells

White blood cells

Platelets

How does plasma look?

Plasma is the yellowish liquid in blood

What does plasma contain?

It contains mainly water and substances like glucose, amino acids, salts, proteins, fats, vitamins, hormones and excretory products like urea

What are the functions of plasma?

Transports blood cells around the body

Transports nutrients from the small intestine to other parts of the body

Transports excretory products from organs to excretory organs for removal

Transports hormones from the endocrine glands to target organs

What are the features of a red blood cell?

Circular, biconcave shape

Contains a red pigment called haemoglobin

Flexible

No nucleus

What is the main function of the red blood cell?

Their main function is to transport oxygen from the lungs to other parts of the body

What are the adaptations of the red blood cell?

Contains haemoglobin that reversibly binds to oxygen

Biconcave shape to increase surface area to volume ratio

Flexible and can change into a bell-shaped structure so it can easily flow through narrow blood capillaries

No nuleus so there is more space for haemoglobin

How does an increase in the surface area to volume ratio of red blood cell benefit the body?

This increases the rate of absorption and release of oxygen

What is formed when haemoglobin binds with oxygen?

Oxyhaemoglobin

What does oxyhaemoglobin do when the oxygen concentration in tissues is low?

Oxyhaemoglobin releases its oxygen to the tissue cells

What are the main 2 types of white blood cells?

Phagocytes

Lymphocytes

What is the function of phagocytes?

To perform phagocytosis

What is phagocytosis?

Phagocytosis is the process by which a white blood cell engulfs and destroys foreign particles like bacteria

Lymphocytes produce antibodies that:

Recognise foreign particles

Destroy disease-causing organisms like bacteria and viruses

Cause bacteria to clump together for easy ingestion by phagocytes

Neutralise the toxins produced by bacteria

White blood cells are regular in shape. (T/F)

False, white blood cells are irregular in shape

What are platelets?

Platelets are fragements of cytoplasm

What do platelets contain?

They contain an enzyme that catalyses the conversion of fibronogen to fibrin threads

What do fibrin threads form?

Fibrin threads form a network that entangles red blood cells to form a clot, preventing excessive blood loss and entry of harmful organisms into the bloodstream

How does blood clot?

Blood exposed to air will soon clot. Platelets are involved in converting the soluble protein, fibronogen into insoluble threads of fibrin, sealing the wound, which prevents excessive blood loss and foreign particles from entering the bloodstream

What happens to people who have haemophilia who are injured?

People suffering from a hereditary disease called haemophilia, the normal blood-clotting mechanism is greatly impaired, so if they are not treated immediately, they might bleed to death of die from internal bleeding

What is organ transplant?

When a person’s tissue or organ is damaged or diseased, it can be replaced with healthy tissue or organ from a donor

What is tissue rejection?

A foreign tissue may be recognised by the white blood cells, which may repond by producing antibodies to destroy the foreign tissue

How to prevent tissue rejection?

Take skin from the same person

Find a tissue match, which is as genetically similar to the recipient’s tissue

Use drugs to inhibit the recipient’s immune system

What are antigens?

Special proteins found on the surface of all your red blood cells

Blood plasma contains antibodies. which are produced by …

the white blood cells, and are always present in the blood

Natural antibodies may not react to antigens in your blood, …

but they may react to antigens in other people’s blood, causing the clumping of red blood cells

What are the different types of blood groups?

A, B, AB and O

Antigens are presented using …

capital letters like A or B

Antibodies against antigens A or B are represented using …

small letters a and b

Antibody a reacts with antigen A. (T/F)

True

What is found in blood group A?

antigen A on red blood cell, antibody b in plasma

What is found in blood group B?

antigen B on the red blood cell, antibody a in plasma

What is found in blood group AB?

both antigen A and B on red blood cell, no antibodies in plasma

What is found in blood group O?

no antigens on red blood cell, both antibody a and b in plasma

What blood groups can recipient with blood group A accept?

O and A

What blood groups can recipient with blood group B accept?

O and B

What blood groups can recipient with blood group O accept?

O

What blood groups can recipient with blood group AB accept?

A, B, O and AB

Blood group O is known as a …

universal donor

Blood group AB is known as a …

universal recipient

What happens to a person with blood group A when blood group B is transfused?

The red blood cells in their blood will agglutinate.

What is the function of blood?

Blood is used to transport various substances from one part of the body to another by flowing continuously around the body.

What do you call the flow of blood

Blood circulation

What are the parts of the circulatory system?

Heart

Artieries

Arterioles

Blood capillaries

Venules

Veins

When the heart relaxes, …

it fills up with blood

When the heart contracts, …

the blood is squeezed out with great force

What are arteries?

Arteries are the blood vessels that carry blood away from the heart

What do you call the large artery that leaves the left side of the heart?

Aorta

What are arterioles?

Arterioles are tiny vessels formed when arteries branch out

The arterioles divide and ultimately, …

their branches become very tiny blood vessels called capillaries

What are capillaries?

Capillaries are microscopic blood vessels found between the cells of almost all the tissues

What are capillaries made from?

Capillaries have walls made up of a single layer of flattened cells

Are cappilaries partially permeable?

Yes, they allow certain substances to diffuse quickly through them

Why do small arteries brach out to become capillaries?

The numerous branches provide a large surface area for the exchange of substances between the blood and tissue cells

When an arteriole branches out into many capillaries, …

The total cross-sectional area of the blood vessels increases, lowering the blood pressure in the capillaries, so the flow of blood decreases, giving more time for th exchange of substances

What are venules?

Small vessels formed before capillaries leave an organ or tissue

What are veins?

Veins are blood vessels formed by venules joining back. Veins carry blood back to the heart.

Arteries receive blood directly from the …

heart

Why are the walls of the arteries thick, muscular and elastic?

Arteries need to be able to withstand the high oressure of the blood forced out of the heart, which is fast moving

The elastic layer of the arteries is much thicker in the arteries ….

nearest to the heart

Why is the elastic walls in the arteries important?

The elasticity enables the artery wall to stretch and recoil or spring back, which helps push the blood in spurts along the artery and also gives rise to the pulse

The contraction and relaxation of muscles in the arterial wall bring about …

constriction and dilation of the artery.

When an artery constricts, …

its lumen becomes narrower and less blood flows through it per unit time

When an artery dilates, …

its lumen becomes wider and more blood flows through it per unit time

What do arteries carry?

Arteries carry oxygenated blood, except for the pulmonary artery, which carries deoxygenated blood from the heart to the lungs

How does blood flow in the veins?

Blood flows slowly and smoothly in the veins

Do veins have elastic tissue?

Yes, but it has less elastic tissue than arteries

What do veins have that arteries and capillaries do not?

Most veins have internal valves along their length to prevent backflow of blood

What do the tiny spaces between tissue cells contain?

Tissue fluid

What is the function of tissue fluid?

Tissue fluid transports dissolved substances between the tissue cells and the blood capillaries

Dissolved food substances and oxygen diffuse from …

the blood in the blood capillaries into the tisue fluid

Metabolic waste products diffuse from …

the cells into the tissue fluid, which are then transferred to the blood capillary walls into the blood

How many times does blood pass through your body in a complete circuit?

2

Blood flows from the other parts of the body to the heart. Then from the heart …

it flows to the lungs and back to the heart again before it is pumped back to the rest of the body

How does circulation between the heart and lungs work?

From the heart, pulmonary arteries carry blood to the lungs. Oxygen enters the blood at the lungs. Oxygenated blood is returned to the heart via the pulmonary veins.

Which side of the heart does oxygenated blood leave from?

The left side

What organ does not receive blood from the arteries?

Lungs

What is the size of a heart?

It is about the size of a clenched fist, with a roughly conical shape

Where does the heart lie?

It lies in the thorax behind the chest bone and between the 2 lungs

What are the atria?

These are the 2 upper chambers- the right atrium and the left atrium

Where does the atria receive blood from?

The atria receives blood from the veins

Do the atria have thick muscular walls?

No, the atria have comparatively thin muscular walls, since they only force blood into the ventricles that lie directly below them, so it does not require a lot of pressure

What are the ventricles?

There are 2 large lower chambers - the right ventricle and the left ventricle

Do the ventricles have thick walls?

Yes, the ventricles have comparatively thick, muscular walls

Why is the left ventricle muscle thicker than the right ventricle ?

The left ventricle muscle is much thicker because it pumps blood around the whole body and this requires high pressure

Why does the right ventricle have thinner walls than the left ventricle?

The right ventricle has thinner walls than the left ventricle since it only pumps blood to the lungs, which is close to the heart

What is the median septum?

This a muscular wall that separates the right and left sides of the heart. It runs down the middle of the heart

What is the function of the median septum?

The median septum prevents the mixing of deoxygenated blood in the right side with the oxygenated blood in the left side

What happens if we have no median septum

The oxygenated blood would mix with the deoxygenated blood, reducing the amount of oxygen carried to the rest of the body

What are all the parts in the heart?

Superior and inferior vena cava

Pulmonary artery

Pulmonary vein

Right atrium and right ventricle

Left atrium and left ventricle

Tricuspid and bicuspid valve

Semi-lunar valves

Aorta

What is the function of the tricuspid valve?

It prevents backflow of blood from the right ventricle to the right atrium

What is the function of the bicuspid valve?

It prevents backflow from the left ventricle to the left atrium

What is the function of the semi-lunar valves?

The Aortic valve prevent backflow from the aorta to the left ventricle, and the pulmonary valve prevents backflow from the pulmonary artery to the right ventricle

What are the 2 types of semi-lunar valves?

Aortic valve
Pulmonary valve

How many flaps does the tricuspic valve have?

3 flaps

How are the flaps attached to the walls of the right ventricle?

These flaps are attached to the walls of the right ventricle by cord-like tendons called chordae tendineae